MRCP revision on the go...

MRCP revision battle 57.1: Stroke thrombolysis

2010-11-22T11:34:00.000Z

Now we're at utterly last minute topics...

MRCP revision battle 57.1: Stroke thrombolysis
MRCP revision battle 57.2: Cardiac tamponade
MRCP revision battle 57.3: Systemic sclerosis
MRCP revision battle 57.4: Tapeworms
MRCP revision battle 57.5: Brown-Sequard Syndrome
MRCP revision battle 57.6: Trigeminal neuralgia

MRCP revision battle 57.1: Stroke thrombolysis

Contraindications to stroke thrombolysis:

evidence of intracranial haemorrhage on CT/MRI
minor neurological defect
symptoms rapidly improving
seizures at onset of stroke
any prior history of stroke and diabetes
stroke within 3 months
systolic BP >185 or diastolic BP >110
hyperglycaemia >25mmol
weight >15 stones
platelets <100

MRCP revision battle 57.2: Cardiac tamponade

2010-11-22T11:33:00.003Z

Cardiac tamponade occurs when pericardial fluid collects to a degree that prevents the heart pumping.

On echo you see RA+/- RV collapse during diastle.

The classic triad is Becks:

falling BP
rising JVP
muffled heart sounds

Other possible signs include:

Kussmauls = rising JVP on inspiration
pulsus paradoxus
JVP - loss of y descent, x descent prominant

ECG may show electrical alternanas

Treatment is ugern pericardiocentesis

MRCP revision battle 57.3: Systemic sclerosis

2010-11-22T11:32:00.000Z

Systemic sclerosis is a connective tissue disease characterised by thickening and fibrosis of skin (scleroderma) and involvement of internal organs.

Female: male 4:1

Commonest in 5th/6th decades

Limited systemic sclerosis = skin involvement is limited to face, hands and feet.
Associated with anti-centromere antibodies in 70-80%

Diffuse systemic sclerosis = more skin involvement
Anti Scl 70 in 40%

Features of sclerosis:

Raynaulds - 1st presentation in 70% of cases
arthralgia
renal failure
scleroderma
GI problems
classical skin presentation:

telangiectasia
peri-oral puckering
smooth shiny skin
livedo reticularis

pulmonary fibrosis/hypertension

ESR/CRP are raised

CREST is a type of limited systemic sclerosis:
- calcinosis, raynaulds, eosophageal dysmotility, sclerodalyl, telangectasia
- renal crsis is rare but pulmonary hypertension is common

Linear scleroderma = coup de sabre

Treatment:

supportive
d-penicillamine
steroids if lung disease
ACE-i to help kidneys

MRCP revision battle 57.4: Tapeworms

2010-11-22T10:53:00.004Z

Cysticercosis:

taenia solum - found in pork
taenia saginata - found in beef
treatment:albendazole

Hydatid disease
:

caused by echinococcus
treatment: albendazole

MRCP revision battle 57.5: Brown-Sequard Syndrome

2010-11-22T10:00:00.000Z

Brown-Sequard Syndrome is caused by a lesion in one half of the cord.

Commonest cause = MS
Other causes:

trauma
tumour
degenerative disease

Result is:

ipsilateral UMN weakness below

increased reflexes
spastic paralysis

ipsilateral dorsal column loss

loss of proprioception and vibration

contralateral spinothalmic loss

loss of pain and temperature sensation

MRCP revision battle 57.6: Trigeminal neuralgia

2010-11-22T09:00:00.000Z

Trigeminal neuralgia is intense stabbing pain in the trigeminal root distribution.

It is unilateral and tends to affect the mandibular or maxillary divisions

Most common in females over 50.

Over 1 in 10 cases will be secondary (to aneuysm, tumour) so ?MRI

Treatment is carbamazepine

MRCP revision battle 56.1: Amyloidosis

2010-11-21T11:06:00.000Z

7 non-waffling battles

MRCP revision battle 56.1: Amyloidosis
MRCP revision battle 56.2: Plasma exchange
MRCP revision battle 56.3: P450 inducers and inhibitors
MRCP revision battle 56.4: Therapeutic drug monitoring
MRCP revision battle 56.5: Vaccines
MRCP revision battle 56.6: Acute lymphoid leukaemia
MRCP revision battle 56.7: Nematodes = roundworms

MRCP revision battle 56.1: Amyloidosis

Amyloidosis is a pathological process characterised by extracellular accumulation of fibrils of insoluble protein.

Inherited forms of amyloidosis are rare but amyloid deposition is central to many diseases including Alzheimers and type 2 diabetes.

Types of amyloid:

1: AL = light chains

secreted by plasma B cells
occurs in 15% of myeloma patients
also occurs in:

Waldenstroms
MGUS

features:

cardiac deposition = 'sparkling' appearence on echo
GI
macroglossia
peri orbital

median survival is 12 months
treatment is to treat the underlying condition, ?prednisolone

2: AA = serum amylase A

this is secondary amyloidosis, with the amyloid derived from serum amylase A which is an acute phase protein
seen in:

RA
TB
bronchiectasis
familial med fever
IBD

commonest organ involved = kidney (congo red stain -->red-green birefrigence under polarised light)
median survival is 24 months

MRCP revision battle 56.2: Plasma exchange

2010-11-21T10:27:00.000Z

A summary of the indications for plasma exchange:

GBS
myathesnia gravis
Goodpastures
ANCA + vasculitis
TTP/HUS
cryoglobulinaemia
some hyperviscosity eg myeloma

MRCP revision battle 56.3: P450 inducers and inhibitors

2010-11-21T10:20:00.000Z

P450 inducers include:

rifampicin
antiepileptics except sodium valproate
griseofulvin
smoking
st johns wort
barbituates
chronic alcohol

P450 inhibitors include:

anti-infection meds

ciprofloxacin
erythromycin
ketoconazole
isoniazid

Anti reflux

cimetidine
omeprazole

Pysch meds

SSRIs
antipyschotics
TCA

sodium valproate
acute alcohol
class IV antiarrhymics

diltiazen
verapamil

MRCP revision battle 56.4: Therapeutic drug monitoring

2010-11-21T10:15:00.000Z

When to take the sample, that is the question....

Lithium: 12 hrs post dose

Digoxin: at least 6 hours post dose

Ciclosporin and pheytoin: immediately post-dose

MRCP revision battle 56.5: Vaccines

2010-11-21T10:10:00.000Z

Live attenuated vaccines:

BCG
MMR
polio
yellow fever
oral typhoid

Whole killed:

rabies
petussis
influenza

Fragment:

tetanus
diptheria
meningococcus
pneumococcus

MRCP revision battle 56.6: Acute lymphoid leukaemia

2010-11-21T10:05:00.000Z

ALL is commonest in children.

There is >60% cure

Treatment is by non-myelosupressive chemo.

Prognosis is worse if:

<1yr or >10yrs
higher WCC
male
philidelphia chromosome +

Better if >47 chromosomes

MRCP revision battle 56.7: Nematodes = roundworms

2010-11-21T10:00:00.001Z

2 main groups to consider for MRCP:

1. Strongyloides stercoralis

AKA threadworm
acquired percutaneously
causes migratory urticaria = larva currens
presents with itching
if it reaches lungs -->pneumonitis
treatment: mebendazole

2. Toxocara canis

caused by ingesting eggs from soil contaminated with dog poo
treatmet: mebendazole

MRCP revision battle 55.1: Trypanosomiasis

2010-11-20T19:37:00.000Z

spread by tsetse fly
caused by

t. rhodesiense - east africa - quicker
t.gambiense - west africa - slower

classical presentation

fever, rigors, headache, hepatosplenomegaly, lymphadenopathy
sleepy during day, awake at night
meningoencephalitis

look for chancre and posterior cervical nodes (=Winterbottom's sign)
diagnosis is by microscopy
treatment:

IV pentamide
IV melarsoprol

Below is an image of t.gambiense:

2. American - Chagas disease

carried by triatomine bugs
caused by t. cruzi
classical presentation

fever, rash, hepatosplenomegaly, lymphadenopathy
myocarditis
meningoencephalitis
megaoesophagus/megacolon

look for:

chagoma (=indurated, erythamatous nodule at site of infection)
periorbital oedema (=Romana's sign)

diagnosis is by blood culture
treatment: benznidazole

Now for some low potassium....

MRCP revision battle 55.2: Hypokalaemia

2010-11-20T19:36:00.000Z

Hypokalaemia is defined as K <3.5mmol; if <2.5mmol it is severe.

Symptoms/signs include:

muscle weakness
hypotonia
cramps
tetany
worsening of dig toxicity
cardiac arrhythmias

ECG may show:

small/inverted T waves
U waves
long PR
depressed ST

Causes of hypokalaemia

Low K with hypertension

raised plasma renin

Cushings
renin-secreting tumour

low plasma renin

Conns
liquorice
Liddles

Low K without hypertension

diuretics
GI loss
CRF
Bartters
Gitelmans
secondary hyperaldosteronism

On to cryoglobulins...

MRCP revision battle 55.3: Cryoglobulins

2010-11-20T19:35:00.000Z

Cryoglobulins are immunoglobulins that undergo reversible precipitation at 4c and dissolve when warmed to 37c.

Cryoglobulins may be IgG, IgM or IgA.

One third of cases are idiopathic.

Type 1 cryoglobulinaemia

monoclonal
high titres, usually >5mg/ml
associated with:

myeloma
Waldenstroms

features include vasculitis, ulceration and Raynaud's

Type 2 cryoglobulinaemia

mixed mono and polyclonal
titres usually >1mg/ml
associated with:

RA
sjogrens
lympoma
CLL
hep C
HIV

features include vasculitis, mesangiocapillary GN

Type 3 cryoglobulinaemia

mixed polyclonal
associated with:

RA
sjogrens
SLE

features include purpura, GN, arthritis

Now on to a similar but distinct topic...

MRCP revision battle 55.4: Cold agglutinins

2010-11-20T19:34:00.000Z

Cold agglutinins are molecules, usually IgM, which act against red cells agglutinising and haemolysing them at low temperatures.

Symptoms of cold agglutinins include:

Raynauds
acrocyanosis
mild haemolytic anaemia

Causes of cold agglutinins include:

idiopathic
CLL
lymphoma
mycoplasma
coxsachie
mononucleosis
HIV

Management is to avoid cold weather.

Now to diversify to neurology....

MRCP revision battle 55.5: Lateral medullary syndrome

2010-11-20T19:33:00.000Z

Lateral medullary syndrome is a condition in which a patient has a set of symptoms as a result of insult to the medulla.

Lateral medullary syndrome is usually due to PICA or vertebral artery occlusion.

Features include:

cerebellar signs
contralateral pain and temperature sensation loss
ipsilateral Horners
ipsilateral loss of pain and temperature sensation on face
ipsilateral paralysis of palate, pharynx and cords

On to some vision loss...

MRCP revision battle 55.6: Purtscher retinopathy

2010-11-20T19:32:00.000Z

Purtscher's retinopathy is characterised by cotton wool spots on fundoscopy with sudden detioration in vision.

It is classically associated with head trauma or chest trauma.

Other associations include:

pancreatitis
fat embolism
amniotic fluid embolism
vascular diseases

There is no treatment.

Finally - optic atrophy...

MRCP revision battle 55.7: Optic atrophy

2010-11-20T19:31:00.000Z

Optic atrophy is loss of fibres of the optic disc. It is characterised by decreased vision (particulary loss of colour vision) and a pale disc on fundoscopy.

Causes include:

Congenital:

Friedrichs ataxia (battle 30.6)
Lebers optic atrophy (battle 46.3)
DMOAD (=diabetes mellitus, optic atrophy and deafness)
retinitis pigmentosa (battle 30.1)

Acquired:

MS
papilloedema
glaucoma
ischaemia
B6, B12, folate deficieny
lead poisoning
arsenic poisoning
methanol
ethambutol
isoniazid
chloramphenicol

MRCP revision battle 54.1: Primary sclerosing cholangitis

2010-11-19T19:58:00.000Z

Today is in pairs: a pair of gastro battles, a pair of cardiology battles, a pair of haematology battles then a strange inherted disorder to finish on....

MRCP revision battle 54.1: Primary sclerosing cholangitis
MRCP revision battle 54.2: Jaundice
MRCP revision battle 54.3: Patent ductus arteriosus
MRCP revision battle 54.4: Cardiac axis
MRCP revision battle 54.5: Haemolysis
MRCP revision battle 54.6: Leukoerythroblastic change
MRCP revision battle 54.7: Gaucher's disease

MRCP revision battle 54.1: Primary sclerosing cholangitis

Primary sclerosing cholangitis is a condition of unknown aetiology in which there is inflammation and fibrosis of bile ducts.

Presentation:

patients may be asymptomatic with an incidental finding of raised ALP
may present as:

jaundice
pruritus
abdo pain
fatigue

Diseases associated with primary sclerosing cholangitis include:

IBD (UC>crohns; 70% of patients with PSC have UC but only 5% of patients with UC have PSC)
HIV
HLA A1, B8, DR3

Males are more frequently affected than females.

Diagnosis is by:

ERCP - shows strictures of the biliary tree and a 'beaded' appearence
liver biopsy - fibrous, obliterative cholangitis
ANA, SMA and ANCA may be positive

Treatment is:

colestyramine for pruritis
ursodeoxycholic acid to improve cholestatis
?stenting of strictures
?liver transplant

Complications include:

decreased absorption of fat-soluble vitamins A,D,E and K

clotting abnormalities and easy bruising
osteoporosis

cholangiocarcinoma (10-30%)
bacterial cholangitis
liver cirrhosis

portal hypertension

Survival tends to be around 10 yrs

As an aside, the other 2 conditions associated with cholangiocarcinoma are:

liver flukes
Caroli's disease = dilation of hepatic ducts

Into the yellow...

MRCP revision battle 54.2: Jaundice

2010-11-19T19:56:00.000Z

Jaundice is yellow pigmentation of the skin caused by raised bilirubin.

It is generally clinically visible above 35micromol/l.

The 'story' of bilirubin is illustrated in the diaphragm below:

phagocytes break haemoglobin down into unconjugated (=insoluble) bilirubin
unconjugated bilirubin is joined with glucoronic acid in the liver, making it conjugated (=soluble)
conjugatde bilirubin passes into the gallbladder and on to the small intestine, where it is converted into urobilinogen and excreted in urine by the kidneys or to stercobilinogen and excreted in faeces

The types of jaundice are:

1. Pre-hepatic = unconjugated

caused by:

haemolysis
lack of UDP: Gilberts, Crigler Najjar

urine/faeces colours normal

2. Hepatic = both conjugated and unconjugated

caused by:

infection: HBV, HCV, EBV
Wilsons
Budd-Chiari
Dubin-Johnson/Rotor syndromes
cirrhosis
drugs:

anti-TB meds
statins
sodium valproate
MAOIs
halothane
paracetamol OD

urine dark, faeces normal

3. Post-hepatic = conjugated = obstructive/cholestatic

gallstones
pancreatic cancer
cholangiocarcinoma
primary bilary sclerosis
sclerosing cholangitis
Mirrizi's syndrome = obstructive jaundice secondary to compression of the common hepatic duct by a gallstone impacted in the cystic duct
Drugs

antibiotics - co-amoxiclav, nitrofurantoin, flucloxacillin
OCP
chlorperazine
sulphonylureas
anabolic steroids

urine pale and faeces pale

Now for something different... PDA...

MRCP revision battle 54.3: Patent ductus arteriosus

2010-11-19T19:55:00.000Z

The ductus arteriosus is a connection between the pulmonary trunk and the descending aortic arch allowing blood flow in the fetus to avoid the fluid-filled lungs.

It should close shortly after birth, being mostly closed within 48 hrs and fully closed within 3 weeks, leaving the ligamentum arteriosum in its place.

Closure is due to 2 mechanisms:

exposure of infants lungs to oxygen promotes bradykinin production which promotes PDA closure
loss of maternal prostaglandins encourages closure

Closure is more likely to fail (=patent ductus arteriosus) in:

premature infants
infants exposed to rubella in 1st trimester
infants at high altitude

Features of patent ductus arteriosus include:

machinery murmur
wide, collapsing pusle
apical heave

If it does not close the infant may fail to thrive or develop heart failure.
Many cases however will be asymptomatic.
5% of patients with PDA go to develop pulmonary hypertension and Eisenmengers.

Treatment:

indomethacin (a prostaglandin antagonist) causes closure in 90%
surgical treatment is also an option

In some cases (eg transposition of the great vessels) keeping the ductus arteriosus open may be beneficial to the infant, in which case IV prostaglandin E1 is given.

On to the cardiac axis...

MRCP revision battle 54.4: Cardiac axis

2010-11-19T19:54:00.000Z

The normal cardiac axis is -30 to +90 degrees.

More negative = left axis deviation
More positive = right axis deviation.

Causes of left axis deviation:

LBBB
LVH
ASD
cardiomyopathies
aortic stenosis
can be normal in:

ascites
pregnancy
obesity

Causes of right axis deviation:

RBBB
RVH --> lung disease
PE
can be normal in:

infancy
thin people

Next: haemolysis

MRCP revision battle 54.5: Haemolysis

2010-11-19T19:53:00.000Z

Haemolysis (=breakdown of red blood cells) may be intravascular or extravascular.
It causes a microcytic anaemia and raised reticulocyte count.

Intravascular haemolysis

Intravascular haemolysis is characterised by:

low haptoglobin (as all used up trying to 'recycle' the broken down red cells)
raised free plasma haemoglobin
haemoglobuinuria: red-brown urine
haemosiderinuria: once haptoglobin binding capacity is surpassed free Hb is filtered by the kidneys and can be detected in the urine in sloughed tubular cells using Prussian blue staining

Causes of intravascular haemolysis include:

cold AIHA
transfusion reaction
G6PD (recall battle 28.4?)
paroxysmal nocturnal haematuria (recall battle 27.6?)
microangiopathic haemolytic anaemia (recall battle 38.6?)

DIC
TTP
mechanical heart valves

Extravascular haemolysis

Extravascular haemolysis may cause splenomegaly.

Causes of extravascular haemolysis include:

warm AIHA (remember battle 39.7?)
cold haemagglutination disease
spherocytosis
haemoglobinopathies
haemolytic disease of the newborn

Now to the second haem battle of the day...

MRCP revision battle 54.6: Leukoerythroblastic change

2010-11-19T19:52:00.000Z

Leukoerythroblastic change is the term used to describe nucleated red cells and primative white cells in the peripheral blood.

Causes of leukoertythroblastic change can be split into 2 catagories:

1. Invasion of bone marrow space

metastatic carcinoma
leukaemia
myeloma
lymphoma
myelofibrosis
Gaucher's disease (covered in next battle)

2. Severe illness

Leukoerythroblastic change may be indicated by:

high leucocyte alkaline phosphatase
Dohle bodies = blue leucocyte inclusions in peripheral cytoplasm of neutrophils
left shift of neutrophils = younger neutrophils than normal -->less nuclei

As an aside, Dohle bodies are also seen in burns, infection and trauma.

Now for the final short skirmish, Gaucher's disease...

MRCP revision battle 54.7: Gaucher's disease

2010-11-19T19:50:00.000Z

Gaucher's disease is the most common of the lysosomal storage disorders.

It is a recessive inherited disorder on chromosome 1 in which lipid accumulates in organs (spleen, liver, brain, kidneys, lungs) and bone marrow due to lack of an enzyme.

Ashkenazi Jews are more affected.

Possible features include:

splenomegaly
hepatomegaly
yellow-brown skin pigmentation
seizures
low IQ
osteoporosis

Treatment can include splenectomy and replacement of the missing enzyme.

MRCP revision battle 53.1: Genital ulcers

2010-11-18T15:00:00.002Z

A day of randomness that starts with the delights of genital ulcers and ends in a cat's scratch...

MRCP revision battle 53.1: Genital ulcers
MRCP revision battle 53.2: Vertebral artery dissection
MRCP revision battle 53.3: Intracranial venous thrombosis
MRCP revision battle 53.4: Infective endocarditis
MRCP revision battle 53.5: Upper GI bleeds
MRCP revision battle 53.6: Meckel's diverticulum
MRCP revision battle 53.7: Cat scratch disease

MRCP revision battle 53.1: Genital ulcers

Genital ulcers. Such a lovely topic. If you really can't face it there is a summary table at the end.

1. Chancroid

This is a sexually transmitted infection, most prevalent in third world countries.
Chancroid begins as a small lump that then turns into an ulcer.
It is painful
The ulcer bleeds easily when rubbed
The ulcer has a greeney-yellow base
One third of affected people will develop inguinal lymph node involvement, with half of these developing abscesses after the lymph nodes become so big they break through the skin.
Chancroid is caused by the gram negative bacteria haemophillus ducreyi
Treatment options are:

1g azithromycin orally or
IM ceftriaxone or
7 days erythromycin

Chancroid lesion filled with pus prior to rupture. From wiki commons, uploaded by Joe Miller

2. Granuloma inguinale = Donovanosis

This is a sexually transmitted infection mainly found in 3rd world countries.
Granuloma inguinale begins as a small lump which then bursts into an ulcer/open lesion that continues to spread until treated
The ulcer is painless and has a 'beefy red' appearence
There is not usually inguinal lymphadenopathy
Granuloma inguinale is caused by klebsiella granulomatis
Donovan bodies are rod-shaped klebsiella granulomatis found in the cytoplasm of phagocytes in infected individuals. They stain dark purple with Wright's stain.
Treatment is

3 weeks erthyromycin or tetracyline

3. Lymphogranuloma venereum

This is a sexually transmitted infection
It is caused by chlamydia trachomatis (L type)
There are several stages of infection:

Primary:

painless pustule which bursts into a painless ulcer
often not noticed by women as may be internal
10% of patients will have accompanying erythema nodosum

Secondary

tender inguinal lymphadenopathy

Tertiary

up to 20 yrs later - protocolitis, tenesmus

Treatment options:

doxycycline or
erythromycin

Image from wiki commons, uploaded by Dr Fred

4. Genital herpes

This is a sexually transmitted infection
Up to 8 in 10 people who contract it have no symptoms
Those who have symptoms tend to develop groups of painful ulcers
Primary infection may last up to 3 weeks
Subsquent infections tend to be less severe
It is highly infective when ulcers are present
It is classically caused by HSV 2 but can be caused by HSV 1.
Oral aciclovir may be given within the first 5 days of symptoms starting as a 5 day course but there is no cure
Subsequent recurrences tend to be less severe.

5. Behcet's disease

This is NOT sexually transmitted
It is associated with oral ulcers and anterior uveitis
See battle 25.2 for more information

Summary of sexually transmitted causes of genital ulcers:

Now for something completely different...

MRCP revision battle 53.2: Vertebral artery dissection

2010-11-18T10:59:00.000Z

Vertebral artery dissection is an important recognised cause of stroke in patients under 45 years of age.

The vertebral arteries themselves arise from the subclavian and join at the base of the medulla oblongata to form the basilar artery.

Presentation of vertebral artery dissection tends to be:

several occipital headache
cerebellar signs
brainstem signs

CN IX, X, XI and XII:

dysarthria
dysphagia

hiccups
loss of sensation to ipilateral face
ipsilateral Horner's syndrome in 1/3 of patients
'crossed signs':

ipisilateral cranial nerve palsy with contralateral hemiparesis or hemiplegia

Causes include:

trauma
stretching of neck

in MRCP questions look for trips to hairdresser, painting ceiling etc

connective tissue disorders

Investigation:

CT
4 vessel angiogram

Treatment:

?neurosurgery
anticoagulate if no associated subarachnoid haemorrhage

Now for some intracranial thrombosis...

MRCP revision battle 53.3: Intracranial venous thrombosis

2010-11-18T10:39:00.001Z

The presentation of intracranial venous thrombosis depends on which venous sinus is affected.

All locations of intracranial venous thrombosis can cause headache.

Isolated sagittal sinus thrombosis (=nearly half of intracranial venous thrombosis) or lateral sinus thrombosis present with:

headache
vomiting
seizures
papilloedema
potentially focal neurological signs

Cavernous sinus thrombosis can cause:

headache
oedematous eyelids
proptosis
painful eye movements/opthalmoplegia

Cavernous sinus thrombosis is often associated with infection spreading from the face or paranasal sinuses.
Remember: cavernous sinus contains CN III, IV, V1, V2 and VI, plus the internal carotid artery.

Sigmoid sinus thrombosis:

headache
cerebellar signs

Inferior petrosal sinus thrombosis:

5th and 6th nerve palsies

Risk factors for developing intracranial venous thrombosis include:

pregnancy
head injury
recent LP
oral contraceptive pill

Investigation is:

MRI/CT

CT may show 'absent delta sign' which implies a filling defect and therefore a thrombosis

?MRV

Management is by specialists, ?heparin

On to the more familiar topic of infective endocarditis...

MRCP revision battle 53.4: Infective endocarditis

2010-11-18T10:37:00.000Z

Infective endocarditis is diagnosed by Dukes criteria, which requires:

2 major criteria OR
1 major and 2 minor criteria OR
all 5 minor criteria.

Major criteria are:

positive blood culture

typical organism in 2 separate cultures OR
persistently +blood cultures

endocardial involvement

positive echo
new valvular regurgitation

Minor criteria are:

fever >38C
vascular/immunological signs
predisposition (IVDU, valve replacemen)
positive blood culture that doesn't mean major criteria
positive echo that doesn't meet major criteria

Vascular/immunological signs include:

Janeway lesions
Oslers nodes
splinter haemorrhages
Roth spots

40% of cases of endocarditis occur in patients with no previous problems.
30% have had rheumatic heart disease.

Commonest causative organism is streptococcus viridans (alpha haemolytic)
Commonest organism in IVDUs is staphlycoccus aureus.
Commoenst organism within 6 weeks of valve surgery is staph epidermidis.

Usually bicuspid valve affected, except in IVDUs where the tricuspid valve is most commonly affected.

Mortality from strep in 5%, staph around 30%

Poor prognostic factors:

s. aureus
prosthetic valve
culture negative
low complement

Treatment:

initial blind therapy: fluclox and gent
prosthetic valve/penicillin allergy: vancomycin and rifampicin and gent
staph: fluclox/vanc and gen
strep: benzylpenicillin and gent

Surgery if:

abscess
recurrent emboli
severe valve incompetence
cardiac failure

Random MRCP facts:

prolongation of PR suggests aortic valve abscess
if causative organism is found to be strep bovis look for an associated bowel malignancy.

On to upper GI bleeds...

MRCP revision battle 53.5: Upper GI bleeds

2010-11-18T10:16:00.001Z

Upper GI bleeds may present with:

haematemesis (=vomiting blood)
coffee ground vomiting or
malaena (=black, tar-like motions)

Commonest causes of upper GI bleeds are:

35% duodenal ulcers
20% gastric ulcers
18% gastric erosins
10% Mallory-Weiss tear

Rarer causes of GI bleeds include:

variceal haemorrhage
aorto-enteric fistula
Meckel's diverticulum
Peutz-Jeghers syndrome

Risk of rebleeding and mortality from upper GI bleeds is calculated using the Rockall score.
Pre-endoscopy Rockall score is calculated based on:

age

0pt <60yrs
1pt 60-79
2pts >80

degree of shock

0pt: BP >100 sys and HR <100
1pt: BP >100 sys but HR >100
2pts: BP <100 sys

co-morbidities

0pt: none
1pt: heart problems
2pts: liver/renal failure
3pts: mets

Mortality is roughly:

1 in 20 with 2 pts
1 in 10 with 3 points
1 in 4 with 4 points
1 in 2 with 7 points

Post endoscopy mortality is calculated based on the initial score, the diagnosis and the signs of haemorrhage seen.

Below is a summary of the Rockall score from the SIGN guidelines:

Management of upper GI bleeds is:

classic ABC resuscitation
if cause suspected to be variceal haemorrhage: IV terlipressin 2mg then 2mg/4hr
urgent endoscopy
surgery if endoscopy unsuccessful
if cause is ulcer: omeprazole after endoscopy
if cause is variceal haemorrhage: consider transjugular intrahepatic portosystemic shunt to prevent rebleeding (note: nearly 25% of people with a TIPS get hepatic encephalopathy)

Now to Meckel's diverticulum...

MRCP revision battle 53.6: Meckel's diverticulum

2010-11-18T10:00:00.000Z

Meckel's diverticulum is the vestigial remnant of the vitellointestinal duct.

Its features are often recalled as a series of '2s':

found in 2% of the population
around 2 inches long
at 2 foot from the ileocaecal valve

It may present with:

painless rectal bleeding
GI obstruction
abdominal pain due to faeces trapped inside diverticulum

Investigation is with radionucleotide scan.

Treatment for complications is surgical.

Now to end on an unusual condition - cat scratch disease.

MRCP revision battle 53.7: Cat scratch disease

2010-11-18T09:48:00.000Z

Cat scratch disease is usually caused by bartonella henselae (a gram negative rod)

Features:

several erythematous, crusted lesions at site of scratch
regional lymphadenopathy
up to half of patients will feel systemically unwell

If confirmation of diagnosis is required an indirect fluorescent antibody test for bartonella is avaliable.

Treatment is generally supportive and resolution tends to occur within 2 months.

Prevention is keeping cats flea- free!

MRCP revision battle 52.1: Zollinger-Ellison Syndrome

2010-11-17T20:39:00.000Z

Finally I have a topic to put under the 'z' catagory in my A to Z index!

Today we have:

MRCP revision battle 52.1: Zollinger-Ellison Syndrome
MRCP revision battle 52.2: Congential Hyperbilinrubinaemia
MRCP revision battle 52.3: Metformin
MRCP revision battle 52.4: Flecainide
MRCP revision battle 52.5: Arrhythmogenic right ventricular cardiomyopathy
MRCP revision battle 52.6: Pulmonary hypertension and cor pulmonale
MRCP revision battle 52.7: Scromboid poisoning

MRCP revision battle 52.1: Zollinger-Ellison Syndrome

Zollinger-Ellison syndrome is a rare condition in which there are multiple gastric and duodenal ulcers in association with gastrin-secreting adenoma.

The adenoma is usually pancreatic in origin but may be found in the stomach or duodenum.

50-60% of the adenomas in Zollinger-Ellison syndrome are malignant.
10-30% are associated with MEN-1.
(quick recap: MEN 1 = pancreatic tumours, parathyroid tumours and pituitary tumours)

Presentation:

epigastric pain from the ulcers
diarrhoea
malabsorption/steatorrhoea from inactivation of pancreatic enzymes

Diagnosis is by a raised fasting gastrin level.
Note gastrin levels will also be raised in achlorhydria - this differential can be eliminated by doing a secretin stimulation test which will cause a raised gastrin level in Zollinger-Ellison syndrome but no rise with achlorhydria.

Treatment is with high dose PPI (eg 60mg/day).
Ocreotide (somatostatin analogue) may help with symptom relief.

On to consider some congenital causes of jaundice...

MRCP revision battle 52.2: Congential Hyperbilinrubinaemia

2010-11-17T20:37:00.001Z

This battle will briefly run through 4 conditions associated with congenital hyperbilinrubinaemia....

1. Gilberts

This is the absolute classic. Gilberts is inherted in an autosomal recessive fashion and affects 1-2% of the population.

Gilberts is due to low levels of UDP glucuronosyltransferase.
It results in a rise in unconjugated bilirubin.

Gilberts is entirely benign and many sufferers only take on a yellow tinge when they have a concurrent illness.

2. Crigler Najjar

There are 2 types of Crigler Najjar - type 1, which is autosomal recessive, and type 2, which is autosomal dominant.

It is due to there being no UDP glucuronosyltransferase
This results in a catastophic rise in unconjugated bilirubin.

Unless the sufferer has a liver transplant they are likely to die as a baby.

3. Dubin Johnson

Dubin Johnson is an autosomal recessive condition in which there is a mutation in the cMOAT transport protein resulting in a defect of hepatic excretion of bilirubin and a rise in conjugated bilirubin.

This manifests as intermittent jaundice with RUQ pain.

Tests to confirm Dubin Johnson include:

coproporphyrin I levels being 3-4x higher than coproporphyrin III- in normal subjects this is reversed
normal levels of urine coproporphyrin but 80% being the I isomer, when normally this would be 25%
at postmortem: liver has black pigmentation

Happily Dubin-Johnson is a benign condition

4. Rotor syndrome

Rotor syndrome is an autosomal recessive disorder which is similar to Dubin-Johnson and is also due to a defective mechanism of excretion of conjugated bilirubin.

It is also benign.

Rotor syndrome can be differentiated from Dubin-Johnson as:

Dubin-Johnson has normal levels of urinary coproporphyrin while Rotor syndrome has high levels
liver in Dubin-Johnson has black pigmentation whereas in Rotor syndrome it is normal

Now on to metformin...

MRCP revision battle 52.3: Metformin

2010-11-17T20:36:00.000Z

Metformin's mechanism of action is:

increasing gluconeogenesis
increasing insulin sensitivity and therefore increasing peripheral utilisation of glucose
possibly by decreasing GI absorption of carbohydrates

Metformin works only in the presence of endogenous insulin and is therefore only effective if there is residual functioning pancreatic islet cells.

Adverse effects of metformin include:

GI upset - to an intolerable degree in up to 20% of subjects
decreased B12 absorption - rarely clinically relevant but popular in MRCP questions
rarely it may provoke lactic acidosis - usually only if there is also renal impairment.

Contra-indications to metformin include:

eGFR <30
IV contrast
stop of morning of general anaesthesia
pregnancy
breast feeding

Now on to a cardiac drug as we enter the cardiology section of today's battles...

MRCP revision battle 52.4: Flecainide

2010-11-17T20:35:00.000Z

Flecainide is a class Ic antiarrhythmic which works by blocking the sodium channels.

Flecainide causes a wider QRS and longer PR.

Indications for flecainide are:

AF
SVT with accessory pathway

Its half life is 16 hrs.

Flecainide is contraindicated post MI.
It should be used with caution in those with pacemakers as it can raise the potential needed for stimulation.

Adverse effects of flecainide include:

negatively inotropic
bradycardic
proarrhythmic
oral parasthesia
visual disturbances
rarely: pneumonitis

Next - Arrhythmogenic right ventricular cardiomyopathy

MRCP revision battle 52.5: Arrhythmogenic right ventricular cardiomyopathy

2010-11-17T20:34:00.000Z

Arrhythmogenic right ventricular cardiomyopathy is the second most common cause of sudden cardiac death in young people after HCM.

It is characterised by fatty and fibrofatty tissue infiltrating predominantly the right ventricle.

It may be inherited in an autosomal dominant fashion with variable penetrance.

Presentation may be:

palpitations
syncope
sudden death

ECG may be normal, or:

T wave inversion V1-V3
epsilon wave = terminal notch in QRS

The investigation of choice is MRI.

Treatment includes:

sotolol
ablation
ICD

An MRCP-gem to remember is Naxos disease, which is the association of arrhythmogenic right ventricular cardiomyopathy with palmoplantar keratosis and wooley hair.

Now for some pulmonary hypertension...

MRCP revision battle 52.6: Pulmonary hypertension and cor pulmonale

2010-11-17T20:33:00.000Z

Definition of pulmonary hypertension

Normal pulmonary artery pressure is 12 to 16 mmHg.

Pulmonary hypertension is defined as pulmonary artery pressure:

>25mmHg at rest OR
>30mmHg on exercising

Note that technically a Swan-Ganz catheter/cardiac catherisation is needed to diagnose pulmonary hypertension; however, cardiac echo is often used. Echo reports tend to quote systolic pulmonary artery pressure rather than mean - to convert to mean multiply by 0.61 and add 2.

Cor pulmonale is right heart failure caused by pulmonary hypertension.

Features of pulmonary hypertension

Tends to present with progressive shortness of breath.

On examination look for signs of right heart failure:

right ventricular heave
raised JVP, a waves
loud P2
pansystolic murmur - tricuspid regurgitation

Types of pulmonary hypertension

Primary - accounts for <1% pulmonary hypertension
10% of cases are familial and inherited in an autosomal dominant fashion

Secondary - commonest cause is COPD
Other secondary causes of pulmonary hypertension include:

IHD
MV disease
left to right shunts
chronic hypoxia

Treatment of pulmonary hypertension

If secondary, treat cause
Give diuretics
anticoagulate
vasodilators:

calcium channel blockers
IV prostaglandins
bosentan = endothelial antagonist
sildenafil = PDE-5 inhibitor

transplant

5 yr survival is less than 50%

On to a fishy battle...

MRCP revision battle 52.7: Scromboid poisoning

2010-11-17T20:31:00.000Z

Scromboid poisoning is caused by the ingestion of amines, mainly histamines, which are produced by bacterial decarboxylation of histadine in fish meat (mainly tuna, mackeral, sardines, anchoives, marlin)

The commonest cause of scromboid poisoning is ingestion of spoiled fish following improper refridgeration. Cooking well will not inactivate the hisatmines that have been produced.

Degree of symptoms correlates to amount of fish consumed.

Symptoms include:

nausea
abdo pain
diarrhoea
flushing
rash
headache
palpitations
hypo or hypertension

Onset of symptoms tends to be within 10 to 30 mins but may take up to 2 hours
Symptoms tend to settle within 36 hours

Treatment is with antihistamine; corticosteroids are not indicated.

People with asthma or on isoniazid may be more severely affected.

MRCP revision battle 51.1: Rheumatic fever

2010-11-16T06:10:00.005Z

Today includes a triple helping of cardiology with some random topics mixed in...

MRCP revision battle 51.1: Rheumatic fever
MRCP revision battle 51.2: Hypothermia
MRCP revision battle 51.3: Dilated cardiomyopathy
MRCP revision battle 51.4: Coeliac's Disease
MRCP revision battle 51.5: Botulism
MRCP revision battle 51.6: Hypertrophic cardiomyopathy
MRCP revision battle 51.7: Bacterial vaginosis

MRCP revision battle 51.1: Rheumatic fever

Rheumatic fever is a systemic infection caused by group A beta haemolytic strep.

Diagnosis is by the revised Jones criteria which stipulates:

evidence of preceeding streptococcl infection AND
2 major criteria OR 1 major and 2 minor criteria

Major criteria are:

carditis
polyarthritis
chorea
erythema marginatum
subcutaneous nodules

Minor criteria are:

fever
arthralgia
raised ESR/CRP
long PR
previous rheumatic fever

The cardiac histological marker is the aschoff nodule

Treatment is:

bed rest until CRP normal for 2 weeks
aspirin
penicillin

60% of patients with carditis develop chronic rheumatic heart disease, with the mitral valve most commonly affected.

Rheumatic fever may recur so prophylaxic penicillin should be given until the age of 30 and when dental procedures are being carried out after that.

Now for a cold topic...

MRCP revision battle 51.2: Hypothermia

2010-11-16T06:09:00.002Z

Mild hypothermia is defined as a core body temperature less than 35C.
Severe hypothermia is core body temperature less than 28C

Signs of hypothermia include:

bradycardia
hypoventilation
hypotension
muscle stiffness
fixed and dilated pupils

Metabolic acidosis is common and may predispose to pancreatitis.

ECG changes in hypothermia include:

J waves
long PR, QT and QRS
under 28C increasing risk of VF

Primary hypothermia is hypothermia due to exposure.
Secondary hypothermia is hypothermia due to a medical illness, for example hypothyroidism or hypoglycaemia

Treatment is passive rewarming for mild to moderate hypothermia and core rewarming (eg peritoneal lavage) for severe hypothermia.

Next - dilated cardiomyopathy

MRCP revision battle 51.3: Dilated cardiomyopathy

2010-11-16T06:08:00.002Z

Dilated cardiomyopathy is exactly what it says it is: a dilated heart.

It is associated with:

alcohol excess
hypertension
coxsackie virus
HIV
doxorubicin
haemochromatosis
sarcoidosis

Possible presentations include fatigue, dyspnoea or AF.

Clinically there may be a displaced apex, S3 gallop, TR or MR

The ECG may show poor R wave progression

Treatment is as per heart failure. ?cardiac transplant

Now on to coeliac disease...

MRCP revision battle 51.4: Coeliac's Disease

2010-11-16T06:07:00.004Z

Coeliac disease is a T cell mediated autoimmune disease of the small bowel.

There is intolerance to prolamins (proteins found in wheat, barley, rye) which results in villous atrophy and malabsorption.

Gliadin (found in gluten) is a form of prolamin.

Presentation may be with:

abdominal pain
weight loss
nausea and vomiting
steatorrhoea
bloating

Patients must eat gluten for 6 weeks prior to testing.

NICE recommends diagnosis is by tissue transglutaminase (TTG) antibodies (IgA)
Endomysial antibodies and anti gliadin antibodies may also be found but are not recommended by NICE.

Jejenal biopsy may show:

villous atrophy
crypt hypoplasia
raised intraepithelial lymphocytes
lamina propria infiltrates with lymphocytes

Associations with coelic disease include:

dermatitis herpetiformis
type 1 diabetes
autoimmune hepatitis

Management is by careful diet.

Now on to some botulism...

MRCP revision battle 51.5: Botulism

2010-11-16T06:06:00.004Z

Botulism is caused by clostridium botulinum (gram positive rod)

The toxin causes a descending flaccid paralysis by binding irreversibly to the presynaptic membranes of the neuromuscular junction, blocking acetylcholine release.

Signs include:

flaccid paralysis
dysarthria
ptosis
fixed/dilated pupils
dry mouth
respiratory arrest

Botulism may be caused by food or by wound infection. Heroin users are at high risk.
All commericial canned food has to undergo a 'botulum cook' at 121C.
Honey can contain botulum and as a result it is not recommended to give honey to infants under 1 yr of age.

Botulism may cause a false positive tensilon result.

Treatment is with an antitoxin and ITU support.

Next up: hypertrophic cardiomyopathy

MRCP revision battle 51.6: Hypertrophic cardiomyopathy

2010-11-16T06:05:00.002Z

Hypertrophic obstructive cardiomyopathy is a condition in which there is left ventricular outflow tract obstruction due to asymmetric septal hypertrophy.

It is inherited in an autosomal dominant fashion but 50% of cases are sporadic.

Presentation may be with:

angina
syncope
shortness of breath
sudden death
palpitations

Signs include:

jerky pulse
ESM radiating to axilla

increases with valsalva, decreases with squatting

large a waves
double apical beat
?MR
?split S2

On ECG look for:

LVH
TWI
Q waves
possibly AF

Associations include:

WPW
phaechromocytoma
Friedreichs ataxia

Poorer prognosis if:

younger
family history of sudden death
syncope

No correlation between degree of LVOT obstruction and prognosis.

On angio look for a difference between the LV and aortic systolic pressures - in a normal patient they should be the same, in HCOM aortic pressure will be lower than LV pressure.

Management is:

avoid

nitrates
ACE-i
inotropes
atropin

give beta blockers
?amiodarone
?ICD
?surgery

Annual mortality is 2.5% in adults, 6% in children.

Lets finish on the smelly topic of bacterial vaginosis...

MRCP revision battle 51.7: Bacterial vaginosis

2010-11-16T06:04:00.001Z

Bacterial vaginosis is caused by an overgrowth of bacteria. Lactobacillus tend to predominate.

It produces a thin white-grey discharge with a fishy odour.
It is not normally itchy or sore.

Diagnosis is made by Amsel's criteria, which requires 3 of the following 4:

thin grey-white discharge
fishy odour on adding an alkali
pH >4.5 (normal pH 3.8-4.2)
clue cells on microscopy

Treatment is given to symptomatic ladies.
Options include metronidazole and clindamycin.

MRCP revision battle 50.1: Gangrene and Necrotising Fasciitis

2010-11-15T06:07:00.001Z

A day dedicated to dermatology...

MRCP revision battle 50.1: Gangrene and necrotising fasciitis
MRCP revision battle 50.2: Acne Rosacea
MRCP revision battle 50.3: Seborrhoeic dermatitis
MRCP revision battle 50.4: Alopecia
MRCP revision battle 50.5: Discoid lupus erythematosus
MRCP revision battle 50.6: Bullous Pemphigoid and Pemphigus Vulgaris
MRCP revision battle 50.7: Erythrasma

MRCP revision battle 50.1: Gangrene and necrotising fasciitis

A couple of grim topics: gangrene and necrotising fasciitis.

Gangrene

Gangrene is death of tissue due to ischaemia. It can be subdivided into:

dry gangrene = ischaemia only
wet gangrene = ischaemia plus infection

Management is surgical with debridement and IV antibiotics

Necrotising fasciitis

Necrotising fasciitis is a rapidly spreading infection of the deep fascia.

Type 1 is caused by mixed anaerobes and aerobes, classically occuring in diabetes and post surgery
Type 2 is usually caused by streptococcus pyrogenes, which is a group A beta haemolytic strep.

Fournier's gangrene is a subtype of necrotising fasciitis which affects male genitalia/the perineal area.
Meleney's gangrene is a subtype of necrotising fasciitis which occurs after an operation

Treatment of necrotising fasciitis is with debridement.

Mortality is around 70%.

Onwards to acne rosacea...

MRCP revision battle 50.2: Acne Rosacea

2010-11-15T06:05:00.001Z

Acne rosacea is a skin condition that affects the face.

The first sign is often facial flushing.

Other features of acne rosacea include:

erythema of face
papules/pustules
telangiectasia
eye involvement - eg dry eyes
rarely rhinophyma

The cause is not known although demodex follicularum is hypothesised to be involved as it occurs in larger numbers on suffers of acne rosacea than the general population. Overuse of topical steroids can cause a condition like acne rosacea.

If the condition is mild topical metronidazole is used.
In severer cases oral oxytetracycline is given.

On to some flakey skin....

MRCP revision battle 50.3: Seborrhoeic dermatitis

2010-11-15T06:04:00.003Z

Seborrhoeic dermatitis, AKA seborrhoeic eczema, is a skin condition characterised by dandruff and sometimes dry, erythematous flakey skin.

It is associated with a fungus called Malassezia furfur (previously known as Pityrosporum ovale). However, it is not contagious.

Treatment is with ketoconazole 2% shampoo and anti-fungal cream.

Severe forms of seborrhoeic dermatitis are associated with Parkinson's disease and HIV.

Complications include otitis externa and blepharitis.

Now for some hair loss...

MRCP revision battle 50.4: Alopecia

2010-11-15T06:04:00.002Z

This is a topic close to many men's hearts - alopecia (=hair loss).

We will consider alopecia in 3 sections:

autoimmune
scarring
non-scarring

Alopecia areata

Alopecia areata is thought to be an autoimmune condition in which there are 'patches' of hair loss.
hair regrows in 50% of sufferers within a year
hair regrows in 80-90% of sufferers eventually
it is associated with:

autoimmune thyroid disease
pernicious anaemia
addisons
vitiligo
nail dystrophy
cataracts

alopecia totalis refers to complete loss of all hair on scalp
alopecia universalis refers to loss of all body hair

Scarring alopecia

Causes of scarring alopecia include:

infections: TB, syphyllis
radiotherapy
sarcoidosis
lichen planus

Non-scarring alopecia

Causes of non-scarring alopecia include:

areata
hypopituitarism
hypo/hyper thyroidism
pregnancy
OCP
carbimazole
thiouracil
lithium
iron deficiency
chronic illness

Next up... some discoid lupus...

MRCP revision battle 50.5: Discoid lupus erythematosus

2010-11-15T06:03:00.001Z

Discoid lupus erythematosus is a skin condition characterised by:

erythematous plaques with
slight scaling with the
inside hypopigmented compared to the edge. As they age they develop
keratin plugs in the centre.

Young females tend to be most commonly affected.

The lesions are photosensitive and tend to occur on the face, neck and scalp.

It is associated with SLE but less than 5% of cases progress to SLE.

First line treatment is topical steroids.
Second line treatment is hydroxychloroquine.

Now to a pair of blistering diseases that have always confused me...

MRCP revision battle 50.6: Bullous Pemphigoid and Pemphigus Vulgaris

2010-11-15T06:01:00.002Z

Personally I have always mixed up bullous pemphigoid and pemphigus vulgaris so I'm hoping by tackling them in the same battle the differences will become apparent...

Note that pemphigus vulgaris can be drug-induced, with culprits including penicillamine, captopril and cephalosporin.

Pemphigus vulgaris is more common in Ashkenazi Jews.

On to something that glows coral red under woods lamp...

MRCP revision battle 50.7: Erythrasma

2010-11-15T06:00:00.002Z

Erythrasma is a skin condition characterised by asymptomatic initially pink patches that become brown as the skin sheds.

Erythrasma is caused by corynebacterium, a gram positive bacteria.

If a woods lamp is held near a patch of erythrasma the erythrasma glows coral red due to porphyrins released by the bacteria.

It is commonest amongst diabetics and the obese.

Treatment is with topical fusidic acid/clindamycin or oral erythromycin if extensive.

MRCP revision battle 49.1: Homocystinuria

2010-11-14T06:10:00.001Z

Today is back to being a mixed set of battles with some familiar topics and some utterly unusual ones...

MRCP revision battle 49.1: Homocystinuria
MRCP revision battle 49.2: Nail-patella syndrome
MRCP revision battle 49.3: Golfers and Tennis Elbow
MRCP revision battle 49.4: Whipples disease
MRCP revision battle 49.5: Hypermagnesaemia
MRCP revision battle 49.6: Osteoporosis
MRCP revision battle 49.7: Osteogenesis Imperfecta

MRCP revision battle 49.1: Homocystinuria

Homocystinuria is an autosomally recessive inherited condition in which there is decreased activity of cystathionine beta synthase resulting in accumulation of homocysteine and methionine which interferes with collagen cross-linkage.

Features include:

Marfanoid body habitus
spontaneous retinal detachment
downwards lens dislocation
osteoporosis
venous and arterial thrombosis
low IQ

Diagnosis is with the cyanide nitroprusside test which detects elevated urinary homocysteine.

Treatment is:

methionine restriction
cysteine supplements
pyridoxine supplements

Now to nail-patella syndrome...

MRCP revision battle 49.2: Nail-patella syndrome

2010-11-14T06:09:00.001Z

Nail-patella syndrome occurs as a possible answer in a fair few MRCP questions so an insight into it is helpful...

Nail-patella syndrome affects 1 in 50,000

It is characterised by:

nail abnormalities, classically loss of the ulnar half of the thumb nail
small patella
boney spines over posterior iliac crests (70%)
renal abnormalities (30-50%)
over-extension of joints

On to some elbows...

MRCP revision battle 49.3: Golfers and Tennis Elbow

2010-11-14T06:08:00.002Z

Golfer's Elbow

medial epicondylitis
pain worse on pronating forearm/ wrist flexion
may have an assocaited ulnar neuropathy

Tennis Elbow

lateral epicondylitis
pain worse on elbow/wrist extension
usually lasts 6 to 12 weeks
commoner than Golfer's elbow

Both are treated with:

ice
NSAIDs
? corticosteroid injection
?physio

Back to the world of esoteric medicine...

MRCP revision battle 49.4: Whipples disease

2010-11-14T06:07:00.001Z

Whipple's disease is a rare cause of GI malabsorption. It is caused by a gram positive bacterium Tropheryma whippelei.

Presentation is:

weight loss
arthralgia
diarrhoea
malaise
fever

Other symptoms may occur in relation to the malabsorption, for example signs of hypocalcaemia or vitamin C deficiency.

Possible clinical signs include:
• lymphadenopathy
• perioral hyperpigmentation

Cardiac involvement can result in an endocarditis, and CNS involvement can cause a reversible dementia.

It is commonest in males (9:1) and is associated with HLA B27.

Treatment is 2 weeks IV ceftriaxone then oral co-trimoxazole for one year.

Now for some excess magnesium...

MRCP revision battle 49.5: Hypermagnesaemia

2010-11-14T06:06:00.002Z

Hypermagnesaemia generally becomes clinically relevant above 4mmol

Symptoms and signs include:

lethargy
nausea
areflexia
hypotension
heart block
bradycardia
double vision

Treatment is with IV calcium.

Next up: osteoporosis

MRCP revision battle 49.6: Osteoporosis

2010-11-14T06:05:00.001Z

Osteoporosis literally means 'porous bone'.

It is diagnosed by DEXA scan:

T to -1 SD = normal
T -1 to -2.5 SD = osteopenia
T below -2.5 SD = osteoporosis

Fracture risk is increased by 2x with each standard deviation of the T score.

Common fracture sites include:

vertebrae and neck of femur = trabecular bone
distal radius and humerus = cortical bone

Factors increasing the risk of OP include:

being slim
smoker
alcoholic
inactive
old
steroid use
early menopause
thyrotoxicosis
primary biliary sclerosis
cushings

Primary prevention of OP is with alendronate.

Now to the final battle of the day, osteogenesis imperfecta

MRCP revision battle 49.7: Osteogenesis Imperfecta

2010-11-14T06:04:00.000Z

Osteogenesis Imperfecta is an autosomal dominant inherited condition in which there is abnormal and or insufficient type 1 collagen synthesis.

This results in:

bone fractures
blue sclerea
deafness secondary to otosclerosis
muscle weakness

The photo below demonstrates the classical blue sclera (from wiki commons, posted by Dr Fred)

There is no cure, so treatment is trying to prevent bone fractures.

MRCP revision battle 48.1: Genital warts

2010-11-13T06:10:00.001Z

Today's battles have a distinctly dermatological flavour to them...

MRCP revision battle 48.1: Genital warts
MRCP revision battle 48.2: Livedo reticularis and erythema ab igne
MRCP revision battle 48.3: Antiphospholipid syndrome
MRCP revision battle 48.4: Skin conditions associated with malignancy
MRCP revision battle 48.5: Sturge-Weber Syndrome
MRCP revision battle 48.6: Erythema multiforme
MRCP revision battle 48.7: Toxic Epidermal Necrolysis and Steven-Johnson Syndrome

MRCP revision battle 48.1: Genital warts

Genital warts are not a topic I want to dwell on so lets make this very concise.

Posh medical name for genital warts = condylomata accuminata

Cause: HPV, most commonly strains HPV 6 and HPV 11.
Less than 1% of people who become infected with HPV develop warts.

Prevention: gardasil vaccine protects against HPV 6 and 11 (associated with warts) and 16 and 18 (associated with cervical cancer)

Treatment:

1st line: topical podophyllin/cryotherapy
2nd line: imiquimod

Lets move rapidly onwards...

MRCP revision battle 48.2: livedo reticularis and erythema ab igne

2010-11-13T06:09:00.001Z

livedo reticularis is a mottled, reticulated vascular pattern that appears like 'purple lace' on the skin.

Click here for an image
Click here for another

Causes of livedo reticularis include:

idiopathic - commonly occurs in young females
secondary

rheumatological: RA/SLE/PAN/dermatomyositis/antiphospholipid syndrome
pancreatitis
infections: TB/lyme disease/syphillis
lymphoma

Note how similar it looks to erythema ab igne (AKA livedo recticularis e calore) which is a rash caused by prolonged heat exposure, for example by sitting by a radiator or holding a hot water bottle. (photo form wiki commons, taken by Dr Heilman)

Now lets move on to look at one of the causes of livedo reticularis, antiphospholipid syndrome

MRCP revision battle 48.3: Antiphospholipid syndrome

2010-11-13T06:08:00.001Z

Antiphospholipid syndrome is characterised by:

recurrent venous/arterial thromboses
fetal loss
thrombocytopenia

Livedo reticularis may also be a feature.

Antiphospholipid syndrome is associated with:

lupus anticoagulant - an inhibitor of the coagulation pathway in vitro; pro-coagulant in vivo
anti cardiolipin antibodies - IgG and IgM

Management is with aspirin post thrombus, or if recurrent thromboses despite aspirin warfarin.

In pregnancy expert advice is needed; in general aspirin is taken once pregnant and LMWH started once the fetal heart is seen. This is continued until 34 weeks. This regime results in 70% success compared with 10% with nothing.

Now for some pictures...

MRCP revision battle 48.4: Skin conditions associated with malignancy

2010-11-13T06:07:00.001Z

A brief run-through of a few skin conditions that can be associated with malignancy.

1. Acanthosis nigricans

Acanthosis nigricans is a brown, velvety pigmentation of the skin, as illustrated below.

Acanthosis nigricans is associated with:

insulin resistance

diabetes
acromegaly
cushings
obesity
hypothyroidism

PCOS
adenocarcinoma - particularly of GI tract/stomach

2. Acanthosis palmaris

Acanthosis palmaris, also known as 'tripe palms' is associated with lung or GI cancer.

3. Erythema gyratum repens

Erthema gyratum repens can be just the most beautiful swirly patterned erythema - click here to see a picture. Unfortunately it is associated with lung cancer.

4. Necrolytic migratory erythema

From a beautiful rash to a truelly ugly one - necrolytic migratory erythema is associated with glucagonomas. Click here for more information and images.

5. Sweets syndrome

These are tender purple-red plaques associated with haematological malignancy and IBD. The patient is likely to have a fever. The picture below is from wiki commons, posted by Cohen:

On to a very brief battle, Sturge-Weber syndrome...

MRCP revision battle 48.5: Sturge-Weber Syndrome

2010-11-13T06:06:00.001Z

Sturge-Weber syndrome is the association of a port wine stain on the face with ipsilateral vascular malformations and epilepsy.

Glaucoma and learning difficulties may also be features.

Now for some target lesions...

MRCP revision battle 48.6: Erythema multiforme

2010-11-13T06:05:00.001Z

Erythema multiforme is characterised by target lesions.

Two pictures of erythema multuforme are below; the second is by Dr Heilmann.

50% of cases of erythema multiforme are idiopathic.

Secondary causes include:

drugs

penicillin
sulphonamides
phenytoin
carbamazepine
ACE-i
barbituates
NSAIDs
thiazides

infections

mycoplasma
herpes
orf

Management is to treat the underlying cause and supportive treatment.

For the final battle of the day on to what used to be considered as a severe form of erythema multiforme....

MRCP revision battle 48.7: Toxic Epidermal Necrolysis and Steven-Johnson Syndrome

2010-11-13T06:04:00.001Z

Steven-Johnson Syndrome and Toxic Epidermal Necrolysis (TEN) are now consider to be varients of the same entity, with TEN being more severe.

They are characterised by irregular purpuric macules with occasional blistering and most patients also have extensive mucosal involvement.

Although the appearence may initially seem similar to erythema multiforme (ableit more severe) histologically they are different:

erythema multiforme - cell-rich infiltrate, lots of T lymphocytes
SJS/TEN - cell-poor infiltrate, macrophages and dendrocytes

The difference between SJS and TEN is arbitrarily defined as SJS involves <10% body surface while TEN involves >30%.

The commonest cause of SJS/TEN is medication, with sulphonamides being the most commonly implicated drug.

Other drug precipitants include:

phenytoin
carbamazepine
barbituates
allopurinol
penicillin
NSAIDs

The commonest time for SJS/TEN to develop is 9 to 14 days after starting a new drug.

Infections can also cause SJS/TEN.

In addition to the rash patients are systemically unwell and have a + Nikolsky's sign.

Management is:

stop precipitating drug
often ITU
IV IG
?immunosupression ?plasmophoresis

MRCP revision battle 47.1: Membranous glomerulonephritis

2010-11-12T06:10:00.010Z

A final assault on renal medicine!

MRCP revision battle 47.1: Membranous glomerulonephritis
MRCP revision battle 47.2: Diffuse proliferative glomerulonephritis
MRCP revision battle 47.3: Acute interstitial nephritis
MRCP revision battle 47.4: Chronic interstitial nephritis
MRCP revision battle 47.5: Alport's syndrome
MRCP revision battle 47.6: Renal papillary necrosis
MRCP revision battle 47.7: Mesangiocapillary glomerulonephritis

MRCP revision battle 47.1: Membranous glomerulonephritis

Membranous glomerulonephritis is the commonest cause of nephrotic syndrome in adults, accounting for around 30% of cases.

Peaks in incidence of membranous glomerulonephritis occur in the 2nd and 6th decade of life.

The key feature is IgG and C3 on the basemement membrane

The complication to be aware of is renal vein thrombosis which occurs in 5% of cases.

Secondary causes of membranous glomerulonephritis include:

malignancy
connective tissue disease: RA/SLE/sjogrens
infection: HBV/HCV/malaria/syphilis
drugs: NSAIDs/gold/penicillamine/captopril
other: GBS/sarcoid

In terms of prognosis 1/3 recover spontaneously, 1/3 recover after treatment with immunosupression and 1/3 develop renal failure.

Now on to another glomerulonephritis...

MRCP revision battle 47.2: Diffuse proliferative glomerulonephritis

2010-11-12T06:09:00.003Z

Diffuse proliferative glomerulonephritis classically presents after a streptococcal infection or impetigo. It tends to affect children and young adults.

Diffuse proliferative glomerulonephritis tends to cause nephritic syndrome or acute renal failure.

Immunofluorescence shows C3 and IgG.
Serology shows decreased C3 and raised ASOT

Treatment is supportive and >95% recover.

Now lets consider nephritis...

MRCP revision battle 47.3: Acute Interstitial Nephritis

2010-11-12T06:08:00.003Z

Interstitial nephritis is inflammation of the renal interstitium.

Acute interstitial nephritis

This is an immune reaction to drugs or infection.
It accounts for 2% of all acute renal failure but 25% of drug-induced renal failure.

Features include:

acute renal failure
hypertension
systemic symptoms

rash
fever
eosinophilia, raised IgE

>1% urinary eosinophils suggests diagnosis

Renal biopsy would show infiltration of the renal interstitium with:

T lymphocytes
macrophages
plasma cells

Causes include:

infections: hanta virus, leptospirosis, mycobacterium, staph, strep
drugs: methicillin, NSAIDs, rifampacin, allopurinol, penicillin, cephalosporins, furosemide, thiazides, amphotericin, aspirin
sarcoid

Lets move on to consider a hat-trick of causes of chronic interstitial nephritis

MRCP revision battle 47.4: Chronic interstitial nephritis

2010-11-12T06:07:00.004Z

Chronic interstitial nephritis/tubulointerstitial nephritis can be caused by many conditions and results in fibrosis and tubular loss which manifests clinically as chronic renal failure

Analgesic nephropathy

Analgesic nephropathy is associated with long-term use of NSAIDs, and to a lesser degree paracetamol.

It may present as:

sterile pyuria
chronic renal failure
renal pain (due to papillary necrosis)

An IVU will show 'cup and spill' calyces
Renal biopsy may show interstitial nephritis

Treatment is to stop the analgesics and managed any renal failure.

There is an increased risk of urothelial tumours.

Reflux Nephropathy

Reflux nephropathy is defined as small and irregularly scarred kidneys associated with vesico-ureteric reflux.

Almost always only occurs in first 5 yrs of life.

Associated with an increased risk of renal stones.

Balkan Nephropathy

Balkan nephropathy is a chronic interstitial renal disease found in a distribution along the River Danube.

It is associated with coppery yellow pigmentation of palms and soles.
There is raised beta 2 microglobinuria.

Urothelial malignancy is much increased - up to 200x risk.

Now on to Alport's syndrome...

MRCP revision battle 47.5: Alport's syndrome

2010-11-12T06:06:00.002Z

Alport's syndrome is an inherited kidney disease with an incidence of 1 in 5000.

It is inherited in an X-linked dominant fashion 85% of the time; 15% are autosomal recessive.

Alport's is an abnormality in the gene that codes for type IV collagen.

It is associated with:

abnormal GBM - 'basket weave' --> chronic renal failure, 30% nephrotic
sensorineural deafness
occular defects in 40%

lenticonus = bulging lens capsule on slit lamp exam
retinitis pigmentosa

Treatment is treating symptoms.

Onwards...

MRCP revision battle 47.6: Renal papillary necrosis

2010-11-12T06:05:00.004Z

Renal papillary necrosis is a form of nephropathy involving the renal papilla (= location where medullary pyramids empty urine into minor calyx)

It can cause pain and a sterile pyuria.

An IVU may show 'cup and spill' calyces.

Causes of renal papillary necrosis may be recalled as 'POSTCARDS'

pyelonephritis
obstruction of renal tract
shock
TB
cirrhosis of liver
analgesic nephropathy
renal transplant rejection
diabetes
sickle cell

On to the final battle of the day, mesangiocapillary glomerulonephritis...

MRCP revision battle 47.7: Mesangiocapillary glomerulonephritis

2010-11-12T06:04:00.001Z

Mesangiocapillary glomerulonephritis, also known as membranoproliferative glomerulonephritis is a rare form of glomerulonephritis.

There are 3 subtypes:

Type 1:

subendothelial immune deposits
caused by cryoglobulinaemia, hepatitis C
also associated with:

hep B
bacterial endocarditis
SLE
malaria
sickle cell disease

Type 2:

intramembranous electron-dense material --> 'double tramline'
associated with partial lipodystrophy
C3b nephritic factor present in 70%
low C3

Type 3:

associated with hepatitis B and C

Treatment is with steroids

50% of patients progress to end stage renal failure.

MRCP revision battle 46.1: Classification of bacteria

2010-11-11T06:10:00.001Z

A completely random mixed bag today, bursting full of random nuggets of MRCP knowledge...

MRCP revision battle 46.1: Classification of bacteria
MRCP revision battle 46.2: Tumour supressor genes and Li Fraumeni Syndrome
MRCP revision battle 46.3: Mitochondrial disorders and Leber's Optic Atrophy
MRCP revision battle 46.4: Cytotoxic Agents
MRCP revision battle 46.5: Congenital infections
MRCP revision battle 46.6: Rheumatoid factor
MRCP revision battle 46.7: Lichen Planus

MRCP revision battle 45.1: Classification of bacteria

MRCP questions just love commenting on the colour/shape of bacteria. Hopefully my simple picture below (which was also stuck next to the loo during finals!) might help you. Note that gram positive bacteria have walls so stain purple/blue while gram negative bacteria don't and stain pink.

My way of remembering them is 'SES ('says') ABCD then L....MN then all the rest'

As well as their colour/shape their 'pattern' is useful to know too:

pairs of cocci (= diplococci): neisseria gonorrhoea, neisseria meningitidis
chains of cocci: streptococci, enterococci
clumps of cocci: staphylococci

Now for some genetics...

MRCP revision battle 46.2: Tumour supressor genes and Li Fraumeni Syndrome

2010-11-11T06:09:00.001Z

Tumour supressor genes code for proteins that provide a 'stop' signal to prevent cell division. They therefore act as a barrier to the development of cancer. As they are recessive genes both copies of the gene would have to be mutated to stop functioning.

The most famous tumour supressor gene is p53.

p53 is:

found on chromosome 17
the most commonly mutated gene in breast, colon and lung cancer
a key regulator of apoptosis and prevents entry into the S phase of the cell cycle until the DNA is checked.

Li Fraumeni Syndrome is a rare condition in which there is an autosomal dominant p53 mutation. More rarely it may be caused by a CHEK-2 mutation. Li Fraumeni syndrome is characterised by early onset of cancer, especially breast, sarcoma or soft tissue.

Lets move on to mitochondrial disorders...

MRCP revision battle 46.3: Mitochondrial disorders and Leber's Optic Atrophy

2010-11-11T06:08:00.002Z

mDNA mutates 10x more frequently than normal DNA. However, there is a poor genotype to phenotype correlation so the mutations are often not noticed.

Since sperm do not contain mitochondria mitochondrial disorders are passed exclusively from mother to child.

The most famous mitochondrial disorders are:

Kearns Sayre - see battle 15.5
Leber's hereditary optic neuropathy.
Some forms of sensorineural deafness

Leber's hereditary optic neuropathy

mDNA mutation
progressive loss of central vision due to optic atrophy, begins in young adulthood
if LHON 'plus' also:

multiple-sclerosis type symptoms
Wolff-Parkinson White

Next up - some cytotoxic agents (which sadly sounds more exciting than it is)

MRCP revision battle 46.4: Cytotoxic Agents

2010-11-11T06:07:00.001Z

A quick run-through of the main mechanisms of action and MRCP-relevant side-effects of some common cytotoxic agents.

Vincristine

Inhibits microtubule formation
Used in:

lyphoma
leukaemia
breast and lung cancer

Side effects

peripheral paraesthesia
loss of tendon reflexes
abdominal pain

Cisplatin

Cross-links DNA
Used in:

testicular, cervical, bladder, lung, head and neck cancers

Side effects

nephrotoxic
ototoxic
peripheral neuropathy
hypomagnesaemia
myelosupression

Bleomycin

Degrades DNA
Used in:

metastatic germ cell cancers
non-Hodgkins lymphoma

Side effects

increased pigmentation
pulmonary fibrosis

Doxorubicin

inhibits RNA/DNA synthesis
used in:

leukaemia
lyphoma
breast cancer

Side effects

red colouration of urine
SVT
cardiomyopathy

Methotrexate

inhibits dihydrofolate reductase
used in:

non-Hodkins lymphoma
choriocarcinoma
RA

Side effects

excreted by kidneys so should be avoided in renal disease
should be avoided in significant ascites/pleural effusion as may accumulate then suddenly return to circulation causing myelosupression
myelosupression
mucositis
pneumonitis

Cyclophosphamide

alkylating --> cross links DNA. Inactive until metabolised by liver
used in:

CLL
lymphoma
sarcoma

Side effects

haemorrhagic cystitis

To continue the randomness of the 46th set of battles lets look at congential infections

MRCP revision battle 46.5: Congenital infections

2010-11-11T06:06:00.001Z

A few short notes on 5 infections mummies may have during pregnancy which can adversely affect the fetus...

Maternal rubella

fetus is nearly always affected if rubella occurs during first 7 weeks of gestation
fetus is nearly always OK if rubella occurs after 17 weeks of gestation
Effects of rubella on fetus:

sensorineural deafness
congenital cateracts
congenital heart disease
glaucoma

Maternal toxoplasmosis

fetus will only be affected if it is the first time the mother is exposed, unless she is immunosupressed
classical triad is:

cerebral calcification
hydrocelphalus
chorioretinitis

Maternal chickenpox

if this occurs during the 1st trimester risk of limb deformity
if mum has been in contact with chickenpox and is not sure if she is immune test for antibodies and if no natural immunity give immunoglobulin

Maternal CMV

at least 75% of fetus' exposed to CMV are undamaged
however, there is a risk of:

intracranial calcification
microcephaly
cardiac/GI abnormalities

Maternal Parvovirus B19

generally either fetal death or complete recovery

Now for a spot of rheumatoid factor

MRCP revision battle 46.6: Rheumatoid factor

2010-11-11T06:05:00.001Z

Rheumatoid factor is an autoantibody against the Fc portion of IgG.

Rheumatoid factor is found in 4% of the 'normal' population and 25% of elderly.

Rheumatoid factor is positive in low titres in chronic infections, for example:

10% syphyllis
20% pulmonary TB
50% leprosy

Rheumatoid factor is often positive in high titres in connective tissue disease, for example it is positive in:

70% of patients with RA
virtually 100% of patients with RA with extra-articular manifestations
>75% sjogrens
20-40% SLE
30% scleroderma

It may also be present in other immunological diseases, for example autoimmune liver disease or sarcoidosis.

Very high titres of rheumatoid factor may be found in cryoglobulinaemias

Rheumatoid factor is only useful in RA as an assessment of prognosis. It is not useful for diagosis or or measuring level of activity.

Rheumatoid factor is detected by the Rose-Waaler test (sheep red cell agglutination) or the latex agglutination test.

Now to the final battle of the day - lichen planus

MRCP revision battle 46.7: Lichen Planus

2010-11-11T06:04:00.000Z

Lichen planus is an intensely itchy rash characterised by purple papules with flat tops, often with white lines on the surface (=Wickham's striae).

The picture below (taken by Dr Tag-El -Din Anbar) illustrates lichen planus on an arm:

Mucus membranes may also be affected.

Management may be symptomatic, or with steroid creams.

Half of cases have resolved within 6 to 9 months and the majority of the rest will be gone within 18 months.

A lichenoid-like rash can also be caused by some medications, including:

NSAIDS
thiazide diuretics
antimalarials
betablockers
gold injections
mercury fillings

MRCP revision battle 45.1: Dialysis and complications

2010-11-10T06:10:00.007Z

Back to my old nemesis renal medicine for another 7 battles...

MRCP revision battle 45.1: Dialysis and complications
MRCP revision battle 45.2: Anaemia in chronic renal failure
MRCP revision battle 45.3: Diuretics
MRCP revision battle 45.4: Proteinuria
MRCP revision battle 45.5: Renal osteodystrophy
MRCP revision battle 45.6: Radio-contrast nephropathy
MRCP revision battle 45.7: Minimal change disease

MRCP revision battle 45.1: Dialysis and complications

Lets start with a very matter-of-fact battle on dialysis and its complications

Brief overview of types of renal replacement therapy

Haemodialysis

semi-permeable membrane
solute transfer by diffusion
excess fluid removed by creating a negative transmembrane pressure = ultrafiltration

Haemofiltration

highly permeable membrane
solute transfer by convection
ultrafiltrate replaced by an equal volume of substitute fluid
takes longer and is more expensive than haemodialysis but less haemodynamic instability so used for critically ill patients

Peritoneal dialysis

dialysis fluid put into abdominal cavity via tenchkoff catheter
solutes diffuse across peritoneal membrane
ultrafiltration achieved by adding glucose to the dialysis fluid

Complications of dialysis

Disequilibration syndrome

occurs on initial dialysis
manifests as nausea, vomiting, headache and altered consciousness
caused by rapid changes in plasma osmolality

Vascular disease
Heart valve calcification - especially aortic valve
Beta-2 microglobulin amyloidosis
Arthritis
Infections

Now to consider anaemia in renal failure...

MRCP revision battle 45.2: Anaemia in chronic renal failure

2010-11-10T06:09:00.002Z

Anaemia is common in chronic renal failure and is usually due to:

decreased production of erythropoetin
iron deficiency

Treatment should be considered when Hb <11
The target for treatment should be Hb between 10.5 and 12.5

Correct any iron deficiency first; note that oral iron is often not enough and IV iron therapy may be needed.

If there is still anaemia the likely eryropoetin deficiency must be addressed. Options are:

Eryropoetin replacement with either epoetin (=recombinant human erythropoetin) or
darbepoetin (=hyperglycosylated derivative of epoetin with a longer half life)

Side effects of epoetin include:

hypertension (25%)
bone aches
'flu'
rashes, urticaria
pure red cell aplasia

low reticulocyte count
anaemia
antibodies

increased risk of DVT as increased PCV

If no response to epoetin consider if the patient has an infection, inflammatory condition or aluminium toxicity, all of which can impair epoetin's effectiveness.

Note that blood transfusions are generally avoided in renal patients as they would make matching for transplants more difficult

Cross your legs as we move on to a battle of diuretics...

MRCP revision battle 45.3: Diuretics

2010-11-10T06:08:00.002Z

Before I started my revision I thought I was very au-fait with diuretics - after all, I prescribe them daily. However, a quick bond with the British National Formulary revealed some interesting gems. So here's a quick recap of diuretics with a sprinkling of hopefully new information.

1. Loop diuretics

work on the Na-K-2Cl transporter in the ascending loop of Henle
examples include furosemide and bumetanide
bumetanide is 40x more potent than furosemide for the same dose
both work within 30 mins (if given IV) or 1 hr (if given orally) and their action is completed within 6 hours
possible side effects include:

hypokalaemia/natraemia
retention if enlarged prostate
tinnitus
pancreatitis

2. Thiazide diuretics

work on the Na-Cl co-transporter in the DCT
examples include bendroflumethiazide, indapamide and metolazone
they work within 1 to 2 hours and have a duration of action of 12 to 24 hours
possible side effects include:

hypokalaemia/naturaemia
hyperglycaemia
pancreatitis

3. Aldosterone antagonists

work by antagonising aldosterone
examples include spironolactone and eplerenone
possible side effects include:

hyperkalaemia
impotenence
gynaecomastia

Now for the differentials of proteinuria...

MRCP revision battle 45.4: Proteinuria

2010-11-10T06:07:00.002Z

Normal protein excretion in urine is <150mg/day

Causes of proteinura include:

Renal causes

UTI
glomerulonephritis
myeloma
diabetes
hypertension
amyloid

Extra-renal causes

fever
exercise
psoriasis
pregnancy

Orthostatic proteinuria is proteinuria which disappears when recumbant. The cause of this is unknown but it is felt to be benign.

On to renal osteodystrophy...

MRCP revision battle 45.5: Renal osteodystrophy

2010-11-10T06:06:00.002Z

Renal osteodystrophy refers to the bone pathology which results from the endocrine and electrolyte imbalances caused by chronic renal failure.

Derangements include:

raised phosphate
low calcium
secondary hyperparathyroidism
low vitamin D
acidosis

The result on bones include:

osteomalacia
osteitis fibrosa cystica = hyperparathyroid bone disease
osteoporosis
osteosclerosis 'rugger jersey' spine

Management is:

calcichew - to bind phosphate in the gut
vit D analogues - eg adcal D3/calceos/calcichew = colecalciferol

On to the slightly more stimulating contrast nephropathy...

MRCP revision battle 45.6: Radio-contrast nephropathy

2010-11-10T06:05:00.003Z

Radiocontrast nephropathy complicates up to 10% of procedures involving contrast.

Contrast nephropathy presents as non-oliguric acute renal failure 1 to 5 days post procedure.

Risk of contrast nephropathy can be reduced by:

good hydration/normal saline
oral n.acetyl cysteine

Risk of contrast nephropathy is increased by:

increased amount of contrast
hypovolaemia
myeloma
increasing age
diabetes
raised calcium
chronic renal failure

Remember that metformin must be withheld before and for 48 hrs post IV contrast due to risk of lactic acidosis.

Now to end on a high with a battle with minimal change disease...

MRCP revision battle 45.7: Minimal change glomerulonephritis

2010-11-10T06:04:00.000Z

Minimal change glomerulonephritis almost always presents as nephrotic syndrome

It is responsible for 80% of cases of nephrotic syndrome in children and around a quarter of cases in adults.

Its name 'minimal change' comes from the fact that under a light microscope the kidney looks normal; if an electron microscope is used you can see podocyte fusion.

Minimal change glomerulonephritis causes a highly selective proteinuria with only smaller proteins leaked.

Most causes are idiopathic but 10-20% are associated with:

NSAIDs/gold/rifampacin
hodgkins, thyroma
mononucleosis

It is believed to be T-lymphocyte mediated.

Treatment is with corticosteroids - 80% of cases respond
Cyclophosphamide can be used in non-responders.

The prognosis for minimal change glomerulonephritis is (fairly) good:

1/3 recover completely
1/3 suffer infrequent relapses
1/3 suffer frequent relapses
BUT - <1% proceed to end-stage renal failure

Tomorrow's battles will be a completely random bag, then a final renal push (the end of the hattrick) will occur the day after.

MRCP revision battle 44.1: Antipsychotic medication

2010-11-09T09:09:00.000Z

Today is a psychiatry and overdose fest...

MRCP revision battle 44.1: Antipsychotic medication
MRCP revision battle 44.2: SSRIs
MRCP revision battle 44.3: Serotonin syndrome
MRCP revision battle 44.4: Baby blues, post natal depression and psychosis
MRCP revision battle 44.5: Quinine toxicity/overdose
MRCP revision battle 44.6: Theophylline overdose
MRCP revision battle 44.7: Ethylene glycol poisoning

MRCP revision battle 44.1: Antipsychotic medication

Antipsychotic medications are used in the treatment of schizophrenia, severe anxiety, mania and occasionally for their sedative properties.

Antipsychotic medications have an immediate sedative action but their antipsychotic action may tak up to 3 weeks to become effective.

Atypical antipsychotics

Atypical antipsychotics are the newer drugs. They produce a highly selective blockade of the mesolimbic D2 receptors and serotonin 5HT2A receptors.

Examples include amisulperide, olanzapine, quetiapine, risperidone and clozapine.

Side effects include:

weight gain
nausea, dyspesoa
hyperglucaemia and impaired glucose tolerance
increased risk DVT
increased risk stroke (especially olanzapine and risperidone)
clozapine only:

1% agranulocytosis/neutropenia - therefore weekly blood tests for 1st 6 months then fortnightly afterwards
3% seizures

All antipsychotics have roughly the same effectiveness except clozapine, which is better. However, in light of its worse side effect profile clozapine is only recommended if 2 others have already failed.

Typical antipsychotics

Typical antipsychotics are the older drugs,
Examples include haloperidol, chorpromazine, phenothiazine and sulperide.

Side effects of the typical antipsychotics include:

extrapyramidal side effects
anticholingergic effects
antihistaminergic effects
photosensitivity (especially phenothiazine)
prolonged QT
lower seizure threshold
hyperprolactinaemia.

Now on to SSRIs...

MRCP revision battle 44.2: SSRIs

2010-11-09T09:08:00.000Z

Selective Serotonin Reuptake Inhibitors (SSRIs) do exactly what their name implies: selectively inhibit serotonin reuptake.

Examples include citalopram, escitalopram, fluoxetine, paroxetine and sertraline.

They are widely used for depression, anxiety, post-traumatic stress disorder and panic disorder.
Fluoxetine, paroxetine and sertraline can be used in OCD.

There are many side effects, the commonest of which is GI disturbance.

Other possible side effects to be aware of include:

interaction with platelet function --> increase risk of GI bleed
hyponatraemia
urinary retention

Given the increased risk of bleeding SSRIs should be avoided if on heparin/warfarin - use mirtazepine instead.

The safest SSRI post MI is sertraline.

If combined with MAOIs/moclobemide there is a serious risk of toxicity and serotonin syndrome - do not start MAOIs until 5 weeks after stopping fluoxetine, 2 weeks after stopping sertraline or 1 week after stopping any other SSRI. Conversely you must wait 2 weeks after stopping MAOIs before starting an SSRI.

Triptans and SSRIs must also not be combined due to increased risk of serotonin syndrome.

When SSRIs are stopped they should be reduced over 4 weeks to decrease withdraw. Paroxetine is worst on stopping.

Now on to the next battle to explore serotonin syndrome....

MRCP revision battle 44.3: Serotonin syndrome

2010-11-09T09:07:00.000Z

Serotonin syndrome is characterised by the triad of:

autonomic hyperactivity

hypertension
hyperthermia
tachycardia
mydriasis

neuromuscular abnormality

hyperreflexia
clonus
tremor
hypertonicity

mental state changes

Drugs associated with serotonin syndrome include:

lithium
carbamazepine
triptans
illegal drugs

LSD
cocaine
MDMA

antidepressants

MAOIs
SSRIs
St Johns Wort

Treatment:

remove cause
supportive treatment
cyproheptadine - a 5HT antagonist
chlorpromazine for hyperthermia and agitation

Now for some postnatal depression...

MRCP revision battle 44.4: Baby blues, post natal depression and psychosis

2010-11-09T09:05:00.000Z

Every now and then the MRCP exam will throw a slightly curve-ball question about a woman who has recently given birth being depressed. The key facts to know ready to deal with this are:

'baby blues'

affects 60-70% of mothers
tends to last for 3 to 7 days
characterised by being weepy and irritable

post natal depression

affects 10% of mothers
begins 1 to 3 months after childbirth

postpartum psychosis

affects 0.2% of mothers
riskiest period is 2 to 3 weeks post partum
there is a 20% risk of reccurence with subsequent births

Next - on to an overdose

MRCP revision battle 44.5: Quinine toxicity/overdose

2010-11-09T09:04:00.000Z

Quinine is used in the prevention of falciparum malaria and the treatment of nocturnal leg cramps.

It is very toxic in overdose and can be toxic in some individuals at therapeutic doses.
Quinidine, a stereoisomer of quinine and a class Ia antiarrythmic, can be toxic in a single dose.

Signs/symptoms include:

tinnitus
hearing loss
abdominal pain
blurred vision
hypotension (due to alpha blockade)
long QT

There is a risk of irreversible blindness.

Treatment is recurrent doses of activated charcoal and supportive management

Now for another overdose requiring activated charcoal...

MRCP revision battle 44.6: Theophylline overdose

2010-11-09T09:03:00.000Z

Theophylline/aminophylline has a narrow therapeutic window so overdoses may occur accidentally.

Signs and symptoms of toxicity include:

vomiting
tachycardia
arrythmias
seizures
confusion

Treatment is with repeated doses of activated charcoal. Haemoperfusion and haemodialysis may also be considered.

And to finish off the day, and the hattrick of overdoses - an antifreeze overdose

MRCP revision battle 44.7: Ethylene glycol poisoning

2010-11-09T09:02:00.000Z

Ethylene glycol = antifreeze.

The stages of ethylene glycol poisoning are:

alcohol drunk-like state
metabolic acidosis with high anion gap
acute renal failure

Treatment is fomepizole, an inhibitor of alcohol dehydrogenase.
The old-fashioned treatment failing this is to give lots of ethanol which competes with the ethylene glycol for liver metabolism and prevents glyclic acid being produced.

Haemodialysis is a final option.

MRCP revision battle 43.1: Post renal-transplant complications

2010-11-08T11:31:00.003Z

I'll admit it: I've been avoiding renal revision. It's complicated I never understand it and it leaves me internally angry. However dear friends I'm afraid the time has come to face a fully renal day. On the menu is...

MRCP revision battle 43.1: Post renal-transplant complications
MRCP revision battle 43.2: Polycystic kidney disease and renal cysts
MRCP revision battle 43.3: Renal tubular acidosis
MRCP revision battle 43.4: Haematuria
MRCP revision battle 43.5: Renal calculi
MRCP revision battle 43.6: Focal Segmental Glomerulonephritis
MRCP revision battle 43.7: Acute renal failure

MRCP revision battle 43.1: Post renal-transplant complications

A kidney transplant can give a renal patient their life back as it frees them from endless dialysis sessions. However, with kidney transplants come the risk of rejection/failure, complications and the burden of immunosupression...

Rejection

Acute rejection (less than 6 months post graft) presents as rising creatinine, possibly with fever and graft pain. Biopsy would show immune cell infiltration. Treatment is with high dose IV methylprednislone

Chronic rejection (greater than 6 months post graft) presents as gradually rising creatinine and proteinuria. Biopsy would show fibrosis. There is no effective treatment.

Overall graft survial is around 90% at 1 yr, 70% at 5 yrs and 50% at 10 yrs.

Non-renal complications

Non-Hogkins Lymphoma - 20-50x increased risk due to ciclosporin use
Skin cancer - 5-20x increased risk due to azothioprine
Widespread warts/fungi/herpes zoster due to T cell supression by immunosupressives
Cardiovascular disease - 10-20x increased risk
CMV - give oral ganciclovir
Pneumocystis carini pneumonia - give cotrimoxazole prophylaxis for first 6 months post transplant
if previous TB give isoniazid for first year
gout
Diabetes - develops in 3-5%, ?due to tacrolimus

The common immunosupressants

Ciclosporin

inhibits T cell phosphatase calcineurin
can cause tremor, hypertension, gum hypertrophy

Tacrolimus

decreases T cell activation
?risk of diabeets

Azothioprine

contraindicated with allopurinol as risk of life-threatening bone marrow supression
is an anti-proliferation drug
TPMT test can be used to look for patients prone to toxicity
side effects include bone marrow supression and pancreatitis.

Mycophenolate

anti-proliferative
causes diarrhoea

Sirolimus

blocks IL2 so inhibits T cell division
can provoke hyperlipidaemia

Now lets move on to polycystic kidney disease....

MRCP revision battle 43.2: Polycystic kidney disease and renal cysts

2010-11-08T11:20:00.000Z

The classical cause of renal cysts is polycystic kidney disease.

Polycystic kidney disease affects around 1:1000.

Type 1 is inherited on chromosome 16
Type 2 is inherited on chromosome 4

The US criteria for diagnosing polycystic kidney disease in a patient with a positive family history is:

2 cysts if aged less than 30
2 cysts in both kidneys if aged 30-59
4 cysts in both kidneys if aged greater than 60

Signs/symptoms of polycystic kidney disease include:

renal enlargement
abdominal pain
hypertension
renal failure

Associated features include:

liver cysts
subarachnoid haemorrhage
mitral valve prolapse

Other causes of renal cysts include:

autosomal recessive polycystic kidney disease

chromosome 6
tend to develop end stage renal failure in childhood
fibrosis of liver

Von-Hippel-Lindau (see battle 15.2)

autosomal dominant on chromosome 3
pre-maligant

tuberous sclerosis

auto dom on chromosome 9 or 16

simple cysts

occur in less than 2% of under 50s but up to 20% of over 70s.

Now for some renal tubular acidosis...

MRCP revision battle 43.3: Renal tubular acidosis

2010-11-08T11:19:00.000Z

Renal tubular acidosis is a condition caused by the kidneys failing to correctly acidify the urine.

All types of renal tubular acidosis are associated with:

hyperchloraemic metabolic acidosis
normal anion gap

The three main types of renal tubular acidosis are:

Type 1 renal tubular acidosis: Distal

This is due to the kidney not excreting hydrogen ions in the distal tubule

Causes:

idiopathic
SLE/RA
hypercalcaemia
drugs: lithium, amphotericin

Complications:

ricketts
growth failure
nephrocalcinosis
renal calculi - calcium phosphate stones
low potassium

Diagnosis is by oral acid load with ammonium chloride - the urine should acidify, but in type 1 renal tubular acidosis urine pH will remain >5.5

Treatment is with oral bicarbonate

Type 2 renal tubular acidosis: proximal

This is due to the kidneys failing to reabsorb bicarbonate in the proximal tubule

Causes include:

Wilson's syndrome
Fanconi syndrome
cystinosis
myeloma
interstitial nephritis
drugs - lead, acetazolamide, old tetracycline

Complications include:

osteomalacia
low potassium

Diagnosis is by IV bicarbonate loading , which will result in a high fractional excretion of bicarb.

Treatment is with oral bicarbonate.

Type 4 renal tubular acidosis

This is caused by hypoaldosteronism, resulting in hyperkalaemia.

Treatment is to treat cause and control hyperkalaemia

The astute amongst you may have noted the lack of a type 3 - this is because those clever renal physicians decided that, upon reflection, what they had named type 3 was probably just a combination of types 1 and 2.

If you had to boil the above battle down to a set of key facts, I'd go with:

all cause hyperchloraemic metabolic acidosis with a normal anion gap
types 1 and 2 both cause hypokalaemia and are both treated with oral bicarb
type 3 causes a hyperkalaemia and is treated by treating the cause

Now on to a symptom-based battle...