Tuesday 16 November 2010

MRCP revision battle 51.1: Rheumatic fever

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

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

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

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

    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

    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

    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.