MRCP revision battle 41.1: Horner's syndrome

Today is another day of completely random battles... with a mnemonic of a addicts hammock and some fevers of unknown cause hopefully each battle should have something of interest in it...


MRCP revision battle 41.1: Horner's syndrome
MRCP revision battle 41.2: Gynaecomastia
MRCP revision battle 41.3: Gingival Hyperplasia
MRCP revision battle 41.4: Leptospirosis
MRCP revision battle 41.5: Opioid and benzo conversions
MRCP revision battle 41.6: Pyrexia of unknown origin
MRCP revision battle 41.7: Fitness to fly



MRCP revision battle 41.1: Horner's syndrome

Horner's syndrome is the triad of:

• miosis
• ptosis
• anhydrosis

 It is caused by an interruption of the sympathetic pupillomotor fibres



Causes may be:

• central - which causes anhydrosis of the face, arm and trunk
• pre-ganglionic = second order - which causes anhydrosis of face
• post-ganglionic = third order - which causes no anhydrosis

A general way to remember the causes is PC Stem:

• pancoast tumour
• cervical rib
• cluster headache
• carotid artery dissection
• stroke
• syringomyelia
• trauma
• thyroidectomy
• encephalitis
• multiple sclerosis

 An alternative way to try and learn them by their location is:

• central: STEMS 
• stroke
• tumour
• encephalitis
• multiple sclerosis
• syringomyelia
• pre-ganglionic: PCT
• pancoast tumour
• cervical rib
• trauma
• thyroidectomy
• post ganglionic: 2Cs
• carotid artery dissection
• cluster headache

Now for some big breasts...

MRCP revision battle 41.2: Gynaecomastia

Gynaecomastia = enlargement of male breast tissue.


Causes can be divided into:


Physiological

• adolescence
• increasing age - due to low testosterone

Drugs (a mnemonic to remember drugs causing gynaecomastia is a addicts hammock)

• antipsychotics
• ACE inhibitors
• digioxin
• diazepam
• isoniazid
• cimetidine
• TCA
• spironolactone
• heroin
• amiodarone
• metronidazole
• marijuana
• omeprazole
• calcium channel blockers
• ketoconazole

Pathological

• klinefelters
• liver cirrhosis
• hyperthyroidism

So from enlarged breasts to enlarged gums...

MRCP revision battle 41.3: Gingival Hyperplasia

Gingival hyperplasia is the overgrowth of the ginival (=gum) tissue.


Photos of gingival hyperplasia have appeared in part 2 written exams so a grasp of the main differentials is worthwhile.


Conditions to consider include:

• poor oral hygiene leading to gingivitis
• AML
• vitamin C deficiency
• pregnancy
• drug-induced casues:
• phenytoin
• ciclosporin
• calcium channel blockers (nifedipine, verapamil)

Now for a change to a spirochaete...

MRCP revision battle 41.4: Leptospirosis

Leptospirosis, also known as Weil's disease, is a disease caused by infection with the spirochaete leptospira interrogans.


It is classically caught from water contaminated with rat's urine, so suspect it as a diagnosis in those in questions who have recently fallen into rivers/out of rowing boats.


After a 2 to 20 day incubation period the patient develops:

• fever
• myalgia
• cough/haemoptysis
• headache

The patient then either makes a good recovery or develops:

• meningitis
• jaundice
• renal failure (50%)

Treatment is with penicillin/amoxicillin/doxycycline.



Lets move on to some conversions...

MRCP revision battle 41.5: Opioid and benzo conversions

Occasionally in real-life/MRCP exam you may need to convert between different drugs in the same family, so this revision battle briefly covers 2 popular families: the opioids and the benzos.



Opioids

First, as an aside: remember opiate refers to a substance derived from opium (from the poppy) while opioids are synthetic/semi-synthetic versions of opiates.

• PO codeine to PO morphine: divide by ten
• PO tramadol to PO morphine: divide by five
• PO morphine to PO oxycodone: divide by two
• PO morphine to S/C morphine: divide by two
• PO morphine to S/C diamorphine: divide by three
• PO morphine to S/C oxycodone: divide by three
• morphine to fentyl: divide by 100

Other misc notes:

• codeine relies on conversion to an active form by the P450 enzyme group.  Not all patients are able to do this (roughly 10% of the population struggle), and other drugs (such as SSRIs) may interfere with the effectiveness of conversion so the same amount of codeine may have a very variable analgesic effect on different people.
• doses of all opioids should be reduced in renal failure except fentanyl
• if asked to prescribe a breakthrough dose this is usually 1/6th of the total 24hr dose.

Benzos (and derivative)


Rough conversions are:

Chlordiazepoxide 15mg = Temazepam 10mg = Diazepam 5mg = Lorazepam 0.5mg


Decrease by 1/8th every 2 weeks.



Now for a little pyrexia of unknown origin...

MRCP revision battle 41.6: Pyrexia of unknown origin

Petersdorf and Beeson defined pyrexia of unknown origin (PUO) as:

• fever >38.3C on several occasions
• longer than 3 weeks
• with no diagnosis reached after 1 week of inpatient investigation

Causes:

• infections:
• abscesses
• TB
• malaria
• any other varient...
•  malignancy
• lymphoma
• hypernephroma
• leukaemia
• atrial myxoma
• connective tissue disease
• RA
• SLE

Daily spikes: abscess; TB; schistosomiasis
Twice daily spikes: leishmaniasis


On to the final battle of the day - fitness to fly...

MRCP revision battle 41.7: Fitness to fly

When a patient can fly pops up intermittently, particularly in part 1 written.  The following periods after various medical events at which it is considered safe to fly are quoted from the excellent patient.co.uk website and references can be found there.

• uncomplicated MI: 7 days
• complicated MI: 4 weeks
• CABG: 10 days
• PCI: 5 days

• pneumothorax: 2 weeks post resolved CXR

• pregnancy: contraindicated after 36 weeks gestation in singleton pregnancy or 32 weeks gestation if multiple pregnancy

• laparoscopy/colonoscopy: 24 hrs
• abdominal surgery: 10 days

• cast: 24 to 48 hrs

• CVA: 10 days

• sickle cell: needs in flight oxygen