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Saturday 30 June 2012

Erythema gyratum repens



- characteristic concentric erythematous bands forming a wood-grain appearance
- associated with malignancy in up to 80% of patients
- most develop the eruption before the symptoms of malignancy

POEMS syndrome

- rare multisystem disease that occurs in the setting of plasma cell dyscrasia
- P - polyneuropathy (symmetrical and distal)
  O - organomegaly (liver, spleen and lymph nodes)
  E - endocrinopathy
  M - monoclonal gammopathy
  S - skin abnormalities (hyperpigmentation and hypertrichosis)

Saturday 23 June 2012

Warfarin reversal guideline



Warfarin reversal: consensus guidelines, on behalf of the Australasian Society of Thrombosis and Haemostasis. MJA 2004

Tuesday 19 June 2012

Ethylene glycol poisoning

- commonly used as a coolant and preservative and is found in polishes and detergents
- ethylene glycol poisoning often exhibits three distinct clinical phases after ingestion due to toxic metabolites glycolate, glyoxalate and oxalate
- first 12 hours - CNS effect predominate, patient appears intoxicated
- 12-24 hours - cardiopulmonary effect predominate, tachycardia, tachypnea and raised BP are common
- 24-72 hours - renal effects predominate
- hypocalcemia may result from precipitation of calcium oxalate in tissues and may be severe enough to cause tetany and typical ECG changes
- high anion gap metabolic acidosis
- treatment: gastric lavage within 1 hour of ingestion
- inhibit metabolism with intravenous ethanol (competitive inhibitor of alcohol dehydrogenase). Ethanol requires treatment on the ITU because of risk of respiratory depression
- fomepizole is an alternative treatment, being more potent than ethanol but generally more expensive

Sunday 10 June 2012

Sarcoidosis


- multisystem granulomatous disorder of unknown cause
- prevalence highest in Northern Europe
- 20-40% asymptomatic, discovered incidentally after routine CXR
- acute sarcoidosis presents with erythema nodosum and polyarthralgia which resolves spontaneously
- serum ACE elevated in 60% of patients, presumably reflecting macrophage activity
- transbronchial biopsy provide positive histology in 80% of patients
- Kveim reaction, a granulomatous reaction appearing 4 weeks after intradermal injection of sarcoid spleen or lymph node extract is positive in 50-60% of patients
- Mikulicz syndrome : sarcoidosis with parotid gland enlargement
- Heerfordt's syndrome (uveoparotid fever) : Mikulicz syndrome with acute uveitis and facial nerve palsy







Saturday 9 June 2012

Refsum's disease

- autosomal recessive disorder
- caused by defective alpha oxidation of phytanic acid leading to its accumulation in tissues
- onset normally in late teens or 20s
- characterised by sensorimotor peripheral neuropathy, sensorineural deafness, anosmia, cerebellar ataxia, pes cavus, night blindness (retinitis pigmentosa), cardiac conduction abnormalities, epiphyseal dysplasia (shortening of 4th toe)
- elevated serum phytanic acid level
- treatment: dietary restriction of foods containing phytanic acid (chlorophyll)

Thursday 7 June 2012

Dextrocardia



ECG findings of dextrocardia
- right axis deviation
- positive QRS complex in aVR
- lead I : global negativity (inversion of all complexes)
- absent R wave progression in chest leads (dominant S wave throughout)

von Willebrand disease

- most common inherited bleeding disorder
- VWF serves two roles
  i) major adhesion molecule that tethers the platelet to exposed subendothelium
  ii) binding protein for FVIII
- males and females are equally affected but disease manifestation is more obvious in female due to menstruation and associated menorrhagia
- screening test are PT, APTT, factor VIII activity, vWF activity and vWF antigen level determination
- ristocetin is an antibiotic that causes vWF to bind to and activate platelet causing platelet agglutination. Degree of platelet agglutination is proportional to concentration of plasma vWF

 

Trigeminal neuralgia

- a.k.a tic douloureux
- incidence: 4.5 per 100,000 individuals
- characterised by excruciating paroxysms of pain in the lips, gums, cheek or chin (maxillary and mandibular branches, rarely ophthalmic branch)
- pain seldom last more than a few seconds or a minute or two
- may occur spontaneously or with speaking, chewing or smiling
- essential feature: objective signs of sensory loss cannot be demonstrated on examination
- symptoms result from ectopic generation of action potentials in pain sensitive afferent fibres of 5th cranial nerve roots just before it enters the lateral surface of the pons
- treatment: carbamazepine 100mg od increased gradually to maintenance dose of 200mg qid, alternative is oxcarbazepine 300-1200mg bd
- if medical treatment fails, consider microvascular decompression