Sunday, April 12, 2009

Magic Medicine Formula (4)

Dear friends, time for some medical formulas again;) This time the topic is about poisoning. A fairly common problem to encounter in ER, as well as popular in exam questions, and more importantly, you usually can't obtain any history from the patients! So the "clues" are crucial in helping to reach the diagnosis. Below are some tips that I found useful:

Check if the patient's having:
- Respiratory depression? Think of opiates, benzodiazepine toxicity;
- Coma? Think of benzodiazepines, alcohol, opiates, barbiturates;
- Constricted pupils? Think of opiates or organophosphates;
- Dilated pupils? Think of tricyclics, amphetamines;
- Hyperthermia? Think of amphetamines, ecstacy, aspirin, cocaine;
- Tachycardia? Think of salbutamol, antimuscarinics, tricyclics;
- Metabolic acidosis? Think of alcohol, paracetamol, theophylline, methanol;
- Seizures? Think of tricyclics, phenothiazines, theophyllines.

Quick mnemonics to help in diagnosis/ management:

Think that patient with cholinergic toxicity (eg organophosphate) is "wet" and look for DUMBELS:

D - Diarrhea/ diaphoresis
U - Urination
M - Miosis
B - Bradycardia
E - Emesis
L - Lacrimation
S - Salivation

*Presentation of Glyphosate poisoning can mimic organophosphote poisoning but the management is VASTLY different - must be aware of that!

Anticholinergic toxicity, in contrast, is very "dry" and look for:
"Hot as hades, blind as a bat, dry as a bone, red as a beet, mad as a hatter"!

For tricyclic antidepressants, main presentation can be remembered as:
TCA = Three C's = Convulsion, Coma, Cardiotoxic (remember to do a stat ECG!)

For paracetamol overdose, the important King's college criteria for liver transplantation can be remembered as:
pH less than 7.3 OR all three of PCM:
P - PT>100 sec
C - Creatinine > 300 mmol/L
M - Major encephalopathy (Grade III/ IV)

Severe poisoning of certain drugs might require hemodialysis and they are BLAST:
B - Barbiturates
L - Lithium
A - Alcohol
S - Salicylates
T - Theophylline

And just to remember that the first & last alphabet i.e. Barbiturates & theophylline - hemoperfusion can be done too.

And lastly, must know the antidote for specific overdose/ poisoning and certainly not searching for books when you see a poisoning case! ;)

Related posts:
Magic Medicine Formula (1)
Magic Medicine Formula (2)
Magic Medicine Formula (3)

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