Differentials
Ischaemic hepatitis
SIGNS / SYMPTOMS
Ischaemic hepatitis occurs in the setting of sustained hypotension or low-flow state in the liver, which is unusual in paracetamol overdose.
INVESTIGATIONS
Serum paracetamol level will be negative. However, this is not a definitive differentiating test. By the time liver failure develops, it would be unlikely for the paracetamol level to be detectable.
Acute hepatitis A
SIGNS / SYMPTOMS
There may be a history of travel to an endemic region, foodborne outbreak, close contact with an infected person, or men who have sex with men.
INVESTIGATIONS
Hepatitis A IgM positive.
Acute hepatitis B
SIGNS / SYMPTOMS
There may be a history of travel to an endemic region, intravenous drug use, contact with an infected person, or men who have sex with men.
INVESTIGATIONS
Hepatitis B core antigen positive.
Hepatitis B surface antigen will be positive 2 to 10 weeks after exposure.
Other hepatotoxins
SIGNS / SYMPTOMS
An important differentiating factor is an exposure history such as exposure to mushrooms (e.g., Amanita phalloides) or herbal preparations (e.g., cascara, chaparral, comfrey, kava, ma-huang).
Medications and other exposures include anaesthetic agents (e.g., halothane), industrial chemicals (e.g., carbon tetrachloride, trichloroethylene, paraquat), ACE inhibitors, anabolic steroids, aspirin, calcium-channel blockers, ibuprofen, isoniazid, ketoconazole, methotrexate, naproxen, phenytoin, statins, or valproic acid.
INVESTIGATIONS
Serum paracetamol level will be negative. However, this is not a definitive differentiating test. By the time liver failure develops, it would be unlikely for the paracetamol level to be detectable.
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