Blood alanine aminotransferase levels >1,000 IU/l - causes and outcomes.

Standard medical education dictates that the vast majority of cases of an alanine aminotransferase (ALT) level >1,000 IU/l will be due to acute ischaemia, acute drug-induced liver injury (DILI) (usually paracetamol) or acute viral hepatitis. There are very few references in the literature to other potential causes of an ALT >1,000 IU/l nor to the prognosis ascribed to each aetiology. In this study, we have confirmed that the main causes of a dramatic ALT rise are ischaemic liver injury, DILI and viral hepatitis. Common bile duct stones and hepatitis E are two causes for which there needs to be a high index of suspicion as the necessary tests may not be in the clinician's first-line investigation panel. Failing to find a cause and determining that the cause was ischaemic both have poor prognostic implications. © Royal College of Physicians 2015. All rights reserved.