Extreme serum elevations of aspartate aminotransferase.

OBJECTIVE

To determine the frequency, etiology, and associated mortality of extreme elevations of serum AST.

METHODS

The medical records were reviewed of all patients with a serum AST over 3000 U/L during 1 full calendar year at a large, tertiary-care hospital. Serum AST, with an upper limit of normal at 35 U/L, is included in the automated, 18-test chemistry profile run on virtually all clinically ill patients admitted to this hospital.

RESULTS

Of 23,125 admissions, 56 patients had or developed serum AST concentrations greater than 3000 U/L, an occurrence rate of approximately two per 1000 admissions. Either liver or skeletal muscle was the origin of virtually all such AST elevations. Acute hypotension (ischemic or hypoxic hepatitis) accounted for the majority (29/56) of the cases; toxic (seven) or viral (four) hepatitis together accounted for 11/56 cases. Overall mortality, on this admission, was 31/56 (55%).

CONCLUSIONS

Extreme elevations of AST are most often attributable to hypoxic hepatitis. Patients with extreme AST due to hypoxic hepatitis had a 22/29 (75%) mortality compared with 9/27 (33%) for all other causes combined.