Non-icteric fulminant hepatitis and Reye's syndrome: comparison of laboratory data.

Twenty-eight patients with suspected Reye's syndrome (RS) were seen in our Department from 1974 through 1987. Liver biopsy confirmed the diagnoses of RS and non-icteric fulminant hepatitis (NIFH) in 7 and 5 cases, respectively. NIFH was the most common RS mimicker. Total bilirubin, LDH and serum ammonia levels showed no significant differences between RS and NIFH. However, the levels of serum GOT and GPT were significantly higher in the NIFH group. Serum and urinary carnitine levels were measured in both groups, but the results were inconclusive. Amino acid analysis in one RS and two NIFH patients showed no significant differences in the ratio of branched chain to aromatic amino acids. However, one RS patient showed a high level of lysine. Histological findings in the liver of two NIFH patients showed minor mitochondrial swelling and microvesicular fat, but the major finding was hepatic necrosis. Our experience indicates that NIFH and RS cannot be differentiated by routine laboratory tests. Liver biopsy is essential for the accurate diagnosis of RS.