Brain and liver pathology in a patient with carnitine deficiency.

The ultrastructural brain and liver pathology in an infant, who died of acute encephalopathy due to systemic carnitine deficiency (CD), an important condition mimicking Reye's syndrome (RS), was reported. The major finding in the brain was swelling of astrocyte cytoplasm. Expanded mitochondria in nerve cells and myelin sheath splitting in the white matter, which have been reported to be specific to RS, were not observed. Also in contrast to findings in RS, hepatocytes were filled with macrovesicular fat droplets without expanded mitochondria. These findings suggest significant differences in the pathophysiology of acute encephalopathy in CD and RS, although the clinical and laboratory findings during an episode of acute encephalopathy in the former are usually very similar to those in the latter.