Acute onset of X-linked adrenoleukodystrophy mimicking encephalitis.

We report the case of a 6-year-old boy with X-linked adrenoleukodystrophy (ALD). In view of the acute onset of vomiting, fever, and coma, encephalitis was initially suspected. However, brain magnetic resonance imaging demonstrated a pattern of demyelination that was consistent with ALD; this diagnosis was confirmed by the finding of elevated plasma very long-chain fatty acids levels. At presentation, the patient was hyponatremic. That this metabolic disturbance and the coma resolved within hours of the initiation of corticosteroid therapy suggests that the presenting symptoms were secondary to adrenal cortical insufficiency. Primary adrenal failure was confirmed by endocrinologic evaluation. Thrombocytopenia, hepatic transaminase abnormalities, anemia and leukopenia developed during the subsequent course of therapy with oleic acid and erucic acid.