Cerebellar atrophy following acute phenytoin intoxication

A 25-year-old woman was admitted to our hospital with encephalopathy and cl inical signs of cerebellar dysfunction. She had recently received an overdo se of phenytoin. On admission, plasma phenytoin level was high (50 mu g/ml, therapeutic range 10-20 mg/ml). Magnetic resonance imaging showed no signs of cerebellar atrophy. The patient's neurological condition improved rapid ly after withdrawal of phenytoin. Eight months later, the neurological exam ination disclosed minimal cerebellar disorders and magnetic resonance imagi ng showed cerebellar atrophy. Cerebellar atrophy due to acute phenytoin int oxication is very unusual but few cases have been reported. The present cli nical and radiological findings suggest that short-term phenytoin overdose alone may cause cerebellar atrophy.