Irreversible Cerebellar Atrophy as a Complication of Short-Term Phenytoin Exposure: Clinical Improvement Following Discontinuation of the Culprit.

Phenytoin (diphenylhydantoin) is a widely used antiepileptic drug for controlling both generalized and partial seizures. Reversible cerebellar symptoms, including cerebellar ataxia, have been recognized as an adverse event of phenytoin use for many years. On the other hand, cerebellar degeneration has been reported with chronic use in an epileptic patient treated with this drug. We are reporting an interesting case of phenytoin induced acute pan-cerebellar syndrome with cerebellar atrophy on neuro-imaging that improved many years after discontinuation of the drug. Discontinuation of phenytoin may give a chance for the patient to recover slowly, months after stopping the drug. It is very important for the attending neurologist to educate the patients and their families on some common clinical manifestations suggestive of drug toxicity and perform a regular follow-up and clinical examination at regular intervals.