Severe transitory encephalopathy with reversible lesions of the claustrum.

Reversible bilateral lesions of the claustrum and external capsule in a 12-year-old girl suffering from a severe, transitory encephalopathy are reported. After a prodromal stage of feeling uncomfortable a sudden onset of status epilepticus occurred, followed by recurrent complex partial and myoclonic seizures for 3 weeks, with psychotic symptoms and temporary loss of vision, speech and hearing. After treatment with phenytoin the patient became free of seizures and recovered completely without neurological deficit. The initial cranial CT was normal; however, cranial MRI 7 days later showed bilateral selective lesions of the claustrum and external capsule, which disappeared completely 5 weeks later. The aetiology of these lesions remains obscure; repeated cerebrospinal fluid and blood tests were negative for herpes simplex virus and other infectious agents. The clinical and radiological improvement were concomitant. This may indicate a functional disturbance of the claustrum grey matter, rather than lesions of the white matter of the external and extreme capsules.