Pregabalin-withdrawal encephalopathy and splenial edema: a link to high-altitude illness?

A postherpetic-neuralgia patient abruptly discontinued pregabalin. Thirty hours later, unexplained nausea, headache, and ataxia developed, progressing to delirium 8 days later. Magnetic resonance imaging indicated T2-hyperintense lesions of her splenium. Similar magnetic resonance imaging abnormalities, interpreted as focal vasogenic edema, develop in some epileptic patients after rapid anticonvulsant withdrawal. Patients with high-altitude cerebral edema have similar splenial-predominant magnetic resonance imaging abnormalities that accompany these same neurological symptoms. This case is the first to associate anticonvulsant-withdrawal splenial abnormalities with neurological symptoms, with gabapentin-type anticonvulsants, and is among the first in nonepileptic patients, suggesting that sudden anticonvulsant withdrawal alone, unaccompanied by seizures, can initiate symptomatic focal brain edema. The similarity of this syndrome to high-altitude cerebral edema suggests a possible common pathophysiology and offers potential therapies.