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Phenytoin neuropathy: Structural changes in the sural nerve
Author(s) -
Ramirez José A.,
Mendell Jerry R.,
Warmolts John R.,
Griggs Robert C.
Publication year - 1986
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410190209
Subject(s) - phenytoin , medicine , sural nerve , remyelination , peripheral neuropathy , anesthesia , electrophysiology , axonal degeneration , polyneuropathy , pathology , central nervous system , endocrinology , epilepsy , myelin , psychiatry , diabetes mellitus
Abstract Phenytoin has been implicated as a causative agent in peripheral neuropathy, although structural changes in nerve have not been characterized. A 47‐year‐old man was seen with clinical and electrophysiological signs of peripheral neuropathy after 30 years of phenytoin administration. Despite a modest dose of phenytoin (300 mg/day) blood levels were 31 to 38 μg/ml. A sural nerve biopsy showed a loss of large myelinated nerve fibers and a nonrandom clustered distribution of segmental demyelination and remyelination. The latter findings were accompanied by axonal shrinkage. Sixteen months after phenytoin was stopped, the patient's clinical and electrophysiological findings reflected improvement. These data indicate that long‐term phenytoin administration can cause a reversible neuropathy characterized by axonal shrinkage and secondary demyelination.