Adolescence peroneal neuropathy associated with rapid marked weight reduction: case report and literature review

We report herein an uncommon presentation of peroneal nerve palsy and possible myelopathy in an adolescent associated with marked uncontrolled weight loss during a relatively short period.

He presented with left drop foot accompanied with sensory impairment at the foot dorsum. Neurophysiologic studies revealed a severe neuropathy of the left peroneal nerve with evidence of a conduction block at the left fibular head suggestive of entrapment neuropathy.

As for the underlying etiology of acute peroneal neuropathy (PN) and possible myelopathy associated with marked weight loss, it has been suggested that rapid loss of the subcutaneous tissue may lead to entrapment of the peroneal nerve at the fibular head leading to foot drop. Body fat percentage was found remarkably low for age at 10% (normal value for age for males: 22.3%) indicative of massive rapid weight reduction markedly depleting fat stores.

When an adolescent presents with acute foot drop, PN associated with rapid uncontrolled weight reduction should be taken into account. Prompt resumption of a balanced diet including vital nutritional ingredients may avoid permanent neurological damage and probably assist in recovery from severe flaccid weakness of the lower extremity.