Hereditary Neuropathy with Liability to Pressure Palsy: A Recurrent and Bilateral Foot Drop Case Report

Filipa Flor-De-Lima,Manuel Melo-Pires,Ricardo Taipa,Liliana Macedo,Maria Lurdes Rodrigues

doi:10.1155/2013/230541

Abstract

Hereditary neuropathy with liability to pressure palsy is characterized by acute, painless, recurrent mononeuropathies secondary to minor trauma or compression. A 16-year-old boy had the first episode of right foot drop after minor motorcycle accident. Electromyography revealed conduction block and slowing velocity conduction of the right deep peroneal nerve at the fibular head. After motor rehabilitation, he fully recovered. Six months later he had the second episode of foot drop in the opposite site after prolonged squatting position. Electromyography revealed sensorimotor polyneuropathy of left peroneal, sural, posterior tibial, and deep peroneal nerves and also of ulnar, radial, and median nerves of both upper limbs. Histological examination revealed sensory nerve demyelination and focal thickenings of myelin fibers. The diagnosis of hereditary neuropathy with liability to pressure palsy was confirmed by PMP22 deletion of chromosome 17p11.2. He started motor rehabilitation and avoidance of stressing factors with progressive recovery. After one-year followup, he was completely asymptomatic. Recurrent bilateral foot drop history, “sausage-like” swellings of myelin in histological examination, and the results of electromyography led the authors to consider the diagnosis despite negative family history. The authors highlight this rare disease in pediatric population and the importance of high index of clinical suspicion for its diagnosis.

Highlights

Hereditary neuropathy with liability to pressure palsy (HNPP) is an autosomal dominant disorder characterized by acute, painless, recurrent mononeuropathies that are secondary to minor trauma or compression [1]
The disease is associated with deletions in chromosome 17p11.2, where the peripheral myelin protein 22 (PMP22) gene is localized [1]
Foot drop is a common and distressing problem that can lead to falls and injury and it can be caused by nerve injury, muscle or nerve disorders, or brain and spinal cord disorders

Summary

Introduction

Hereditary neuropathy with liability to pressure palsy (HNPP) is an autosomal dominant disorder characterized by acute, painless, recurrent mononeuropathies that are secondary to minor trauma or compression [1]. Typical episodes of palsy begin in the second or the third decades of life. Cases with symptomatic HNPP in the first decade are very rarely reported and frequently underestimated, mainly when there is no family history [1,2,3]. The prevalence is unknown, mainly due to the inexistence of detailed epidemiological studies, and it has been estimated in 2–16/100000 [3]. The disease is associated with deletions in chromosome 17p11.2, where the peripheral myelin protein 22 (PMP22) gene is localized [1]. The authors report a case of a 16-year-old boy with recurrent and bilateral foot drop

Case Report

Findings

Discussion