Hereditary Neuropathy with Liability to Pressure Palsies Masquerading as Slowly Progressive Polyneuropathy

Abstract

Hereditary neuropathy with liability to pressure palsies (HNLPP) is a peripheral nerve disorder in which recurrent pressure palsies are associated with pathological swelling (‘tomacula’) of myelinated nerve internodes. We report a patient with a slowly progressive polyneuropathy associated with substantial slowing of conduction velocities initially suggestive of an acquired or hereditary demyelinating polyneuropathy. However, repeat electrodiagnostic studies demonstrated that conduction slowing and partial conduction block were localized primarily to common sites of nerve compression and entrapment. Sural nerve biopsy revealed multiple tomacula consistent with the diagnosis of HNLPP.

Recurrent polyradiculoneuropathy with the 17p11.2 deletion

“…11 This autosomal dominant disorder, mostly associated with a 17p11.2 deletion including the PMP-22 gene, 2 may have atypical phenotypes. 3,8,9 We report here the first case of molecular genetically confirmed HNPP manifested by a recurrent polyradiculoneuropathy.…”

“…4 The prevalence of the 17p11.2 deletion was 68% in the series of HNPP patients reported by Mariman et al 10 and 90% in our own series, 7 diagnosed in accordance with the electrophysiological criteria described by Gouider et al 4 Sporadic cases with the 17p11.2 deletion have also been reported. 2 Clinically atypical forms of HNPP, namely sensorimotor polyradiculoneuropathies with a chronic progressive course, have recently been described: two reports based on biopsy data 3,8 and one on a genetic study. 1,9 However, only 1 case of acute and recurrent polyneuropathy has previously been reported 6 : focal tomaculous thickenings were observed, but deletion studies could not be carried out at that time.…”

Fulminant case of hereditary neuropathy with liability to pressure palsy

“…These include increased distal motor latencies, mildly decreased nerve conduction velocities, and multiple superimposed mononeuropathies including a focal conduction block at a site of common compression (peroneal neuropathy at the fibular head). 4,11 The fulminant nature of this case underscores its inclusion into the differential diagnosis of subacute polyneuropathies. Indeed, most cases of HNPP are documented as single-nerve palsies appearing sequentially in a more chronic setting.…”

“…There are rare instances of HNPP presenting as a distal polyneuropathy with a duration in the order of years. 4,10,15,16 The more typical pattern is that of single-nerve involvement resolving in days to months and then followed by a motor deficit in the same or in another distribution. Of the 69 acute nerve palsies that Gouider et al 6 studied in 13 families with documented HNPP, only 4 cases were found that occurred simultaneously in different limbs.…”

Mutation analysis of PMP22 in Slovak patients with Charcot-Marie-Tooth disease and hereditary neuropathy with liability to pressure palsies

“…In the majority of cases patients recover from palsies completely, however, repeated attacks can prevent full reversal, and with aging, patients frequently develop a largely symmetric polyneuropathy that mimics CMT1. This can easily lead to the establishment of wrong diagnosis (Felice et al 1994). Additional presenting phenotypes are acute brachial paralysis, confluent mononeuropathy multiplex and the disputed category of oligosymptomatic patients (Pareyson et al 1996;Kumar et al 1999).…”