Generalized Peripheric Nerve Hyperexcitability with Neuropathy: Case Series with Long-Term Outcome

Peripheric nerve hyperexcitability (PNH) syndromes are a rare, heterogenous group of diseases characterized by continuous muscle overactivity due to spontaneous discharges of the lower motor neurons.

Here we report four patients presented with painful cramps, generalized muscle twitches and lower extremity weakness. All patients had evidence of neuropathy and neuromyotonic discharges on electrodiagnostic studies. Screening for a broad panel of anti-neuronal antibodies proved uncharacterized neuropil antibodies in one patient. Despite extensive serologic and genetic investigations, no definitive etiology was found in our cohort. One out of three patients responded well to immunotherapy. No other diseases including malignancy appeared for 1.5-3 years follow-up duration.

Our case series indicate a putatively high prevalence of neuropathy in PNH and emphasize anti-neuronal antibody positivity and early diagnosis as potential favorable prognostic factors.