Comparison of clinical and electrophysiological features of patients with hereditary neuropathy with liability to pressure palsies with or without pain.

BACKGROUND: Hereditary neuropathy with liability to pressure palsies (HNPP) is a rare neuropathy with a heterogeneous clinical profile. Painless recurrent palsies are the usual presentation, but neuropathic pain could be predominant or inaugural. Browsing the medical literature, we only found two articles reffering to this important clinical feature. Whether there are differences between patients with or without pain is unclear. The main objective of this study was to compare the clinical and electrophysiological features of these patients and to evaluate the impact on their disability. METHODS: All patients diagnosed with HNPP at the Limoges University Hospital Centre were included and separated into two groups according to the presence or absence of neuropathic pain. In each case, the clinical, genetic, electrodiagnostic, therapeutic features and the modified Rankin Scale (mRS) were evaluated. RESULTS: Out of 23 patients, 52% presented with neuropathic pain. There was no difference between groups regarding to clinical and electrophysiological features, except for the amplitude of the ulnar sensory nerve (p < 0,003). The amplitudes of sensory nerve action potentials (SNAPs) seemed to be higher in patients with pain, but were below the lower limit of normal. Patients with pain had a higher mRS than patients without pain (p < 0,007). CONCLUSION: This study supports previous published results and highlights a trend for higher sensory amplitudes in HNPP patients with pain. We found a prevalence of neuropathic pain of 52% in patients with HNPP, underlining the need to systematically assess pain in such patients in order to improve their management.