A Report of Hereditary Neuropathy with Liability to Pressure Palsy (HNPP) Presenting with Brachial Plexopathy: The Value of Complete Electrodiagnostic Testing

ABSTRACT. Patients with hereditary neuropathy with liability to pressure palsy (HNPP) typically present with a mononeuropathy (particularly peroneal or ulnar palsy) or a brachial plexopathy. Careful electrodiagnostic testing has an important role in establishing the diagnosis of HNPP, differentiating this condition from other inherited or acquired neuropathies as well as obviating the need for unnecessary surgeries. We present a case of a patient who presented with a painless brachial plexopathy who was found to have multiple sites of segmental demyelination on nerve conduction studies, consistent with HNPP. We review the clinical and electrodiagnostic features of HNPP including the key electrodiagnostic findings to screen for this disorder.