Clinical characteristics of peripheral nerve hyperexcitability syndrome.

Objective To summarize the clinical characteristics of peripheral nerve hyperexcitability syndrome (PNHS). Methods and Results Ten patients with PNHS were admitted to He'nan Provincial People's Hospital from October 2018 to April 2022, with the clinical phenotypes of Morvan syndrome in 5 cases, Issacs syndrome in 4 cases, and cramp-fasciculation syndrome (CFS) in one case. There were 10 cases with clinical manifestations of muscle twitching, 8 of dysautonomia, 7 of central nervous system symptoms, 7 of limb weakness, 6 of sensory deficits, and 2 of cramping and muscle stiffness. Five cases were positive for autoimmune antibodies. Two cases had MRI abnormalities located in the brainstem, left occipital lobe and right thalamus. Ten cases had EMG abnormalities, including afterdischarges of F-wave in 10 cases, unit potential of spontaneous motion abnormalities in 10 cases, fasciculation potentials in 10 cases, myokymic discharges in 8 cases, and neuromyotonic and myokymic discharges in 3 cases. Three cases underwent only symptomatic therapy, and 7 cases underwent symptomatic therapy and immunomodulatory treatments. Except for one case who lost of follow-up, 5 cases had a good prognosis, 2 cases with poor prognosis, and 2 cases died. Conclusions PNHS is a heterogeneous group of clinical manifestations. Electrophysiological appearance of afterdischarges may be a sensitive indicator for the diagnosis of PNHS. [ABSTRACT FROM AUTHOR]