Myasthenia in Acquired Neuromyotonia

BACKGROUND: Acquired neuromyotonia (NMT) forms part of the spectrum of acquired peripheral nerve hyperexcitability syndrome, and is thought to be caused by antibodies to voltage-gated potassium channels (VGKC). Exertional weakness is unusual unless autoimmune myasthenia gravis (MG) is superimposed. CASE REPORT: A case of acquired NMT accompanied by exertional weakness without coexistence of seropositive MG is reported herein. CONCLUSIONS: Clinical and electrophysiological observations suggest that the cholinergic overactivity in NMT can compromise the safety factor sufficiently to cause a defect in neuromuscular junction transmission.