Neuromyotonia

Abstract

Neuromyotonia is a rare condition of spontaneous and continuous muscle fibre activity of peripheral nerve origin. It represents the more severe phenotype of peripheral nerve hyperexcitability, and when acquired is often associated with antibodies to voltage-gated potassium channels. There are no specific published electromyographic or clinical diagnostic criteria for this disorder. This review highlights the classical clinical, electrophysiological and immunological features of this disorder from what is currently known in the literature to date, and also from the author's own patients' studies. Neuromyotonia is best classified as a moderately severe disorder of peripheral nerve hyperexcitability, with electromyographic features of spontaneous, continuous, irregularly occurring doublet, or multiplet single motor unit (or partial motor unit) discharges, firing at a high intraburst frequency (30-300Hz). Invariably, patients develop persistent muscle contraction, often worse following exercise. About 40% of patients with acquired neuromyotonia will have detectable voltage-gated potassium-channel antibodies. Clinical, electrophysiological and immunological measurements are important in defining the phenotype of neuromyotonia, and other, milder forms of peripheral nerve hyperexcitability.

Periferik Nöropati İle Isaacs Sendromu (Nöromiyotoni) Birlikteliği

“…Hafif formlarında, özellikle bacaklarda kas seyirmeleri dikkat çekmektedir. Ciddi formlarında, sürekli ve aşırı kas kontraksiyonu, el bileği fleksiyonda, parmaklar ektensiyonda, rijit bir kol ve anormal postür oluşturabilir (3,6 sonucu olarak bazal metabolizma hızı artmakta ve aşırı terleme oluşmaktadır (5,6,10,12,13,14). Aynı nedenle baldır kaslarında hipertrofi ortaya çıkmaktadır (12).…”

“…Ciddi formlarında, sürekli ve aşırı kas kontraksiyonu, el bileği fleksiyonda, parmaklar ektensiyonda, rijit bir kol ve anormal postür oluşturabilir (3,6 sonucu olarak bazal metabolizma hızı artmakta ve aşırı terleme oluşmaktadır (5,6,10,12,13,14). Aynı nedenle baldır kaslarında hipertrofi ortaya çıkmaktadır (12). İkinci olguda daha belirgin olmak üzere, her iki olgumuzda da distal kas zayıflığı, kas seyirmeleri, derin tendon reflekslerinin alınamaması veya hipoaktifliği, aşırı terleme, kas ağrı ve krampları, çabuk yorulma ve özellikle el kaslarında belirgin olan kavrama sonrası gevşeme güçlüğü mevcuttu.…”

Syndrome of inappropriate secretion of thyrotropin associated with thymoma-related peripheral nerve hyperexcitability

“…thymoma, myasthenia gravis or rheumatoid arthritis) and non-immune-associated type (e.g. toxic exposure or genetic disorder) [7]. Recent evidence indicates that nerve hyperexcitability in most patients with the former type is associated with the antibody against VGKC [8].…”

A 6-Year-Old With Leg Cramps

“…6 Therefore, imaging of the neck, chest, and abdomen is indicated to look for neoplasm, and inflammatory markers and a paraneoplastic autoantibody panel should be sent.…”