Anesthetic management of a patient with sodium-channel myotonia: a case report

Sodium-channel myotonia (SCM) is a nondystrophic myotonia, characterized by pure myotonia without muscle weakness or paramyotonia. The prevalence of skeletal muscle channelopathies is approximately 1 in 100,000, and the prevalence of SCM is much lower. To our knowledge, this is the first report on anesthetic management of a patient with SCM. A 23-year-old woman with congenital nasal dysplasia and SCM was scheduled to undergo rhinoplasty with autologous costal cartilage. Total intravenous anesthesia without muscle relaxants was administered followed by continuous intercostal nerve block. Although transient elevation of potassium level in the blood was observed during surgery, the patient did not show exacerbation of myotonic or paralytic symptoms in the postoperative period. Total intravenous anesthesia and peripheral nerve block can be administered safely to a patient with SCM. However, careful monitoring of the symptoms and electrolytes is recommended.