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612 Potassium-aggravated myotonia

definition

Potassium-aggravated myotonia (PAM) is a muscular channelopathy presenting with a pure myotonia dramatically aggravated by potassium ingestion, with variable cold sensitivity and no episodic weakness. This group includes three forms: myotonia fluctuans, myotonia permanens, and acetazolamide-responsive myotonia (see these terms).