G71.1
Myotonic disorders
Coding guidance (WHO 2019)
Dystrophia myotonica [Steinert] Myotonia: chondrodystrophic drug-induced symptomatic Myotonia congenita: NOS dominant [Thomsen] recessive [Becker] Neuromyotonia [Isaacs] Paramyotonia congenita Pseudomyotonia Use additional external cause code (Chapter XX), if desired, to identify drug, if drug-induced.