ICD-10 Code for Myotonia
Also indexed as (acquisita) (intermittens)
The ICD-10-CM code for myotonia is M62.89 — Other specified disorders of muscle. This is the code the Alphabetic Index gives for myotonia with no further qualifier, valid for FY2027 (October 1, 2026 – September 30, 2027).
M62.89 is billable but unspecified. If the documentation names a type, site or cause, one of the more specific codes below is likely expected.
Which myotonia code should you use?
The Alphabetic Index lists 6 codes under Myotonia. Which one applies depends on the qualifier documented in the record — the type, site, cause, or associated condition. Find the qualifier below, then verify the code in the Tabular List before using it.
By type
| atrophica | G71.11 | Myotonic muscular dystrophy | |
| chondrodystrophic | G71.13 | Myotonic chondrodystrophy | |
| congenita | G71.12 | Myotonia congenita | |
| drug-induced | G71.14 | Drug induced myotonia | |
| dystrophica | G71.11 | Myotonic muscular dystrophy | |
| fluctuans | G71.19 | Other specified myotonic disorders | |
| levior | G71.12 | Myotonia congenita | |
| permanens | G71.19 | Other specified myotonic disorders | |
| symptomatic | G71.19 | Other specified myotonic disorders |
Index terms and codes are reproduced from the official ICD-10-CM FY2027 release. The Alphabetic Index is a finding aid — a code must always be verified in the Tabular List before it is reported. Data sources