ICD-10 Code G71.19 – Other specified myotonic disorders (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G71.19 – Other specified myotonic disorders
What it is
Use this code for a myotonic disorder that does not fit a more specific ICD-10-CM category. It covers abnormal muscle relaxation after contraction when the provider documents an “other specified” myotonic condition.
Clinical signs
Typical findings include delayed muscle relaxation, stiffness, and difficulty releasing grip or opening the hand after use. Clinical features vary; refer to documentation.
When to use this code
Assign G71.19 when the provider identifies a myotonic disorder but does not name a specific subtype such as myotonic dystrophy. Use it when the record clearly states an other specified myotonic disorder or gives enough detail to support that wording.
Do not infer this code from nonspecific muscle weakness alone. If the documentation names a different neuromuscular condition, code that condition instead.
Do not use for
Do not use this code for myotonic dystrophy or for muscle stiffness without documented myotonia. Check documentation.
Coding tip
Code the exact provider wording; if the subtype is named, choose the more specific myotonic disorder code.