G71.11

HCC Category Mapping

What This Code Means

Myotonic muscular dystrophy is a genetic muscle disease where muscles become weak and stiff, and have difficulty relaxing after contraction. Patients experience progressive muscle weakness and may have other complications affecting the heart, eyes, and endocrine system.

Coding Tips

• •Verify the specific type of myotonic dystrophy (type 1 vs type 2) in the medical record, as G71.11 specifically indicates type 1; type 2 would be coded differently
• •Look for associated manifestations such as cardiac arrhythmias, cataracts, or endocrine disorders that should be coded separately to capture the full clinical picture

Clinical Significance

Myotonic muscular dystrophy (Steinert disease/DM1) is a multisystem disorder with unique features including myotonia (delayed muscle relaxation), progressive weakness, and involvement of cardiac, endocrine, ocular, and central nervous systems. It is the most common adult-onset muscular dystrophy. Accurate coding captures the systemic nature and complexity of care required for these patients.

Documentation Requirements

• ✓Genetic testing confirming CTG trinucleotide repeat expansion in DMPK gene
• ✓Clinical features: myotonia, progressive distal-predominant weakness, facial weakness
• ✓Multisystem assessment: cardiac (conduction defects, cardiomyopathy), endocrine (diabetes, thyroid), ocular (cataracts)
• ✓Severity assessment and disease progression
• ✓Current treatment: symptom management, cardiac monitoring protocol
• ✓Provider's explicit diagnosis of myotonic muscular dystrophy

Commonly Confused Codes