ICD-10 Code G21 – Secondary parkinsonism (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G21 – Secondary parkinsonism
What it is
G21 identifies parkinsonian symptoms caused by another condition, medication, or toxin rather than primary Parkinson disease. Use it when documentation supports a secondary cause.
Clinical signs
Typical findings include bradykinesia, rigidity, tremor, and gait or balance problems. Clinical features vary; refer to documentation for the underlying cause and pattern.
When to use this code
Use G21 when the record states secondary parkinsonism, drug-induced parkinsonism, or another specified secondary cause. Code the underlying condition or exposure first when documented and supported by the record. If the cause is unclear, check documentation.
Do not use for
Do not use this code for idiopathic Parkinson disease or nonspecific tremor alone. If the note describes another neurologic disorder without parkinsonism, choose the more specific diagnosis.
Coding tip
Look for the documented cause, because secondary parkinsonism coding often depends on linking the movement disorder to an underlying condition.