Secondary parkinsonism, unspecified

This code describes a form of parkinsonism that arises as a consequence of another underlying medical condition, medication, or toxin, rather than being idiopathic Parkinson's disease. It encompasses cases where the specific cause of the secondary parkinsonism has not been identified or documented.

Assign this code when documentation clearly indicates parkinsonian symptoms (e.g., tremor, rigidity, bradykinesia, postural instability) are secondary to another factor, but the specific etiology remains unknown or unspecified. This code is appropriate when the provider has ruled out idiopathic Parkinson's disease but has not yet pinpointed the exact cause of the secondary parkinsonism.

• Always attempt to identify and code the underlying cause of the secondary parkinsonism first, if known.
• Distinguish carefully from idiopathic Parkinson's disease (G20) and other specified forms of secondary parkinsonism (G21.0-G21.8).
• Review medication lists for drugs known to induce parkinsonism; if identified, code the adverse effect of the drug as the primary cause.