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v1.0.0
ICD-10 Guide
ICD-10 CodesG21.9

G21.9

Billable

Secondary parkinsonism, unspecified

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 G21.9 is a billable code used to indicate a diagnosis of secondary parkinsonism, unspecified.

Key Diagnostic Point:

Secondary parkinsonism refers to a group of movement disorders that resemble Parkinson's disease but are caused by other underlying conditions or factors. Unlike primary Parkinson's disease, which is idiopathic, secondary parkinsonism can result from various etiologies, including neurodegenerative diseases, vascular issues, infections, metabolic disorders, and exposure to certain medications, particularly dopaminergic agents. Symptoms typically include bradykinesia, rigidity, and tremors, which may vary in severity and presentation based on the underlying cause. Accurate diagnosis is crucial, as treatment strategies differ significantly depending on the etiology. For instance, if secondary parkinsonism is due to medication, adjusting or discontinuing the offending agent may alleviate symptoms. Clinicians must conduct thorough evaluations, including patient history, neurological examinations, and possibly imaging studies, to determine the cause of the parkinsonism. This code is used when the specific cause is not identified or documented, necessitating careful clinical assessment and documentation to ensure appropriate coding and treatment.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variety of potential underlying causes
  • Need for thorough clinical documentation
  • Differentiation from primary parkinsonism
  • Potential for overlapping symptoms with other movement disorders

Audit Risk Factors

  • Insufficient documentation of the underlying cause
  • Inconsistent use of secondary parkinsonism versus primary parkinsonism codes
  • Failure to document medication history related to symptoms
  • Lack of comprehensive neurological evaluation notes

Specialty Focus

Medical Specialties

Neurology

Documentation Requirements

Detailed neurological assessments, medication history, and imaging results.

Common Clinical Scenarios

Patients presenting with tremors, rigidity, and bradykinesia after starting new medications or with a history of stroke.

Billing Considerations

Ensure clear documentation of the timeline of symptom onset in relation to medication changes or other potential causes.

Geriatrics

Documentation Requirements

Comprehensive geriatric assessments, including cognitive evaluations and functional status.

Common Clinical Scenarios

Older adults presenting with movement disorders after polypharmacy or with comorbid conditions.

Billing Considerations

Consideration of age-related factors and polypharmacy effects on movement disorders.

Coding Guidelines

Inclusion Criteria

Use G21.9 When
  • According to ICD
  • 10 coding guidelines, G21
  • 9 should be used when the specific cause of secondary parkinsonism is not documented
  • Coders must ensure that all relevant clinical information is captured to support the diagnosis and any associated treatments

Exclusion Criteria

Do NOT use G21.9 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

99214CPT Code

Office or other outpatient visit for the evaluation and management of an established patient

Clinical Scenario

Used when managing a patient with secondary parkinsonism in an outpatient setting.

Documentation Requirements

Document the patient's history, examination findings, and treatment plan.

Specialty Considerations

Neurologists should ensure detailed neurological assessments are included.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more precise coding of secondary parkinsonism, facilitating better tracking of the condition's causes and improving treatment strategies. This specificity aids in research and quality improvement initiatives.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more precise coding of secondary parkinsonism, facilitating better tracking of the condition's causes and improving treatment strategies. This specificity aids in research and quality improvement initiatives.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more precise coding of secondary parkinsonism, facilitating better tracking of the condition's causes and improving treatment strategies. This specificity aids in research and quality improvement initiatives.

Resources

Clinical References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Coding & Billing References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Frequently Asked Questions

What is the difference between G21.9 and G20?

G21.9 is used for secondary parkinsonism when the cause is unspecified, while G20 is for idiopathic Parkinson's disease. Accurate documentation is essential to differentiate between the two.