Parkinson’s Disease: Tremor vs. Dyskinesia and ICD-10-CM Coding

A recent question to the AHA Coding Clinic asked whether Parkinson’s Disease (PD) with tremor could be coded as Parkinson’s Disease with dyskinesia. The official guidance was clear:

“Codes in subcategory G20.B-, Parkinson’s disease with dyskinesia, should only be assigned when dyskinesia associated with Parkinson’s disease is specifically documented by the provider.”

ICD-10-CM Updates for Parkinson’s Disease (Effective October 1, 2023)

• G20.A1 – Parkinson’s disease without dyskinesia, without mention of fluctuations
• G20.A2 – Parkinson’s disease without dyskinesia, with fluctuations
• G20.B1 – Parkinson’s disease with dyskinesia, without mention of fluctuations
• G20.B2 – Parkinson’s disease with dyskinesia, with fluctuations
• G20.C – Parkinsonism, unspecified

Tremor vs. Dyskinesia in Parkinson’s Disease

Both tremor and dyskinesia are movement disorders associated with PD, but they differ significantly in cause, presentation, and treatment. Here's a breakdown:

Tremor in Parkinson’s Disease

Definition: Involuntary, rhythmic, oscillatory movement of a body part

Typical Type in PD: Resting tremor — appears when the body part is at rest and improves with movement

Characteristics:

• Frequency: 4–6 Hz
• Location: Commonly begins in one hand (e.g., “pill-rolling” tremor between thumb and fingers)
• Asymmetry: Often starts on one side of the body
• Triggers: Worse at rest, improves with movement or posture

Cause: Dopamine depletion in the basal ganglia

Treatment:

• Dopaminergic medications (e.g., Levodopa)
• Deep Brain Stimulation (DBS) in advanced cases

Dyskinesia in Parkinson’s Disease

Definition: Abnormal, involuntary movements that are fluid, dance-like, or jerky

Type in PD: Levodopa-induced dyskinesia (LID) — occurs as a side effect of long-term levodopa therapy

Characteristics:

• Timing: Occurs at peak dopamine levels or during medication transitions
• Appearance: Chorea (random jerky movements), dystonia (sustained contractions), or both
• Location: May involve limbs, trunk, or face
• Triggers: High-dose or long-term levodopa use

Cause: Pulsatile dopamine stimulation causes maladaptive changes in the basal ganglia

Treatment:

• Adjusting levodopa (e.g., smaller, more frequent doses)
• Adding adjunct therapies (amantadine, dopamine agonists)
• Advanced options: DBS or continuous infusion (e.g., Duodopa)

Key Clinical Differences Between Tremor and Dyskinesia

Nature:

• Tremor: Rhythmic and oscillatory
• Dyskinesia: Irregular, flowing, or jerky

Timing:

• Tremor: Worse at rest, better with movement
• Dyskinesia: Tied to medication timing (often peak-dose)

Cause:

• Tremor: Dopamine deficiency
• Dyskinesia: Long-term use of levodopa

Treatment Focus:

• Tremor: Dopamine replacement
• Dyskinesia: Medication adjustment or adjuncts

Clinical Pearls for Documentation and Coding

• Tremor is a core symptom of Parkinson’s and may be present at diagnosis.
• Dyskinesia is typically a treatment-related complication, appearing after years of therapy.
• Proper distinction between tremor and dyskinesia is essential for correct coding and treatment planning.

Coding Clinic Clarification on Parkinson’s Disease Symptoms

“Parkinson’s disease is a progressive neurodegenerative condition presenting with motor symptoms (e.g., tremors of hands, arms, legs, or head) and non-motor symptoms (e.g., depression, anxiety, pain).

Dyskinesia is defined as involuntary movements of the face, arms, legs, or trunk.

Fluctuations refer to alternating ON episodes (positive response to levodopa) and OFF episodes (return of symptoms as medication wears off).”

Works Cited

American Hospital Association. (2023). Parkinson’s disease with tremor vs. dyskinesia. AHA Coding Clinic for ICD-10-CM/PCS, Fourth Quarter 2023.

American Hospital Association. (2023). ICD-10-CM code updates for Parkinson’s disease. AHA Coding Clinic for ICD-10-CM/PCS.