Primary Care Coding Alert

Question: What’s the difference between Parkinson’s disease and secondary Parkinsonism? The primary care provider I work for sees nursing home residents and I sometimes see these diagnoses.

Florida Subscriber

Answer: Parkinson’s disease is a primary neurodegenerative disorder, meaning it is the causative condition for resulting brain and nervous system degeneration. Parkinson’s disease symptoms typically progress slowly, but consistently, over time. Generally, diagnosis and treatment are focused on managing the symptoms and slowing the disease progression.

Secondary Parkinsonism is a collection of signs and symptoms caused by external factors like certain medications, trauma to the brain, or other medical conditions. The symptoms can appear rather suddenly and vary depending on the cause. Treatment depends on managing the underlying condition.

You can code Parkinson’s disease with ICD-10-CM code G20 (Parkinson’s disease). Use this for all residents suffering from Parkinson’s disease, as well as:

• Hemiparkinsonism
• Idiopathic Parkinsonism or Parkinson’s disease
• Paralysis agitans
• Parkinsonism or Parkinson’s disease not otherwise specified (NOS)
• Primary Parkinsonism or Parkinson’s disease

It’s also important to know when some Parkinson’s disease signs or symptoms merit additional diagnosis coding. According to AAPC’s Codify, you should use another code to report these signs, symptoms, or manifestations if they’re related to the dementia/Parkinson’s disease: anxiety, behavioral disturbance, mood disturbance, or psychotic disturbance.

To code secondary Parkinsonism, report one of the following codes:

• G21.0 (Malignant neuroleptic syndrome)
• G21.1- (Other drug-induced secondary parkin­sonism)
• G21.2 (Secondary parkinsonism due to other external agents)
• G21.3 (Postencephalitic parkinsonism)
• G21.4 (Vascular parkinsonism)
• G21.8 (Other secondary parkinsonism)
• G21.9 (Secondary parkinsonism, unspecified).

Rachel Dorrell, MA, MS, CPC-A, CPPM, Development Editor, AAPC