What Causes Secondary Parkinsonism?

Parkinson’s disease is the most well-known form of parkinsonism, but it’s not the only one. A less commonly discussed but equally important condition is secondary parkinsonism. So, what causes secondary parkinsonism, and how is it different from primary Parkinson’s disease?

What Causes Secondary Parkinsonism?
Secondary parkinsonism refers to a group of conditions that present with similar motor symptoms to Parkinson’s disease—such as tremor, rigidity, slowness of movement, and balance problems—but are triggered by external or identifiable causes rather than by the neurodegenerative process that defines classic Parkinson’s disease.

Here are the most common causes of secondary parkinsonism:

1. Medications
Some drugs, particularly antipsychotics (used for mental health conditions like schizophrenia) and certain anti-nausea medications, can block dopamine receptors in the brain. This mimics the dopamine deficiency seen in Parkinson’s disease and leads to parkinsonian symptoms. In many cases, symptoms improve once the medication is discontinued.
2. Toxins
Exposure to certain environmental toxins and chemicals—such as carbon monoxide, manganese, and some pesticides—has been linked to secondary parkinsonism. These substances can damage the brain's dopamine-producing neurons.
3. Head Trauma
Repeated head injuries, especially those seen in contact sports or traumatic accidents, can lead to brain damage that mimics Parkinson’s symptoms. This condition is sometimes seen in former athletes and is referred to as post-traumatic parkinsonism.
4. Stroke
When strokes occur in parts of the brain that control movement—particularly the basal ganglia—they can cause vascular parkinsonism. This condition may not always respond to Parkinson’s medications and tends to affect the lower body more than the upper body.
5. Brain Infections and Other Neurological Disorders
Infections such as encephalitis (inflammation of the brain) or diseases like Wilson’s disease (a rare genetic disorder affecting copper metabolism) can cause symptoms of parkinsonism.
6. Normal Pressure Hydrocephalus (NPH)
This condition involves an abnormal buildup of cerebrospinal fluid in the brain, causing walking difficulties, dementia, and urinary incontinence. NPH is often misdiagnosed as Parkinson’s but requires different treatment.
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Unlike primary Parkinson’s disease, which is progressive and without a known single cause, secondary parkinsonism has identifiable causes and may be reversible or manageable if treated early and appropriately.
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Support and Resources from PASWFL
Whether you’re living with Parkinson’s disease or secondary parkinsonism, support and education are essential. The Parkinson’s Association of Southwest Florida (PASWFL) has served the community for over 25 years by offering free, effective programs and services designed to improve quality of life for those affected by Parkinson’s and related neurological disorders.

Each week, PASWFL hosts more than 25 free programs and support groups for individuals with Parkinson’s and their care partners. Membership is completely free, and anyone affected by PD or related conditions is encouraged to join and take part.
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For more information, visit www.parkinsonassociationswfl.org.

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