No definitive tests exist for Parkinson's disease, so it can be difficult to diagnose, especially in the early stages. And parkinsonism — the symptoms of Parkinson's disease — can be caused by many other types of problems. Examples include:
- Other neurological disorders. Essential tremor, dementia with Lewy bodies, multiple system atrophy and progressive supranuclear palsy each feature some symptoms common to Parkinson's disease.
- Drugs. Antipsychotic medications — such as chlorpromazine (Thorazine) and haloperidol (Haldol) — block dopamine, as do anti-nausea drugs like prochlorperazine (Compazine) or metoclopramide (Reglan). If you take any of these drugs, you may develop parkinsonism, although it is reversible when the drug is stopped.
- Toxins. Exposure to carbon monoxide, cyanide or certain other toxins can produce symptoms similar to Parkinson's disease.
- Head trauma. Both solitary head injuries and the repetitive variety of head trauma common in boxing have been linked to Parkinsonism, although risks are small.
- Structural problems. Strokes or fluid buildup in the brain (hydrocephalus) may occasionally mimic Parkinson's disease.
A diagnosis of Parkinson's disease is based on your medical history and a neurological examination. As part of your medical history, your doctor will want to know about any medications you take and whether you have a family history of Parkinson's. The neurological examination includes an evaluation of your walking and coordination, as well as some simple hand tasks.
A diagnosis of Parkinson's is most likely if you have:
- At least two of the three cardinal Parkinson's symptoms — tremor, slowing of motion and muscle rigidity
- Onset of symptoms on only one side of the body
- Tremor more pronounced at rest, for example, when your hands are resting in your lap
- Strong response to levodopa, a Parkinson's drug