What causes Parkinson's?
Parkinson's disease (PD) is a chronic, progressive condition that affects an area of the brain known as the substantia nigra. This deterioration results in decreased output of a chemical called dopamine, one of several chemicals called neurotransmitters that relay messages between brain cells.
The cause of Parkinson's disease is unknown but, as with so many other conditions, age is a major factor: the risk of the disease rises with age, although it can hit younger people, too.
Researchers know that genetics play a small role in Parkinson's disease. You have a greater risk of getting Parkinson's disease if you have a relative with it, and the more relatives you have with Parkinson's disease, the higher your risk. Exposure to toxins may also increase the risk of Parkinson's disease.
Symptoms of Parkinson's
The main symptoms of Parkinson's include:
- muscle rigidity or stiffness
- slowness of movement
- balance problems
Other symptoms can include:
- constipation and urinary difficulties
- gradual loss of "automatic movements" such as blinking and smiling
- muscle weakness
- sleep disturbances
- speech deterioration
In the latter stages of the disease, a significant proportion of people develop dementia.
There is no specific test for Parkinson's, although it's generally not hard to make the diagnosis from the symptoms alone.
Treatment of Parkinson's disease
There is no cure for Parkinson's disease, but medications can help improve symptoms. Levodopa with carbidopa is one of the main medications used to treat Parkinson's disease. Levodopa is converted into dopamine in the brain (dopamine itself cannot get into the brain because it can't cross the blood-brain barrier, but levodopa can). Carbidopa prevents the conversion of levodopa to dopamine until levodopa reaches the brain. Levodopa helps with slowed movements and rigidity and can help tremor too. However, with prolonged treatment, it does not work as well or for as long and can cause fluctuations in movement control.
Amantadine, selegiline, and anticholinergic medications (e.g., benztropine) are often used in the early stages of Parkinson's disease. Another group of medications called dopamine agonists (e.g., bromocriptine, pramipexole, ropinirole) stimulate dopamine receptors in the brain and are particularly helpful in the later stages of Parkinson's disease. Other medications that reduce the breakdown of dopamine in the brain (e.g., entacapone, tolcapone) can be helpful when used with levodopa. Rasagiline, a medication similar to selegiline, can be used in later stages as well.
In later stages of Parkinson's disease when medications aren't helping, surgical procedures such as lesioning or deep brain stimulation (DBS) may be done. For lesioning, specific areas of the brain are intentionally damaged to reduce symptoms. For deep brain stimulation, electrodes are implanted in the brain and are stimulated by an electrical device. Deep brain stimulation can help improve symptoms and reduce the need for medication.
For anyone with Parkinson's disease, remaining active and getting regular exercise are important. If you're not sure what you can do safely, talk to your doctor or physiotherapist. You may also need assistance from other health care professionals such as speech therapists and occupational therapists.
Written and reviewed by the MediResource Clinical Team