What is Parkinson’s disease?

Parkinson’s disease is a chronic (long-term) neurological condition. It is progressive and symptoms worsen over time. It is named after Dr James Parkinson who first described the condition in 1817.

People with Parkinson’s disease experience a loss of nerve cells in the part of their brains responsible for controlling voluntary movements. This part of the brain is called the substantia nigra (a small cluster of cells deep in the centre of the brain within an area called the basal ganglia). The nerve cells in the substantia nigra usually produce a chemical called dopamine which helps transmit messages from the brain to the rest of the body via the central nervous system (the brain and spinal cord). As these cells are lost, people with Parkinson’s disease experience a loss of dopamine and the messages controlling movement stop being transmitted efficiently.

Parkinson’s disease is more common as people get older but it can affect younger adults. Men tend to be affected in slightly higher numbers than women.

What causes Parkinson’s disease?

We do not know what causes Parkinson’s disease. There is some evidence to suggest that there is a genetic factor which increases the risk of Parkinson’s disease within some families. Also, there might be an increased risk if people have come into contact with a particular toxin (poison) or toxins found in the environment via pesticides and other chemicals used in agriculture. The specific toxin or toxins have not yet been identified but there is ongoing research into this possible cause.

What are the symptoms?

Each person is affected differently by Parkinson’s disease and no two people will experience exactly the same symptoms. The impact of Parkinson’s disease can be unpredictable and it is common for people to have good days and bad days.

The main symptoms of Parkinson’s disease are:

• tremor (involuntary trembling or shaking movements; the most common symptom)
• rigidity (stiffness)
• slowness of movement (bradykinesia)
• balance problems
• problems with posture (particularly a tendency to stoop forwards)

Other possible symptoms include difficulty initiating movement (for example, when getting up from a chair), a shuffling gait when walking, and freezing when trying to move (especially in confined spaces such as doorways). People might experience a loss of facial expression, speech problems (softened voice, slurred speech), swallowing problems, bowel and bladder problems, difficulties at night (discomfort in bed, cramps, disturbed sleep) and tiredness during the day. Skin can become greasy and people might experience excessive sweating. Sexual problems are common. People often experience depression and anxiety. Another common symptom is small handwriting (micrographia).

Other less common symptoms can include pain and memory problems.

Parkinsonism

For some people, the main symptoms of Parkinson’s disease (tremor, rigidity, and slowness of movement) are caused by other conditions and health problems. Doctors tend to refer to this as Parkinsonism rather than Parkinson’s disease. Parkinsonism can also be caused by some medications which affect the release of dopamine in the brain (drug-induced Parkinsonism).

Some of the conditions that can cause Parkinsonism include multiple system atrophy (MSA), progressive supranuclear palsy (PSP), vascular disease, benign essential tremor, encephalitis, Wilson’s disease, and hydrocephalus.

Tests and investigations

When people first notice symptoms developing, they usually visit their GP who can refer them to a neurologist or other specialist. Parkinson’s disease cannot be diagnosed after just one hospital test and doctors will usually carry out a series of tests and investigations. The first stages of a diagnosis of Parkinson’s disease will involve checking your medical history and carrying out a thorough neurological examination. Commonly, this involves a series of questions about your symptoms and a physical assessment of your ability to perform various tasks with your hands, arms, and legs. The doctor will observe you walking, talking and getting up from a chair. They will check your facial expression and might ask for a sample of your handwriting. They might also check your pulling and pushing strength and test your reflexes.

CT scan / MRI scan

A CT scan (Computerised Tomography scan) is a special type of X-ray which takes pictures of the brain from different angles. An MRI scan (Magnetic Resonance Imaging scan) produces detailed pictures of the brain using strong magnetic fields and radio waves. Neither scan can confirm whether you have Parkinson’s disease but they can help doctors rule out other conditions which could potentially be causing your symptoms.

(You might like to read our brain and spine scans fact sheet for further information.)

PET scan / SPECT scan

A PET scan (Positron Emission Tomography scan) or a SPECT scan (Single Photon Emission Computed Tomography scan) can be used to confirm a diagnosis of Parkinson’s disease. You will be injected with a very small amount of radioactive dopamine which is picked up by the scanners and enables doctors to check dopamine activity in the brain. These scans are not widely available in the UK and might not be available in a hospital in your area.

What are the treatments?

Unfortunately, there is currently no cure for Parkinson’s disease.

Symptoms can be mild in the early stages of the condition and people might not need immediate treatment. Your doctor and specialist will monitor your situation.

There are several different types of drug used to treat Parkinson’s disease. Drug treatments are tailored to each individual’s needs and are likely to involve a combination of different drugs. Your medication should be reviewed regularly. It is likely that, over time, changes will be made to the types of drug you take and the doses you take each day.

The main types of drug treatment for Parkinson’s disease are:

• Drugs which replace dopamine (levodopa; the most common drug treatment)
• Drugs which mimic the role of dopamine (dopamine agonists)
• Drugs which inhibit the activity of acetylcholine (a chemical which becomes overactive due to a lack of dopamine and can cause tremor)
• Drugs which prevent the body breaking down dopamine
• Other drugs such as anti-sickness medication

Everybody is affected differently by medication. The possible side effects of Parkinson’s disease drugs include nausea (feeling sick), vomiting (being sick), tiredness and dizziness. Some people might experience confusion, nightmares and hallucinations. For some people, dopamine agonists have been linked to compulsive behaviour such as addictive gambling or hypersexuality (an abnormally high sex drive and interest in sex).

The effectiveness of the main drug treatment levodopa can wear off over time and its long-term use can cause some people to develop involuntary twisting or writhing movements of the arms, legs or face (dyskinesia). To reduce the risk, doctors might delay the use of levodopa for younger people.

Surgery

Surgery to treat Parkinson’s disease is not suitable for everyone and is usually only discussed as a possibility for people who have severe symptoms that have not improved with different drug treatments.