Understand Parkinson’s

An overview of Parkinson’s disease – from symptoms and causes to diagnosis, treatment and prognosis.

What is Parkinson’s disease?

Parkinson’s disease is a disorder of the nervous system. The most prominent symptoms are slowness and stiffness of movement, and often, but not always, tremors. The symptoms usually begin in one arm or leg. In reality, Parkinson’s is probably several different diseases, but at present it is difficult to distinguish between them. For example, some people have tremor as the dominant symptom, while others have never had, and will never develop, tremor.

The symptoms are both motor symptoms, which affect movement, and non-motor symptoms, which are not related to movement at all. No one with Parkinson’s disease has every symptom, but everyone has several symptoms.

Motor symptoms include, for example, clumsiness, slowness and difficulty with fine motor tasks such as buttoning clothes. People who have tremors almost always have tremors at rest, which disappear when they move the affected body part, often the hand or fingers. Some people also have difficulty initiating certain movements, such as walking.

Non-motor symptoms are often more diffuse and harder to notice, such as reduced sense of smell, constipation, vivid dreams with talking and/or movements, and sensitivity to stress.

Some people experience pain, while others notice that their speech becomes quieter. Sleep may also be affected, partly due to the motor symptoms.

The cause is largely unknown. It is probably a combination of genetics and environmental factors.

There are certain genes that can be linked to Parkinson’s disease, but in Sweden these variants are very uncommon. There are also certain environmental factors that are considered risk factors, such as various pesticides. On the other hand, there are also so-called protective factors, meaning factors that appear to protect against Parkinson’s, such as coffee, smoking and tomatoes.

The disease process probably begins many years, perhaps decades, before the motor symptoms become noticeable. What happens in the brain is that certain nerve cells die. The cells that use dopamine as a signalling substance become fewer, and when the majority of these cells have disappeared, the motor symptoms appear.

The diagnosis is made solely through a medical examination.

There is no blood test or imaging examination that can detect Parkinson’s disease. The doctor examines different movements and feels the arms and legs, where a stiffness in the muscles, known as rigidity, may be detected.

Brain imaging is sometimes performed using MRI to rule out other causes of the symptoms, or PET imaging to confirm that the dopamine system is affected. These techniques can sometimes help distinguish between different types of Parkinson-like diseases, known as atypical parkinsonism.

Sometimes a cerebrospinal fluid test, known as a lumbar puncture, is also performed, which may sometimes strengthen the suspicion of atypical parkinsonism.

The diagnosis is quite difficult to make, and it is common for it to take 1–2 years after the first symptoms appear.

The basis of treatment is to replace the dopamine that is missing. This can be done with different medications. The most common is levodopa, which forms new dopamine when it reaches the brain. Many people also use dopamine mimics, known as dopamine agonists, which resemble dopamine. The third most common type of medication is MAO-B inhibitors, which reduce the breakdown of dopamine in the brain. These medications can be combined in many different ways. They continue to help throughout life, even as the disease progresses.

Some people with Parkinson’s eventually experience fluctuations in mobility and may then need treatment with a medication pump or deep brain stimulation, DBS.

All treatments currently available are symptomatic treatments. They relieve symptoms so effectively that life expectancy has normalised compared with the time before Parkinson’s medications were available.

There are currently no disease-modifying treatments or cures, but a great deal of research is being carried out in this area.

The prognosis is very difficult to predict in an individual case, at least in the early stages of the disease. After a few years, it usually becomes clearer how the disease is developing. Some people become noticeably worse, while others remain essentially stable for many years.

Parkinson’s is a so-called neurodegenerative disease, which means that it worsens over time. The progression is usually slow, and effective treatments can relieve symptoms so well that the worsening may not be noticeable.

Usually, more symptoms appear over time, which may require adjustments to treatment. Thanks to medication, the disease usually does not affect life expectancy.