What is Parkinson disease?
Parkinson disease (or Parkinson) is
the most common form of Parkinsonism, a group of motor system disorders. It is a disease
that slowly gets worse over time. It is caused by the loss of brain cells that make
dopamine. Dopamine is a substance that helps with smooth and coordinated muscle
movement. Parkinson often has these symptoms:
- Tremor or trembling of the arms, jaw, legs, and face
- Stiffness or rigidity of the limbs and trunk
- Slowness of movement (bradykinesia)
- Problems with balance and
What causes Parkinson disease?
The cause of Parkinson is unknown.
Experts believe the symptoms are linked to a chemical imbalance in the brain caused by
brain-cell death. Parkinson is chronic. Symptoms grow worse over time.
This disease may appear in younger
people (even teenagers). But it often affects people in late middle age. It is not
Experts think that in most people
the cause of Parkinson is a mix of genetics and environmental exposure. Studies have
shown that rural living, exposure to well water, and exposure to agricultural pesticides
and herbicides are linked to Parkinson. But these factors do not guarantee you will get
the disease. Nor does their absence prevent it.
In the other forms of Parkinsonism,
either the cause is known or suspected. Or the disorder occurs as a secondary effect of
some other neurological problem. These forms are sometimes called Parkinson syndrome,
atypical Parkinson, or, simply, Parkinsonism. They may be caused by:
- Tumors in the brain
Repeated head trauma, such as from
Long-time use of certain medicines, such as phenothiazines, butyrophenones, or
reserpine for mental health problems, and metoclopramide for stomach upset
Toxins, such as manganese and carbon monoxide
Postencephalitic Parkinsonism, a viral disease that causes
Striatonigral degeneration, a disease that affects the
part of the brain called the substantia nigra
Parkinsonism may also occur with other nervous system problems. These include:
- Shy-Drager syndrome
- Progressive supranuclear palsy
- Wilson disease
- Huntington disease
- Hallervorden-Spatz syndrome
- Alzheimer disease
- Creutzfeldt-Jakon disease
- Olivopontocerebellar atrophy
- Post-traumatic encephalopathy
- Dementia with Lewy bodies
Who is at risk for Parkinson disease?
The biggest risk factor for
Parkinson is advancing age. The average age for Parkinson symptoms to start is 60 years.
Men are affected more than women. But the reason for this is unclear.
Family history is another key risk
factor. A person with an affected parent or sibling has a 4% to 9% higher chance of
getting Parkinson. This higher risk is most likely because of a mix of environmental and
genetic factors. Having 1 or more close relatives with Parkinson raises the risk of the
disease. But unless the person has a known genetic change (mutation) for Parkinson, the
increased risk is 2% to 5%.
What are the symptoms of Parkinson disease?
These are the most common symptoms of Parkinson:
- Rigid muscles. Stiffness when the arm, leg, or neck is moved back and forth.
- Resting tremor. Tremor (involuntary movement from contracting muscles) that is most obvious at rest.
- Bradykinesia. Slowness in starting movement.
Postural instability. Poor posture
and balance that may cause falls or gait problems.
Symptoms of Parkinson vary from
person to person. The symptoms may appear slowly and in no certain order. Early symptoms
may be subtle. They may slowly get worse over many years before reaching a point where
they mess with normal daily activities.
Other symptoms are divided into motor (movement-related) and non-motor symptoms.
- Slow movement (bradykinesia)
- Rigidity and freezing in place
- Stooped posture
- Shuffling gait
- Decreased arm swing when walking
- Trouble getting up from a chair
- Small, cramped handwriting (micrographia)
- Lack of facial expression
- Slowed activities of daily living (for example, eating, dressing, and bathing)
- Trouble turning in bed
- Staying in a certain position for a long period of time
- Diminished sense of smell
- Low voice volume (hypophonia)
- Trouble speaking (dysarthria)
- Painful foot cramps
- Sleep problems
- Emotional changes (fearful and insecure)
- Skin problems
- Increased sweating
- Urinary frequency or urgency
- Male erectile dysfunction
As the disease gets worse, walking
may become affected. It may cause the person to stop in mid-stride or “freeze” in place,
and maybe even fall over. People also may start walking with a series of quick, small
steps as if hurrying forward to keep balance. This is known as festination.
The symptoms of Parkinson may look
like other health problems. Always see your healthcare provider for a diagnosis.
How is Parkinson disease diagnosed?
Diagnosing Parkinson in the early
stages can be hard. At first, signs and symptoms may look like other health problems or
the effects of normal aging. For this reason, your healthcare provider may want to watch
your symptoms for some time until they are consistently there.
Right now, there are no blood or
lab tests to diagnose Parkinson. Diagnosis of Parkinson is based mainly on a health
history and nervous system exam. Brain scans or lab tests may be done to help rule out
other diseases or conditions. But brain scans generally will turn out to be normal with
You may need:
Neurological exam. This includes looking at symptoms and
how serious they are.
Trial test of medicines. When symptoms are severe, a trial
test of medicines (mainly levodopa or L-dopa) may be used. If symptoms are eased from
the use of levodopa, this suggests Parkinson.
CT scan. An imaging test that uses
X-rays and a computer to make images ) of the body, including the bones, muscles,
fat, and organs. CT scans are more detailed than general X-rays.
MRI. A test that uses large magnets,
radio waves, and a computer to make detailed images of organs and structures within