Parkinson’s Disease
Parkinson’s disease (PD) is a brain disorder that leads to shaking (tremors) and difficulty with walking, movement, and coordination. PD encompasses a variety of syndromes, all of which are progressive and degenerative.
Researchers believe that in most people, Parkinson's is caused by a combination of environmental and genetic factors.
Doctors use your medical history and physical examination to diagnose Parkinson's disease (PD). No blood test, brain scan or other test can be used to make a definitive diagnosis of PD.
The symptoms of Parkinson’s and their degree of severity are different for every person.
Medications are available to lessen Parkinson's movement and non-movement symptoms, making it possible for people to lead fulfilling and productive lives for many years.
Not necessarily. While a small percentage of Parkinson’s cases are caused by a single genetic mutation, the large majority are not.
Early in the disease process, it may be difficult to know whether symptoms indicate Parkinson's or a disease that looks like it.
Parkinson’s Disease Symptoms
Parkinson’s disease symptoms include tremors, muscle rigidity, slow movement, and impaired balance and coordination known as postural instability. However, each of these symptoms is shared by other movement disorders.
Movement disorders have a big impact. All combined, gait disorders that affect movement and walking are experienced by about 32 percent of adults over 60 (not including those patients who live in hospitals, nursing homes, and other institutions).
Doctors often treat other types of movement disorders with Parkinson’s disease medication, although these don’t always work well.
Message UsWhat Raises Someone's Risk for Parkinson's?
Age.
Since it mostly affects people 60 and older, your risk goes up as the years go by.
Family history.
If your parent, brother, or sister has it, you’re a little more likely to get it.
Job.
Some types of work, like farming or factory jobs, can cause you to have contact with chemicals linked to Parkinson’s.
Serious head injury.
If you hit your head hard enough to lose consciousness or forget things as a result of it, you may be more likely to get Parkinson’s later in life.
Where you live.
People in rural areas seem to get it more often, which may be tied to chemicals used in farming.
Gender.
Men get it more than women. Doctors aren’t sure why.
Parkinson’s Disease
Movement Disorders Similar to Parkinson’s
Conditions causing excess movement or decreased movement that are sometimes associated with Parkinson’s disease-like symptoms include:
- Progressive supranuclear palsy. This brain disorder affects walking and balance often resulting in falls. The condition can also cause problems with vision and eye movement. It does not usually respond to medication.
- Multiple system atrophy. A rare but progressive nervous system disorder, this condition shares some of the same symptoms as Parkinson’s disease. It can cause poor coordination, slurred speech, problems with breathing, difficulty swallowing, and constipation. Parkinson’s medications may provide some relief.
- Viral parkinsonism. Some viral diseases, such as encephalitis lethargica (sleeping sickness), Western equine encephalomyelitis, Eastern equine encephalomyelitis, and Japanese B encephalitis — all infections of the brain — can cause Parkinson’s-like symptoms.
- Essential tremor. An essential tremor produces tremors, or uncontrolled shaking, in the hands and sometimes the head, that progress over time. The tremor is not associated with other Parkinson’s disease symptoms. Certain medications can be helpful in managing an essential tremor, but Parkinson’s disease medication is not effective.
- Drug- and toxin-induced parkinsonism. Taking certain medications, like Thorazine (chlorpromazine), Haldol (haloperidol), Reglan (metoclopramide), reserpine, can bring on Parkinson’s disease symptoms. Exposure to toxins such as manganese dust, carbon disulfide, and carbon monoxide can as well. Symptoms normally subside once you stop taking the medication or stay away from the toxin.
- Post-traumatic parkinsonism. Severe or frequent head injuries can cause post-traumatic parkinsonism. This condition can also be associated with dementia. Boxers, other athletes, and people whose professions put them at increased risk for blows to the head may be susceptible to this condition.
- Arteriosclerotic parkinsonism. Sometimes the brain damage incurred by small strokes can lead to Parkinson’s–like symptoms. When this is the case, Parkinson’s disease medication will not alleviate the symptoms.
- Parkinsonism-dementia complex of Guam. This disease affects the indigenous people of Guam and the Mariana Islands. Unlike people with Parkinson’s disease, who do not usually die of the disease, people with parkinsonism-dementia complex of Guam typically die within five years.
- Cortical basal ganglionic degeneration. This condition occurs when the areas of your brain known as the cerebral cortex and the basal ganglia waste away. As with Parkinson’s disease, rigidity and impaired balance may begin on one side of the body and eventually spread to the other side. However, unlike Parkinson’s, this degenerative condition does not usually respond to treatment with medication.
- Lewy-body disease. Lewy bodies are abnormal proteins that disrupt neurological functioning and deplete dopamine levels in the brain. They can lead to symptoms like those of Parkinson’s and Alzheimer’s disease, as well as to hallucinations, delusions, and sometimes depression. Parkinson’s disease medication can ease some Lewy-body disease symptoms, but these medications tend to make hallucinations and delusions more severe.
- Normal pressure hydrocephalus (NPH). A build up of fluid within the brain may cause difficulties with walking and balance, which might be confused with Parkinson’s disease. Usually, there will also be signs of dementia and loss of bladder control with this disorder, though. Once diagnosed, NPH can be cured with the placement of a shunt to drain excess fluid.
What Movement Disorder Could I Have?
When making a Parkinson’s diagnosis, your doctor will review your medical history and symptoms, perform a careful neurological exam, and, if necessary, carry out further tests to rule out other movement disorders.
Your symptoms may be caused by a movement disorder other than Parkinson’s disease if:
- You display Parkinson’s disease symptoms and features that are characteristic of an additional movement disorder.
- The results of a brain imaging study or laboratory test, such as a blood test, confirm the presence of another movement disorder.
- Your symptoms do not respond to Parkinson’s disease medication.
Because movement disorders are not all treated the same way, it is important to get a proper diagnosis as early as possible so you can formulate the right treatment plan with your doctor.
Risk factors
Several environmental factors may increase the risk of developing Parkinson’s disease.
These include:
- Past traumatic brain injuryTrusted Source: Head injuries from contact sports, for example, may increase the risk of the condition.
- Toxin exposure: Such as pesticides, solvents, metals, and other pollutants.
- Gender: Males are 50% more likely to develop the condition than females, although one 2016 study suggests the risk for females may increase with age.
- Age: The condition often appears from the ages of 60 years.
- Some drugs and medications: Certain medicines can lead to Parkinsonism, where a person has tremors and other symptoms but does not have Parkinson’s disease.
Symptoms usually appear from the age of 60 years. However, 5–10%Trusted Source of people with the disease have early onset Parkinson’s, which starts before the age of 50 years.
Do racial factors affect the risk?
In the past, statistics have suggested that Parkinson’s disease is less likely to affect Black people than other people of other ethnicities in the United States.
However, expertsTrusted Source now say this may be due to a lack of awareness about how the disease can affect Black individuals and a higher chance of misdiagnosis due to inequities in health provision.
Causes
Low dopamine levels
Parkinson’s disease symptoms mainly result from low or falling levels of dopamineTrusted Source, a neurotransmitter. It happens when cells that produce dopamine die in the brain.
Dopamine plays a role in sending messages to the part of the brain that controls movement and coordination. Therefore, low dopamine levels can make it harder for people to control their movement.
As dopamine levels continue to fall, symptoms gradually become more severe.
Low norepinephrine levels
Parkinson’s disease may also involveTrusted Source damage to the nerve endings that produce another neurotransmitter, norepinephrine, which contributes to blood circulation and other automatic body functions.
Low levels of norepinephrine in Parkinson’s disease may increase the risk of both motor and nonmotor symptoms, such as:
- stiffness and rigidity
- postural instability
- tremor
- anxiety
- difficulty focusing
- dementia
- depression
This may explainTrusted Source why people with Parkinson’s disease commonly experience orthostatic hypotension. This refers to when a person’s blood pressure changes when they stand up, leading to lightheadedness and a risk of falling.
Lewy bodies
A person with Parkinson’s disease may have clumps of proteinTrusted Source known as alpha-synuclein, or Lewy bodies, in their brain.
The accumulation of Lewy bodies can cause a loss of nerve cells, leading to changes in movement, thinking, behavior, and mood. It can also lead to dementia.
Lewy body dementia is not the same as Parkinson’s disease, but people may have both as the symptoms are similar.
Genetic factors
Experts have identified changes in several genes that appear to have links with Parkinson’s disease, but they do not consider it a hereditary condition.
Genetic factors appear to cause only 10%Trusted Source of cases, mostly among people with early onset disease.
Autoimmune factors
In a 2017 studyTrusted Source, scientists found a possible genetic link between Parkinson’s disease and autoimmune conditions, such as rheumatoid arthritis.
In 2018, researchers investigating health records in Taiwan found that people with autoimmune rheumatic diseases had a 1.37-higher chance of also having Parkinson’s disease.
