About Parkinson's Disease

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What is Parkinson's disease?

Who develops Parkinson's disease?

What causes Parkinson's disease?

What are the symptoms of Parkinson's disease?

How is Parkinson's disease diagnosed?


What is Parkinson's disease?

Parkinson's disease (PD) is a progressive disorder of the nervous system. PD belongs to a group of conditions called movement disorders. The main symptoms of PD are:

  • tremor, or trembling in hands, arms, legs, jaw, or head
  • rigidity, or stiffness of the limbs and trunk
  • bradykinesia, or slowness of movement
  • postural instability, or impaired balance.

Other symptoms may include loss of facial expression, reduction in speech volume and clarity, difficulty swallowing, change in size of handwriting, dry skin, constipation, urinary difficulties, and depression.

Parkinson's disease is both chronic, meaning it lasts for a long time, and progressive, meaning its symptoms grow worse over time.

There is currently no cure for Parkinson's disease; however symptoms can be managed with medications.


Who develops Parkinson's disease?

Approximately one million Americans have Parkinson's disease. More than 50,000 Americans are diagnosed with PD each year. The average age of onset is 60 years, and the risk of developing PD goes up with age.

About 5 to 10 percent of people with Parkinson's have "early-onset" disease, which begins before the age of 50.

It's hard to know exactly how many people have PD because there are no tests to diagnose the disease. Many people in the early stages of the disease think their symptoms are due to normal aging and do not seek help from a doctor. Also, it is sometimes difficult to make a diagnosis because other conditions may produce the same symptoms as PD.


What causes Parkinson's disease?

PD occurs when nerve cells (neurons) in a small part of the brain that controls movement become damaged or die. Normally, these neurons produce an important brain chemical (neurotransmitter) called dopamine. When these cells die or become impaired, they produce less dopamine. The shortage of dopamine causes the movement problems (motor symptoms) that affect people with PD.

People with PD also have loss of the nerve endings that produce the neurotransmitter norepinephrine. Norepinephrine is important for the control of functions of the body, such as heart rate and blood pressure. The loss of norepinephrine may explain some of the non-movement symptoms of PD, such as fatigue, irregular blood pressure, constipation and postural hypotension. Postural hypotension is a sudden drop in blood pressure when a person stands up from a sitting or lying-down position. Postural hypotension may cause dizziness, lightheadedness, loss of balance or fainting.

We do not know what causes PD to develop in most people. Some cases of Parkinson's disease appear to be hereditary. A few cases can be traced to specific genetic mutations. However, most cases of PD are sporadic, meaning the disease occurs randomly and does not seem to run in families. Many researchers now believe that Parkinson's disease results from a combination of genetic and environmental factors.


What are the symptoms of Parkinson's disease?

Parkinson/s disease (PD) causes a wide range of symptoms and complications. The four primary motor (movement) symptoms of PD are resting tremor, bradykinesia, rigidity and postural instability. In addition, there are other secondary motor and non-motor symptoms. Early signs may be subtle, occur gradually and can go unnoticed.

Many symptoms can be treated with medication or physical therapy. No one can predict which symptoms will affect an individual person, and the intensity of the symptoms varies from person to person.

Friends or family members may be the first to notice changes in someone with early PD. They may see that the person's face lacks expression and animation (known as "masked face") or that the person does not move an arm or leg normally. They also may notice that the person seems stiff, unsteady or unusually slow.

Many people note that prior to experiencing motor problems of stiffness and tremor, they had symptoms of a sleep disorder, constipation, decreased ability to smell and restless legs.

Primary Motor (Movement) Symptoms of PD

The diagnosis of PD depends on the presence of one or more of the four most common motor symptoms of the disease. Symptoms typically begin on one side of the body and usually remain worse on that side even after symptoms begin to affect both sides.

  • Tremor – Shaking or trembling in the hands, arms, legs, jaw or head. Tremor often begins in a hand. It is most obvious at rest or when under stress and usually disappears during sleep or improves with a deliberate movement. The shaking or tremor may make it difficult to hold utensils steady or read a newspaper. Tremor is usually the symptom that causes people to seek medical help.
  • Rigidity – Muscle stiffness that results in a resistance to movement. Rigidity affects most people with PD. All of our muscles have an opposing muscle. When we try to move a muscle, it becomes active, and the opposing muscle relaxes. In rigidity, the muscle tone of an affected limb is always stiff and does not relax. When muscles remain constantly tensed and contracted, this can cause pain and cramping. Rigidity becomes obvious when another person tries to move the arm of a person with PD, which will move only in ratchet-like or short, jerky movements. This is known as "cogwheel" rigidity.
  • Bradykinesia – Slowing down and loss of the ability to start and continue movement. A person with bradykinesia will probably also have incomplete movement and sudden stopping of ongoing movement. Trouble initiating or continuing movement is known as freezing. Bradykinesia makes simple tasks – such as walking, washing or dressing – difficult because you cannot rapidly perform routine movements. Activities once performed quickly and easily may take several hours.
  • Postural instability – Impaired balance and coordination. Postural instability causes people to fall easily and can result in a stooped posture with a bowed head and droopy shoulders.

Secondary Motor (Movement) Symptoms of PD

The secondary motor symptoms include those listed below; however, not all people with PD will experience all of these symptoms.

  • Stooped posture, a tendency to lean forward
  • Dystonia – sustained muscle contractions cause twisting and repetitive movements or abnormal postures
  • Impaired fine motor dexterity and motor coordination
  • Akathisia – unpleasant sense of discomfort or restlessness in a body part that typically feels like a need to move or difficulty sitting still
  • Fatigue
  • Speech problems, such as softness of voice or slurred speech, caused by lack of muscle control
  • Loss of facial expression, or "masking"
  • Micrographia (small, cramped handwriting)
  • Difficulty swallowing
  • Sexual dysfunction
  • Drooling

People with PD often develop a parkinsonian gait that includes a tendency to lean forward, walk with short, shuffling steps as if hurrying forward, and reduced swinging of the arms.

Non-motor Symptoms of PD

A number of other symptoms may accompany PD. Some are minor; others are not. Many can be treated with medication or physical therapy. Non-motor symptoms may appear many years before the classic motor symptoms of PD.

  • Depression. This is a common problem and may appear early in the course of the disease, even before other symptoms are noticed. Depression usually can be successfully treated with antidepressant medications.
  • Emotional changes. Some people with PD become fearful and insecure. Perhaps they fear they cannot cope with new situations. They may not want to travel, go to parties, or socialize with friends. Some lose their motivation and become dependent on family members. Others may become irritable or uncharacteristically pessimistic.
  • Difficulty with swallowing and chewing. Muscles used in swallowing may work less efficiently in later stages of the disease. In these cases, food and saliva may collect in the mouth and back of the throat, which can result in choking or drooling. These problems also may make it difficult to get adequate nutrition. Speech therapists, occupational therapists, and dieticians can often help with these problems.
  • Speech changes. The majority of people with PD have problems with speech. They may speak too softly or in a monotone, hesitate before speaking, slur or repeat their words, or speak too fast. A speech therapist may be able to help reduce some of these problems.
  • Urinary problems or constipation. In some people, bladder and bowel problems can occur due to the improper functioning of the autonomic nervous system, which is responsible for regulating smooth muscle activity. Some people may become incontinent, while others have trouble urinating. In others, constipation may occur because the intestinal tract operates more slowly. Constipation can also be caused by inactivity, a poor diet, or drinking too little fluid. The medications used to treat PD also can contribute to constipation. It can be a persistent problem and, in rare cases, can be serious enough to require hospitalization.
  • Skin problems. In PD, it is common for the skin on the face to become very oily, particularly on the forehead and at the sides of the nose. The scalp may become oily too, resulting in dandruff. In other cases, the skin can become very dry. These problems are the result of an improperly functioning autonomic nervous system. Standard treatments for skin problems can help. Excessive sweating, another common symptom, can usually be controlled with medications used for PD.
  • Sleep problems. Sleep problems common in PD, include difficulty staying asleep at night, restless sleep, nightmares and emotional dreams, and drowsiness or sudden sleep onset during the day. People with PD should never take over-the-counter sleep aids without consulting their physician.
  • Dementia or other cognitive problems. Some, but not all, people with PD may develop memory problems and slow thinking. In some of these cases, cognitive problems become more severe, leading to a condition called Parkinson's dementia late in the course of the disease. This dementia may affect memory, social judgment, language, reasoning, or other mental skills. There is currently no way to halt PD dementia, but medications may slightly reduce the symptoms.
  • Orthostatic hypotension. Orthostatic hypotension is a sudden drop in blood pressure when a person stands up from a lying-down position. This may cause dizziness, lightheadedness, and, in extreme cases, loss of balance or fainting. The medications used to treat PD also may contribute to this symptom.
  • Muscle cramps and dystonia. The rigidity and lack of normal movement associated with PD often causes muscle cramps, especially in the legs and toes. Massage, stretching, and applying heat may help with these cramps. PD also can be associated with dystonia — sustained muscle contractions that cause forced or twisted positions. Dystonia in PD is often caused by fluctuations in the body's level of dopamine. It can usually be relieved or reduced by adjusting the medication regimen.
  • Pain. Many people with PD develop aching muscles and joints because of the rigidity and abnormal postures often associated with the disease. Treatment with levodopa and other dopaminergic drugs often alleviates these pains to some extent. Certain exercises also may help. People with PD also may develop pain due to compression of nerve roots or dystonia-related muscle spasms. In rare cases, people with PD may develop unexplained burning, stabbing sensations. This type of pain, called "central pain," originates in the brain. Dopaminergic drugs, opiates, antidepressants, and other types of drugs may all be used to treat this type of pain.
  • Fatigue and loss of energy. The unusual demands of living with PD often lead to problems with fatigue, especially late in the day. Fatigue may be associated with depression or sleep disorders, but it also may result from muscle stress or from overdoing activity when the person feels well. Fatigue also may result from akinesia – trouble initiating or carrying out movement. Exercise, good sleep habits, staying mentally active, and not forcing too many activities in a short time may help to alleviate fatigue.
  • Sexual dysfunction. PD often causes erectile dysfunction because of its effects on nerve signals from the brain or because of poor blood circulation. PD-related depression or use of antidepressant medication also may cause decreased sex drive and other problems. These problems are often treatable.
  • Mental disturbances. Certain mental disturbances – such as hallucinations, delusions, and paranoia – are possible complications of PD and/or its treatment.

How is Parkinson's disease diagnosed?

There are no blood or laboratory tests that have been proven to help in diagnosing PD. The diagnosis is based on a person’s medical history and a neurological examination, but the disease can be difficult to diagnose accurately.

A number of disorders can cause symptoms similar to those of PD. Doctors may sometimes request brain scans or laboratory tests in order to rule out other diseases.

People with Parkinson's may sometimes be told by their doctors that they have other disorders, and people with diseases similar to Parkinson's may be incorrectly diagnosed as having Parkinson's.