Because no definitive tests exist for Parkinson's disease (PD), the condition can be difficult to diagnose, especially in the early stages. Signs and symptoms of Parkinson's disease, including gait changes, trembling, and trouble speaking or writing, may be generally thought of as the effects of aging, particularly in older adults with the disease. Parkinson's disease in younger adults may also be misdiagnosed by doctors due to the misconception that only older adults get the condition.
Medical history and physical examination: A diagnosis of PD is based on the individual's medical history, observations of signs and symptoms, and a neurological examination. As part of the medical history, a doctor will discuss past and present medical conditions, surgeries, and medications. The doctor will also discuss the family history of the individual to determine if heredity may play a role in developing PD.
The neurological examination includes an evaluation of walking, coordination, and simple tests for dexterity. A doctor may also notice subtle signs of parkinsonism, such as reduced facial expressions, a lack of gestures, or a subtle tremor when taking the medical history.
Diagnosis is based on symptoms and ruling out other disorders that produce similar symptoms.
An individual must have two or more of the primary symptoms, including tremor, rigidity, bradykinesia (resting tremor), and impaired balance and coordination. In many cases, this diagnosis is made after observing that symptoms have developed and become established over a period of time.
Imaging techniques: After a thorough medical history, physical, and neurological exam, the doctor may order a computerized tomography (CT) or magnetic resonance imaging (MRI) scan to determine if other criteria for a diagnosis of PD exists, such as ruling out a brain tumor or stroke (a lack of oxygen to the brain causing neurological damage) that produce parkinsonian symptoms.
Blood tests: Blood tests
may include a complete blood count (CBC), a creatine kinase test, and a DNA analysis (to determine if the disorder is genetic). In some cases, a cerebrospinal fluid (CSF) analysis also is performed.
Spinal tap: Cerebrospinal fluid (surrounds the brain and spinal cord) analysis involves performing a spinal tap or lumbar puncture. In this procedure, about two tablespoons of cerebrospinal fluid is drawn into a needle, which is inserted between two lumbar vertebrae. The fluid is then examined under a microscope. This procedure is usually performed in a hospital or clinic under local anesthesia, although general anesthesia can be used. Side effects include pain and tenderness in the area of puncture.
signs and symptoms
Individuals with idiopathic (unknown cause) Parkinson's disease, or PD, may develop several symptoms over time, but they typically develop the primary symptoms- bradykinesia, tremor, rigidity, and parkinsonian gait, or manner of walking. Most individuals with PD do not develop all of the symptoms associated with the disease.
Not every person with Parkinson's disease (PD) develops all signs or symptoms of the disease. Some individuals experience tremor as the primary symptom, while others may not have tremor but do have balance problems. The disease may progress quickly or gradually over years. Many people become profoundly disabled and others function relatively well.
Symptoms may vary from day to day or even moment to moment. There is no clear reason for the fluctuation of symptoms. Variance may be attributable to the disease process or to anti-parkinson medications.
Tremor: In the early stages of the disease, about 70% of individuals experience a slight tremor in the hand or foot on one side of the body, or less commonly in the jaw or face. It appears as a slight beating or pulsing movement in the cheek, face, or jaw. Because the Parkinson's tremor usually appears when an individual's muscles are relaxed, it is called resting tremor. The affected body part trembles when it is not doing work and it usually subsides when a person begins an action. The tremor often spreads to the other side of the body as the disease progresses, but remains most apparent on the original side of occurrence. Hand tremors are often referred to as a "pill rolling" motion, as if the individual is rolling a pill between the thumb and fingers.
Rigidity: Rigidity, also called increased muscle tone, means stiffness or inflexibility of the muscles. Muscles normally stretch when they move and then relax when they are at rest. In rigidity, the muscle tone of an affected limb is always stiff and does not relax, sometimes resulting in a decreased range of motion. An individual with rigidity may not be able to swing the arms when walking because the muscles are too tight. Rigidity can cause pain and cramping.
Bradykinesia: Bradykinesia is the phenomenon of an individual experiencing slow movement. In addition to slow movements, an individual with bradykinesia will probably also have incomplete movement, difficulty initiating movements and sudden stopping of ongoing movement. Individuals who have bradykinesia may walk with short, shuffling steps (called festination). Bradykinesia and rigidity can occur in the facial muscles, reducing an individual's range of facial expressions.
Impaired balance and coordination: Individuals with PD often experience instability when standing or impaired balance and coordination. These symptoms, combined with other symptoms such as bradykinesia, increase the probability of falling. Individuals with balance problems may have difficulty making turns or abrupt movements. They may go through periods of freezing, which is when the individual feels stuck to the ground and finds it difficult to start walking. The slowness and incompleteness of movement can also affect speaking and swallowing.
Secondary symptoms of PD can be, for many, as troublesome as the primary movement symptoms of the disease. Secondary symptoms include speech changes; loss of facial expression, or masking; micrographia or small, cramped handwriting; difficulty swallowing; drooling; pain; dementia or confusion; sleep disturbances; constipation; skin conditions such as boils or eczema; depression and anxiety; sexual dysfunction; urinary problems; a soft, whispery voice, termed hypophonia; fatigue or excessive tiredness; compulsive behavior; and cramping.
risk factors and causes
Age: Age is one of the main risk factors for Parkinson's disease (PD). Although the disease can rarely affect adults in their 20s, it ordinarily starts in middle or late life. The risk of developing PD continues to increase with age.
Heredity: Having one or more close relatives with PD increases the chances that the individual will also develop the disease. The risk of developing PD is still less than five percent if a relative has the condition.
Sex: Men are more likely to develop PD than women, possibly due in part to decreased levels of estrogen in men.
Exposure to pesticides and herbicides: Ongoing exposure to herbicides and pesticides puts an individual at slightly increased risk of developing PD. There is also an increased risk if the individual is involved in farming, lives in a rural area, or drinks well water. Local health departments can test well water for contaminants such as pesticides.
Reduced estrogen levels: Reduced estrogen levels may increase the risk of PD. Menopausal women who receive little or no hormone therapy (such as estrogen and progesterone) and those who have had hysterectomies may be at an increased risk for developing PD. Menopausal women using hormonal therapy appear to have a decreased risk, as do women taking birth control pills. However, taking hormonal therapy as a combination therapy (estrogen plus progestin) can increase the risk of serious side effects such as heart disease and cancer.
Medications: A number of drugs taken for long periods of time or in excessive dosages can cause symptoms of PD. These include medications such as haloperidol (Haldol®) and chlorpromazine (Thorazine®), which are prescribed for certain psychiatric disorders. Other medications used to treat nausea, such as prochlorperazine (Compazine®) and metoclopramide (Reglan®), may also cause symptoms of PD. The anti-seizure drug valproic acid (Depakene® or Depakote®) may cause some of the features of parkinsonism, especially severe tremor. These medications do not cause PD, and the symptoms of PD disappear when the drugs are stopped.
Depression and emotional disturbances: As many as half of the individuals with Parkinson's disease (PD) develop depression. In some cases, depression may occur months or even years before PD is diagnosed. Although physical limitations resulting from PD can be frustrating and stressful, depression in someone with PD isn't usually a reaction to physical disability. Instead, it more likely arises from underlying brain changes associated with the disease itself.
Dementia: In addition, some people with PD eventually develop dementia, a condition that can include memory loss, impaired judgment, and personality changes.
Other complications: Other complications of PD may include difficulty chewing and swallowing. In the later stages of the condition, the muscles used to swallow may be affected, making eating more difficult.
PD may also cause either urinary incontinence (difficulty controlling the urine flow) or urine retention (difficulty to urinate). Certain medications used to treat the disease, especially anticholinergic drugs (such as tolterodine or Detrol®), may also cause difficulty in urinating.
Many individuals with PD develop constipation because the digestive tract works more slowly. Constipation may also be a side effect of medications used to treat the disease. Studies have found that chronic (long-term) constipation may be a risk factor associated with the development of PD, but further research needs to be performed in this area.
Individuals with Parkinson's disease often have trouble falling asleep and may wake up frequently throughout the night.
Some individuals with PD may notice a decrease in libido or sexual desire. This may be caused by a combination of psychological and physical factors, or it may be the result of physical factors alone. Medications may also cause a decrease in libido, including antidepressant medications such as fluoxetine (Prozac©) or amitriptyline (Elavil®).