Parkinson's disease is a chronic, progressive brain disorder caused by loss of dopamine-producing brain cells. An estimated 500,000 men and women in the United States have Parkinson's disease, according to the National Institute of Neurological Disorders and Stroke. Symptoms of early-stage Parkinson's primarily reflect loss of movement control and coordination. With disease advancement, various body organs manifest abnormalities caused by the loss of nerve cells deep within the brain.
Brain
The signs and symptoms of Parkinson's disease arise because of the deterioration of specific brain cells, or neurons. The primary site of neuron loss with Parkinson's disease is an area of the brainstem known as the substantia nigra, reports the University of Wisconsin-Madison Medical School. The neurons of the substantia nigra communicate with movement-controlling neurons in other brain areas through the release of the chemical dopamine. Degeneration and death of the neurons of the substantia nigra cause a deficit in brain dopamine, leading to loss of movement control.
People with Parkinson's disease exhibit characteristic movement abnormalities associated with the destruction of the substantia nigra. Maintaining an upright posture often proves difficult. Loss of balance is also common. Characteristic hesitancy frequently occurs when trying to begin voluntary movement, such as walking or getting up from a chair. Tremors and stiffness also characterize the disease. Medications that increase the dopamine level in the brain can ease movement-related symptoms. Disease progression, however, remains unaltered by the medical treatment of Parkinson's symptoms.
Intestines
A specialized network of nerves known as the autonomic nervous system controls many of the functions of the body organs. Parkinson's disease frequently disrupts the autonomic nervous system, causing a variety of organ malfunctions. Decreased autonomic nervous system stimulation of the digestive tract commonly causes intestinal sluggishness, which may lead to constipation. Constipation is one of the most frequent autonomic nervous system-related symptoms experienced by people with Parkinson's disease, reports Dr. Marian Evatt and colleagues in a 2009 article published in the journal "Movement Disorders." Medications used to treat Parkinson's disease may worsen existing constipation.
Urinary Bladder
People living with Parkinson's disease may experience abnormalities in bladder function, reports Johns Hopkins Department of Neurology and Neurosurgery. Some people have difficulty starting the flow of urine; others have problems preventing unintentional urine leakage. Mobility problems often make it difficult to reach a bathroom quickly. Among people with Parkinson's disease, the combination of urinary urgency and impaired mobility may lead to the development of urinary incontinence, or the accidental loss of urine. Bladder control symptoms often prove most problematic as medication levels in the blood decrease between doses.
References
- National Institute of Neurological Disorders and Stroke: Parkinson's Disease: Hope Through Research
- University of Wisconsin-Madison Medical School Medical Neurosciences: Brainstem, Substantia Nigra
- "Movement Disorders"; Dysautonomia Rating Scales in Parkinson's Disease: Sialorrhea, Dysphagia, and Constipation---Critique and Recommendations by Movement Disorders Task Force on Rating Scales for Parkinson's Disease; Marian L. Evatt, M.D., M.S., et al.; 2009
- Johns Hopkins Medicine, Neurology and Neurosurgery: Parkinson's Disease
- Merck Manual for Healthcare Professionals: Parkinson's Disease, Signs and Symptoms
