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Johns Hopkins Symptoms and Remedies

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Parkinson's Disease

What is it?

Parkinson's disease, named after the English physician who first described it in 1817, is caused by the progressive death of nerve cells (neurons) within a layer of gray matter in the brain (substantia nigra). Neurons communicate with one another by releasing highly specialized chemicals called neurotransmitters. The substantia nigra produces the neurotransmitter dopamine, which is essential for fast, smooth, and coordinated movement. In Parkinson's disease, the gradual deterioration of dopamine-producing neurons results in the slowness, shaking, stiffness, and uncoordinated movements characteristic of the disorder. Parkinson's disease, one of the most common degenerative diseases of the nervous system, typically begins between the ages of 55 and 70.Men are affected slightly more often than women. Symptoms usually begin gradually and may not be noticeable at first, or may be mistakenly attributed to aging. Although there is no definitive diagnostic test for Parkinson's disease, worsening of symptoms over time eventually allows a diagnosis to be made with certainty. The cause of Parkinson's disease remains unknown, and there is as yet no cure. However, medications can alleviate many symptoms and greatly improve the quality of life for patients.

What Causes It?

  • The cause of Parkinson's disease is unknown. It is believed to be due to genetic and environmental factors combined with the aging process.
  • Brain injury, tumors, postinfluenza encephalitis, and possibly carbon monoxide poisoning may cause symptoms and signs resembling Parkinson's disease.
  • Certain medications, notably those that interfere with dopamine (such as antipsychotics and antiemetics), may cause symptoms that mimic those of Parkinson's disease (parkinsonism).

Prevention

  • There are no known measures for preventing Parkinson's disease.

Diagnosis

  • Patient history and physical examination by a physician or neurologist experienced in Parkinson's disease. The physician will rule out other disorders that cause similar symptoms. These include strokes, tumors,Wilson's disease (copper accumulation), progressive supra-nuclear palsy, and sometimes Alzheimer's disease.

How to Treat It

  • Treatment may not be necessary in the early stages if the symptoms are not interfering with functioning. When symptoms worsen, a variety of medications can provide relief. It takes time and patience to arrive at the appropriate medication and dosage. The medications for treating Parkinson's disease have a number of side effects, including too much movement as doses get higher.
  • Levodopa (L-dopa) is the mainstay of therapy to relieve symptoms of Parkinson's disease.Within the brain, L-dopa is converted to the missing neurotransmitter dopamine. L-dopa is combined with a decarboxylase inhibitor (carbidopa or benserazide) to enhance efficiency and limit side effects of L-dopa by preventing the conversion of L-dopa to dopamine from occurring outside of the brain. (Side effects include nausea and vomiting, and dizziness when sitting or standing up from a reclining position.) Because the effectiveness of L-dopa gradually decreases with time, doctors will often withhold the drug until symptoms interfere greatly with normal activities.
  • Deprenyl, also known as selegiline, may be prescribed immediately upon diagnosis. This drug may slow the progression of symptoms, thus postponing the time before L-dopa becomes necessary.
  • Anticholinergic drugs such as trihexyphenidyl block certain nerve impulses and may be prescribed to reduce tremor and stiffness.
  • Benztropine mesylate and antihistamines such as diphenhydramine may also be used to decrease tremor and stiffness.
  • Amantadine, which increases the release of dopamine in the brain, may be prescribed to reduce tremor, stiffness, and difficulty in movement.
  • Dopamine agonists (such as bromocriptine, pergolide, pramipexole, and ropinirole), which work directly in the dopamine receptors in the brain, can be added to L-dopa for additional control of symptoms and are being used increasingly as initial therapy for early Parkinson's disease.
  • COMT (catechol-O-methyltransferase) inhibitors, such as tolcapone, are added to L-dopa for improved control of symptoms.
  • For disabling tremor, consideration should be given to surgical therapy, with either a thalamotomy (in which a small group of cells in the thalamus portion of the brain is destroyed) or the placement of an electrical stimulator in the thalamus cells to shortcircuit them.
  • For the motor fluctuations that often complicate advanced Parkinson's disease, another surgical option is pallidotomy in which a lesion is made in the globus pallidus to reduce the overactive nerve cells. Electrical stimulation of the globus pallidus and other areas is under investigation and looks promising.
  • Implantation of fetal tissue into the basal ganglia has shown promise in a few patients.
  • Patients should stay active and exercise regularly to keep muscles as flexible as possible.
  • Physical and speech therapy may help patients adapt to the limitations imposed by the disease.
  • Psychological counseling may be advised for patients to combat depression and provide emotional support. Family members of Parkinson's patients may also benefit from counseling.
  • To allow L-dopa to work better, your doctor may advise dietary changes, such as consuming the majority of the daily protein allotment with the evening meal and maintaining a seven-to-one ratio of carbohydrates to protein.
  • Call your local branch of the National Parkinson Foundation, the United Parkinson Foundation, or the American Parkinson's Disease Association for more information, results of current research, and support groups in your area.

When to Call a Doctor

  • Call a doctor if you develop symptoms of Parkinson's disease.
  • Call a doctor if new, unexpected symptoms develop during treatment (some medications prescribed may have significant side effects, such as low blood pressure, confusion, and hallucinations).