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Parkinson's disease (idiopathic parkinsonism) is characterized by three major symptoms: rigidity, tremor, and akinesia. Voluntary movements suffer a marked retardation, while muscular strength is well preserved. Speech is often slow and monotonous. Parkinson's Disease is caused by a reduction in dopamine containing nerve cells of the midbrain in the substantia nigra that project to the caudate nucleus (putamen). Once approximately 80% of such cells die, the patient begins to develop symptoms of bradykinesia, immobile facies, stooped posture and resting tremor. Ten to thirty percent of Parkinson's patients also develop dementia. Pathologically there is considerable overlap in the findings of these latter patients with individuals who have pure Alzheimer's disease. Parkinson's Disease Staging * Stage I: Unilateral Involvement * Stage II: Bilateral Involvement but no postural abnormalities * Stage III: Bilateral Involvement with mild imbalance * Stage IV: Bilateral Involvement with postural involvement * Stage V: Severe, full developed disease (restriction to bed/wheelchair) Parkinson's disease affects 1% of the US population over 50 years of age. The differential diagnosis in patients with suspected Parkinson's disease is very important because therapeutic agents have little or no effect on other Parkinsonian syndromes. Similarly, agents used in conditions that can be mistaken for Parkinson's (e.g. essential tremor) are relatively ineffective for Parkinson's disease. Causes for secondary parkinsonism, including postinfectous, drug-induced, and toxin-induced (MPTP), must also be ruled out. It is also becoming increasingly important to diagnose Parkinson's disease early, as new trends in treatment of this disease are based on early treatment that delay the natural progression of the disease. Parkinson's disease is believed to be caused by a reduction in nerve cells in the substantia nigra. These midbrain neurons send projections to the striatum (putamen), where they release the neurotransmitter dopamine. The loss of these cells results in a decreased concentration of endogenous striatal dopamine. Once approximately 80% of these cells die, the patient begins to develop symptoms. The putamen of Parkinson's patients show a characteristic deficit in DOPA uptake. The symptoms of Parkinson's disease can sometimes be alleviated by treatment with L-DOPA, which increases the amount of dopamine that is synthesized in the patient's brain. This is believed to facilitate the activity of the remaining dopaminergic neurons. -- Ron Vetter 1936, '84 PD dz mailto:[log in to unmask] http://www.ridgecrest.ca.us/~rfvetter