Parkinson's Disease

A chronic progressive CNS disorder characterized by slowness of purposeful movement, resting tremors, and muscle rigidity.  Also called "Parkinsonism" and "Paralysis Agitans"

Dorland's Medical Dictionary describes the Parkinsonian complex as "neurologic disorders characterized by hypokinesia, tremors and muscular rigidity. It typically occurs late in life, although juvenile forms have been described."

The diagnosis for their disorder is made from the history and physical examination. Findings upon examinations are mask-like faces, a fenestrating gait, brady-kinesia, muscular weakness, poor balance, palmomental reflex, and a positive globella test. Patients often complain about excessive sweating and leg cramps. They may also experience speech loss, memory loss, and mild depression.

The disease and its symptoms result form an accelerated loss of dopamine (a neurotransmitter) from an area in the brain called the substantia nigra.  It should be noted that everyone, as they age, will lose dopamine to some degree. Parkinson's signs occur when the amount of dopamine being produced is less than 80%.

Conventional treatment of this disorder is only palliative: a cure has yet to be discovered. Medicines are directed towards increasing dopamine in the brain, and others are used to counteract the side effects of the primary drugs. Monoamine oxidase B inhibitors, such as selegiline, have also shown some success.

Surgery has been tried in this disorder: A pallidotomy (a dissection of an area of the brain called the pallium) has been used since the 1940s.  Symptomatic relief is expected; however, side effects, such as blindness and stroke, are possible. A brain pacemaker has been utilized in the attempt to relieve sincere tremors.

The  patient  is  typically middle-aged or elderly when symptoms begin. The disease is extremely gradual in

progression. In the majority of patients it is not a familial disorder, but occurs randomly. Although the syndrome

is well presented in a worldwide distribution and the manifestations often are clearly distinguishable and easily

diagnosed, the disease is idiopathic and the pathophysiology poorly understood.

There is usually a loss of cells in the substantia nigra, locus ceruleus, and in other pigmented cells, as well as

a decrease in the dopamine levels in the axon terminals of cells connecting the substantia nigra to the caudate

nucleus and putamen.

The disease initially presents as a unilateral disorder, but in later stages becomes symmetrical. It has an insidious onset, and may not become incapacitating for many years. After World War I, there was an encephalitis outbreak that led to numerous patients developing symptoms almost exactly like Parkinson's, as the same cells that become disordered in Parkinson's were the same ones to be affected by the encephalitis, which is one of the known causes

of the disease. Generally, however, only the idiopathic version of the disease is termed Parkinsonism.