-IBIS-1.5.0-
tx
nervous system
Parkinson's disease
diagnoses
definition and etiology
definition:
A chronic progressive CNS disorder characterized by slowness of purposeful movement, resting tremor, and muscle rigidity. Also called "Parkinsonism" and "Paralysis Agitans".
etiology:
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.
signs and symptoms
signs and symptoms:
Pathognomonic for Parkinsonism:
Cogwheel rigidity: This describes the rachet-like catches that occur when a sufferer's arm is put through passive movements. It is due to the hypertonia of muscles that equally affects opposing muscles.
Lead-pipe rigidity: This describes another possible presentation of the muscle rigidity and is a general resistance to movement.
With either muscle rigidity, there may be pain, cramping and decreased strength. However, the patient retains normal sensation and reflexes in the limbs. The patient's writing becomes small and hard to read.
Bradykinesia: the patient exhibits a general slowing of all voluntary movements.
Akinesia: the patient exhibits a paucity or even an absence of spontaneous movements associated with the typical animation of a normal individual.
Festinating gait: This term describes the patient's difficult process for initiating walking from a standing position. The patient takes several small, awkward steps and then breaks into a jog or run to prevent himself from falling. The typical patient pose during walking includes small, shuffling steps often dragging the feet, a slightly bent over posture, and having the arms in 90 degree flexion and held tightly at his sides.
Propulsion or Retropulsion: This describes the patient who falls forward or backward, respectively, upon being pushed.
Fixed facial mien: The typical facial expression of the Parkinson patient is one of a fixed, immobile nature, with a monotonous voice. There may be drooling at the corners of the mouth. The eyes stare and do not blink as often as normal.
Resting tremor: This is the classic tremor of the Parkinson patients. It occurs during rest, and is described as a pill-rolling of the fingers with the hand bent in flexion. It is often unilateral, but may become bilateral. Although it is most pronounced in the hands, it is also seen in the legs, lips, tongue, and eyelids (when they are firmly closed). The tremor disappears upon voluntary movement and during sleep. It worsens with fatigue, emotional stress and embarrassment, and many patients will try to hide the affected hand by keeping in their pocket, or by covering it with their unaffected hand during the interview.
Depression: About half of Parkinson patients present with or will develop depression.
lab findings:
Generally unremarkable.
course and prognosis
There is no cure: only symptomatic treatment. The course is progressive and very gradual, and patients may live their normal lifespan with the disease. Others may become increasingly incapacitated and eventually wind up in wheelchairs or dependent on others for normal daily activities, such as dressing and preparing food, etc.
differential diagnosis
Benign essential tremor.
Hysterical tremor.
Involutional depression.
Cerebral arteriosclerosis.
Wilson's disease and Farr's disease: when patients under 30 years old present with symptoms.
MPTP, reserpine or phenothiazine drug usage.
footnotes