Case 2. A 65 year old man has been bothered by shaking of his hands and generalized stiffness of his body, w/c have become progressively more severe over the past 4 yrs. On entering the examining room, he moves slowly and deliberately, shuffling his feet, his shoulders and trunk are stooped forward, and his arms are at his sides and not swinging. His face remains mask-like with no changes of expression all the time. In both hands, a resting tremor of the pill-rolling type stops only when the patient performs a voluntary movement such as removing his eyeglasses or picking up a pen. Examination reveals the presence lead-pipe rigidity manifested by a generalized hypertonicity with greatly increased resistance to passive movement. Although the patient moves infrequently, examination reveals no paralysis or sensory disturbances in any part of the body.

PARKINSON’S DISEASE/ PARALYSIS AGITANS:

degenerative changes (neuronal degeneration and depigmentation) in the substantia nigra (pars compacta) and locus ceruleus

dopaminergic neurons that project to the striatum and thus lead to the depletion of dopamine in the caudate nucleus and putamen

Striatal projections to the internal globus pallidus and the substantia nigra (pars reticulata) become less active, whereas projections to the external globus pallidus become more active

result in loss of inhibition of the output neurons of the basal ganglia, and increased inhibition of thalamocortical neurons

allow the caudate and putamen to become overly active and possibly cause continuous output of excitatory signals to the corticospinal motor control system.

these signals could certainly excite many or all of the ms of the body, leading to rigidity

RIGIDITY ( increased resistance to passive movement)

when the examiner passively flexes or extends one the pxn’s extremities, an increased resistance occurs that suddenly gives way and then returns sequentially as the movement continues, in the manner of a cogwheel

TREMOR

different from that of cerebellar tremor, w/c occurs only when the person performs intentionally initiated movements and therefore is called intention tremor

typically occurs when the pxn is at rest and consists of 4-6 cps flexion-extension movt’s of the fingers and wrists, at times in the form of pill-rolling movement

AKINESIA

more distressing to the pxn because to perform even the simplest movement in severe parkinsonism, the person must exert the highest degree of concentration. Movements are usually stiff and staccato in character, instead of smooth.

AKINESIA

manifested as difficulty in initiating and performing volitional movements of the most common type, including standing, walking, eating, and writing

OTHER SYMPTOMS:

lines of the face are smooth, the expression is fixed (“masked face”), and there’s little overt evidence of spontaneous emotional responses

pxn stands with the head and shoulders stooped and walks with short, shuffling steps

arms are held at the sides and do not automatically swing in rhythm with the legs as they should

although patients have difficulty in starting to take their first steps, once under way, the pace becomes more and more rapid, and pxn have trouble in stopping the progress on reaching their goal. These abnormality of walking is called “ festinating gait”

muscle stretch (deep tendon) reflexes usually are normal

TREATMENT:

L-dopa – is converted in the brain into dopamine, and the dopamine then restores the normal balance between inhibition and excitation in the caudate nucleus and putamen.

-Administration of dopamine itself does not have the same effect because dopamine has a chemical structure that will not allow it to pass through the blood-brain barrier

L-deprenyl – inhibits monoamine oxidase, w/c is responsible for destruction of most of the dopamine after it has been secreted

surgical lesions were made in the ventrolateral and ventroanterior nuclei of the thalamus, which blocked feedback circuit from the basal ganglia to the cortex; currently, surgical therapy is directed at the globus pallidus rather than the thalamus