A progressive disorder of the autonomic nervous system in which chronic orthostatic hypotension is associated with bladder and bowel incontinence, Parkinsonism, cerebellar ataxia, impotence, visual troubles, tremor and disturbances of sweating, and muscle wasting leading to severe invalidism. Central nervous system manifestations may be identical to those of Parkinson's. Autonomic neurones are degenerated and there may be atrophic areas in the basal ganglia, midbrain and brainstem. Onset usually takes place in the sixth or seventh decades, most persons becoming disabled within 5 to 7 years. More males than females are affected. Frequency is 1 in 10.000 persons. The aetiology is unknown.
In 1960 Dr. Milton Shy from National Institutes of Health and Dr Glenn Drager from the Baylor College of Medicine, Houston, described two patients who shared common clinical symptoms. Both were men who became sexually impotent and developed bladder problems at the ages of 39 and 49 respectively. The urinary problems became worse, and within a few months both men complained of dizziness on arising from a sitting or lying position, causing momentary "blackouts." They later developed constipation, urinary and rectal incontinence, slowness of movement, unsteady gait, slurring of speech, mild tremor and other Parkinsonian symptoms. On examination they had very low blood pressure when standing, and in addition to some Parkinsonian findings they also had wasting of muscles in hands and feet, dry skin due to loss of sweating, and loss of pigment in the iris of the eyes. Additional tests revealed an abnormal function of the autonomic nervous system. The second patient subsequently died and the autopsy examination provided evidence that he had a distinct and unique disease. Shy and Drager recognized that there was a link between low blood pressure during erect posture (orthostatic hypotension) and disturbance in the central autonomic nervous system.
- G. M. Shy, G. A. Drager:
A neurological syndrome associated with orthostatic hypotension. A clinical- pathological study.
Archives of Neurology, Chicago, 1960, 2: 511-527.