What are the characteristic urologic manifestations of neurodegenerative disorders?

Updated: Dec 27, 2018
  • Author: Frances M Dyro, MD; Chief Editor: Robert A Egan, MD  more...
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Answer

The urologic manifestations of neurodegenerative disorders, including Parkinson disease (PD), [19, 20, 21] multisystem atrophy, and Huntington chorea, have been studied by several groups. [22, 23, 24, 25, 26]

Galloway, [22] Murnaghan, [23] Eardley et al, [24] and Mathers et al [25] studied the urethral and anal sphincters in addition to performing cystometrography in patients with PD. (About 90% of patients with late-stage PD have voiding dysfunction.) The patients all had detrusor hyperactivity or instability. The actual electromyographic (EMG) patterns were normal with no denervation, but a sphincteric “tremor” and failure to relax while voiding were noted.

Brusa et al showed that initiation of L-dopa therapy worsened bladder overactivity and reduced capacity, but long-term use improved sensation of bladder filling and capacity. [27]

Constipation is a common complaint in parkinsonism and is thought by some to be a result of autonomic dysfunction and lack of activity. Bowel biopsies have shown autonomic involvement, but a contributing factor may be a phenomenon observed by Mathers et al, [25] who reported paradoxical anal sphincter contraction during simulated defecation, with straining producing a sort of anismus obstruction.

These investigators also reported impaired relaxation of the external urethral sphincter and the presence of Lewy bodies in the colonic mesenteric plexus. [25] The degree of sphincteric involvement appears to be a function of autonomic involvement.

Patients with multisystem atrophy and autonomic failure have considerable difficulty with incontinence. Sphincter EMG of these patients has shown abnormal motor units and increased motor unit durations. Patients with multisystem atrophy and Shy-Drager syndrome are known to have cell loss in the motor nuclei at S2-S4; this finding has led to increased speculation concerning the autonomic properties of these neurons. [28]

Paviour et al reviewed 37 patients with multisystem atrophy who underwent sphincter EMG and concluded that the changes seen were not specific. [29]

Huntington chorea is a neurodegenerative disorder of autosomal-dominant inheritance characterized by progressive neuronal loss in the caudate nuclei, the basal ganglia, and the cortex. Wheeler et al studied 6 patients with Huntington chorea and incontinence; 2 had normal study results, and 4 had detrusor hyperreflexia but normal motor units in the sphincter. [30] “Choreiform” contractions of the pelvic floor muscles were noted during bladder filling but were suppressed by voiding contractions. The patients were not dyssynergic.

The incontinence in Huntington chorea and in other dementing illnesses is synergic loss of urine caused by the loss of central inhibitory pathways. Normal or near-normal sphincter activity is preserved in most disorders of muscle or anterior horn cells.

The findings of degenerative changes in the presence of autonomic dysfunction give some credence to speculations that the cells of the Onuf nucleus may be a sort of unique transitional neuron with autonomic properties. The myopathies, which mostly affect type II muscle fibers, are likely to have little effect on the type I fibers of the sphincters.

Cerebrovascular disease can result in voiding dysfunction, usually in the context of bilateral hemispheric lesions. During the acute phase, urinary retention is typical. Later, during recovery, symptoms such as frequency, urgency, urge incontinence, or inappropriate voiding are more common. The loss of frontal connections results in a pattern of bladder function resembling that seen in non–toilet-trained children. Incontinence is a common occurrence in normal pressure hydrocephalus, usually resolving after shunting.

Pontine lesions or lesions below the level of the pontine micturition center result in the loss of coordinated (synergic) voiding. Incontinence has been reported in bilateral putaminal lesions, [31] but the type of incontinence was not specified.

Children with cerebral palsy frequently have small bladder capacity and urge incontinence. Enuresis with uninhibited detrusor contractions or inappropriate relaxation of the sphincter with loss of small amounts of urine may be the presenting complaint in a child with very subtle cerebral palsy.

Spinal cord infarction is a serious complication of surgery on the thoracic aorta. Acute occlusion of the artery of Adamkiewicz by thrombus, embolus, or dissection of the aorta produces a devastating picture of paraparesis with loss of bladder function accompanied by denervation of the urethral and anal sphincters from involvement of the conus medullaris. The net result is a large, atonic, painless bladder that empties by overflow.


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