To examine the pathophysiology of "stress induced urinary incontinence" (urinary incontinence evoked by abdominal straining) in patients with spinocerebellar degeneration.Methods
Micturitional symptoms of 184 patients with spinocerebellar degeneration who were admitted to hospital were studied repeatedly. Urodynamic studies were made in symptomatic patients, and consisted of uroflowmetry, measurement of residual urine, urethral pressure profilometry, medium fill water cystometry, and external sphincter EMGResults
Twenty nine (15.8%) patients with spinocerebellar degeneration showed stress induced urinary incontinence. Twenty of the 29 patients had detrusor overactivity, low compliance detrusor, or residual urine, resembling urgency and overflow types of incontinence (complicated form). The other nine had none of these findings (pure form), but showed decreased maximum urethral closure pressure in four, absence of bulbocavernosus reflex in two, absence of voluntary sphincter contraction in one, incompetent urinary storage even at the first sensation in two, and high amplitude and polyphasic neurogenic changes in three of five patients studied, indicative of neurogenic sphincter dysfunction.Conclusions
Stress induced urinary incontinence in spinocerebellar degeneration had various underlying mechanisms. Some of the patients only showed evidence of pudendal denervation, which can cause external sphincter weakness and may reflect lesions of the sacral Onuf's nucleus and the pudendal nerve. Urodynamic studies are necessary to evaluate stress induced urinary incontinence in patients with spinocerebellar degeneration, to prescribe appropriate therapies.