Carbon dioxide cystometry and postural changes in patients with multiple sclerosis.

Ninety-one subjects with multiple sclerosis were evaluated by carbon dioxide cystometry in the supine, sitting, and standing positions, and by water cystometry in the supine position. Detrusor responses in supine studies were characterized as normal, hyperreflexic, or areflexic. Carbon dioxide and water cystometry were without difference in determining types of detrusor responses. Positional changes (particularly standing) resulted in reassessing of normal supine bladder responses as hyperreflexic. Hyperreflexia was aggravated with sitting and standing. Positional changes did not demonstrate conversion of areflexia to hyperreflexia. The relatively small proportion of dyssynergic sphincter responses probably represents a population of patients with early stage multiple sclerosis. Carbon dioxide cystometry, with positional changes, is relatively safe, easily performed, and an accurate method of evaluating detrusor response in patients with multiple sclerosis who have a changing clinical course or unresponsiveness to treatment.