Bladder cooling reflex in patients with multiple sclerosis

Purpose: We describe the effect of intravesical ice water instillation in p atients with multiple sclerosis and without an overactive bladder. Materials and Methods: Of 131 consecutive patients with multiple sclerosis who presented with a urinary disorder we selected for study 10 men and 29 w omen with a mean age plus or minus standard deviation of 50 +/- 9 years who had multiple sclerosis without an overactive bladder. Nonoveractive bladde r was defined as no involuntary detrusor contraction up to 400 ml. of maxim um fill on routine cystometry. We performed cystometry with saline at 25 to 30C at an infusion rate of 50 and 100 ml. per minute, and with ice water a t 0 to 4C at a rate of 100 ml. per minute. Ice water cystometry was conside red positive when an involuntary detrusor contraction occurred before 200, and between 200 and 400 ml. of filling. Ice water cystometry was considered negative when there was no involuntary detrusor contraction during ice wat er filling up to 400 ml. Results: Ice water cystometry enabled us to elicit involuntary detrusor con tractions in 21 patients, which remained undetected by warm water cystometr y at rates of 50 and 100 ml. per minute. The test was positive before 200, and between 200 and 400 ml. in 10 and 11 cases, respectively. Positive ice water cystometry was significantly associated with irritative signs or sign ificant post-void residual urine volume. Conclusions: An involuntary detrusor contraction was not elicited by cystom etry at 50 or 100 ml. per minute, implying that the afferent mechanorecepto r reflex limb via A Delta fibers is not involved. In contrast, ice water cy stometry at 100 ml. per minute elicited an involuntary detrusor contraction , suggesting involvement of an afferent reflex limb via capsaicin sensitive C fibers. These involuntary detrusor contractions revealed by ice water cy stometry are probably relevant to an overactive bladder. In urinary disorde rs such a positive test indicates a spinal lesion. In multiple sclerosis it may have pathophysiological value, indicating a spinal rather than cerebra l mechanism of overactive bladder, and diagnostic value, indicating multifo cal demyelination.