Intravesical capsaicin as a treatment for refractory detrusor hyperreflexia: a dual center study with long-term followup

Neurological disorders of micturition and their treatment

An overview of the current concepts of the neurological control of the bladder is given, based on laboratory experiments and PET scanning studies in human subjects. This is followed by a description of the various causes of the neurogenic bladder, discussed in a hierarchical order starting with cortical lesions and descending through the basal ganglia and brainstem, spinal cord, conus and cauda equina to disorders of peripheral innervation. Then follows a description of the condition of isolated urinary retention in young women. The article concludes with a review of the methods available for treating neurogenic bladder disorders. These are largely medical but brief mention of appropriate surgical procedures is made.

Desensitization of bladder sensory fibers by intravesical capsaicin or capsaicin analogs. A new strategy for treatment of urge incontinence in patients with spinal detrusor hyperreflexia or bladder hypersensitivity disorders

Recent experimental studies have identified a category of unmyelinated type C bladder afferent fibers in the pelvic nerves which are extremely sensitive to capsaicin. Sensory input conveyed by these fibers triggers a spinal reflex which, in chronic spinalized animals, facilitates and controls micturition. In addition, bladder C fibers were also shown to have a role in bladder pain perception. In humans capsaicin-sensitive afferent fibers also innervate the bladder and contribute to the reflexogenic control of the detrusor muscle and to bladder pain perception. Desensitization of such fibers by intravesical administration of capsaicin, presumably by blocking sensory transmission, has been shown to reduce involuntary micturition and to increase bladder capacity in patients with detrusor hyperreflexia of spinal origin, and to reduce the intensity of bladder pain in patients with bladder hypersensitivity. Very recently, resiniferatoxin, an ultrapotent capsaicin analog, was shown to have a similar clinical effect in this subset of patients. However, unlike capsaicin, resiniferatoxin did not evoke acute irritative urinary symptoms during bladder instillation.

Use of intravesical capsaicin for urge urinary incontinence and irritative voiding syndromes

Intravesical capsaicin has been used in the management of selected patients with urge urinary incontinence throughout this decade, but the past 12 months has seen considerable interest in this and related compounds. It is no coincidence that during the same period the capsaicin receptor was cloned and named the vanilloid receptor subtype 1 and the European dual centre study of intravesical capsaicin reported that overall 80% of patients derived some clinical benefit. In spite of this, ultrapotent capsaicin analogues such as resiniferatoxin, which also interact with the vanilloid receptor subtype 1, are being studied. Preliminary reports of the potential advantages of intravesical resiniferatoxin are beginning to emerge, and in the future drugs that manipulate the vanilloid receptor may become universally important in the management of neurogenic overactive bladders.

Bladder cancer in patients with multiple sclerosis treated with cyclophosphamide

PURPOSE

We define the risk of bladder cancer in multiple sclerosis related to the use of indwelling catheters and cyclophosphamide administered as an immunomodulating agent.

MATERIALS AND METHODS

We retrospectively reviewed the records of 2,351 patients with multiple sclerosis referred to the National Center for Multiple Sclerosis.

RESULTS

Of the 2,351 patients 2 women and 5 men (0.29%) had bladder cancer. Of the 850 chronically catheterized patients the incidence was 0.7%. One patient with cancer performed intermittent catheterization for a rate of 0.23% in this group. In a subgroup of 70 patients treated with cyclophosphamide 5 chronically catheterized patients (5.7%) had bladder cancer. Hematuria was the most common presenting symptom. These data were compared with those in the literature on bladder cancer in spinal cord injury.

CONCLUSIONS

These data suggest a possible synergistic role of cyclophosphamide and chronic catheterization in the induction of secondary bladder cancer. Regular cystoscopy is warranted in these patients to allow early detection of bladder tumors. Nitric oxide metabolism may be an important factor in the carcinogenesis of this type of bladder cancer.

Bladder cancer in patients with multiple sclerosis treated with cyclophosphamide

PURPOSE

We define the risk of bladder cancer in multiple sclerosis related to the use of indwelling catheters and cyclophosphamide administered as an immunomodulating agent.

MATERIALS AND METHODS

We retrospectively reviewed the records of 2,351 patients with multiple sclerosis referred to the National Center for Multiple Sclerosis.

RESULTS

Of the 2,351 patients 2 women and 5 men (0.29%) had bladder cancer. Of the 850 chronically catheterized patients the incidence was 0.7%. One patient with cancer performed intermittent catheterization for a rate of 0.23% in this group. In a subgroup of 70 patients treated with cyclophosphamide 5 chronically catheterized patients (5.7%) had bladder cancer. Hematuria was the most common presenting symptom. These data were compared with those in the literature on bladder cancer in spinal cord injury.

CONCLUSIONS

These data suggest a possible synergistic role of cyclophosphamide and chronic catheterization in the induction of secondary bladder cancer. Regular cystoscopy is warranted in these patients to allow early detection of bladder tumors. Nitric oxide metabolism may be an important factor in the carcinogenesis of this type of bladder cancer.