Pathophysiology of urinary incontinence

Urinary incontinence is a highly prevalent and potentially devastating disorder which has a tremendous social impact, and adversely affects the daily living and productivity of sufferers. Millions of individuals worldwide are affected, the vast majority being women. Stress, urge and mixed urinary incontinence are the most common types, although other types of incontinence also occur. Men frequently develop incontinence following prostatic surgery. Urinary incontinence occurs when there is a failure of the storage function of the lower urinary tract; this may be due to inappropriate activity of the bladder (detrusor) muscle or incompetence of the continence maintaining mechanisms. The pathophysiological mechanisms that underlie the various types of incontinence have long been debated and still remain the subject of much research. In this article we will review the most common theories for the development of incontinence with emphasis on the two commonest types of incontinence (stress and urge). To fully understand the causative mechanisms it is vital that the normal function and innervation of the lower urinary tract is appreciated and this is also covered at the outset of this review.