Bladder instability and incontinence are very common problems that affect both men and women. Instability (or "over-activity") refers to the condition in which the bladder muscle cannot stay in a relaxed state long enough for complete bladder filling. Most men and women should be able to hold about 500mL in their bladder, sometimes more. Instability occurs when the bladder muscle becomes "twitchy" before this reserve is reached, and the patient experiences the urge to go to the toilet more often than is normal, and often with more urgency, a need to rush instead of being able to hold on. There can be numerous causes for instability, and sometimes no obvious cause is apparent. Known causes include damage to the nerve supply of the bladder - through diabetes, neurological conditions or spinal injury; damage or irritation to the bladder lining itself - from infections, radiation, surgery; obstruction to outflow of urine from the bladder, typically from an enlarged prostate in men. In many patients, both men and women, aging can cause poorer bladder control.
Incontinence refers to involuntary loss of urine. This is usually classified as one of two types - Urge Incontinence - the patient has a very strong urge to go to the toilet and cannot hold on till reaching the toilet, essentially the bladder starts to empty too soon. Secondly, Stress Incontinence refers to loss of urine due to a loss of the normal anatomical supports that keep the urethra closed until voluntary urination is commenced. This means that the patient leaks urine with any significant rise in abdominal pressure, like coughing, standing up from sitting, exercise, carrying heavy items, and even during intercourse. Patients not uncommonly can suffer from both forms of incontinence. There are many causes for both types of incontinence, and the urologist will take a detailed history and perform a thorough physical examination to determine the likely causes in a particular patient. In addition urologists often order a test called Urodynamics to clarify the nature of the problem in the instability-incontinence complex. This involves placing small pressure lines inside the bladder and filling the bladder with sterile water and measuring the pressure changes in the bladder as it is filled. When combined with x-ray imaging at the same time, this can provide valuable information as to whether the problem is just physiological (something wrong with how the bladder muscle is behaving) or also anatomical (the bladder has lost some of its normal supports).
Treatment for instability/over-activity is usually with a group of medications called "anti-cholinergic" drugs, which relax the bladder muscle and allow the patient to hold on for long. Common drugs in this group include oxybutinin, solifenacin, darifenacin and tolterodine.
Treatment for incontinence is also with the same drugs if it is urge incontinence in type, or with surgery in the case of stress incontinence. A number of different surgical procedures have been developed to restore the normal supports of the urethra and bladder to restore continence, and these are selected and tailored to each patient based on their needs.