By Dr Milton Lum

THE kidneys produce urine which passes through the ureters to enter the bladder, a hollow and distensible organ that sits on the pelvic floor that has a hammock-like structure comprising muscles and connective tissue. the pelvic floor supports organs like the bladder, intestines, and the uterus in females and has a narrow gap through which the urethra, rectum, anus, and vagina traverse.

The urine exits the bladder through the urethra. This occurs when both the bladder?s internal and external sphincters are opened. the control of the former is involuntary and the latter, which is a circular muscle around the urethra, voluntary. Although there is individual variation in bladder capacity, it is generally accepted that the capacity in the adult is about 500 ml. the desire to urinate occurs when the bladder volume is about 300 to 350 ml. as the bladder continues to fill, the desire to urinate increases and becomes more difficult to ignore.

The bladder can store a large volume of urine without much increase in internal pressure. When there is an increase in intra-abdominal pressure, e.g. coughing, sneezing, laughing, heavy lifting, exercising, or changing position, this is usually transmitted equally to the pelvic floor and organs, including the bladder.

However, when there is weakness of the pelvic floor muscles and/or external sphincter, or malfunction of the external sphincter, an involuntary leakage of urine can occur when the intra-abdominal pressure is increased. This is because the external sphincter cannot stay closed to prevent urine flow from the bladder, and this is called stress urinary incontinence (SUI).

SUI has to be distinguished from urge incontinence, which is due to overactive bladder muscles that leads to a strong urge to urinate even when there is little urine in the bladder.

There may be situations in which there is both SUI and urge incontinence. there are also other causes of incontinence like prostate problems and nerve damage.

In short, urinary incontinence is tantamount to loss of bladder control. the symptoms can range from mild leaks to uncontrollable ones. it can happen at any age but is more common with increasing age.

Irrespective of whether the amount of urine leaked is small or large, incontinence can be distressing and embarrassing.

 >> Next