Urine is produced in the kidney and passes through the nephron tubules to be stored in the bladder. The bladder is a sac made of special muscle fibres; its interior is covered by special cells and is known as “transitional epithelium”. When a person is ready to urinate, the muscles covering the walls of the bladder contract; at the same time, the sphincter at the level of the urethra (i.e. the tube through which urine passes before being finally expelled from the human body) relaxes. The sphincter acts like a valve that allows urine to be expelled at certain times. Neurological diseases or anatomical issues in the area may cause the sphincter to malfunction. Certain medicines also cause urinary incontinence.
In women, changes in the anatomy of the urinary tract, the muscles or the nerves that control these muscles may contribute to urinary incontinence:
Childbirth is one of the most important causes of urinary incontinence. When a baby is born, the muscles of the pelvic floor stretch and weaken. The muscles are no longer able to exert the necessary pressure to keep the urethra closed; whenever extra pressure is applied (e.g. running, coughing, laughing) a quantity of urine leaks.
- The anatomy of the body
Due to the anatomy of their body, women are more susceptible to urinary incontinence. The female urethra is only 5 cm long, while that of men is approximately 25 cm long. This renders women more vulnerable to urinary tract infections, which can cause incontinence.
Approximately half of pregnant women have had urinary incontinence symptoms during their pregnancy. This may be caused by a hormone that is secreted during the early stages of pregnancy, which causes the muscles of the abdomen to relax. This particular hormone, however, also relaxes the muscles of the sphincter: as a result, it is difficult to contain the flow of urine. In combination with the baby’s weight, which exerts additional pressure on the bladder, the incontinence issue is exacerbated.
- Hormonal changes during the menopause
The hormonal changes that happen at the start of the menopause, especially the decrease in oestrogen levels, cause episodes of urinary incontinence. In spite of this, scientific studies have not yet been able to prove that incontinence may be caused by hormonal disorders alone. The low levels of oestrogens, however, increase the risk of urinary incontinence due to changes in the vaginal wall.
Increased weight contributes to the muscles of the pelvic floor being stretched further. This exerts constant pressure on the abdomen and the bladder; the result is incontinence.
- Other reasons, such as trauma, neurological disease, chronic cough, etc. are often linked to the onset of incontinence.
In men, in general, incontinence has different causes than in women.
Urinary incontinence in men may primarily be caused by prostate conditions, such as cancer, benign hyperplasia, radiation of the pelvic area, bladder cancer and, lastly, sleep apnoea syndrome. Finally, obesity also plays a negative role, as it exerts constant pressure on the abdomen and bladder, causing urinary incontinence.
Kindly contributed by Urologist – Andrologist Surgeon, Dr Charalambos P. Asvestis