The following four variants are the most common manifestations of incontinence. They are each based on different causes:
- Stress incontinence
- Urge incontinence
- Overflow incontinence
- Reflex incontinence
Stress incontinence
This type of incontinence has nothing to do with stressful, psychological factors - the reason for the loss of urine is that the muscles which close off the bladder to the urinary tract are too weak. If the pressure in the abdominal cavity and, as a consequence, the pressure on the bladder is increased in special stress situations, this results in the involuntary leakage of urine. A distinction is made between three degrees of stress incontinence depending on the degree of muscle weakness:
- Grade I: Incontinence only when coughing, sneezing or laughing.
- Grade II: incontinence during abrupt movements or when sitting down or standing up
- Grade III: Incontinence when lying down or during effortless movements.
There are various reasons why the sphincter muscles of the urinary bladder can no longer fulfil their function. Usually, pelvic floor weakness occurs, for example, after operations in the lower abdominal area or after several births.
Another reason in women would be the lowering of the bladder, uterus and vagina in the pelvis. Normally, these organs are held in their original position by ligaments and muscles - but if these are too weak, the organs and the urethra slip a little deeper into the pelvis, impairing the function of the closing muscles of the urinary bladder.
In rare cases, the muscles of the urethra itself are not strong enough, resulting in incontinence. Normally, however, the urethral muscles are strengthened by the other muscles of the pelvic floor.
In men, stress incontinence can occur after prostate surgery if the muscles of the urethra have been damaged by the surgery.
Urge incontinence
This form is also known as overactive bladder syndrome, urge incontinence or irritable bladder. Urge incontinence is characterized by a sudden, unsuppressible urge to urinate that forces the person to go to the toilet immediately. The sudden urge to urinate is caused by the following two mechanisms:
- motor urge incontinence: in this case, the nerve impulses that activate the detrusor muscle (the muscle that empties the urinary bladder) are overactive, resulting in sudden and premature urination. Normally, the detrusor muscle is regulated by the central nervous system - over-activation can occur in brain diseases such as tumours, strokes, dementia and inflammation.
- Sensory urge incontinence: In this case, the perception of bladder filling is disturbed and there is an early signal that the bladder is full. This disorder can be triggered by inflammation, bladder stones, bladder tumours or remodelling processes of the bladder mucosa (as a result of an oestrogen deficiency during the menopause).
Overflow incontinence
Overflow incontinence is caused by a constantly overfull bladder that is difficult to empty naturally due to drainage problems. If the pressure in the bladder rises above the resistance in the urethra, the bladder "overflows" and a constant dribbling of urine is the result.
There are several causes of overflow incontinence:
- The most common cause is an enlarged prostate (prostate gland), which often occurs in men over the age of 60. Since the prostate completely surrounds the urethra just below the bladder, enlargement can cause the urethra to become constricted.
- Diabetes mellitus can cause damage to the nerves that should activate the detrusor muscle (the muscle that empties the bladder). Urine can no longer be forced out of the bladder and overflow incontinence occurs.
- The nerve to the detrusor muscle can also be damaged during the surgical removal of, for example, uterine or ovarian tumours and during injuries to the lower spinal cord.
- During pregnancy, overflow incontinence can also develop temporarily due to increased pressure on the bladder.
Reflex incontinence
Reflex incontinence is caused by damage to the nerve pathways between the brain and the bladder centre in the spinal cord, such as occurs in paraplegics. The damage results in reflex-like contractions of the bladder muscles due to the predominance of activity impulses, causing the bladder to empty.
Fistulas
Fistulas are newly formed pathological connecting ducts between an internal hollow organ and another organ or the surface of the skin. Fistulas can develop as a result of a chronic inflammatory process (for example Crohn's disease), after abdominal surgery or complicated childbirth.
If the urinary bladder is connected to the intestine, vagina or skin surface via a fistula, urine can pass through this channel without resistance.