Types of urinary incontinence
Many things can go wrong with the complex system that allows us to control urination. Incontinence is categorized by the type of problem and, to a lesser extent, by differences in symptoms.
If urine leaks out when you jump, cough, or laugh, you may have stress incontinence. Any physical exertion that increases abdominal pressure also puts pressure on the bladder. The word "stress" actually refers to the physical strain associated with leakage. Although it can be emotionally distressing, the condition has nothing to do with emotion. Often only a small amount of urine leaks out. In more severe cases, the pressure of a full bladder overcomes the body's ability to hold in urine. The leakage occurs even though the bladder muscles are not contracting and you don't feel the urge to urinate.
Stress incontinence occurs when the urethral sphincter, the pelvic floor muscles, or both these structures have been weakened or damaged and cannot dependably hold in urine. Stress incontinence is divided into two subtypes. In urethral hypermobility, the bladder and urethra shift downward when abdominal pressure rises, and there is no hammock-like support for the urethra to be compressed against to keep it closed. In intrinsic sphincter deficiency, problems in the urinary sphincter interfere with full closure or allow the sphincter to pop open under pressure. Many experts believe that women who have delivered vaginally are most likely to develop stress incontinence because giving birth has stretched and possibly damaged the pelvic floor muscles and nerves. Generally, the larger the baby, the longer the labor, the older the mother, and the greater the number of births, the more likely that incontinence will result.
Age is likewise a factor in stress incontinence. As a woman gets older, the muscles in her pelvic floor and urethra weaken, and it takes less pressure for the urethra to open and allow leakage. Estrogen can also play some role, although it is not clear how much. Many women do not experience symptoms until after menopause.
In men, the most frequent cause of stress incontinence is urinary sphincter damage sustained through prostate surgery or a pelvic fracture.
Lung conditions that cause frequent coughing, such as emphysema and cystic fibrosis, can also contribute to stress incontinence in both men and women.
Overactive bladder (urge incontinence)
If you feel a strong urge to urinate even when your bladder isn't full, your incontinence might be related to overactive bladder, sometimes called urge incontinence. This condition occurs in both men and women and involves an overwhelming urge to urinate immediately, frequently followed by loss of urine before you can reach a bathroom. Even if you never have an accident, urgency and urinary frequency can interfere with work and a social life because of the need to keep running to the bathroom.
Urgency is caused when the bladder muscle, the detrusor, begins to contract and signals a need to urinate, even when the bladder is not full. Another name for this phenomenon is detrusor overactivity.
Overactive bladder can result from physical problems that keep your body from halting involuntary bladder muscle contractions. Such problems include damage to the brain, the spine, or the nerves extending from the spine to the bladder — for example, from an accident, diabetes, or neurological disease. Irritating substances within the bladder, such as those produced during an infection, might also cause the bladder muscle to contract.
Often there is no identifiable cause for overactive bladder, but people are more likely to develop the problem as they age. Postmenopausal women, in particular, tend to develop this condition, perhaps because of age-related changes in the bladder lining and muscle. African American women with incontinence are more likely to report symptoms of overactive bladder than stress incontinence, while the reverse is true in white women.
A condition called myofascial pelvic pain syndrome has been identified with symptoms that include overactive bladder accompanied by pain in the pelvic area or a sense of aching, heaviness, or burning.
In addition, infections of the urinary tract, bladder, or prostate can cause temporary urgency. Partial blockage of the urinary tract by a bladder stone, a tumor (rarely), or, in men, an enlarged prostate (a condition known as benign prostatic hyperplasia, or BPH) can cause urgency, frequency, and sometimes urge incontinence. Surgery for prostate cancer or BPH can trigger symptoms of overactive bladder, as can freezing (cryotherapy) and radiation seed treatment (brachytherapy) for prostate cancer.
Neurological diseases (such as Parkinson's disease and multiple sclerosis) can also result in urge incontinence, as can a stroke. When hospitalized following a stroke, 40% to 60% of patients have incontinence; by the time they are discharged, 25% still have it, and one year later, 15% do.
If you have symptoms of both overactive bladder and stress incontinence, you likely have mixed incontinence, a combination of both types. Most women with incontinence have both stress and urge symptoms — a challenging situation. Mixed incontinence also occurs in men who have had prostate removal or surgery for an enlarged prostate, and in frail older people of either gender.
If your bladder never completely empties, you might experience urine leakage, with or without feeling a need to go. Overflow incontinence occurs when something blocks urine from flowing normally out of the bladder, as in the case of prostate enlargement that partially closes off the urethra. It can also occur in both men and women if the bladder muscle becomes underactive (the opposite of an overactive bladder) so you don't feel an urge to urinate. Eventually the bladder becomes overfilled, or distended, pulling the urethra open and allowing urine to leak out. The bladder might also spasm at random times, causing leakage. This condition is sometimes related to diabetes or cardiovascular disease.
Men are much more frequently diagnosed with overflow incontinence than women because it is often caused by prostate-related conditions. In addition to enlarged prostate, other possible causes of urine blockage include tumors, bladder stones, or scar tissue. If a woman has severe prolapse of her uterus or bladder (meaning that the organ has dropped out of its proper position), her urethra can become kinked like a bent garden hose, interfering with the flow of urine.
Nerve damage (from injuries, childbirth, past surgeries, or diseases such as diabetes, multiple sclerosis, or shingles) and aging often prevent the bladder muscle from contracting normally. Medications that prevent bladder muscle contraction or that make you unaware of the urge to urinate can also result in overflow incontinence.
If your urinary tract is functioning properly but other illnesses or disabilities are preventing you from staying dry, you might have what is known as functional incontinence.
For example, if an illness rendered you unaware or unconcerned about the need to find a toilet, you would become incontinent. Medications, dementia, or mental illness can decrease awareness of the need to find a toilet.
Even if your urinary system is fine, it can be extremely difficult for you to avoid accidents if you have trouble getting to a toilet. This problem can affect anyone with a condition that makes it excessively difficult to move to the bathroom and undress in time. This includes problems as diverse as having arthritis, being hospitalized or restrained, or having a toilet located too far away.
If a medication (such as a diuretic used to treat high blood pressure or heart failure) causes you to produce abnormally large amounts of urine, you could develop incontinence that requires a change in treatment. If you make most of your urine at night, the result might be nocturnal incontinence, or bedwetting.
Reflex incontinence occurs when the bladder muscle contracts and urine leaks (often in large amounts) without any warning or urge. This can happen as a result of damage to the nerves that normally warn the brain that the bladder is filling. Reflex incontinence usually appears in people with serious neurological impairment from multiple sclerosis, spinal cord injury, other injuries, or damage from surgery or radiation treatment.