What causes overactive bladder?

Overactive bladder can result from physical problems that keep your body from controlling involuntary bladder muscle contractions. Such problems include damage to the brain, the spine, or the nerves extending from spine to 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 changes in the bladder lining and muscle associated with aging. 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. (If urine leaks out when you jump, cough, or laugh, you may have stress incontinence.)

For men and women, 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 known as benign prostatic hyperplasia (BPH) can cause urgency, frequency, and sometimes urge incontinence.

In addition, prostate surgery for 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.

An overactive bladder can be caused by drinking too much water, but it can also be a symptom of a urinary tract infection or diabetes. Watch urologist Harry Fisch, MD, explain the various reasons you may be experiencing frequent urination symptoms.