Overactive bladder is a medical condition that causes the sudden urge to urinate, which is known as urinary urgency. This urge may be difficult to control and may lead to urinary incontinence. While the main cause of an overactive bladder is a malfunction of the detrusor muscle, there are a number of things that can cause this malfunction and overactive bladder to occur.
Neurological Diseases
Neurological diseases that cause the detrusor muscle to malfunction can be responsible for overactive bladder. Examples of neurological diseases include spinal cord lesions, stroke, Parkinson's disease and multiple sclerosis. These diseases damage the nerves and nerve pathways, which interferes with the signals that are sent when the bladder is empty or full. These signals can create urinary urgency that is difficult to control. As a result, people with neurological diseases may experience urinary incontinence.
Cancer
Bladder cancer and prostate cancer can cause the detrusor muscle to malfunction, especially if the cancer has spread into the wall of the bladder. Bladder cancer can form in the hollow portion of the bladder and extend into the fatty tissues and muscles of the bladder. Prostate cancer starts in the prostate, but can spread to the bladder and other organs due to their close proximity. Tumors growing in these organs can cause interference with the transmission of nerve impulses. This leads to overactive bladder.
Nerve Damage
Nerve damage that affects the nerve signals that control urination can cause overactive bladder. Nerve damage can occur due to motor vehicle accidents, vaginal childbirth, diabetes and heavy metal poisoning. Infections of the brain and spinal cord can also lead to nerve damage that causes urinary urgency. Some children are born with a condition known as neurogenic bladder. This condition makes it difficult for the nerves and muscles that are responsible for urination to work together properly. This can also lead to overactive bladder and incontinence.
Bladder Abnormalities
Bladder abnormalities that press on the nerves and cause the detrusor muscle to malfunction can be responsible for overactive bladder. Acute conditions, such as bladder stones, may cause overactive bladder temporarily. Once the stones are passed from the urinary tract, urinary urgency should subside. Chronic conditions such as interstitial cystitis may cause persistent overactive bladder that does not get better with time.
Medications
Some medications can cause overactive bladder as a side effect of treatment. This occurs with medications that cause urine to be produced rapidly. Diuretics used to treat congestive heart failure and high blood pressure can cause overactive bladder. These medications increase water and sodium excretion in the urine and may cause the muscles of the bladder to contract involuntarily. The three types of diuretics are potassium-sparing diuretics, thiazide diuretics and loop diuretics, all of which increase urine production.
