Overactive bladder (OAB) affects 17-20 million Americans. It is characterized by the sudden urge to urinate with or without the loss of urine. This results in frequent urges to urinate usually both day and night. In many instances, there is an urge so strong that it results in loss of urine. The loss may be anywhere from a few drops of urine to the complete emptying of the bladder. This condition affects daily quality of life. People may avoid social interaction as well as curtail travel plans. Around 60% of OAB people are dry and have only urgency. The other 40% have urgency with incontinence.
Stress Urinary Incontinence (SUI) is a separate kind of urinary incontinence distinctly different from OAB. Stress incontinence is common in women after childbirth and in men after prostate surgery. Sudden cough, sneeze, or any sudden, unexpected movement leads to loss of urine. Usually, there is no associated urge to urinate.
Mixed incontinence is a combination of OAB and SUI. This occurs when a cough or sneeze pushes down on the bladder, and that pressure starts an uncontrollable bladder contraction or bladder spasm. To most patients, SUI and mixed incontinence appear to be the same.
The difference is significant in that OAB responds to medication, and SUI requires surgery to resuspend the bladder. To confuse things even more, bladder suspension surgeries that are tightened too much can convert SUI to OAB.
Overflow incontinence is associated with leakage from the bladder that is overfilled and incompletely emptied. Often, people have lost the sensation that they are full. They often leak at night, wetting the bed (enuresis). They may note leakage while sitting for long periods of time. They report getting up after sitting to find that the chair or sofa is wet, and they never felt the leakage.
Causes of OAB
The cause of OAB is not always obvious. The most common neurologic conditions that cause OAB are stroke, Parkinson’s disease, and a spinal cord injury. Multiple sclerosis and peripheral nerve damage in the lumbar spine can also cause OAB. Non neurologic causes are bladder cancer, prostate enlargement or BPH, and interstitial cystitis. Bladder stones and urinary infections may cause OAB symptoms. Some medications may induce OAB symptoms.
Symptoms of Overactive Bladder
- Sudden urge to urinate
- Urinating 2 or more times a night
- Incontinence of urine
- More frequent urination than 8 times per 24-hour period
Diagnosis of Overactive Bladder
The diagnoses of SUI and OAB are first separated by a complete history. A complete history will help answer the following questions:
- When does it occur?
- How long has it been going on?
- Does it occur with change of position? Is it lying to sitting or sitting to standing?
- Does it occur when you are running water in the sink or pumping gasoline into your car?
- Does it wake you up at night needing to go to the toilet?
- Does leakage occur without warning?
- When going someplace new, is the location of the bathroom the first thing you look for?
- Do you have blood in your urine?
- Do you have painful intercourse?
Tests for Overactive Bladder
Urinalysis is used to look for blood and/or infection.
Noninvasive, painless bladder scanning is used to look for incomplete emptying. Catheterization is used in some offices if no bladder scanner is available.
Focused neurological examination may be needed.
Pelvic examination looks for leakage with cough and cystocele formation. Cystoceles form when the bladder falls into the vagina. This is most commonly found after childbirth.
X-rays may be ordered if the urinalysis is abnormal and the urine contains blood or shows signs of infection.
Cystoscopy may be needed to evaluate the inside of the bladder. This is an endoscopic inspection of the bladder lining. The evaluation looks for bladder stones, BPH, tumors, and signs of infection.
A urine cytology is used to check the urine for cancer cells.
Urodynamics or cystometrics can be used. This procedure fills the bladder with water and measures the bladder’s filling pressure and its response to filling, such as unstable bladder contractions.
Blood is drawn to assess kidney function and to look for diabetes.
Treatments for OAB
Medication is the first line of treatment for OAB and mixed incontinence. The bladder nerves are modulated by a chemical transmitter called acetylcholine. Acetylcholine attaches to the muscarinic (M2 and M3) receptors in the bladder to stimulate muscle contractions. The medications for OAB are called anticholinergic or antimuscarinic medications. These medications attach to the muscarinic receptors and block these bladder receptors thus blocking the bladder spasms. The commonly available medications are Detrol (Tolterodine), Ditropan and Gelnique (Oxybutynin), Enablex (Darifenacin), Levsin (Hyoscyamine), Sanctura (Trospium), Toviaz (Fesoterodine), and VESIcare (Solifenacin).
The major side effects of this group are constipation and dry mouth. Older drugs such as oral generic Oxybutynin have more of these side effects and have been associated with decline in cognitive function in the elderly. Dry mouth is common, and you should see your dentist every 6 months. Dry mouth leads to an increase in cavities and gum disease. Watch for signs of urinary retention or the inability to urinate. While retention is rare, it can occur. Men are more likely to have retention than women. In men, these medications are almost always used in combination with an alpha blocker such as Flomax (Tamsulosin) to prevent retention. Dry eyes may be noted and are treated with eye drops. Occasionally, the dry mouth causes you to drink more, and this increased fluid intake worsens OAB. Likewise, constipation caused by these medications can worsen OAB. Your insurance likely has a list of approved drugs. Not all people with OAB respond equally well to all medications. You need to ask your doctor for a trial of all medications available until you find one that works for you without excessive dry mouth or constipation. Once you find one with acceptable side effects, it will take several months for your system to fully calm down the OAB.
The newest addition to the OAB market is Myrbetriq (Mirabegron). This is a new class of drug called a beta agonist. It stimulates beta-3 adrenergic receptors. This relaxes the bladder avoiding the side effect of constipation that is so common among the anticholinergic drugs.
Behavioral Therapies for Overactive Bladder
Some people will benefit from changes in their daily routine. Avoidance of stimulants such as caffeine may reduce the number and intensity of the urges. Cutting back on alcohol intake also helps. Kegel’s exercises may be done for both SUI and OAB. Weight loss lessens the downward pressure the abdominal contents put on the pelvis and bladder. Keeping a voiding diary may give you insight into triggers for your OAB. Fluid management is helpful in some cases. Be sure not to cut back on fluids to the point of dehydration. Biofeedback helps some people learn to relax their pelvic muscles, and this lessens the urgency.
Avoiding spicy foods, acidic foods, alcohol, and caffeine-containing beverages may help.
Constipation should be prevented with an increased intake of fiber or with stool softeners. Constipation leads to an increase in frequency and urgency.
Neuromodulation of Overactive Bladder
Neuromodulation with implantable sacral nerve root stimulators may help people not responding to medications and behavioral modifications. The brand name for this device is an Interstim. This treatment relies on insertion of an electrode into the S3 sacral foramen to the 3rd sacral nerve root. This electrode is then hooked to a pacemaker-like generator. Before the permanent device is implanted, a temporary device is used for 4-5 days to see if the treatment is right for you. If you get relief, then the permanent generator is placed under the skin just like a pacemaker.
Botox Injection for Overactive Bladder
Recently, the FDA approved Botox for direct injection into the bladder. Its role in OAB is not yet fully worked out. The dosing schedule is about every 4-6 months. It requires the direct injection of Botox into about 20 sites in the bladder wall. In some studies, it was shown as many as 30% of patients develop urinary retention. They must then learn to do self, clean, intermittent catheterization on themselves.
Surgery for Overactive Bladder
In women having prolapse of the bladder, surgical repair to support the bladder may relieve urgency. Mild cystoceles that undergo repair may or may not relieve urgency with incontinence. Occasionally after SUI surgery, OAB symptoms will start or worsen especially if the sling is too tight or if there is postoperative urinary retention.