Symptoms & Causes
Affecting an estimated 33 million Americans, overactive bladder (OAB) is a term used to describe a collection of symptoms that include:
- Frequency of urination: urinating at least eight times per day
- Nocturia: getting up and urinating at least two times per night
- Urge incontinence: a seepage of urine when the urge to urinate occurs
- Urinary urgency: failure to postpone the need to urinate
OAB occurs when the muscles of the bladder start to contract involuntary, regardless of the volume of urine, due to a disruption in the signals between the brain and bladder. The involuntary contraction is what causes the sensation of needing to urinate. This condition occurs mostly in women but may also occur in men, and can be a source of embarrassment for those living with it.
What are the risk factors for developing OAB?
While the most common risk factor for OAB is increasing age, other common factors may include:
- Consuming alcohol or caffeine
- Diabetic nerve damage
- Having multiple pregnancies
- Infection, such as a urinary tract infection (UTI)
- Nerve damage due to multiple sclerosis (MS)
- Parkinson’s disease
- Previous pelvic surgery
- Previous stroke resulting in nerve damage
- Prostate surgery
- Spinal cord injury
- Taking certain medications
How is OAB diagnosed?
After ruling out an infection or a neurological issue, a urologist may order a urodynamic test to assess function of the bladder. Types of urodynamic tests include:
Assessing bladder pressures
This test (known as cystometry) measures pressure in the bladder and surrounding region. During the procedure, a catheter is fed into the bladder and fills it with warm water. An additional catheter with a sensor is placed in the rectum or vagina that identifies if the bladder is experiencing involuntary muscle contractions, or is unable to store urine under low pressure.
Patients may also be asked to participate in a pressure flow study, which measures the amount of pressure used to empty the bladder. It is usually used to confirm or rule out an obstruction.
It should be noted that this test is generally used for patients with established neurological diseases that affect the spinal cord.
Measuring urine left in the bladder
This test is used to determine if the bladder doesn’t empty completely after urination or is experiencing urinary incontinence. Any leftover urine may cause symptoms that mimic the symptoms of OAB. To check for leftover urine, an ultrasound may be ordered. The bladder may also be drained by the urologist via catheter and measured.
Measuring the volume and speed in which urine leaves the body
Known as uroflowmetry,this test uses a device patients urinate into that measures changes in the rate at which urine flows.