Diagnosing Urinary Incontinence

A complete medical history, which includes a voiding diary and incontinence questionnaire, physical examination, and one or more diagnostic procedures helps the physician determine the type of urinary incontinence and an appropriate treatment plan.

Medical History

By asking you questions, your physician can better understand your particular situation and type of incontinence. Questions focus on bowel habits, patterns of urination and leakage (for example, when, how often, how severe), and whether there is pain, discomfort, or straining when voiding. Your doctor will also want to know whether or not you have had any illnesses, pelvic surgeries, and pregnancies, as well as what medications you currently use. In certain situations (such as an elderly person with dementia), a mental status evaluation and assessment of social and environmental factors may be performed.

Physical Examination

A physical examination includes tests of the nervous system and examination of the abdomen, rectum, genitals, and pelvis. The cough stress test, in which the patient coughs forcefully while the physician observes the urethra, allows observation of urine loss. Instantaneous leakage with coughing suggests a diagnosis of stress incontinence. Leakage that is delayed or persistent after the cough suggests urge incontinence. The physical examination also helps the physician identify medical conditions that may be the cause of incontinence. For instance, poor reflexes or sensory responses may indicate a neurological disorder.

Voiding Diary

Your physician may ask you to keep a record of your bladder activity. In the voiding diary, you record fluid intake, fluid output, and any episodes of incontinence. This contributes valuable information to help your physician understand your situation.

Pad Test

The pad test is an objective test that determines whether the fluid loss is in fact urine. You may be asked to take a medication that colors the urine. As fluid leaks onto the pad, it changes color indicating that the fluid lost is urine. The pad test may be performed during a one-hour period or a 24-hour period. The pads may be weighed before and after use to assess the severity of urine loss (1 gram of increased weight = 1 mL of urine lost).

Urine Studies

• Because bladder infection, or urinary tract infection, can cause symptoms similar to urge incontinence, your doctor may obtain a sample of urine for urinalysis and urine culture to see if any bacteria or infection is present.
• Bladder cancer such as carcinoma in situ of the urinary bladder (cancer that is confined to the bladder lining cells in which it originated and has not spread to other tissues) can cause symptoms of urinary frequency and urgency, so a urine sample may be examined for cancer cells (cytology).
• A study of the urine called a chemistry 7 profile may be performed to test for poor kidney (renal) function, obstructed ureters, or urinary retention.

Postvoid Residual Volume

The measurement of postvoid residual (PVR) volume is a part of the basic evaluation for urinary incontinence. The PVR volume is the amount of fluid left in the bladder after urination. If the PVR volume is high, the bladder may not be contracting correctly or the outlet (bladder neck or urethra) may be obstructed. To determine the PVR urine volume, either a bladder ultrasound or a urethral catheter may be used. With ultrasound, a wand-like device is placed over your abdomen. The device sends sound waves through the pelvic area. A computer transforms the waves into an image so your doctor can see how full or empty it is. A catheter is a thin tube inserted through the urethra. It is used to empty any remaining urine from the bladder.

The initial attempt to urinate should be evaluated for hesitancy, straining, or interrupted flow. A PVR volume less than 50 mL indicates adequate bladder emptying. Measurements of 100-200 mL or higher on more than one occasion represent inadequate bladder emptying.

Cough Stress Test

A critical part of the pelvic examination is direct observation of urine loss using the cough stress test. The bladder is filled through a catheter with sterile fluid until it is at least half full (250 mL). The patient is instructed to bear down and tense the abdominal muscles while holding your breath (known as a Valsalva maneuver) or simply cough. Leakage of fluid during the Valsalva maneuver or cough indicates a positive test result.

Q-tip Test

This test is performed by inserting a sterile lubricated cotton swab (Q-tip) into the female urethra. The cotton swab is gently passed into the bladder and then slowly pulled back until the neck of the cotton swab is fit snugly against the outflow tract of the bladder (the bladder neck). The patient is then asked to bear down (Valsalva maneuver) or to simply contract the abdominal muscles. Excessive motion of the urethra and bladder neck (hypermobility) with straining is noted as movement of the Q-tip and may correlate with stress incontinence.

Urodynamic Studies

Urodynamics uses physical measurements such as urine pressure and flow rate as well as clinical assessment. These studies measure the pressure in the bladder at rest and while filling. These studies range from simple observation to precise measurements using specialized equipment.

• Uroflowmetry
• Uroflowmetry, or uroflow, is used to identify abnormal voiding patterns. This is a noninvasive test to measure the volume of urine voided (urinated), the velocity or speed of the urination, and its duration.
• This is used as a screening test to evaluate bladder outlet obstruction. Consistently low flow rates generally indicate a bladder outlet obstruction but also may indicate decreased contraction of the bladder wall muscle. To properly diagnose bladder outlet obstruction, pressure-flow studies are performed.
• Cystometry
• Cystometry is a procedure that measures the capacity and pressure changes of the bladder as it fills and empties. The evaluation determines the presence or absence of detrusor overactivity (or instability).
• Simple cystometry detects abnormal detrusor compliance (a bladder that does not expand enough).
• The multichannel, or subtracted, cystometrogram simultaneously measures intra-abdominal, total bladder, and true detrusor (muscle) pressures. With this technique, the doctor can distinguish between involuntary detrusor (bladder) contractions and increased intra-abdominal pressure.
• The voiding cystometrogram, or pressure-flow study, detects outlet obstruction in patients who are able to urinate at will. The voiding cystometrogram is the only test able to provide information about bladder contractility and the extent of a bladder outlet obstruction.
• A filling cystometrogram assesses the amount the bladder can hold (bladder capacity), how much the bladder can expand (bladder compliance), and the presence of contractions. This test may be performed using either gas or liquid to fill the bladder through a catheter (a small tube inserted into the bladder through the urethra).

Assessment of Urethral Function

• Urethral pressure profilometry: This measures the resting and dynamic pressures in the urethra.
• Abdominal leak point pressure
• Determining the abdominal leak point pressure (ALPP), which is also known as Valsalva leak point pressure, is important. First, the bladder is filled with 250 mL of fluid by a catheter. Then, the patient is instructed to bear down (Valsalva maneuver) in gradients (mild, moderate, severe) to demonstrate leakage. The lowest amount of pressure required to generate leakage is recorded as ALPP.
• By determining ALPP, your doctor can determine whether stress urinary incontinence is due to urethral hypermobility, intrinsic sphincter deficiency, or both in combination.
• Cough leak point pressure (CLPP) is determined in a similar way.

Cystogram

A cystogram is a radiograph (x-ray image) of the bladder. In this procedure, a solution containing a radioisotope (contrast media) is instilled into the bladder via a catheter until the bladder is full (or you indicate that the bladder feels full). X-ray images are then taken of the bladder while full and during or after urination.

A cystogram helps to confirm a diagnosis of stress incontinence, the degree of mobility of the urethra, and the presence of cystocele (a condition occurring in women when the wall between the bladder and vagina weakens and allows the bladder to droop into the vagina, which may cause discomfort and problems with emptying the bladder). These radiographs (x-rays) also may demonstrate problems with the sphincter muscle (intrinsic sphincter deficiency). The presence of a connection between the bladder and the vagina (vesicovaginal fistula) also may be documented in this fashion.

Electromyography

Electromyography is a test to evaluate potential nerve damage. This test measures the muscle activity in the urethral sphincter using sensors placed on the skin near the urethra and rectum. Sometimes the sensors are on the urethral or rectal catheter. Muscle activity is recorded on a machine. The patterns of the impulses will show whether the messages sent to the bladder and urethra are coordinated correctly.

Cystoscopy

Cystoscopy, examination of the inside of the bladder, also is indicated for patients experiencing persistent irritative voiding symptoms or blood in the urine (hematuria). The cystoscope has lenses like a telescope or microscope which allow the doctor to focus on the inner surfaces of the urinary tract. Bladder abnormalities, such as a tumor, stone, and cancer (carcinoma in situ) can be diagnosed with cystoscopy. Urethroscopy can be performed to assess the structure and function of the urethral sphincter mechanism.