Mixed Urinary Incontinence

Etiology

There are 3 major types of urinary incontinence:

• Stress urinary incontinence
• Urgency urinary incontinence
• Mixed urinary incontinence[1]

There are also a variety of subtypes including genitourinary (fistula, infectious, congenital) and non-genitourinary (functional, environmental, pharmacological, metabolic). Classification is endorsed by the International Urogynecological Association (IUGA)/International Incontinence Society (ICS).

Stress incontinence is the involuntary loss of urine with increased intraabdominal pressure or physical exertion (coughing, sneezing, jumping, lifting, exercise). The pathophysiology is due to pelvic floor weakness/prolapse and/or loss of the normal urethra vesical angle.

Urge incontinence is the involuntary loss of urine preceded by a sudden and severe desire to pass urine. Bladder contractions may be stimulated by a change in body position (from supine to upright) or with sensory stimulation (running water, hand washing, cold weather). The pathophysiology is uninhibited bladder contractions caused by irritation or loss of neurologic control of bladder contractions.

Mixed urinary incontinence is a combination of stress and urge incontinence. This type may take on the pathophysiology of both.[3]

Epidemiology

Urinary incontinence affects nearly 40% of all adult American women. More than 25% of teenage and college-aged female athletes experience incontinence with more than 90% withholding incontinence information to their primary care providers. In nursing homes, approximately 6% of admissions are due to urinary incontinence. The cost to treat urinary incontinence either medically or surgically is well over $10 billion per year. Urinary incontinence, particularly mixed type, is an issue across all age groups.[4]

Pathophysiology

The pathophysiology of stress incontinence is due to pelvic floor weakness or prolapse and/or loss of the normal urethra vesical angle. The pathophysiology of urge incontinence is uninhibited bladder contractions caused by irritation or loss of neurologic control of bladder contractions.

History and Physical

A thorough history needs to be obtained to help diagnose urinary incontinence. The clinician should ask for this information directly since the patient may be too embarrassed to talk about symptoms of increased frequency, urgency, or dysuria. Signs may include hesitancy, slow stream, straining to void, incomplete emptying, or wetting pads or clothes. Details about the nature of incontinence are invaluable. These can include duration, precipitating events, voiding frequency, and fluid intake. Many validating questionnaires can assess symptomatic effects on daily living. Comorbidities and confounding factors should also be explored. Medications that affect urinary incontinence should be reviewed, particularly cholinergic drugs and diuretics. Lack of estrogen during perimenopause or postmenopause should also be discussed. Bladder diaries may be used by both patient and physician for objective means of quantifying incontinence.[5]

The focus on the physical exam on patients with mixed incontinence should focus on abdominal and pelvic areas. A large panniculus, prior surgical incisions, and suprapubic muscle tone should be noted. The patient should be examined with both a full and empty bladder in standing and supine positions. The grade of uterine, vaginal prolapse should be assessed along with obvious stress urinary incontinence with coughing.[1]

Evaluation

Simple office incontinence testing should be utilized to help differentiate the 3 types of urinary incontinence. A positive cough stress test in both the sitting and supine positions is highly diagnostic for stress incontinence. Vaginal prolapse may mask or decrease incontinence symptoms; therefore, it is important to elevate the areas of prolapse surrounding the urethra and check for incontinence with stress (Marshall Test). A Q-tip test is performed with a cotton-tipped swab to check for urethral mobility. A displacement of the urethral angle of at least 30 degrees with Valsalva is suggestive of urethral hypermobility. A urinalysis and culture should be sent for any infectious process such as cystitis. A post-void residual urine volume is measured to check for overflow incontinence. Indications for multi-channel urodynamics include:

• Abnormal office cystometry tests
• Continuous, unpredictable leakage
• Pelvic radiation
• History of radical pelvic surgery
• Previous incontinence surgery[6]

Treatment / Management

The primary care provider including the general obstetrics and gynecology physician can treat most cases of urinary incontinence with behavioral techniques or pharmacologic agents. However, referral to a urogynecologist and or urologist may be necessary particularly when surgical intervention is necessary with mixed incontinence. Indications for referral may include:

• Uncertain diagnosis
• Unsuccessful medical therapy
• Patients with “heavy” stress urinary incontinence (multiple pads per day)
• Symptomatic pelvic organ prolapse
• Voiding dysfunction (elevated post-void residual)
• Underlying neurologic condition
• Prior failed surgery
• Hematuria without infection
• Recurrent urinary tract infections
• Surgical intervention considered when a patient is not satisfied even when the urge component of mixed incontinence cured[7]

The treatment of mixed urinary incontinence should always begin with the least invasive management to see if symptoms are tolerable or minimized by the patient. Behavioral methods include:

• Dietary changes (no coffee, tea, soda, chocolates, or methylxanthines)
• Bladder retraining (timed voiding)
• Kegel exercises
• Biofeedback
• Electrostimulation
• Collagen injections
• Pessaries (multiple types and sizes  to fit the patient properly so the pessary does not fall out or cause difficulty with voiding)[8]
(A1)

Pharmacologic agents may help improve voiding dysfunction with urge incontinence. Medications include:

• Oxybutynin
• Ca channel blockers
• Tricyclic antidepressants
• Alpha-adrenergics
• Estrogen[9]
(A1)

When mixed urinary incontinence includes significant prolapse with stress urinary incontinence and pelvic pressure symptoms, surgical treatment provides the best overall cure. The current goals of surgery include:

• Restore and/or reinforce the pubourethral ligaments at the mid-urethra level
• Restore and/or reinforce the suburethral vaginal hammock at the mid-urethra
• Reinforce the paraurethral connective tissue

Surgical treatment includes both abdominal and vaginal procedures with similar cure rates:

• Abdominal: Marshall Marchetti Krantz (MMK), Burch, paravaginal repair, laparoscopic procedures
• Vaginal: Modified Pereyra procedure (MPP), Stamey, RAZ, sling procedures (TVT) (TVT-O)[10]

Always attempt conservative treatment first with behavioral techniques or medications even if surgery is planned for mixed incontinence. The patient may be satisfied with improved incontinence if it avoids any surgical procedure, particularly if the patient is high risk.

Differential Diagnosis

• Cystitis

• Multiple sclerosis

• Prostatitis

• Spinal cord neoplasms

• Spinal cord trauma

• Spinal cord abscess

• Urinary obstruction

• Urinary tract infections in males

• Uterine prolapse

• Vaginitis

Prognosis

If the stress urinary incontinence cure is desired (no leakage), proper informed consent for surgical treatment should be discussed and explained to the patient. Counseling regarding surgical success rates. Abdominally or vaginally the rates are approximately 86% for a cure, 7% improvement rate, and 7% failure rate.[10]

A clinical cure, meaning no further incontinence, means the patient does not need postoperative urodynamic testing. Clinical improvement (occasional intermittent incontinence) or failed procedures require urodynamic testing to differentiate stress versus urge or any other subtypes. Behavioral or medical therapy may be necessary in refractory cases with the possibility of another reoperation as a last resort.

Complications

The risk of surgical treatment pertinent to stress urinary incontinence should also be documented and explained to the patient. Risks include:

• Infection
• Bleeding with transfusion
• Injury to the genitourinary or gastrointestinal tract
• Postop dyspareunia[10]
• Persistent or recurrent urinary incontinence or prolapse