Neurogenic Bladder - Dysfunctional Voiding Patterns

NEUROGENIC BLADDER

Neurogenic bladder is a dysfunction that results from a lesion ofthe nervous system. It may be caused by spinal cord injury, spinal tumor, herniated vertebral disk, multiple sclerosis, congenital anomalies (spina bifida or myelomeningocele), infection, or dia-betes mellitus.

Pathophysiology

The two types of neurogenic bladder are spastic (or reflex) blad-der and flaccid bladder. Spastic bladder is the more common type and is caused by any spinal cord lesion above the voiding reflex arc (upper motor neuron lesion). The result is a loss of conscious sensation and cerebral motor control. A spastic bladder empties on reflex, with minimal or no controlling influence to regulate its activity.

Flaccid bladder is caused by a lower motor neuron lesion, commonly resulting from trauma. This form of neurogenic blad-der has increasingly been recognized as a problem in patients with diabetes mellitus. The bladder continues to fill and becomes greatly distended, and overflow incontinence occurs. The blad-der muscle does not contract forcefully at any time. Because sen-sory loss may accompany a flaccid bladder, the patient feels no discomfort.

Assessment and Diagnostic Findings

Evaluation for neurogenic bladder involves measurement of fluid intake, urine output, and residual urine volume; urinalysis; and assessment of sensory awareness of bladder fullness and de-gree of motor control. Comprehensive urodynamic studies are also performed.

Complications

The most common complication of neurogenic bladder is infec-tion resulting from urinary stasis and catheterization. Urolithia-sis (stones in the urinary tract) may develop from urinary stasis, infection, or demineralization of bone from prolonged immobilization. Renal failure can also occur from vesicoureteral reflux (backward flow of retained urine from the bladder into the ureters) with eventual hydronephrosis (dilation of the pelvis of the kidney resulting from obstruction to the flow of urine) and atrophy of the kidney. Indeed, renal failure is the major cause of death of pa-tients with neurologic impairment of the bladder.

Medical Management

The problems resulting from neurogenic bladder disorders vary considerably from patient to patient and are a major challenge to the health care team. There are several long-term objectives ap-propriate for all types of neurogenic bladders:

·      Preventing overdistention of the bladder

·       Emptying the bladder regularly and completely

·       Maintaining urine sterility with no stone formation

·       Maintaining adequate bladder capacity with no reflux

Specific interventions include continuous, intermittent, or self-catheterization, use of an ex-ternal condom-type catheter, a diet low in calcium (to prevent calculi), and encouragement of mobility and ambulation. A lib-eral fluid intake is encouraged to reduce the urinary bacterial count, reduce stasis, decrease the concentration of calcium in the urine, and minimize the precipitation of urinary crystals and sub-sequent stone formation.

To further enhance bladder emptying of a flaccid bladder, the individual may try “double voiding.” After each voiding, the in-dividual remains on the toilet, relaxes for 1 to 2 minutes, and then attempts to void again in an effort to further empty the bladder. This can be effective in patients with disorders characterized by neurogenic bladder (eg, multiple sclerosis) (Halper, 1998).

Use of timed, or habit, voiding is also considered. For exam-ple, a 2-hour voiding schedule may be established to prevent overdistention. A bladder retraining program may be effective in treating a spastic bladder or urine retention (Davies et al., 2000; Joseph, 1999).

PHARMACOLOGIC THERAPY

Parasympathomimetic medications, such as bethanechol (Ure-choline), may help to increase the contraction of the detrusor muscle.

SURGICAL MANAGEMENT

In some cases, surgery may be carried out to correct bladder neck contractures or vesicoureteral reflux or to perform some type of urinary diversion procedure.

CATHETERIZATION

In patients with a urologic disorder or with marginal kidney func-tion, care must be taken to ensure that urinary drainage is ade-quate and that kidney function is preserved. When urine cannot be eliminated naturally and must be drained artificially, catheters may be inserted directly into the bladder, the ureter, or the renal pelvis. Catheters vary in size, shape, length, material, and config-uration. The type of catheter used depends on its purpose.Catheterization is performed to achieve the following:

·      Relieve urinary tract obstruction

·        Assist with postoperative drainage in urologic and other surgeries

·      Provide a means to monitor accurate urine output in criti-cally ill patients

·      Promote urinary drainage in patients with neurogenic blad-der dysfunction or urine retention

·      Prevent urinary leakage in patients with stage III to IV pres-sure ulcers

A patient should be catheterized only if necessary because catheterization commonly leads to urinary tract infection. In ad-dition, urinary catheters have been associated with other compli-cations, such as bladder spasms, urethral strictures, and pressure necrosis.

Indwelling Devices and Infections. 

When an indwelling cath-eter cannot be avoided, a closed drainage system is essential. This drainage system is designed to prevent any disconnections, thereby reducing the risk of contamination. One common system consists of an indwelling catheter, a connecting tube, and a collecting bag with an antireflux chamber emptied by a drainage spout. Another common system has a triple-lumen indwelling urethral catheter attached to a closed sterile drainage system. With the triple-lumen catheter, urinary drainage occurs through one channel. The re-tention balloon of the catheter is inflated with water or air through the second channel, and the bladder is continuously irrigated with sterile irrigating solution through the third channel. Triple-lumen catheters are commonly used after transurethral prostate surgery.

An indwelling catheter can lead to infection. Bacterial colo-nization (bacteriuria) occurs within 2 weeks in half of catheter-ized patients and within 4 to 6 weeks in almost all patients after insertion of a catheter—even if recommendations for infection control and catheter care are followed carefully.

Urinary tract infections are the most commonly occurring nosocomial infections, accounting for 40% of them. Every year, about 1 million patients in acute-care hospitals develop nosoco-mial urinary tract infections, and about 80% of these are associ-ated with the use of indwelling urinary catheters (Phillips, 2000). Most urinary tract infections follow instrumentation of the uri-nary tract, usually catheterization. The pathogens responsible for catheter-associated urinary tract infections include Escherichiacoli and Klebsiella, Proteus, Pseudomonas, Enterobacter, Serratia, and Candida species. Many of these organisms are part of the pa-tient’s endogenous or normal bowel flora or are acquired through cross-contamination by patients or health care personnel or through exposure to nonsterile equipment.

Catheters impede most of the natural defenses of the lower urinary tract by obstructing the periurethral ducts, irritating the bladder mucosa, and providing an artificial route for organisms to enter the bladder. Organisms may be introduced from the ure-thra into the bladder during catheterization, or they may migrate along the epithelial surface of the urethra or external surface of the catheter.

The spout of the urinary drainage bag can become contami-nated when opened to drain the bag. Bacteria enter the urinary drainage bag, multiply rapidly, and then migrate to the drainage tubing, catheter, and bladder. Scanning electron microscopy has demonstrated that thick layers (biofilms) of organisms often colonize the internal surfaces of catheters and drainage systems (Doyle et al., 2001; Godfrey & Evans, 2000; Phillips, 2000).

Suprapubic Catheterization. 

Suprapubic catheterization allowsbladder drainage by inserting a catheter or tube into the bladder through a suprapubic (above the pubis) incision or puncture (Fig. 44-2). 

It may be a temporary measure to divert the flow of urine from the urethra when the urethral route is impassable (be-cause of injuries, strictures, prostatic obstruction), after gyneco-logic or other abdominal surgery when bladder dysfunction is likely to occur, and occasionally after pelvic fractures. Suprapu-bic catheters may also be used on a long-term basis for women with urethral destruction secondary to long-term indwelling ure-thral catheters (Addison, 1999a, 1999b).

For insertion of the suprapubic catheter, the patient is placed in a supine position and the bladder distended by administering oral or intravenous fluids or by instilling sterile saline solution into the bladder through a urethral catheter. These measures make it easier to locate the bladder. The suprapubic area is prepared as for surgery and the puncture site located about 5 cm (2 in) above the symphysis pubis. The bladder is entered through an incision or through a puncture made by a small trocar (pointed instrument). The catheter or suprapubic drainage tube is threaded into the blad-der and secured with sutures or tape; the area around the catheter is covered with a sterile dressing. The catheter is connected to a sterile closed drainage system, and the tubing is secured to pre-vent tension on the catheter.

Suprapubic bladder drainage may be maintained continuously for several weeks. When the patient’s ability to void is to be tested, the catheter is clamped for 4 hours, during which time the patient attempts to void. After the patient voids, the catheter is un-clamped, and the residual urine (the amount of urine remaining) is measured. If the amount of residual urine is less than 100 mL on two separate occasions (morning and evening), the catheter is usually removed. If the patient complains of pain or discomfort, however, the suprapubic catheter is usually left in place until the patient can void successfully. When a suprapubic catheter remains in place indefinitely, it is changed regularly at 6- to 12-week in-tervals (Gujral et al., 1999).

Suprapubic drainage offers certain advantages. Patients can usually void sooner after surgery than those with urethral cath-eters, and they may be more comfortable. The catheter allows greater mobility, permits measurement of residual urine without urethral instrumentation, and presents less risk of bladder infec-tion. The suprapubic catheter is removed when it is no longer necessary, and a sterile dressing is placed over the site.

The patient requires liberal amounts of fluid to prevent en-crustation around the catheter. Other potential problems include the formation of bladder stones, acute and chronic infections, and problems collecting urine. An enterostomal therapist may be con-sulted to assist the patient and family in selecting the most suitable urine collection system and to teach them about its use and care.

Nursing Management During Catheterization

ASSESSING THE PATIENT AND THE SYSTEM

For patients with indwelling catheters, the nurse assesses the drainage system to ensure that it provides adequate urinary drain-age. The color, odor, and volume of urine are also monitored. An accurate record of fluid intake and urine output provides essen-tial information about the adequacy of renal function and urinary drainage.

The nurse observes the catheter to make sure that it is prop-erly anchored, to prevent pressure on the urethra at the peno-scrotal junction in male patients, and to prevent tension and traction on the bladder in both male and female patients.

Patients at high risk for urinary tract infection from catheter-ization need to be identified and monitored carefully. These in-clude women, older adults, and patients who are debilitated, malnourished, chronically ill, immunosuppressed, or diabetic. They are observed for signs and symptoms of urinary tract infec-tion: cloudy malodorous urine, hematuria, fever, chills, anorexia, and malaise. The area around the urethral orifice is observed for drainage and excoriation. Urine cultures provide the most accu-rate means of assessing a patient for infection.

Bladder ultrasonography can be used for noninvasive mea-surement of bladder volume. A portable bladder scan can be per-formed to assess the volume of urine in the bladder, the degree of bladder emptying, and therefore the need for catheterization (Phillips, 2000; Schott-Baer & Reaume, 2001).

ASSESSING FOR AGE-RELATED COMPLICATIONS

Elderly patients with an indwelling catheter may not exhibit the typical signs and symptoms of infection. Therefore, any subtle change in physical condition or mental status must be considered a possible indication of infection and promptly investigated because sepsis may occur before the infection is diagnosed. Figure 44-3 summarizes the sequence of events leading to infection and leak-age of urine that often follow long-term use of an indwelling catheter in elderly patients.

PREVENTING INFECTION

Certain principles of care are essential to prevent infection in pa-tients with a closed urinary drainage system (Chart 44-5). The catheter is a foreign body in the urethra and produces a reaction in the urethral mucosa with some urethral discharge. Vigorous cleaning of the meatus while the catheter is in place is discour-aged, however, because the cleaning action can move the catheter to and fro, increasing the risk of infection. To remove obvious en-crustations from the external catheter surface, the area can be washed gently with soap during the daily bath. The catheter is an-chored as securely as possible to prevent it from moving in the urethra. Encrustations arising from urinary salts may serve as a nucleus for stone formation; however, using silicone catheters results in significantly less crust formation.

A liberal fluid intake, within the limits of the patient’s cardiac and renal reserve, and an increased urine output must be ensured to flush the catheter and to dilute urinary substances that might form encrustations.

Urine cultures are obtained as prescribed or indicated in mon-itoring the patient for infection; many catheters have an aspiration (puncture) port from which a specimen can be obtained.

Controversy exists about the usefulness of taking cultures and treating bacteriuria in patients who have symptoms of infection and who have indwelling catheters. Bacteriuria is considered to be inevitable, and overtreatment may lead to resistant strains of bacteria (Suchinski et al., 1999).

MINIMIZING TRAUMA

Trauma to the urethra can be minimized by:

·      Using an appropriate-sized catheter

·      Lubricating the catheter adequately with a water-soluble lu-bricant during insertion

·      Inserting the catheter far enough into the bladder to prevent trauma to the urethral tissues when the retention balloon of the catheter is inflated

Manipulation of the catheter is the most common cause of trauma to the bladder mucosa in the catheterized patient. In-fection then inevitably occurs when urine invades the damaged mucosa.

The catheter is secured properly to prevent it from moving, causing traction on the urethra, or being unintentionally re-moved, and care is taken to ensure that the catheter position per-mits leg movement. In male patients, the drainage tube (not the catheter) is taped laterally to the thigh to prevent pressure on the urethra at the penoscrotal junction, which can eventually lead to formation of a urethrocutaneous fistula. In female patients, the drainage tubing attached to the catheter is taped to the thigh to prevent tension and traction on the bladder.

Care is taken to ensure that any patient who is confused does not remove the catheter with the retention balloon still inflated. This could cause bleeding and considerable injury to the urethra (Phillips, 2000).

RETRAINING THE BLADDER

When an indwelling urinary catheter is in place, the detrusor muscle does not actively contract the bladder wall to stimulate emptying, because urine is continuously draining from the blad-der. As a result, the detrusor may not immediately respond to bladder filling when the catheter is removed, resulting in either urine retention or urinary incontinence. This condition, known as postcatheterization detrusor instability, can be managed with bladder retraining (Chart 44-6).

Immediately after the indwelling catheter is removed, the pa-tient is placed on a timed voiding schedule, usually every 2 to 3 hours. At the given time interval, the patient is instructed to void. The bladder is then scanned using a portable ultrasonic blad-der scanner. If 100 mL or more of urine remains in the bladder, straight catheterization may be performed for complete bladder emptying. 

After a few days, as the nerve endings in the bladder wall become aware of bladder filling and emptying, bladder func-tion usually returns to normal. If the individual has had an in-dwelling catheter in place for an extended period, bladder retraining will take much longer; in some cases, function may never return to normal. If this occurs, long-term intermittent catheterization may become necessary (Phillips, 2000).

ASSISTING WITH INTERMITTENT SELF-CATHETERIZATION

Intermittent self-catheterization provides periodic drainage of urine from the bladder. By promoting drainage and eliminating excessive residual urine, intermittent catheterization protects the kidneys, reduces the incidence of urinary tract infections, and improves continence. 

It is the treatment of choice in patients with spinal cord injury and other neurologic disorders, such as multi-ple sclerosis, when the ability to empty the bladder is impaired. Self-catheterization promotes independence, results in few com-plications, and enhances self-esteem and quality of life.

When teaching the patient how to perform self-catheterization, the nurse must use aseptic technique to minimize the risk of cross-contamination. The patient, however, may use a “clean” (non-sterile) technique at home, where the risk of cross-contamination is reduced. Either antibacterial liquid soap or povidone-iodine (Betadine) solution is recommended for cleaning urinary cath-eters at home. The catheter is thoroughly rinsed with tap water after soaking in the cleaning solution. It must dry before reuse. It should be kept in its own container, such as a plastic food-storage bag.

In teaching the patient, the nurse emphasizes the importance of frequent catheterization and emptying the bladder at the pre-scribed time. The average daytime clean intermittent catheteri-zation schedule is every 4 to 6 hours and just before bedtime. If the patient is awakened at night with an urge to void, catheteri-zation may be performed after an attempt to void (Reilly, 2001).

The female patient assumes a Fowler’s position and uses a mirror to help locate the urinary meatus. She inserts the catheter 7.5 cm (3 in) into the urethra, in a downward and backward di-rection. The male patient assumes a Fowler’s or sitting position, lubricates the catheter and retracts the foreskin of the penis with one hand while grasping the penis and holding it at a right angle to the body. (This maneuver straightens the urethra and makes it easier to insert the catheter.) He inserts the catheter 15 to 25 cm (6 to 10 in) until urine begins to flow. After removal, the catheter is cleaned, rinsed, and wrapped in a paper towel or placed in a plastic bag or case. Patients following this routine should consult a primary health care provider at regular intervals to assess urinary function and to detect complications.

If the patient cannot perform intermittent self-catheterization, a family member may be taught to carry out the procedure at reg-ular intervals during the day.

Another self-catheterization option is creation of the Mitro-fanoff umbilical appendicovesicostomy, which provides easy access to the bladder. In this procedure, the bladder neck is closed and the appendix is used to gain access to the bladder from the skin surface. A submucosal tunnel is created with the appendix; one end of the appendix is brought to the skin surface and used as a stoma and the other end is tunneled into the bladder. The ap-pendix may be used as an artificial urinary sphincter when an alter-native is necessary to empty the bladder. In children, the most common reason for the procedure is spina bifida. In adults, a sur-gically prepared continent urine reservoir with a sphincter mecha-nism is required in cases of bladder cancer, severe interstitial cystitis, or in males, bladder exstrophy-epispadias complex when a radical cystectomy (surgical removal of the bladder) is necessary. This pro-cedure for surgically creating a sphincter, which is attached to an internal pouch reservoir that can be catheterized, is possible only in individuals who have a healthy appendix (Kajbafzadeh & Chubak, 2001; Uygur et al., 2001).