Neurogenic bladder
Neurogenic bladder: Excerpt from Professional Guide to Diseases (Eighth Edition)
Neurogenic bladder (also known as neuromuscular dysfunction of the lower urinary tract, neurologic bladder dysfunction, and neuropathic bladder) refers to all types of bladder dysfunction caused by an interruption of normal bladder innervation. Subsequent complications include incontinence, residual urine retention, urinary infection, stone formation, and renal failure. A neurogenic bladder can be spastic (hypertonic, reflex, or automatic) or flaccid (hypotonic, atonic, nonreflex, or autonomous).
Causes
At one time, neurogenic bladder was thought to result primarily from spinal cord injury; now, it appears to stem from a host of underlying conditions:
❑ cerebral disorders, such as stroke, brain tumor (meningioma and glioma), Parkinson’s disease, multiple sclerosis, dementia, and incontinence caused by aging
❑ spinal cord disease or trauma, such as herniated vertebral disks, spina bifida, myelomeningocele, spinal stenosis (causing cord compression) or arachnoiditis (causing adhesions between the membranes covering the cord), cervical spondylosis, myelopathies from hereditary or nutritional deficiencies and, rarely, tabes dorsalis
❑ disorders of peripheral innervation, including autonomic neuropathies resulting from endocrine disturbances such as diabetes mellitus (most common)
❑ metabolic disturbances, such as hypothyroidism, porphyria, or uremia (infrequent)
❑ acute infectious diseases such as transverse myelitis
❑ heavy metal toxicity
❑ chronic alcoholism
❑ collagen diseases such as systemic lupus erythematosus
❑ vascular diseases such as atherosclerosis
❑ distant effects of cancer such as primary oat cell carcinoma of the lung
❑ herpes zoster
❑ sacral agenesis.
An upper motor neuron lesion (above S2 to S4) causes spastic neurogenic bladder, with spontaneous contractions of detrusor muscles, elevated intravesical voiding pressure, bladder wall hypertrophy with trabeculation, and urinary sphincter spasms. A lower motor neuron lesion (below S2 to S4) causes flaccid neurogenic bladder, with decreased intravesical pressure, increased bladder capacity and large residual urine retention, and poor detrusor contraction.
Signs and symptoms
Neurogenic bladder produces a wide range of clinical effects, depending on the underlying cause and its effect on the structural integrity of the bladder. Usually, this disorder causes some degree of incontinence, changes in initiation or interruption of micturition, and the inability to empty the bladder completely. Other effects of neurogenic bladder include vesicoureteral reflux, deterioration or infection in the upper urinary tract, and hydroureteral nephrosis.
Depending on the site and extent of the spinal cord lesion, spastic neurogenic bladder may produce involuntary or frequent scanty urination, without a feeling of bladder fullness, and possibly spontaneous spasms of the arms and legs. Anal sphincter tone may be increased. Tactile stimulation of the abdomen, thighs, or genitalia may precipitate voiding and spontaneous contractions of the arms and legs. With cord lesions in the upper thoracic (cervical) level, bladder distention can trigger hyperactive autonomic reflexes, resulting in severe hypertension, bradycardia, and headaches.
Flaccid neurogenic bladder may be associated with overflow incontinence, diminished anal sphincter tone, and a greatly distended bladder (evident on percussion or palpation), but without the accompanying feeling of bladder fullness due to sensory impairment.
Diagnosis
The patient’s history may include a condition or disorder that can cause neurogenic bladder, incontinence, and disruptions of micturition patterns. Voiding cystourethrography evaluates bladder neck function, vesicoureteral reflux, and continence.
Urodynamic studies help evaluate how urine is stored in the bladder, how well the bladder empties, and the rate of movement of urine out of the bladder during voiding. These studies consist of four components:
❑ Urine flow study (uroflow) shows diminished or impaired urine flow.
❑ Cystometry evaluates bladder nerve supply, detrusor muscle tone, and intravesical pressures during bladder filling and contraction.
❑ Urethral pressure profile determines urethral function with respect to the length of the urethra and the outlet pressure resistance.
❑ Sphincter electromyelography correlates the neuromuscular function of the external sphincter with bladder muscle function during bladder filling and contraction. This evaluates how well the bladder and urinary sphincter muscles work together.
❑ Retrograde urethrography reveals the presence of strictures and diverticula. This test may not be performed on a routine basis.
Treatment
The goals of treatment are to maintain the integrity of the upper urinary tract, control infection, and prevent urinary incontinence through evacuation of the bladder, drug therapy, surgery or, less commonly, neural blocks and electrical stimulation.
Techniques of bladder evacuation include Credé’s method, Valsalva’s maneuver, and intermittent self-catheterization. Credé’s method — application of manual pressure over the lower abdomen — promotes complete emptying of the bladder. After appropriate instruction, most patients can perform this maneuver themselves. Even when patients perform this maneuver properly, however, Credé’s method isn’t always successful and doesn’t always eliminate the need for catheterization.
Intermittent self-catheterization — more effective than either Credé’s method or Valsalva’s maneuver — has proved to be a major advance in the treatment of neurogenic bladder because it allows complete emptying of the bladder without the risks that an indwelling catheter poses. Generally, a male can perform this procedure more easily but a female can learn self-catheterization with the help of a mirror. Intermittent self-catheterization, in conjunction with a bladder-retraining program, is especially useful for patients with flaccid neurogenic bladder.
Drug therapy for neurogenic bladder may include bethanechol and phenoxybenzamine to facilitate bladder emptying and propantheline, methantheline, flavoxate, dicyclomine, and imipramine to facilitate urine storage.
When conservative treatment fails, surgery may correct the structural impairment through transurethral resection of the bladder neck, urethral dilatation, external sphincterotomy, or urinary diversion procedures. Implantation of an artificial urinary sphincter may be necessary if permanent incontinence follows surgery for neurogenic bladder.
Special considerations
Care for patients with neurogenic bladder varies according to the underlying cause and method of treatment.
❑ Explain all diagnostic tests clearly so the patient understands the procedure, time involved, and possible results. Assure the patient that the lengthy diagnostic process is necessary to identify the most effective treatment plan. After the treatment plan is chosen, explain it to the patient in detail.
❑ Use strict sterile technique during insertion of an indwelling catheter (a temporary measure to drain the incontinent patient’s bladder). Don’t interrupt the closed drainage system for any reason. Obtain urine specimens with a syringe and small-bore needle inserted through the aspirating port of the catheter itself (below the junction of the balloon instillation site). Irrigate in the same manner if ordered.
❑ Clean the catheter insertion site with soap and water at least twice a day. Don’t allow the catheter to become encrusted. Use a sterile applicator to apply antibiotic ointment around the meatus after catheter care. Keep the drainage bag below the tubing, and don’t raise the bag above the level of the bladder. Clamp the tubing, or empty the bag before transferring the patient to a wheelchair or stretcher to prevent accidental urine reflux. If urine output is considerable, empty the bag more frequently than once every 8 hours because bacteria can multiply in standing urine and migrate up the catheter and into the bladder.
❑ Watch for signs of infection (fever, cloudy or foul-smelling urine). Encourage the patient to drink plenty of fluids to prevent calculus formation and infection from urinary stasis. Try to keep the patient as mobile as possible. Perform passive range-of-motion exercises if necessary.
❑ If urinary diversion procedure is to be performed, arrange for consultation with an enterostomal therapist, and coordinate the care plans.
❑ Before discharge, teach the patient and his family evacuation techniques as necessary (Credé’s method, intermittent catheterization). Counsel him regarding sexual activities. Remember, the incontinent patient feels embarrassed and distressed. Provide emotional support.
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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