Neurogenic bladder
Neurogenic bladder: Excerpt from Handbook of Diseases
Also known as neuromuscular dysfunction of the lower urinary tract, neurologic bladder dysfunction, and neuropathic bladder, neurogenic bladder refers to all types of bladder dysfunction caused by an interruption of normal bladder innervation. Subsequent complications include urinary incontinence, residual urine retention, urinary tractinfection, calculiformation, and renal failure. A neurogenic bladder can be spastic (hypertonic, reflex, or automatic), flaccid (hypotonic, atonic, nonreflex, or autonomous), or uncoordinated (dyssynergic).
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 cerebrovascular accident, brain tumor (meningioma and glioma), Parkinson’s disease, multiple sclerosis, and dementia
❑ spinal cord disease or trauma, such as 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 Guillain-Barré syndrome
❑ 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 the 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 symptoms, 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 an inability to completely empty the bladder. Other signs and symptoms of neurogenic bladder include vesicoureteral reflux, deterioration or infection in the upper urinary tract, and hydroureteral nephrosis.
Spastic neurogenic bladder
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
Features of flaccid neurogenic bladder include overflow incontinence, diminished anal sphincter tone, and a greatly distended bladder (this is evident on percussion or palpation), but without the accompanying feeling of bladder fullness because of sensory impairment.
Diagnosis
The patient’s history may include a condition or disorder that can cause neurogenic bladder, incontinence, and disruptions of micturition patterns. The following tests will help evaluate the patient’s bladder function:
❑ 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.
Bladder evacuation
Techniques of bladder evacuation include Credé’s method, Valsalva’s maneuver, and intermittent self-catheterization.
Credé’s method (applying manual pressure over the lower abdomen) and Valsalva’s maneuver (performing forced exhalation against a closed glottis) promote complete emptying of the bladder. (For patient-teaching information, see Dealing with neurogenic bladder.)
After appropriate instruction, most patients can perform Credé’s method themselves; however, even when performed properly, this method isn’t always successful and doesn’t always eliminate the need for catheterization.
CLINICAL TIP: Credé’s method can result in autonomic dysreflexia in patients with spinal cord injuries. With this medical emergency, blood pressure rises to potentially fatal levels because of stimulation of the sympathetic nervous system.
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 urinary catheter poses.
Drug therapy
With neurogenic bladder, drug therapy may include bethanechol and phenoxybenzamine to facilitate bladder emptying, and propantheline, methantheline, flavoxate, dicyclomine, and imipramine to facilitate urine storage.
Surgery
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 the method of treatment.
❑ Use strict aseptic technique during insertion of an indwelling urinary 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).
❑ 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.
CLINICAL TIP: 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, including fever and cloudy or foul-smelling urine.
❑ Try to keep the patient as mobile as possible. Perform passive range-of-motion exercises, if necessary.
❑ If a urinary diversion procedure is to be performed, arrange for consultation with an enterostomal therapist, and coordinate the care.
❑ Before discharge, teach the patient and his family evacuation techniques, such as Credé’s method and intermittent self-catheterization, as necessary.
Pictures
Book Source Details
- Book Title: Handbook of Diseases
- Author(s): Springhouse
- Year of Publication: 2003
- Copyright Details: Handbook of Diseases, Copyright © 2003 Lippincott Williams & Wilkins.
More About Neurogenic bladder
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Medical Books Excerpts
- Urethral Discharge
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Handbook of Diseases
Authors: Springhouse
Publisher: Lippincott Williams & Wilkins
Copyright: 2003
ISBN: 1-58255-266-5
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