Bladder Dysfunction

Updated: Dec 23, 2024
  • Author: Gregory T Carter, MD, MS; Chief Editor: Elizabeth A Moberg-Wolff, MD  more...
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Overview

Practice Essentials

In the practice of physical medicine and rehabilitation, voiding disorders are usually a result of neurologic conditions such as spinal cord injury (SCI) or disease, cerebrovascular accident (CVA), traumatic brain injury (TBI), multiple sclerosis (MS), or dementia. Incontinence and urinary retention can cause social embarrassment and added morbidity, such as infections, stones, or renal injury. [1] Evaluation of bladder dysfunction can involve laboratory studies; imaging studies, including with radiography and ultrasonography; and other procedures, such as cystometry and electromyography. Management can include rehabilitation, bladder training, facilitative techniques and maneuvers, catheterization, pharmacologic therapy, and surgery. [2, 3, 4, 5, 6, 7]

Signs of bladder dysfunction

In general, patients may be symptomatic or asymptomatic and can present with urinary retention, urinary incontinence, or a mixed picture of incomplete emptying and incontinence.

Workup in bladder dysfunction

Laboratory studies indicated in the workup of a patient with neurogenic bladder dysfunction include the following:

  • Urinalysis and urine culture with sensitivity to rule out infection
  • 24-hour creatinine clearance
  • Residual urine volume

Ultrasonography is used for the routine assessment of the upper urinary tract (which consists of the kidneys and ureters) and may be employed to identify the presence of ureteral obstruction, scarring, masses, and either renal or bladder calculi.

Computed tomography (CT) scanning or plain radiography used with ultrasonography can determine the presence of radiopaque calculi in the urinary tract, bladder, and kidneys. Excretory urography or intravenous pyelography (IVP) may be used for visualization of the collecting system. Isotope studies (eg, technetium-99m dimercaptosuccinic acid [DMSA]) are used for the evaluation of renal cortex function.

Cystometry is the measurement of bladder volume and intravesical pressure during filling and storage phases for the purpose of evaluating detrusor function.

Electromyography (EMG) is used to diagnose the mechanistic cause of urinary retention and incontinence through the measurement of electrical potentials generated by depolarization of the detrusor muscle and the urethral sphincter.

Management

Early mobilization and transfer training are recommended to minimize urinary incontinence and other complications such as pressure sores.

Various techniques are used to maintain continence or empty the bladder, including the Credé maneuver (involving manual compression of the bladder) and pinching or stimulation of the lumbar and sacral dermatomal levels to provoke reflex bladder contraction (which may be used in spinal cord injuries [SCIs] if there is no outlet obstruction or detrusor-sphincter dyssynergia).

The practice of clean intermittent catheterization (CIC) is used primarily in patients with neurogenic bladder disease, such as is seen in cases of SCI.

Cholinergic agonists are used in patients with detrusor areflexia. The alpha-adrenergic blocking agent phenoxybenzamine is useful for reducing bladder outlet resistance in patients with SCIs, as long as detrusor bladder contractions are present, while anticholinergic agents may help to alleviate symptoms in patients with urinary incontinence resulting from uninhibited bladder contractions secondary to suprasacral lesions. Tricyclic antidepressants (TCAs) may (1) have peripheral alpha-adrenergic and central anticholinergic effects, (2) suppress bladder contractions, and (3) enhance bladder neck resistance.

Transurethral resection of the bladder neck is indicated in patients who have obstruction at the bladder neck, when medical therapy has failed to produce satisfactory results.

External sphincterotomy is indicated in patients who have suprasacral lesions that cause failure to empty, when other therapeutic modalities have not been successful. Candidates for this procedure should have adequate detrusor contractions.

Bladder augmentation is performed primarily in patients with refractory hyperreflexic bladders, when medical treatment has failed to alleviate symptoms. In this procedure, the bladder is opened and patched with a reconfigured segment of bowel. Augmentation also is used to achieve a normal bladder capacity in children and adolescents, often in conjunction with an artificial sphincter.

Pathophysiology

Control of typical bladder function (ie, filling and emptying) involves action of the somatic and autonomic nervous systems on the neuromuscular junctions of the muscles of the bladder, bladder neck, urethra, diaphragm, abdomen, and pelvic floor. Somatic efferent, autonomic sympathetic, and parasympathetic systems are selectively activated by a filling (ie, guarding) reflex or an emptying (ie, voiding) reflex. These reflexes are controlled by the central nervous system (CNS), with involvement of the spinal cord, the pontine micturition center, and the sacral micturition center; further oversight is provided by the medial prefrontal cortex.

The sympathetic nervous system regulates the process of urine storage in the bladder by activating the muscles of the bladder neck and urethra where they form an internal sphincter known as the trigone sphincter, and by relaxing the muscles of the bladder wall. In contrast, the parasympathetic nervous system controls bladder contractions and the passage of urine through a relaxed bladder neck and urethra. The somatic efferent system permits voluntary control over the external periurethral sphincter, also known as the urogenital sphincter.

For bladder contraction to occur, parasympathetic nerve impulses must travel from the S2-S4 ventral gray matter of the CNS via the preganglionic pelvic nerves, to the ganglia near the bladder wall, where acetylcholine is released to stimulate postganglionic neurons that then travel to the smooth muscle cholinergic receptors at the bladder wall and cause muscle contraction. [8]

Sympathetic efferent nerve fibers originate from the lateral gray column of the spinal cord between T11 and L2. The sympathetic system has a long postganglionic chain that runs with the hypogastric nerve to synapse with alpha and beta receptors in the bladder wall and the bladder neck or internal sphincter. Beta receptors are responsible for mediating relaxation of the bladder for filling. Alpha receptors are responsible for tonically contracting the internal sphincter during bladder filling.

The somatic efferent nerve fibers originate from the pudendal nucleus of S2-S4 and supply the external periurethral sphincter. The external sphincter is under voluntary control and normally contracts in response to coughing or the Valsalva maneuver or when a person actively tries to prevent or halt urine flow.

When the bladder retains urine, sympathetic activation of alpha1 receptors on the trigone, bladder neck, and urethra causes contraction of the internal sphincter, while beta-adrenergic receptors in the bladder body induce relaxation of the detrusor muscle to permit filling. Somatic efferent fibers from the cerebral cortex permit voluntary contraction of the external sphincter to provide extra support. Alpha-adrenergic receptors in the trigone, bladder neck, and urethra stimulate sphincter relaxation, while the muscarinic receptors in the detrusor smooth muscle body stimulate contraction to facilitate bladder emptying.

Central control of micturition is performed by three areas: the sacral micturition center, the pontine micturition center, and the cerebral cortex. The sacral micturition center is at the S2-S4 levels and is responsible for bladder contraction. The pontine micturition center is found in the brain stem, and while its primary role is to stimulate urination when activated, it also acts as a central relay and may play a role in the coordination of external sphincter relaxation with bladder contraction. The cerebral cortex plays an inhibitory role in relation to the sacral micturition center.

See the image below.

The pons is a major relay center between the brainThe pons is a major relay center between the brain and bladder. The mechanical process of urination is coordinated by the pons in an area known as the pontine micturition center (PMC).

Etiology

Classification of a neurogenic bladder depends on the location of the lesion along the central nerve pathway and can be categorized as having sacral, suprasacral, or suprapontine lesions, based on level of injury. [3, 9]

Lesions of the peripheral nerves or at the level of the sacral micturition center cause detrusor areflexia (ie, flaccid bladder). These lesions may affect the conus medullaris, the cauda equina, and the S2-S4 peripheral nerves. Common causes of sacral lesions are trauma, stenosis, tumors, peripheral neuropathy, and infection. In general, these lead to variable loss of parasympathetic and somatic nerve function. Detrusor areflexia, bladder neck incompetence, or loss of external sphincter function may occur and present as bladder distention with overflow incontinence.

Lesions of the spinal cord or brain stem below the pontine micturition center but above the sacral micturition center lead to uninhibited bladder contractions with uncoordinated sphincter activity. These suprasacral lesions are associated with the group of neurogenic bladder problems caused by spinal cord lesions from trauma, tumors, or spina bifida, as well as by multiple sclerosis or transverse myelitis. Such lesions interrupt the spinobulbospinal pathway required for the micturition reflex. Two pathologic mechanisms are in play here. The first is acute areflexia and then detrusor hyperreflexia. The second is detrusor-sphincter dyssynergia, where the external sphincter contracts at the same time that the detrusor contracts. Individuals with lesions below the pontine micturition center have detrusor hyperreflexia and detrusor-sphincter dyssynergia.

Suprapontine lesions lead to uninhibited bladder contractions, which may be secondary to loss of cerebral cortex inhibition at the sacral micturition center. These lesions are often due to cardiovascular events, multiple sclerosis, dementia, brain tumors, or trauma. Suprapontine lesions are located at or between the pontine micturition center and the cerebral cortex and involve the spinobulbospinal reflex. They may or may not coincide with sacral lesions. These lesions present as uninhibited bladder contractions with retained voluntary urethral sphincter relaxation during micturition.

Epidemiology

The incidence of neurogenic bladder dysfunction depends on the primary cause. The etiology and the level of CNS or peripheral nervous system injury correlate with different causes and classifications of bladder dysfunction. For instance, estimates of the incidence of urologic symptoms in patients who have sustained a CVA vary, ranging from 33-60% in the acute setting; symptoms persist in 15% at 6 months to 1 year. Bladder disorders are reported in 40-90% of patients with multiple sclerosis. [10]

The reported rate of urologic dysfunction in patients with Parkinson disease ranges from 37-72%, while the rate of urinary incontinence is higher in patients with dementia and other types of cognitive impairment (eg, TBI, CVA, and Parkinson disease) than in the general population. Bladder disorders are nearly universal in children with myelomeningocele and in patients with SCI. [11, 10]

Age-, sex-, and race-related demographics

The age at which bladder disorders occur is related to the age at the time of neurologic disorder onset. The male-to-female ratio varies greatly between disease entities causing neurogenic bladder dysfunction. In one study, the reported incidence of urinary incontinence, regardless of etiology, was 8.5% of females aged 15-64 years; in the same age group, only 1.6% of the male population reported being affected by urinary incontinence. [10] No racial predilection is reported.

A retrospective cohort study by Mckellar et al reported that within a racially diverse population of women aged 18 years or older, the prevalence of overactive bladder (excluding in women with neurogenic bladder or pelvic cancer) was 4.41%, with the highest prevalence found in Hispanic women. [12]

A study by Kinlaw et al found that between 2000 and 2013, antimuscarinic prescriptions were filled for about 1 in 500 children in the United States, most frequently for oxybutynin (78%) and tolterodine (17%), both of which are used for overactive bladders. [13]

Prognosis

The prognosis for recovery depends on the type, severity, and location of the lesion causing the bladder problem and can be organized by dysfunctions that are permanent, dysfunctions that resolve with treatment of the condition, and dysfunctions that require medical and/or surgical intervention.

Patients with permanent bladder dysfunction include those with complete transection of the spinal cord. These individuals remain on intermittent or indwelling catheterization for the rest of their lives.

Causes of temporary, syndromic urinary incontinence include polyneuropathy secondary to vitamin B-12 deficiency, which typically improves with nutritional correction.

Dysfunctions that require medical and/or surgical interventions include upper motor neuron lesions (eg, stroke, multiple sclerosis, spinal cord pathology), for which patients may have to depend on medications for the rest of their lives (although some degree of recovery may be expected). Individuals with anatomic derangements like pelvic floor weakness may find symptomatic improvement with surgical correction.

Patient Education

Patients with bladder dysfunction should receive education on the following aspects of care:

  • Proper techniques of intermittent self-catheterization (including timing, frequency, and proper hygiene)
  • Effects of oral medications on bladder function, as well as possible systemic side effects
  • Management of some emergencies (eg, absence of urine output secondary to a kinked catheter)
  • Prevention and awareness of potential complications and long-term comorbidities (eg, urinary tract infection, bladder cancer, urolithiasis)
  • Use of facilitative bladder emptying techniques, such as the Credé and Valsalva maneuvers, as a conservative measure, although these techniques are generally not recommended due to adverse effects to other abdominal structures, such as increased bladder pressure and the development of pressure-related hernias and hemorrhoids
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