Neurogenic bladder is a term which is frequently used to describe voiding dysfunction due to underlying neurologic disease. Neurogenic bladder is a common problem associated with both traumatic and nontraumatic spinal cord injuries.
Congenital anomalies such as meningomyelocele and diseases/damage of the central, peripheral, or autonomic nervous systems may produce neurogenic bladder dysfunction, which untreated can result in progressive renal damage, adverse physical effects including decubiti and urinary tract infections, and psychological and social sequelae related to urinary incontinence. A comprehensive bladder-retraining program that incorporates appropriate education, training, medication, and surgical interventions can mitigate the adverse consequences of neurogenic bladder dysfunction and improve both quantity and quality of life. The goals of bladder retraining for neurogenic bladder dysfunction are prevention of urinary incontinence, urinary tract infections, detrusor overdistension, and progressive upper urinary tract damage due to chronic, excessive detrusor pressures. Understanding the physiology and pathophysiology of micturition is essential to select appropriate pharmacologic and surgical interventions to achieve these goals. Future perspectives on potential pharmacological, surgical, and regenerative medicine options for treating neurogenic bladder dysfunction are also presented.
Normal micturition involves proper function of both the bladder and urethra. A detrusor of normal compliance and a physiologically competent urethral sphincter are both necessary to maintain urinary continence. Any increase in abdominal pressure, which inherently produces an increase in bladder pressure, is normally counteracted by an even greater increase in urethral pressure.
Normal micturition involves passive, low pressure filling of the bladder during the urine storage phase while voiding requires coordination of detrusor contraction with internal and external urinary sphincter relaxation. This micturition process is controlled by the central nervous system, which coordinates the sympathetic and parasympathetic nervous system activation with the somatic nervous system to ensure normal micturition with urinary continence .
Voiding dysfunction can result from any mechanical or physiologic defects in the micturition system that result in the inability of the urinary sphincter to appropriately increase (or decrease) its pressure in response to increased bladder pressure. Damage or diseases of the central, peripheral, and autonomic nervous systems may result in neurogenic bladder dysfunction.
Neurogenic bladder dysfunction may complicate a variety of neurologic conditions. In the United States, neurogenic bladder affects 40–90% of persons with multiple sclerosis, 37–72% of those with Parkinsonism, and 15% of those with stroke . Detrusor hyperreflexia is seen in 50–90% of persons with multiple sclerosis, while another 20–30% have detrusor areflexia. There are more than 200,000 persons with spinal cord injuries, and 70–84% of these individuals have at least some degree of bladder dysfunction . Bladder dysfunction is also common in spina bifida, which affects approximately 1 per 1000 live births. Vesicoureteral reflux may occur in up to 40% of children with spina bifida by age 5, and up to 61% of young adults with spina bifida experience urinary incontinence . Less common causes of neurogenic bladder include diabetes mellitus with autonomic neuropathy, pelvic surgery sequelae, and cauda equina syndrome due to lumbar spine pathology.
Manack et a examined insurance and pharmacy claims of nearly 60,000 patients with neurogenic bladder over a 4-year period and found a 29–36% rate of lower urinary tract infections, 9–14% rate of urinary retention, and a 6–11% rate of urinary tract obstructions. Upper urinary tract infections were noted in 1.4–2.2% of the neurogenic bladder cohort, and serious systemic illnesses were also diagnosed in this group including septicemia in 2.6–4.7% and acute renal failure in 0.8–2.2%. Neurogenic bladder patients averaged 16 office and 0.5 emergency room visits per year, approximately a third of them leading to hospitalization.
Neurogenic bladder with detrusor overactivity may cause incontinence, which not only leads to embarrassment, depression and social isolation but also may lead to skin decubiti, urethral erosions, and upper urinary tract damage .
Neurogenic bladder dysfunction can be successfully treated to achieve goals of urinary continence, prevention of renal damage from chronically high detrusor pressures, and minimizing risk of urinary tract infections or bladder overdistension. A comprehensive multidisciplinary bladder retraining program can best achieve these goals utilizing patient education, instruction in catheter use/care, medications, and/or bladder or urethral surgical procedures. Experimental works in lumbar-to-sacral nerve rerouting and in regenerative medicine including use of stem cells to mitigate or reverse spinal cord damage producing neurogenic bladder dysfunction are still in their infancy, and more research will be needed to see if the promising results of some small pilot studies are confirmed in larger, controlled studies with long-term followup.