A neurogenic bladder, where neurological damage disrupts urinary system function, is a frequent symptom for people with multiple sclerosis (MS). Over 80% of individuals with MS experience some form of bladder dysfunction because the disease interferes with nerve signals for bladder control. While disruptive, a range of effective management strategies exists to address these challenges.
The Neurological Cause of Bladder Dysfunction in MS
Normal urinary function relies on a coordinated network of signals between the brain, spinal cord, and bladder. The brain sends messages to the detrusor muscle, which forms the bladder wall, and the urinary sphincters. For urination to occur, the brain must signal the detrusor muscle to contract while simultaneously signaling the sphincter muscles to relax.
In multiple sclerosis, the body’s immune system attacks the myelin sheath that protects nerve fibers in the central nervous system (CNS). This process, known as demyelination, creates lesions that can slow or block nerve impulses. When these lesions form in the parts of the brain or spinal cord that regulate urinary function, the communication pathway is disrupted.
The type of bladder problem depends on the location of these CNS lesions. Lesions in the brain may cause the bladder to contract involuntarily. Lesions in the spinal cord can disrupt coordination between the bladder and sphincter, a condition called detrusor-sphincter dyssynergia, where both muscles contract simultaneously and prevent proper emptying.
Types and Symptoms of Neurogenic Bladder
Symptoms of neurogenic bladder fall into two main categories. The first is a “failure to store” urine, known as an overactive or spastic bladder. This common issue occurs when nerve damage causes the detrusor muscle to contract uncontrollably, even when the bladder isn’t full. Symptoms include a sudden need to urinate (urgency), frequent urination, nocturia (waking at night to urinate), and urge incontinence, which is leakage following a strong urge.
The second category is a “failure to empty” the bladder, also called an underactive or flaccid bladder. This condition arises when the bladder muscle is weak or loses its ability to contract, or when the sphincter muscles fail to relax. Symptoms include urinary hesitancy, a weak or intermittent stream, dribbling, and a persistent feeling that the bladder has not completely emptied, known as urinary retention.
It is also possible to have a mixed presentation with symptoms from both categories. For example, a person might have an overactive bladder with frequent, urgent needs to urinate but be unable to empty the bladder completely. This combination can occur when there is a lack of coordination between the bladder and sphincter muscles. These symptoms can fluctuate and change as the disease progresses.
The Diagnostic Process
Diagnosing the specific type of neurogenic bladder begins with a healthcare provider’s evaluation of the patient’s medical history and symptoms. The patient may be asked to keep a bladder diary for several days. This log tracks fluid intake, the timing and volume of urination, and any leakage episodes to help identify patterns and severity.
Clinical tests are performed to rule out other causes. A urinalysis is used to check for a urinary tract infection (UTI), as infections can cause similar symptoms. Blood tests may also be ordered to assess kidney function, as chronic bladder problems can affect the kidneys.
A post-void residual (PVR) measurement is taken to determine how well the bladder is emptying. This non-invasive test uses an ultrasound on the lower abdomen to measure urine left in the bladder after urination. In some cases, a PVR is measured more directly by temporarily inserting a catheter to drain and measure the remaining urine.
For a more detailed assessment, urodynamic studies may be recommended. These tests measure bladder capacity, internal pressures, and urine flow rate. Urodynamic testing provides a precise diagnosis by confirming an overactive bladder, poor contractility, or detrusor-sphincter dyssynergia, which guides the treatment plan.
Treatment and Management Approaches
Managing neurogenic bladder in MS involves a tiered approach, starting with conservative strategies and progressing to advanced therapies as needed. Treatment is tailored to whether the primary issue is bladder storage or emptying. The goal is to improve symptoms, prevent complications like urinary tract infections, and enhance quality of life.
The first line of management involves behavioral and lifestyle adjustments. This includes modifying fluid intake by limiting irritants like caffeine, alcohol, and carbonated drinks. Timed voiding, or urinating on a fixed schedule, helps train the bladder to prevent urgency and leakage, while reducing fluid intake before bed can help with nighttime urination.
Physical therapy is another management strategy. A pelvic health therapist can teach pelvic floor muscle exercises, known as Kegels, to strengthen the muscles that support the bladder. These exercises help control urination and are useful for managing an overactive bladder and stress incontinence.
If lifestyle changes and physical therapy are insufficient, medications may be prescribed. For an overactive bladder, anticholinergics or beta-3 agonists can relax the detrusor muscle to increase storage capacity and reduce urgency. For an underactive bladder, other medications can help stimulate contractions to improve emptying.
For symptoms that do not respond to these measures, more advanced therapies are available. These can include:
- Injections of botulinum toxin (Botox) directly into the bladder muscle to calm an overactive bladder for several months.
- Nerve stimulation therapies, like percutaneous tibial nerve stimulation (PTNS) or implanted sacral neuromodulation devices, to regulate nerve signals.
- Intermittent self-catheterization, which involves using a small tube to empty the bladder on a schedule.
- An indwelling catheter that remains in place for continuous drainage in some cases.