Ask the Expert: How Do You Manage MS-Related Urinary Retention?
Multiple sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system, resulting in a variety of nonspecific neurologic symptoms.1 Bladder problems are one of the many primary symptoms of the disease and are highly prevalent among MS patients.1,2 According to results of the 2005 North American Research Committee on Multiple Sclerosis survey, 65% of MS patients have experienced at least one urinary symptom described as moderate to severe in severity.2 Additionally, analysis of the survey found that approximately 25% of MS patients perform intermittent catheterization, which significantly impacts their quality of life.
When discussing the pathophysiology of urinary retention in MS patients, it is important to consider the role of the bladder detrusor.2 The detrusor muscle is comprised of three overlapping layers of smooth muscle as well as a surrounding extracellular matrix that acts as a support. Sympathetic nervous system stimulation of alpha- and beta- adrenergic receptors relax the detrusor muscle, allowing for bladder filling and storage. Conversely, parasympathetic stimulation of muscarinic cholinergic receptors contract the muscle, causing emptying of the bladder. In patients with MS, urinary retention can be due to an underactive detrusor muscle and/or an obstruction of the bladder outlet due to detrusor sphincter dyssynergia (DSD). Both imaging and data obtained from previous studies indicate that these causes actually occur due to disruptions in neurologic signaling rather than from primary detrusor failure.
Although urological care in MS patients has greatly improved throughout the years, clear-cut strategies for the diagnosis and management of this condition are lacking.2 A recent article written by John Stoffel, MD, of the Department of Urology at the University of Michigan, reviewed the presentation, diagnosis, and treatment of urinary retention in patients with MS. MPR interviewed Dr. Stoffel to discuss each of these topics further as well as his recommendations for optimal care for these patients.
An Interview with John Stoffel, MD
You mention that no standard definition exists for the diagnosis of urinary retention in an MS patient. Why do you think that is and what, in your opinion, are the most important factors to consider when diagnosing a patient?
Urinary retention is as much of a physical finding as it is symptoms. It is challenging to create a measurable definition of the disease that addresses its impact on patients as well. In the past, the definition has been more vague because we have been distinguishing patients who are emptying their bladder versus those who are not. We now have more specific treatments and interventions that measure effectiveness, therefore there is a greater need to create a more specific definition. I believe that this definition should place patients in different categories or phenotypes, similar to the model created for patients with nonneurogenic urinary retention. Creating categories or buckets that patients fall into (i.e. symptomatic, asymptomatic, has impact on short- or long-term outcomes, experiences incomplete emptying, etc.) allows clinicians to treat each patient accordingly.