How Is Multiple Sclerosis Diagnosed? An MS Expert Explains
Multiple sclerosis (MS) is an inflammatory disease in which the immune system attacks the central nervous system, damaging the myelin, the protective covering around certain nerves.
Over the last 20 years, multiple sclerosis has become a highly manageable disease. While there is no cure, new therapies can lessen the effects of MS and improve your quality of life, according to Mount Sinai’s Corinne Goldsmith Dickinson Center for Multiple Sclerosis.
In this Q&A, Ilana Katz Sand, MD, the Center’s Associate Director and Professor of Neurology at the Icahn School of Medicine at Mount Sinai, explains why it can be difficult to diagnose MS and what you can do if you are misdiagnosed.
How is multiple sclerosis diagnosed?
Unfortunately, there is no single diagnostic test for MS. Rather, an MS diagnosis is made by considering all available data and appropriately applying the diagnostic criteria. Clinicians review a patient’s medical history and symptoms, perform a neurological examination, and use magnetic resonance imaging, or MRI, to make a non-invasive scan of the brain and spinal cord. They will sometimes recommend a lumbar puncture (spinal tap) for additional information.
Other testing, such as examining the optic nerves, and blood tests to appropriately rule out other conditions, may also be performed. Any potential “red flags” to an MS diagnosis must be considered and the diagnostic criteria must then be carefully applied.
What are some overlapping symptoms between MS and other conditions?
What can sometimes make the diagnostic process difficult is that symptoms of MS can overlap with those of other conditions. For example, optic neuritis, an inflammation of the optic nerve that can cause pain and vision loss, is a common presenting symptom of MS. It is also a common presenting symptom of other inflammatory conditions such as neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody disorder.
These conditions are also associated with lesions in the brain and spinal cord like MS. Other symptoms that are common in MS, such as fatigue and cognitive fogginess, are common in many other illnesses and are not specific to MS. Clinicians need to use clues from the way the symptoms present, the pattern of lesions on the MRI scan, blood and spinal fluid testing, and sometimes additional diagnostic tests to help differentiate MS from other conditions when it is not initially clear.
How common is it to misdiagnose MS?
Misdiagnosis of MS is not that uncommon. Research suggests that among referrals to medical centers that specialize in multiple sclerosis and offer advanced care, the rate of MS misdiagnosis may be as high as 20 percent. This is consistent with my personal experience over the years.
In my experience, misdiagnosis most commonly occurs when the clinician has not considered a diagnostic “red flag” carefully enough or has inappropriately applied the MS diagnostic criteria when a patient’s history, exam, or MRI findings are not typical for MS.
A change in clinical impression can also occur when new technology becomes available that causes the clinician to see things a different way. However, the numbers we see in research studies do not necessarily mean that one in five people who currently have an MS diagnosis have been misdiagnosed. Patients who are referred to advanced care centers tend to be more challenging cases, so this likely introduces some bias into this figure. The rate of misdiagnosis in the overall population is probably lower.
What should someone do if they have been misdiagnosed with MS but are still experiencing symptoms?
For someone who previously received an MS diagnosis but has since been told the diagnosis was not correct, the most important action is to understand why the clinician has changed their impression.
The next steps will be different depending on whether a new lab test result became available, clinical symptoms have changed (for example, there has been a lack of expected response to treatment), or the MRI scan has evolved in a way that was different than anticipated.
The clinical reasoning should drive next steps for further evaluation of the patient’s ongoing symptoms. The other action item I recommend is focusing on symptom management, taking a holistic view of care that incorporates optimizing things like nutrition, exercise and physical activity, and mental health. Attention to these parts of care can make a really big difference in the way a person feels regardless of their diagnosis.
