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Multiple Sclerosis Centers of Excellence

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Multiple Sclerosis Relapses: What They Are and What To Do

Rebecca Spain, MD, MSPH

By its very name, multiple sclerosis tells us that there are many (multiple) scars (sclerosis) in the brain, spinal cord, and optic nerves. At the time these scars (also called plaques) are formed, they might cause symptoms. New plaque formation accompanied by new symptoms is called a clinical relapse, attack, or exacerbation. Depending on where the plaques form they can cause different symptoms, like vision loss, weakness, sensory changes, balance problems, double vision, slurred speech, or bladder problems. Other times new plaques do not cause any symptoms and can only be detected by magnetic resonance imaging (MRI). These kinds of events are called radiographic relapses.

How do clinical relapses cause symptoms?

Relapse symptoms are caused by disruption of an area of the brain, spinal cord, or optic nerves due to immune cells inappropriately entering the brain and attacking the nervous tissue, a process called neuro-inflammation. While inflammation is present, nerve cells cannot transmit signals well through the area. The signals are either completely blocked and do not reach their targets, or are partly blocked and reach their targets weakly. If the blocked signal should go from the brain to the eventual target of muscles, this causes weakness. If the blocked signal should carry sensory information from the body up to the brain, this causes altered sensation like numbness or tingling, or balance problems. With a radiographic relapse there are no obvious symptoms because the brain and spinal cord are using alternative pathways to send their messages. However, people experiencing radiographic relapses may feel tired from the inflammation or the effort it takes to use the alternative pathways.

Clinical relapses usually last from a few days up to several months until the inflammation goes away and the damage is repaired, allowing signals in nerves to once again reach their targets. Unfortunately, repair may not be perfect so signal conduction may not be as efficient as it was before the relapse, causing some degree of symptoms to persist.

Do all people with MS have clinical relapses?

Not all people with MS have clinical relapses. About 85% of people with MS start off having clinical relapses followed by periods of stability. This is called relapsing-remitting MS (RRMS). Many of these people eventually, after 10-15 years or more, transition to secondary progressive MS (SPMS). In SPMS, clinical relapses become less frequent and eventually stop while the ongoing MS symptoms slowly worsen over time. Some people never have clinical relapses. People with primary progressive MS (PPMS) have MS symptoms that appear gradually and slowly worsen over time with no relapses and remissions, although with some variability from day to day. People with SPMS and PPMS can get radiographic relapses, but these happen much less often than in people with RRMS.

Sometimes people with MS, particularly those with SPMS and PPMS, have sudden worsening of their MS symptoms that may seem like a clinical relapse. However, careful searching finds that these episodes are instead actually caused by medical illnesses or emotional stresses that can temporarily worsen neurological functioning. When it’s not clear if new symptoms are a relapse, an MRI can be helpful to look for new and enhancing MS plaques. This is important because new MS inflammation is generally treated very differently from another medical illness or stress causing symptoms.

What should I do if I think I am having an MS relapse?

First, pay attention to your symptoms. Typically, a relapse causes symptoms you never felt before or symptoms you have felt before but are now more severe than you had them in the past. Next, determine how long your symptoms are lasting; anything lasting less than 24 hours is probably not a relapse. Take note if you have other medical concerns like urinary discomfort, cough or cold symptoms, stomach pain, skin infections, recent vaccines, or major psychological stressors in your life. This information will help your MS provider figure out what is causing the new symptoms, what additional tests might be helpful, and how best to treat you.

How will my MS health care provider determine if I am having a relapse?

Once you’ve gathered this information and your symptoms have lasted at least 24 hours, call your MS health care provider. Depending on the severity of symptoms and other factors, your provider may require an office visit for an examination. Blood and urine testing may be ordered to see if you have an infection or other illness. An MRI may be ordered but is often not necessary. If your symptoms are severe (for example if you cannot walk, see, or urinate, or if you have severe pain) and you cannot wait for your MS provider, see your primary care provider or visit the emergency room for evaluation. Your MS provider will determine if your symptoms are due to a clinical relapse or to a medical condition and make treatment decisions accordingly.

How are MS clinical relapses treated?

MS clinical relapses will respond to steroid treatments. However, steroids only make the symptoms last less long, they do not affect the extent of recovery. Steroids can also have unwanted side effects like high blood sugar, difficulty sleeping, and anxiety or agitation. Therefore, steroids are only prescribed if symptoms are severe or disabling. When prescribed, steroids are given for 3 to 5 days, either intravenously or with pills. If relapse symptoms are mild or non-disabling, treatment may simply be rest and relaxation at home. If an underlying medical illness is found that is suspected to be causing the worsening MS symptoms, the medical problem is treated without steroid treatment. Radiographic relapses do not necessarily need steroid treatments as they are not causing disabling symptoms; however, their appearance may trigger the MS provider to switch maintenance disease-modifying therapy. In all cases of worsening MS symptoms, regardless of their underlying causes, physical, occupational, and speech therapies may be helpful.

In summary, if you have MS and new or worsening neurological symptoms, you should suspect a clinical relapse if you have RRMS, the symptoms last for more than 24 hours, and there are no other medical or psychological stressors present. For worsening of your MS for any reason, please call your MS health care provider to discuss your evaluation and treatment.