If you’re having relapses (flare-ups) more often, or if they leave you feeling significantly worse than before, you may need more aggressive treatment for your multiple sclerosis (MS). Fortunately, several MS medications have earned the name “highly effective disease-modifying therapies” (HE DMTs) because they work so well to slow disease progression and reduce the accumulation of disability. Experts have determined that people with highly active MS should start HE DMTs earlier to get the most benefit.

So, how do you know when it’s time to switch to an advanced treatment for MS? We’ll cover the signs it may be time to consider starting an HE DMT. We’ll also go over what tests your doctor might run to confirm that your MS is highly active. Knowing these signs can help you get the treatment you need sooner rather than later.

5 Signs Your MS May Be Highly Active

There isn’t a single definition for “highly active MS.” Instead, your neurologist will use your test results and symptoms of MS to assess your disease activity. If you’ve noticed any of the following symptoms, it’s time to make an appointment.

1. You’re Having a Hard Time Recovering From a Flare

If you’re struggling to feel better after a relapse (also called a flare, attack, or exacerbation), it might be a key sign that you have highly active MS. Your body is trying to recover from the spike of inflammation, which can affect both your physical and mental health.

You may notice you’re still experiencing fatigue, muscle weakness, numbness, or tingling that lingers longer than normal. Your cognitive function (ability to think and process information) can also be affected. If you’re not bouncing back as quickly as you used to from a flare, let your neurologist know. They might use tools like walking tests, magnetic resonance imaging (MRI) scans, and disability scales to get a clearer picture of how much the flare is affecting you.

2. There’s Less Time Between Your Flares

If your MS is well controlled with medication, you likely won’t have frequent relapses. On the other hand, if you’ve had two or more flares within the past year, it might be a sign that you have highly active MS, especially if you’re taking a DMT consistently as directed.

If you’ve had two or more MS relapses within the past year, it might be a sign that your MS is highly active.

According to the National Multiple Sclerosis Society, an MS flare refers to the development of new symptoms or worsening of your old symptoms. Take note of when your flares begin and end and what symptoms you experienced. A true flare lasts for at least 24 hours and occurs at least 30 days after the previous flare.

If you’re unsure about whether you’re currently experiencing a flare or if you’ve recovered, talk to your neurologist. They can look at how often you have flares to help diagnose highly active MS.

3. You Have Trouble Balancing and Walking

Ataxia is an MS symptom in which nerve damage affects your muscle coordination. Ataxia symptoms show up differently depending on what area of your brain has been affected. For example, your cerebellum is responsible for coordinating movements. If you feel more off-balance or clumsy, or if your gait (how you walk) has changed — especially after a flare — you may have highly active MS.

4. You’re Having More Muscle Spasms and Tremors

Some people also have tremors or uncontrollable shakes that affect their arms, legs, and vocal cords. You may find your arms and legs are shaking more than normal. This can happen while you’re reaching for something or you’re lying down in bed.

Vocal cord spasms can interfere with your speech. You may speak more quietly, slur your words, or take long pauses while you’re talking. Take note if these symptoms have gotten worse after a recent flare.

5. You’re Struggling To Control Your Bowels

Your bowels and anus are controlled by a series of muscle movements. A sign of highly active MS is loss of control over the sphincter muscle that opens and closes the anus. This can lead to bowel leakage or incontinence. If you find you’re having trouble controlling your bowel movements or you can’t sense when they’re coming, let your neurologist know.

How Does Your Doctor Determine if MS Is Highly Active?

Your doctor or neurologist can run a few tests to help determine if you have highly active MS, which we discuss in more detail below.

Checking for New Lesions

MS is an autoimmune disease caused by your immune system attacking your central nervous system (CNS), which is made up of the brain, spinal cord, and optic nerve. Specifically, it attacks myelin, or the fatty coating that cushions your axons (nerve fibers). This creates lesions on your brain and spinal cord, which leads to neurological dysfunction.

Your neurologist may use imaging tests like MRI, with the contrast agent gadolinium, to look for any new lesions that are 3 millimeters or more in size. Having three or more new lesions visible on two MRI scans taken six to 12 months apart is a sign of highly active MS.

Your doctor may order MRI scans and use the EDSS to assess your disability to find out whether your MS is highly active.

Assessing Disability

The Expanded Disability Status Scale (EDSS) measures disability with MS and how it changes over time. The scale ranges from 0 to 10 — with 0 being no disability and 10 being death due to MS.

The Consortium of Multiple Sclerosis Centers (CMSC) states that you’re more likely to have highly active MS if:

• You reach an EDSS score of 4 within five years of your MS symptoms beginning.
• Your EDSS score changes by two or more points within one year.
• Your EDSS score changes and results in new disability.

Other Risk Factors for Highly Active MS

Some people are more likely to develop highly active MS compared to others. Unfortunately, many of these risk factors are out of their control. According to the CMSC, examples include being a male, being African American, and being diagnosed at the age of 40 or later.

Another risk factor for highly active MS is having relapses. According to the CMSC, between 10 percent and 15 percent of people with relapsing MS develop highly active MS. Relapsing forms of MS include relapsing-remitting MS (RRMS), clinically isolated syndrome (CIS), and active secondary progressive MS (SPMS).

HE DMTs for Highly Active MS

Since MS is caused by an overactive immune system, many treatment options focus on blocking the immune system’s effects. HE DMTs prevent your immune cells from attacking your neurons in a few different ways. Some treatments target immune cells known as lymphocytes — they’re responsible for creating inflammation. Others block lymphocytes known as B cells from making antibodies (immune proteins) that target myelin.

If your MS is highly active, your neurologist may recommend you start taking a highly effective DMT to slow disease progression.

Examples of HE DMTs your doctor may prescribe if you have highly active MS include:

• Alemtuzumab (Lemtrada)
• Cladribine (Mavenclad)
• Fingolimod (Gilenya)
• Mitoxantrone (Novantrone)
• Natalizumab (Tysabri)
• Ocrelizumab (Ocrevus)
• Ofatumumab (Kesimpta)
• Ozanimod (Zeposia)
• Rituximab (Rituxan)
• Siponimod (Mayzent)
• Ublituximab-xiiy (Briumvi)

Some HE DMTs are injectable subcutaneously (under the skin), while others are infused intravenously (by IV) at an MS infusion clinic or other medical facility. The frequency of MS infusions varies depending on the DMT you take.

Many people with MS are eligible for financial assistance for HE DMTs and even infusion costs.

Talk With Others Who Understand

MyMSTeam is the social network for people with MS and their loved ones. On MyMSTeam, more than 215,000 members come together to ask questions, give advice, and share their stories with others who understand life with MS.

Have you and your health care provider discussed whether your MS is highly active? Are you currently taking a highly effective disease-modifying treatment? Share your experience in the comments below, or start a conversation by posting on your Activities page.