What happens during an NMOSD relapse?

Most people with neuromyelitis optica spectrum disorder (NMOSD) have a relapsing form of the disease characterized by periods of new or worsening symptoms. Symptoms that develop during an NMOSD relapse, also called an attack or flare, can resolve spontaneously or with treatment, but may sometimes become permanent.

NMOSD is caused by mistaken immune attacks targeting parts of the central nervous system, most often affecting the spinal cord, the optic nerve in the eye, or parts of the brainstem. These attacks lead to inflammation and damage that drive NMOSD symptoms, such as vision problems, difficulties with movement, and pain.

This NMOSD patient guide can help you understand what happens during an NMOSD relapse and how to manage it to prevent long-term complications.

What happens in the body during a relapse

An NMOSD flare reflects a period when the immune system is actively launching an attack on the nervous system, causing new inflammation and damage that appear in the form of lesions on MRI scans.

What happens during an NMOSD attack differs from the regular symptom fluctuations that can occur independently of immune attacks, often when the body is under stress from factors like infections, heat, surgery, medication changes, or dehydration.

This temporary symptom worsening can sometimes feel very much like a true relapse — or a pseudorelapse — but unlike relapses, they do not cause any new NMOSD nervous system damage.

Differentiating between true relapses and temporary symptom fluctuations is critical because they require different management. Failing to appropriately manage even a single relapse could lead to irreversible damage and disability that can impair quality of life.

Common symptoms during a relapse

The symptoms of an NMOSD attack depend on where immune activity is concentrated:

• Optic nerve: vision loss, eye pain
• Spinal cord: muscle weakness, muscle stiffness, movement problems, numbness, pain, abnormal or lost sensations, bowel and bladder issues
• Brainstem: uncontrollable hiccups, nausea, vomiting

A relapse may affect one or multiple parts of the nervous system, either simultaneously or at different points during the same attack.

Relapse symptoms usually come on relatively quickly — over hours or days — and can last several weeks, although the duration varies depending on the severity of the attack and the treatment approach.

How relapses are diagnosed

It can be difficult to diagnose an NMOSD relapse and distinguish it from a pseudorelapse. In general, relapses involve new or worsening symptoms that:

• last at least 24 hours
• providers can’t attribute to an external factor, such as fever, infection, or heat
• result in new damage that is visible as lesions on MRI scans

Some sources also state that a new relapse should occur at least four weeks after the last one in order to consider them separate events.

After an initial NMOSD diagnosis via MRI, most people will have follow-up scans regularly and in the wake of attacks. Comparing a post-relapse MRI to a recent scan from before the flare allows doctors to identify new damage and track disease progression.

Doctors may also use blood tests to rule out symptom triggers and monitor the disease state.

Treatment during a relapse

If you notice any early warning signs of an NMOSD attack, it’s important to contact your healthcare team immediately, because treatment is most effective when started as soon as possible.

NMOSD treatment during a relapse aims to quickly control the immune system in order to resolve symptoms and limit permanent damage. Acute NMOSD management may involve:

• steroids: medications that reduce immune activity and inflammation
• plasma exchange (PLEX): a blood-filtering procedure that removes disease-causing antibodies from the blood
• intravenous immunoglobulin (IVIG): provides antibodies from the blood of healthy donors to normalize immune activity

Usually, doctors will prescribe into-the-vein (intravenous) steroids as the first line of therapy during a relapse. These powerful immunosuppressants can effectively dampen NMOSD inflammation, but they can also cause severe side effects. After three to five days on a high dose, most people switch to oral steroids and then gradually taper off of those.

If the response to steroids is incomplete or if the person hasn’t tolerated or responded well to steroids in the past, PLEX is often used, although IVIG may also be an option in some situations.

A doctor can also advise you on medications or lifestyle changes that might help with symptom relief during an attack.

Coping and support during a relapse

In addition to seeking prompt medical care, there are a few things you can do to better cope with the impact of a relapse on your life, including:

• maintaining open, active communication with your healthcare providers
• planning ahead for a potential relapse
• seeking support from caregivers, friends, family, or other community members

Planning ahead

Relapses can come on suddenly, and you may not be able to predict when they’ll happen. There are a few things you can do ahead of time that will make coping with a relapse easier:

• Keep any supportive equipment you might need, such as walking aids, shower chairs, or easy-to-grip utensils, in a known and easily accessible place
• Have some pre-prepped meals stocked up
• Talk with your support system and make a plan for emergency child, pet, or house care

Jennifer van Amerom, a columnist for Neuromyelitis News, recommends carrying a card with basic information about NMOSD and your medications to help emergency responders quickly understand your medical situation and handle it appropriately.

“We’re those unicorn patients who walk into emergency rooms with a disease that no one has ever heard of,” van Amerom wrote in a column.

It might also be a good idea to keep an overnight bag packed with essential clothing, toiletries, and comfort items in case you unexpectedly need to stay at the hospital.

Emotional support for patients and caregivers

NMOSD relapse recovery can take time, and some damage may be permanent. Many emotions may arise during and after a relapse period, including uncertainty, worry, sadness, and anger. Mental healthcare and emotional support systems, such as therapy or support groups, may help you process these feelings and develop healthy coping strategies.

NMOSD caregivers may also experience significant emotional and practical burdens during a relapse. Counseling, social networks, and support groups can help caregivers process these emotions and adjust to daily life changes in the wake of attacks.

Preventing future relapses

In addition to NMOSD flare-up treatment, many people with the disease receive preventive treatment to reduce the risk of future attacks. In the U.S., there are currently four approved treatments for people with NMOSD who test positive for aquaporin-4 targeting antibodies, the most common type of NMOSD-causing antibodies.

These therapies work in various ways to suppress the immune activity that drives NMOSD attacks, potentially preventing future flares and associated disability.

Currently, there are no approvals for preventive NMOSD treatments for those without anti-aquaporin-4 antibodies. Providers may prescribe other types of immunosuppressants off-label in these cases.