Reviewed by: HU Medical Review Board | Last reviewed: June 2023 | Last updated: August 2023
Neuromyelitis optica spectrum disorder (NMOSD) is a demyelinating disorder. This means it damages the protective coating of nerve cells, which is called myelin. NMOSD is characterized by attacks of damage usually showing up as inflammation of the nerve bundles in the eye (optic neuritis) or spinal cord (transverse myelitis).1
Acute (immediate, short-term) treatment for NMOSD is used to decrease symptoms of the disease when they happen. Acute treatment includes high-dose steroids and plasma exchange (PLEX).2
High-dose steroids also help limit long-term, irreversible damage to the spinal cord during an NMOSD attack that includes transverse myelitis.4
Examples of steroids
There are many different types of steroids available. The most common steroid used for NMOSD is intravenous (in the vein, or IV) Solu-medrol (methylprednisolone). Oral (swallowed pill) steroids may be prescribed after IV therapy. Prednisone and prednisolone are commonly prescribed oral steroids.2,5,6
What are the possible side effects of steroids?
Because steroids act to suppress the immune system, this treatment increases the risk for infection but typically only when used for longer periods of time. This is dangerous and can be life-threatening. Additional side effects of steroids can occur. Some are linked to short-term use, while others only appear with prolonged steroid therapy. These side effects may include:3,5,6
- Fluid retention
- High blood pressure
- Mental effects, like mood swings, behavior changes, confusion
- Round appearance to the face (moon face)
- Weakening of bones (osteoporosis), which increases the risk for fractures
- High blood sugar, which can cause or worsen diabetes
- Weight gain
- Increased pressure in the eye (glaucoma)
- Decreased adrenal gland hormone, which can lead to severe tiredness (fatigue), muscle weakness, loss of appetite
Things to know about steroids
It is difficult to predict how fast or how completely steroids will work for each person. Steroids may or may not be effective for some people.
The decision to continue steroids or add a new treatment is based on your symptoms and MRI findings. Steroids may be continued in pill form for a period of time after IV therapy.3
Steroids are used in NMOSD to speed improvement of symptoms from an attack. Given their long-term side effects, high-dose steroids are not an ideal long-term therapy to prevent further attacks of the disease. Because of this, your doctor will prescribe other drugs and treatment to help prevent attacks and further nerve damage. Low-dose steroids may be needed for long-term therapy. Talk to your doctor about your treatment plan, as well as the risks and benefits of all drugs.3,6
What is plasma exchange (plasmapheresis or PLEX)?
Antibodies are proteins in your body that normally protect you from different germs that can make you sick. In autoimmune diseases such as NMOSD, some antibodies mistake healthy cells for harmful ones and attack them. This leads to various damage and symptoms, depending on the location of the attack.7
In NMOSD, the antibody AQP4-IgG (AQP4-IgG) can result in damage to the myelin on nerve cells and nerve cells themselves in the optic nerve, spinal cord, and brain. While many people with NMOSD have AQP4-IgG in their blood, 1 in 4 people do not. This adds to the complexity of the disease.8,9
Blood is made up of different components, including the blood cells (red blood cells, white blood cells, and platelets) and the fluid the blood cells move through, called plasma. Plasma also carries products your body uses to fight infection (including antibodies), as well as other molecules and products.
Plasma exchange (PLEX) may be an effective treatment in people with NMOSD who have sudden, severe attacks that do not respond to high-dose IV steroids. PLEX involves removing blood and plasma through a large IV and using a machine to separate the blood cells from the plasma. Blood cells are then mixed with a replacement solution and returned to the body.10,11
PLEX removes AQP4-IgG antibodies and other harmful immune system components.11
Studies have shown that PLEX may improve NMOSD symptoms during an acute attack. However, this treatment should be started early for it to be effective.11
What are the possible side effects of plasma exchange?
Plasma exchange is a common procedure. Like other procedures, PLEX can have possible side effects. Side effects of PLEX relate to fluid and blood balance problems. These may include:12
- Muscle spasms
- Tingling in fingers or toes
- Itching and rash (urticaria)
- Blood pressure problems
- Belly pain, nausea, and vomiting
- Allergic reaction
- Low potassium, calcium, or clotting factors in the blood
Things to know about plasma exchange
Plasma exchange can affect the levels of drugs in your body. Talk to your doctor about your current drug regimen and what changes you may need to take before or after the procedure.12,13
An IV catheter will need to be placed in your arm or neck. You may have discomfort or bruising at the insertion site. You may be instructed to keep your arm propped on a pillow during the procedure. You may have to squeeze and release your fist (pump your fist) to help promote blood flow.13
While plasma exchange may help NMOSD symptoms during an attack, it does not cure the disease. Plasma exchange may be part of your treatment plan. Talk to your doctor about the various treatment options you have.13