Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease where the immune system attacks the central nervous system, including the optic nerve, the spinal cord, and the brainstem. In most cases, people with NMOSD experience recurring episodes of inflammation (called relapses), with periods of remission in between.
If you are living with NMOSD, it is important to understand the wide range of symptoms that can occur during a relapse. Here, we look at how inflammation in different parts of the central nervous system can result in different symptoms, and why you should talk to your healthcare providers about any new symptoms or any changes in how you feel.
The optic nerve
There are two characteristic symptoms of NMOSD. One of these symptoms is called optic neuritis, inflammation of the optic nerves. The optic nerves are made up of millions of nerve fibers and connect the retina at the back of each eyeball to the brain. The optic nerves play an essential role in vision, providing a path for visual information that enters the eyes to travel to the brain. When the optic nerve is inflamed, a person may have reduced vision, may not be able to see clearly, and may have pain in the affected eyes. These symptoms can occur in one eye or both eyes.
The spinal cord
The other characteristic symptom of NMOSD is called transverse myelitis, inflammation of the spinal cord. This can occur before, after, or during optic neuritis.
The spinal cord is a tube of nerve tissue that connects the brain to the rest of the body. It extends from the base of the brain down the back. It is housed inside and protected by the vertebrae.
Inflammation of the spinal cord will disrupt the connection between the brain and the rest of the body. This can cause a variety of symptoms, depending on how severe the inflammation is and the section of the spinal cord that is inflamed. Symptoms can include:
- Pain, including pain along the spine, in the limbs, and/or headaches
- Numbness, tingling, or other abnormal sensations, such as sensitivity to touch, heat, or cold
- Problems with bladder and bowel control, or changes in bladder and bowel habits, like difficulty urinating or constipation
- Weakness or paralysis in the lower limbs
- Stiffness in the neck and/or back
Symptoms can occur on both sides of the body or only one side of the body.
The brainstem
NMOSD can also affect the brainstem. The brainstem is the part of the brain that connects to the spinal cord. The brainstem helps control and regulate many functions—including breathing, heart rate, blood pressure, swallowing, reflexes, balance, and coordination.
NMOSD can cause damage to the brainstem, resulting in a condition called area postrema syndrome (APS). The characteristic symptoms of APS are episodes of intractable nausea, vomiting, or hiccups. Episodes of these symptoms can last several weeks.
APS can occur alongside other symptoms of NMOSD, but APS sometimes occurs on its own, either at the onset of NMOSD or during a relapse. It is often misdiagnosed as a gastrointestinal problem.
Other areas of the brain
Lesions in other parts of the brain have been found in people who have NMOSD, but it is not known how frequently these occur. In addition to the symptoms discussed above, sleep disorders, problems with blood pressure, frequent urination, cognitive impairment, and depression have also been reported among people who have NMOSD.
What this means for a person living with NMOSD—every symptom, and any change in the way you feel, is worth discussing with your healthcare providers.
