Symptoms of NMOSD

The primary symptoms of neuromyelitis optica spectrum disorder (NMOSD), including vision problems, difficulty with movement, and nerve pain, result from inflammation and damage in specific areas of the nervous system, most commonly the spinal cord and optic nerves.

This damage is caused by the immune system’s mistaken attack on healthy parts of the nervous system, often driven by self-reactive antibodies against the aquaporin-4 protein.

In most cases, NMOSD follows a relapsing course, meaning symptoms flare unpredictably and then partially improve. While NMOSD symptoms may ease between attacks, each untreated relapse can cause lasting damage and may eventually lead to serious disability. Because of this, it is important to recognize and report symptoms promptly so that appropriate treatment can begin.

Common symptoms of NMOSD

NMOSD can appear in several ways, but symptoms most often fall into a few hallmark groups:

• optic neuritis: includes symptoms such as eye pain and vision changes caused by inflammation and damage in the optic nerves that connect the eyes and brain
• transverse myelitis: includes symptoms such as mobility problems, pain, bladder or bowel control issues, and sexual dysfunction caused by spinal cord damage
• area postrema syndrome: includes nausea, vomiting, and uncontrollable hiccups caused by inflammation in a specific area of the brainstem

Optic neuritis symptoms and transverse myelitis are the most common early symptoms of NMOSD. Area postrema syndrome is less common but is considered highly specific to NMOSD.

Not everyone with NMOSD will experience all of these symptoms. The specific symptoms vary depending on which parts of the nervous system are affected.

NMOSD attacks are often unpredictable, with symptoms developing over hours or days. Attacks may last from a few days to several weeks and can involve one or more symptom groups. The time between relapses varies widely from person to person.

Vision-related symptoms

Around two-thirds of people with NMOSD may experience optic neuritis, which can cause significant vision problems. NMOSD vision symptoms may include:

• eye pain, particularly with movement
• partial or total vision loss
• loss of color vision
• blurred vision

Vision problems usually affect one eye only, but both eyes can be involved. Repeated optic neuritis attacks may eventually lead to permanent vision loss.

Movement-related symptoms

Movement problems are among the most common NMOSD spinal cord symptoms. Studies suggest they may occur in up to 90% of patients. These symptoms may include:

• muscle spasms or other involuntary movements
• tremors, or uncontrollable shaking
• weakness in the legs
• muscle stiffness
• difficulty walking, including partial or total paralysis

Damage to the spinal cord can lead to severe and permanent disability. In some cases, people may eventually become wheelchair-dependent.

Pain and sensory changes

Nerve pain is a consequence of spinal cord inflammation in NMOSD and is estimated to affect up to about 85% of patients. Pain and sensory changes may include:

• numbness and tingling
• increased heat sensitivity
• increased touch sensitivity
• burning or a feeling of heat in the skin
• painful itching

For some people, sensations that are usually mild or painless, such as clothing brushing against the skin, can trigger pain.

Bladder, bowel, and sexual dysfunction

Spinal cord damage in NMOSD can also affect involuntary bodily functions, including control of the bladder, bowels, and sexual organs. These symptoms may occur in up to about three-quarters of patients.

• NMOSD bladder problems may include urinary urgency, frequency, or leakage.
• Bowel dysfunction in NMOSD most commonly involves constipation.
• Sexual problems may include erectile dysfunction, reduced sexual desire, or difficulty reaching orgasm. These issues can result from nerve damage or occur secondary to other NMOSD symptoms.

Brainstem-related symptoms

NMOSD can sometimes affect the brainstem, a part of the brain that controls many involuntary bodily functions. One common result of brainstem involvement is area postrema syndrome.

Area postrema syndrome symptoms may include:

• persistent hiccups
• unexplainable nausea and vomiting

Involvement of other brainstem areas can lead to additional NMOSD signs such as:

• trouble swallowing or speaking
• dizziness or vertigo
• weakness of the face and eye muscles

Fatigue and psychological symptoms

Physical and mental fatigue are also common in people with NMOSD and often occur alongside cognitive and emotional symptoms, such as:

• depression
• cognitive impairment
• anxiety

The exact cause of these symptoms is not fully understood. They may result directly from nerve damage or develop as a secondary effect of living with a chronic disease.

Other possible symptoms

In rarer cases, NMOSD can affect other parts of the brain, leading to symptoms such as:

• excessive sleepiness or narcolepsy
• low body temperature or blood pressure
• hormonal and menstrual changes
• confusion, memory loss, or personality changes
• seizures

When to seek medical care

Even a single NMOSD symptom flare can cause lasting disability and significantly affect quality of life. For this reason, it is important to contact a healthcare provider promptly if new or worsening symptoms develop.

NMOSD relapse symptoms to watch for include:

• sudden vision loss or movement problems
• new or worsening pain, numbness, or abnormal sensations
• loss of bladder or bowel control
• sudden and unexplained nausea, vomiting, or hiccups

Prompt treatment can help control a relapse and reduce the risk of lasting damage.