Imagine having sudden nausea, vomiting, and hiccups out of nowhere. Your symptoms are relentless and may last weeks at a time. You would be pretty desperate for answers, right? Now, imagine going to the doctor in search of answers and not getting any. Or being misdiagnosed with a stomach bug or anxiety.1
Unfortunately for those with neuromyelitis optica spectrum disorder (NMO), this is often their reality. About 10 to 20 percent of those with NMO may also have episodes of nausea, vomiting, or hiccups. These episodes may last up to a month at a time.1
What is NMO?
NMO is a rare inflammatory disease of the central nervous system (eye nerves, spinal cord, and brain).2
NMO is a demyelinating disorder. Myelin is the protective coating that surrounds the nerve fibers in your brain, spinal cord, and eye. Damage to the myelin layer is called demyelination. Demyelination causes nerve signals to slow or stop, leading to brain and nerve problems.2,3
NMO is also an autoimmune disorder. This means that the immune system cannot tell the difference between healthy cells and invaders like viruses, fungi, or bacteria. Because the body cannot tell the difference, it begins to attack and damage healthy cells.4
The symptoms of NMO can be different depending on which part of the body is affected. Symptoms also vary in severity and how long they last.5
AQP4 and inflammation
Antibodies are proteins the immune system makes to kill germs. In some diseases, antibodies can also be harmful. An antibody that attacks AQP4 causes inflammation and damage to the brain, spinal cord, and eye nerve (optic nerve).6
AQP4 is found on brain cells called astrocytes and helps control water balance in the brain. The brain, spinal cord, and eye nerve (optic nerve) have AQP4. AQP4 antibodies (AQP4-IgG) damage the protective coating (myelin) of the brain cells and cause more inflammation.6
How does NMO cause nausea, vomiting, and hiccups?
Nearly half of those with NMO have nerve fiber damage in the brainstem. Most of these people have AQP4 antibodies. This may involve damage to the nerve fibers in a specific area of the brain stem known as the area postrema (AP). The AP region is rich in AQP4. AQP4 antibodies (AQP4-IgG) bind to AQP4 in this region of the brain, causing a condition known as area postrema syndrome (APS). Symptoms of APS include:2,7
- Nausea
- Loss of appetite or aversion to food (anorexia)
- Vomiting
- Hiccups
NMO may present as unrelenting nausea, vomiting, or hiccups. This is challenging for both the person who is experiencing the symptoms and the doctor trying to figure out what is wrong. NMO can be difficult to diagnose. Misdiagnosis is common.1,2,5
How are these symptoms diagnosed?
Because general stomach upset is a common symptom, your doctor will need to do a full history and physical exam, including additional diagnostic tests to determine the real cause of your symptoms. Some of these tests may include:1
- Magnetic resonance imaging (MRI): MRI machines use magnets to generate images of the brain and spine. This allows doctors to view areas of demyelination (lesions).
- Lumbar puncture (LP or spinal tap): This procedure collects the clear, colorless fluid surrounding the brain and spinal cord known as cerebral spinal fluid (CSF). It is useful to test CSF to rule out other diseases, infections, and inflammatory conditions.
- AQP4 and MOG antibody blood tests: These are used to determine the presence of antibodies in the blood. AQP4 antibodies (AQP4-IgG) are present in 3 out of 4 people with NMO. The antibodies that target myelin oligodendrocyte glycoprotein (MOG) may be present in people with MOG antibody NMO (MOG-IgG NMO).
Additional tests may be needed, depending on your symptoms. Your doctor will determine which test is best.
How are nausea, vomiting, and hiccups treated?
Once your doctor determines that your symptoms are related to NMO, you will likely be prescribed IV steroids. These potent anti-inflammatory drugs will rapidly decrease inflammation on the nerves, improving your symptoms. IV steroids are usually given over several days. You will then have to take steroids for some time by mouth, tapering steroid use over several days or longer.8,9Plasma exchange (plasmapheresis) might be necessary. This is a procedure that removes the harmful antibodies from your blood plasma and replaces them with either your own cleaned plasma or donor plasma.9
Long-term drugs that turn down (suppress) your immune system will help to prevent attacks of NMO. As of early 2021, 3 drugs have been approved to do this. Talk to your doctor about the risks and benefits of these drugs and what treatment plan you need.9
Nausea and vomiting are some of the most common nonspecific symptoms that people report when going to the doctor or hospital. Many times, doctors will link these symptoms to a problem with your gut or belly and not your brain or spine. This can lead to delays in the diagnosis and treatment of NMO. Rapid diagnosis and treatment is key to preventing attacks of NMO, which can lead to disabling paralysis or blindness if not treated and controlled early.1,2,5
