Area postrema syndrome is associated with uncontrollable hiccuping or vomiting. It is a clinical feature of another condition, called neuromyelitis optica spectrum disorder (NMOSD).

A person who experiences area postrema syndrome (APS) should speak with a doctor, who can provide a diagnosis and explain the treatment options.

This article discusses APS, how it relates to NMOSD, and more.

Experts define APS as hard-to-control hiccups, nausea, or vomiting. It may occur in short durations, or it can be constant. Experts describe it as acute or subacute, meaning that it generally comes on suddenly.

A doctor will only diagnose APS if the symptoms have lasted at least 48 hours and it is not possible that another condition is responsible for them.

The presence of anti-aquaporin-4 (AQP4) or anti-myelin oligodendrocyte glycoprotein (MOG) antibodies can be a biological marker for APS resulting from NMOSD. However, people who have APS as a symptom of other disorders will not have AQP4 antibodies.

Connection with NMOSD

APS is a core clinical feature of NMOSD. However, not all people who have NMOSD will develop APS.

NMOSD is more common among females than males, and it typically develops in the fourth or fifth decade of life. Attacks can occur at the onset of NMOSD and throughout the course of the condition.

NMOSD, also known as Devic disease, is a chronic condition that affects the brain and spinal cord. The key characteristics include optic neuritis and myelitis, which are inflammation of the option nerve and spinal cord, respectively.

A person will typically experience periods of acute symptoms, known as flares or attacks, that alternate with periods of remission. The cycle can take weeks, months, or years.

Experts still do not fully understand several key aspects of APS, including the:

  • onset
  • frequency of attacks
  • duration of attacks
  • severity
  • associated symptoms
  • treatment response

APS causes three main symptoms, all of which are uncontrollable or hard to control:

  • hiccups
  • vomiting
  • nausea

If a person is also living with NMOSD, they may experience additional symptoms related to optic nerve and spinal cord involvement. These symptoms, which may sometimes only affect one side of the body, include:

  • pain in the eye
  • loss of acute vision
  • loss of bladder or bowel control
  • pain in the spine or limbs
  • partial or full paralysis in the lower limbs
  • headaches
  • exaggerated reflexes in tendons

Experts generally accept that APS often occurs because of NMOSD and may be the first symptom a person with this condition experiences. They note that the hiccuping or vomiting may be due to inflammation in the dorsal medulla, which is the back side of the lowest part of the brain that connects to the spinal cord.

The majority of people with NMOSD have no family history of the disease. However, about 50% have a family member with an autoimmune disorder. The exact role that autoimmunity plays in NMOSD is still unknown.

The process of diagnosis typically involves multiple steps, including:

  • reviewing the person’s medical and family history
  • conducting a thorough clinical evaluation
  • identifying physical symptoms, such as uncontrollable hiccups or vomiting associated with APS
  • using diagnostic tests, such as AQP4-IgG blood tests, imaging tests (CT or MRI scan), or the examination of fluids, such as cerebrospinal fluid

In some cases, a person may present with APS as the first symptom of NMOSD. This may result in a misdiagnosis, which can lead to further complications when treatment for NMOSD becomes delayed.

When other symptoms of NMOSD occur first, doctors may sometimes mistake the condition for multiple sclerosis.

Area postrema may occur throughout the course of NMOSD. In most cases, treating NMOSD should help alleviate the hiccuping and vomiting.

The treatment options for NMOSD include:

  • eculizumab (Soliris), inebilizumab-cdon (Uplinza), and satralizumab-mwge (Enspryng), which are medications for people who have the AQP4 antibody
  • corticosteroids
  • plasma exchange, which may be effective for people who do not respond to steroids
  • immunosuppressive drugs
  • low doses of carbamazepine
  • antispasticity agents

When people experience an APS attack, symptomatic treatments — such as antiemetics or IV fluids — generally do not work. People who seek emergency room services may get admitted to the hospital.

The most effective treatments involve immunotherapy medications, such as methylprednisolone or plasmapheresis. In a 2018 study, 88% of people who took these medications saw improvements in their symptoms within 2 days.

People living with NMOSD will need continued treatment for the remainder of their life. Maintenance treatments can help stop the condition from getting worse and prevent attacks or flares from occurring. As a result, it is important for a person to get an accurate diagnosis of NMOSD to help keep their symptoms under control.

Although more than 90% of people living with NMOSD will experience repeat attacks, the advent of newer treatment methods has helped reduce the percentage of people who require a wheelchair or become functionally blind as a result of an attack.

Area postrema syndrome is a characteristic syndrome associated with NMOSD. It is the result of inflammation or lesions on the brain stem, and its symptoms include nausea, uncontrollable vomiting, hiccupping, or a combination of these. The symptoms typically last more than 48 hours.

A person who experiences the syndrome will likely find that treating the underlying condition of NMOSD will help improve their APS.