Recent news reports of acute flaccid myelitis in Washington state (and nationally) have caught the attention of worried parents. Dr. Jeff Duchin, Health Officer at Public Health – Seattle & King County, weighs in on the risk and clarifies some of the confusing details.
Q: What is acute flaccid myelitis (AFM)?
A: AFM is a rare condition with sudden onset of weakness in one or more limbs (arms or legs) sometimes accompanied by weakness in the face or eye muscles (such as facial drooping or difficulty speaking). In severe cases, breathing muscles can be affected.
Q.: How serious is AFM? Do people with AFM recover?
A: AFM is uncommon, but can be a serious illness. In some patients, the breathing muscles can become weak and mechanical ventilation (intubation) may be required. According to the Centers for Disease Control and Prevention (CDC), some people with AFM do recover. The CDC did a survey of patients from cases in the U.S. in 2014. A small number had complete recovery of limb function after about 4 months, but some had no improvement.
Q: How is AFM diagnosed?
A: AFM is difficult to diagnose with certainty because it can look nearly identical to other conditions or syndromes. It is diagnosed based on a careful clinical examination by a healthcare provider, symptoms, an imaging test called a magnetic resonance imaging (MRI) test, and laboratory results that look for known causes of AFM. Abnormalities in nerve cells of the spinal cord (called grey matter) can be seen using the MRI test.
Q: What causes AFM?
A: Infection with several types of viruses has been linked to AFM. Enteroviruses are a common cause of respiratory and diarrheal infections children that rarely cause AFM. Other viruses have also been linked to AFM including West Nile and other mosquito-borne viruses (St. Louis encephalitis and Japanese encephalitis viruses), cytomegalovirus, Epstein-Barr virus, and adenoviruses. Poliovirus is a cause of AFM that was once common in the US, but that is rare now due to vaccination and is not responsible for the current cases in the US. Autoimmune diseases and environmental toxins can also cause AFM.
Often, despite extensive laboratory testing, a cause for AFM is not found. It’s not known why some people develop AFM while others don’t. For most reported cases across the US in recent years the cause has not been identified.
Q: Is there a treatment for AFM?
A: There is no specific treatment for AFM other than what doctors call supportive care (treating symptoms and making the patient comfortable). A doctor who specializes in treating brain and spinal cord illnesses (neurologist) may recommend certain medical care on a case-by-case basis.
Q: What is the situation in WA? How many cases are there? Are these cases connected to each other?
A: The most accurate case counts can be found on the Washington Department of Health website. Public Health- Seattle & King County, Washington State Department of Health, CDC and Seattle Children’s Hospital have been working together to investigate the cases and to understand the cause of the illnesses.
Q: How common is AFM?
A: AFM is quite rare. In Washington state, two cases were reported in 2014 and none in 2015. Clusters of AFM cases similar what is occurring in Washington currently have happened elsewhere in the US, for example in Colorado and Arizona.
Q: What should I do if I’m concerned my child may have AFM?
A: If you believe you or your child has symptoms that are compatible with AFM, please contact your doctor as soon as possible to determine whether additional evaluation is needed.
Q: How can I prevent AFM?
A: You can help protect yourselves from known causes of AFM by washing your hands often with soap and water, avoiding close contact with sick people, and cleaning surfaces with a disinfectant, especially surfaces that a sick person has touched. Washing your hands the right way is one of the best things you and your children can do to protect against getting sick. Wash your hands often, and especially before you touch food; after going to the bathroom, blowing your nose, changing a baby’s diaper, or touching an animal, an animal’s food, urine or feces; and before and after taking care of a sick person or a cut or wound.
During times of the year when mosquitos are active, remove standing or stagnant water from nearby property to minimize the number of mosquitoes.
Being up to date on recommended vaccinations, including poliovirus, can also protect from diseases that can cause AFM. Check with your doctor to make sure your family is up to date on all recommended vaccines and be sure to get recommended vaccine before international travel.
Q: Some people are saying vaccines cause AFM – is that true?
A: AFM occurs in children of different ages and also less commonly occurs in adults, usually following symptoms of a viral respiratory infection or diarrhea. AFM is known to be linked to infection with certain viruses. Although the cause of many AFM cases is not known, there is no evidence that vaccines cause AFM.