Acute Flaccid Myelitis
Learn about Acute Flaccid Myelitis, its reported features, relevant specialists, and questions to discuss at a medical consultation.
Also known as: AFM
The sources compiled here do not cover: prognosis. Ask the treating doctor about these.
What is acute flaccid myelitis (AFM)?
From: MedlinePlus, National Library of Medicine
Acute flaccid myelitis (AFM) is a neurologic disease. It is rare, but serious. It affects an area of the spinal cord called gray matter. This can cause the muscles and reflexes in the body to become weak.
Because of these symptoms, some people call AFM a "polio-like" illness. But it is different from polio. AFM is not caused by polioviruses.
What causes acute flaccid myelitis (AFM)?
From: MedlinePlus, National Library of Medicine
AFM can be caused by several different viruses. Researchers think that enteroviruses have been causing the recent increases in the number of children with AFM. AFM can also be caused by other viruses, including flaviviruses, herpesviruses, and adenoviruses.
Most people with AFM had a mild respiratory illness or fever (like you would get from a viral infection) before they got AFM.
Who is more likely to develop acute flaccid myelitis (AFM)?
From: MedlinePlus, National Library of Medicine
Anyone can get AFM, but most cases (more than 90%) have been in young children.
What are the symptoms of acute flaccid myelitis (AFM)?
From: MedlinePlus, National Library of Medicine
Most people with AFM will suddenly have:
Some people also have other symptoms, including:
Sometimes AFM can weaken the muscles that you need for breathing. This can lead to respiratory failure, which is very serious. If you get respiratory failure, you may need to use a ventilator (breathing machine) to help you breathe.
If you or your child develops any of these symptoms, get medical care right away.
- Arm or leg weakness
- A loss of muscle tone and reflexes
- Facial drooping/weakness
- Trouble moving the eyes
- Drooping eyelids
- Trouble swallowing
- Slurred speech
- Pain in the arms, legs, back, or neck
How is acute flaccid myelitis (AFM) diagnosed?
From: MedlinePlus, National Library of Medicine
AFM causes many of the same symptoms as other neurologic diseases, such as transverse myelitis and Guillain-Barre syndrome. This can make it difficult to diagnose. To find out if you have AFM, your doctor may use:
- A neurologic exam, including looking at where there is weakness, poor muscle tone, and decreased reflexes
- An MRI to look at the spinal cord and brain
- Lab tests on the cerebrospinal fluid (the fluid around the brain and spinal cord)
- Nerve conduction and electromyography (EMG) studies. These tests check nerve speed and the response of muscles to the messages from the nerves.
It is important that the tests are done as soon as possible after the symptoms start.
What are the treatments for acute flaccid myelitis (AFM)?
From: MedlinePlus, National Library of Medicine
There is no specific treatment for AFM. A doctor who specializes in treating brain and spinal cord illnesses (neurologist) may recommend treatments for specific symptoms. For example, physical and/or occupational therapy may help with arm or leg weakness. Researchers do not know the long-term outcomes of people who get AFM.
Can acute flaccid myelitis (AFM) be prevented?
From: MedlinePlus, National Library of Medicine
There is no specific way to prevent AFM. But you can take steps to prevent getting sick from a virus by:
- Washing your hands often with soap and water
- Avoiding touching your face with unwashed hands
- Avoiding close contact with people who are sick
- Cleaning and disinfecting surfaces that you frequently touch, including toys
- Covering coughs and sneezes with a tissue or upper shirt sleeve, not hands
- Staying home when sick
Understanding terms used in the source
These definitions explain medical words used above. A definition is not evidence that another condition is present, and it does not predict how a symptom will develop. Ask the clinician which terms apply to the actual examination or test result.
- Respiratory failure
- A severe form of respiratory insufficiency characterized by inadequate gas exchange such that the levels of oxygen or carbon dioxide cannot be maintained within normal limits.
Which doctor should you see?
The suggested department for discussing Acute Flaccid Myelitis is Neurology, with a neurologist as the relevant type of clinician. Urgent in-person medical assessment; emergency department if severe or deteriorating.
This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.
How to prepare for an assessment
Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.
Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.
- Which nervous-system findings help explain the symptoms?
- Would an assessment of walking, communication or daily function be helpful?
- Are rehabilitation or other specialist services relevant?
Treatment discussions and follow-up
Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.
Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.
The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.
When to seek emergency help
Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.
This condition is usually assessed by a neurologist. Every profile shows the doctor’s registration and what has been checked.
Sources
- MedlinePlus, National Library of Medicine — Acute Flaccid Myelitis — Public-domain health-topic summary
- Human Phenotype Ontology Consortium — terminology definitions — HPO licence; definitions reproduced without alteration
- Government of India — Emergency Response Support System — Official reference for India emergency number
Source: MedlinePlus, National Library of Medicine. Orphadata Science: Free access data from Orphanet. © INSERM 1999; July 2026 data, CC BY 4.0. This product uses the Human Phenotype Ontology (hp/releases/2026-09-01). Only sources listed for this article apply. Source material has been selected and arranged; HPO definitions are reproduced without alteration. No source organisation endorses this compilation. Köhler S et al. The Human Phenotype Ontology project: linking molecular biology and disease through phenotype data. Nucleic Acids Research 2014;42(D1):D966–D974. doi:10.1093/nar/gkt1026.
General information, not advice about your situation. Errors can be reported through the corrections process. Reference TDI-C-0083.