Acute Flaccid Myelitis in Children

Acute flaccid myelitis is a relatively new disease, which closely resembles polio but isn't the same thing. Learn more.
Acute Flaccid Myelitis in Children

Last update: 29 November, 2021

In the summer of 2012, cases of children with sudden-onset flaccid muscle paralysis began to be reported in California, USA. Until this point, these little ones had been otherwise healthy, and the cause of this event wasn’t entirely clear. Although the clinical presentation of their condition was very similar to polio, doctors were unable to isolate the causative virus in samples from infants.

At first, this condition was called “polio-like syndrome” and finally, it was given the proper name of acute flaccid myelitis (AFM).

Years later, in the summer of 2014, the CDC (Centers for Disease Control and Prevention) gave notice of a new outbreak of this disease. This time, it was linked to other non-polio enteroviruses, which also have an affinity for the central nervous system. Among the most prominent, enterovirus A71 and enterovirus D68 were identified.

Outbreaks of AFM were repeated in 2016 and 2018, between late summer and early fall in the United States. Although the percentage of cases was around 1%, by 2019, more than 600 cases had already been confirmed throughout the United States and outbreaks had been reported on all 5 continents.

Despite being a rare disease, the importance of knowing about it lies in the potential severity and in the lack of treatment. For this reason, we want to tell you what preventive measures can be implemented at home, in order to reduce the circulation of the viruses that cause it.

What is acute flaccid myelitis?

AFM is an inflammatory neurological disease that affects the spinal cord and causes paralysis of the various muscles of the body. When this happens, they become flaccid, reduce their reflex response, and fail to contract enough to carry out their functions.

Among the most affected muscle groups are the following:

  • Upper and lower members
  • Trunk and back
  • Neck
  • Face
  • Diaphragm and other respiratory muscles

In general, the compromise is usually of sudden onset and occurs a few days after a common respiratory condition. The child, until then healthy, begins to suffer from muscle weakness that prevents them from carrying out certain movements with their body.

Unfortunately, 90% of the time AFM affects children, and the average age is 6 years (CDC, 2020).

Causes of acute flaccid myelitis in children

A vial of blood labeled "enterovirus".

So far, a strong correlation between AFM cases and seasonal outbreaks of enterovirus D68 has been determined.

However, other viruses have been postulated as possible causes of this condition. Among them, the enterovirus A71, some arboviruses (such as the Nile virus, Zika and, dengue), some strains of the Coxsackie virus family, among others.

Symptoms of the disease

Children with AFM usually start with banal and unspecific symptoms the days before the onset of paralysis. These can be respiratory (fever, cough, rhinitis, bronchospasm) or gastrointestinal (diarrhea or vomiting).

Between day 3 and day 5 of the onset of this condition, muscle weakness appears suddenly. In general, the upper limbs (arms, hands, shoulders) on one of the two sides are weakened and this is accompanied by pain and absence of reflexes at these sites.

Although the lower limbs can also be affected, most often, they maintain their usual tone and strength. This produces a characteristic asymmetry between the arms and legs, which allows the differential diagnosis with another type of muscular paralysis.

In addition to the limbs, paralysis can appear in the muscles of the trunk or those of the face, causing difficulties in breathing, speaking, or swallowing.

To summarize, the characteristic symptoms of AFM are as follows:

  • Sudden onset muscle weakness.

  • Upper limb and trunk involvement, with less involvement of lower limbs.

  • Loss of tendon reflexes in the affected areas.

  • Catarrhal or gastrointestinal symptoms the previous days.

  • It can involve difficulties in speech, swallowing, and breathing.

Diagnosis and treatment

The diagnosis of AFM is clinical and some complementary tests are carried out in order to rule out other causes that generate similar conditions. For example, transverse myelitis, Guillain Barré syndrome, or polio.

In the first place, the doctor must resort to detailed questioning in order to know the evolution of the current condition. Likewise, they need to verify the child’s vaccination schedule.

Then, a complete physical examination is performed, especially focused on the child’s neurological status.

Finally, some imaging or laboratory studies may be ordered to confirm the suspected diagnosis. Among them, the following stand out:

  • Lumbar puncture to obtain cerebrospinal fluid. It’s used to analyze the appearance of this fluid and to detect the presence of germs.
  • Magnetic resonance imaging of the brain and spine in order to detect the site of neurological involvement.
  • A culture of body fluids, such as feces and blood.
  • Blood laboratory, to check inflammation and infection parameters.

Regarding the treatment of this condition, at the moment, there are no curative measures available. All doctors can do is offer the necessary vital support until the child’s body manages to recover from the damage caused by the virus.

In general, the same care is offered as in the rest of flaccid paralyzes: Mechanical respiratory assistance, urinary rhythm control, intravenous hydration, among others.

At the moment, there’s no evidence to ensure the efficacy of some commonly used treatments, such as intravenous corticosteroids, immunoglobulin therapy, or plasmapheresis. More studies are needed to determine the degree of benefit over the risk of their use.

Can it be prevented?

Yes, it’s possible to prevent infection by those viruses that cause acute flaccid myelitis with some simple measures:

  1. Wash your hands with soap and water frequently.
  2. Ventilate rooms and clean everyday objects.
  3. Use insect repellants and tulle in your baby’s crib.
  4. Avoid contact with sick people, and in case of illness, rest at home until completely healed.
  5. Sneeze into a paper towel or the crook of your elbow to avoid spreading viruses.
  6. Keep your children’s immunization schedule up to date.

Acute flaccid myelitis in children isn’t polio

Although at one time it was thought that it was a re-outbreak of polio, this disease has been eradicated in several countries of the world thanks to vaccination. However, other members of the poliovirus family with similar characteristics will emerge and give rise to conditions like this one.

The fundamental thing is to be alert, know what symptoms to consult your doctor about, and implement all the prevention measures that are within our reach. Among them, guaranteeing the vaccination of our children, as a way of caring for them and taking care of everyone around them.



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