10/21/18: ACUTE FLACCID MYELITIS (AFM): THE POLIO-LIKE NEUROLOGICAL DISORDER SUDDENLY IN THE NEWS; Though Rare, CDC Reports Surge in AFM Cases, More Than 90 Percent in Children

CDC

Just over a month ago, I shared with you my reaction to the recent death of a 28-year-old man who contracted paralytic polio from the Sabin oral polio vaccine as an infant—what I termed a “never event”—and an insider’s account of the known risk of being infected by the poliovirus in this live vaccine as early as 1962. (See blog, 9/19/18.)

My father worked and was friends with U.S. Surgeon General Luther Terry, who oversaw the mass immunization program with the Sabin vaccine and knew of the occurrence of vaccine-associated paralytic polio cases before the program went nationwide. Dr. Terry was Dad’s boss at the Marine Hospital in Baltimore, subsequently renamed the U.S. Public Health Service Hospital, and later at the National Institutes of Health in Bethesda, Md.

According to my father, Dr. Terry told him that he was going ahead with the vaccine program despite the outbreak of cases because statisticians assured him that the risk of polio infection from the Sabin sugar cube was “insignificant.”

Dad didn’t buy it. He said: Statistics are little consolation for the one person who gets polio.

I thought about my father’s words recently when I read about the surge in cases of the polio-like disorder, acute flaccid myelitis, that are being reported to the U.S. Centers for Disease Control and Prevention (CDC). Once again, epidemiologists—medicine’s statisticians—are emphasizing how rare this potentially fatal illness that predominantly affects children is. (Ninety percent of AFM patients are children, the CDC says.)

The risk: Less than one in a million people in the United States get AFM each year.

But if you’re a parent of the one child who has been confirmed to have died of AFM this year—there is one—these statistics do not console you. Probability will not heal your profound loss and grief.

CDC’s Warning, AFM Symptoms

To their credit, CDC officials took the unusual step on Oct. 16 of warning the public about the increase in AFM, a condition that is as mysterious as it is rare, having no known causes, although a variety are suspected: viruses, environmental toxins, and genetic disorders, to name the most likely.

According to the online CDC, patients’ symptoms have been most similar to complications of infection with certain viruses, including poliovirus, which is an enterovirus; non-polio enteroviruses; adenoviruses; and West Nile virus.

Enteroviruses infect the gastrointestinal tract and cause mild illness, but they also can spread to the nervous system, causing neurologic illness such as meningitis and encephalitis.

Reportedly, the CDC has ruled out the poliovirus and the West Nile virus as causes.

Acute flaccid myelitis comes on quickly, usually after a viral infection, notably of the respiratory tract, and affects the area of a child’s spinal cord called gray matter, causing weakness in one or more limbs and paralysis of different muscles.

In addition to sudden arm or leg weakness and loss of muscle tone and reflexes, some AFM patients experience:

*facial droop/weakness
*difficulty moving the eyes
*drooping eyelids, or
*difficulty with swallowing or slurred speech

The face and eye symptoms indicate cranial nerve involvement.

Numbness and tingle are rare symptoms of AFM, but some people report pain in their arms or legs and an inability to urinate. The most severe symptom is respiratory failure, which can happen when the breathing muscles become weak.

Because AFM is a “pretty dramatic disease,” Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases, told The Washington Post, U.S. health officials want to raise awareness about AFM symptoms to make sure that parents seek medical care immediately for their symptomatic children.

Although there is no specific treatment for AFM—and certainly no cure—the CDC reports that neurologists who specialize in treating brain and spinal cord illnesses recommend certain interventions, such as physical and occupational therapies, on a case-by-case basis. It is too early to know the long-term prognosis of AFM patients who have/have not undergone therapy.

Once diagnosed, some patients recover quickly, while others continue to have paralysis in their arms and/or legs and require ongoing care, Dr. Messonnier said. Some children paralyzed by AFM eventually have regained their ability to walk, but they have needed extensive physical therapy and time.

What Are the Numbers?

So far in 2018, the CDC has received reports of 62 confirmed and 65 suspected cases (for a total of 127 cases) of acute flaccid myelitis, in 22 states, as compared with 33 confirmed AFM cases in 2017, in 16 states.

The CDC started tracking AFM in 2014. Although the number of case reports in 2016 exceeded the number so far this year—149 confirmed cases in 39 states and the District of Columbia—the CDC did not issue a public warning then. I cannot tell you why. The 2016 incidence was much higher than in 2015, when there were 22 confirmed cases in 17 states.

All of these case counts represent only those cases for which information has been sent to the CDC and that have been confirmed by the agency. It is quite possible that AFM is under-reported by pediatricians and other physicians who may not know what they’re seeing.

AFM is a subtype of acute flaccid paralysis (AFP), which is the acute onset of flaccid weakness absent features that suggest an upper motor neuron disorder. An umbrella term, AFP encompasses multiple clinical entities, including Guillain-Barre syndrome, toxic neuropathy, and acute transverse myelitis. A physician could easily misdiagnose AFM as one of these syndromes.

The CDC is asking doctors to be alert for patients with AFM symptoms and to collect information (see tests below) and send it to their health departments.

CNN reports confirmed cases of AFM in Arizona, Colorado, Georgia, Indiana, Iowa, Massachusetts, Minnesota, New Jersey, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Texas, and Wisconsin. According to The Washington Post, Maryland has received five case reports, but none has been reported in Virginia or the District of Columbia.

States are under no obligation to send information about AFM cases to the CDC: Their reports are strictly voluntary.

Diagnosis and Prevention

According to the CDC, AFM is diagnosed through a combination of evidence: 1) the results of a neurological exam (e.g., testing of reflexes and tone in limbs); 2) magnetic resonance imaging of the patient’s spinal cord and brain; and 3) lab tests on the cerebrospinal fluid (CSF), which is around the brain and spinal cord. These tests should be “done as soon as possible after the patient develops symptoms,” the CDC advises.

The online Council of State and Territorial Epidemiologists (CSTE) advises obtaining a patient’s vaccine and travel history, along with a stool test, to rule out polio.

So far, the CDC has not seen a correlation between vaccines and AFM.

If I were the parent of a child whose arm and/or leg muscles suddenly became weak and flaccid, I would rush that child to the emergency department of the best hospital within driving distance. Once there, I would advocate for immediate examination, the testing of all biological specimens (CSF, respiratory secretions, serum, and stool), and an MRI.

According to the CSTE, spinal-cord lesions may not be present on an initial MRI. It says that a normal or negative MRI performed within the first 72 hours after onset of limb weakness does not rule out AFM and advocates repeating the imaging.

The prevention methods recommended by the CDC are basic:

*Get vaccinated against polio, with the injected Salk killed-virus vaccine, not the oral Sabin live vaccine.

*Protect yourself from mosquito bites by using insect repellant and taking the other steps that I advise in my 6/14/18 blog. (This is to thwart West Nile virus.)

*Wash your hands often with soap and water.

Now that the CDC has put acute flaccid myelitis on the public’s radar screen, we can hope that before too long science will catch up with the disease.
Ann, 10/24/18

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