A Perspective on Acute Flaccid Myelitis

Occasionally diseases that are actually pretty rare attract enough attention though media (and social media), that they are perceived to be far more prevalent and threatening than they actually are. Current prime example:  AFM, an acronym for acute flaccid myelitis, a serious condition similar to polio in its clinical picture. It affects the nervous system, specifically the spinal cord, causing weakness and paralysis in arms and legs, and, like polio, affects mostly young children.  The CDC began keeping track of this illness only since there was a prominent jump in cases in 2014, and the reason for its recent media attention was a recent spike in the number of cases from August to October  of this year.  There were similar sudden increase in cases in 2014 and 2016, also in the summer and early fall, almost all in children, bring the total to about 120  for 2018, and a few more than 400 since 2014.

The illness generally starts with fever and mild respiratory or GI symptoms, followed by the development of the neuromuscular signs of arm/leg weakness and sometimes pain.  The clinical picture may also include weakness of eye/eyelid activity, speech, swallowing, and even respiratory failure.  Diagnosis is based on  history and  exam,  as well as blood and spinal fluid studies and MRI findings in the brain and spinal cord.  There is no specific treatment available, though a number of therapeutic measures have been tried though not in controlled studies.   The recovery pattern is highly variable, with some patients recovering rather quickly, but others having to deal with lengthy periods of paralysis.

The most prominent question about AFM remains without a solid answer:  what is the cause of this affliction?  Since polio was caused by infection with a particular virus, it might have seemed that this was too.  However, this has not been nearly so straightforward .  Several viruses, including other members of the enterovirus family that includes poliovirus, have been detected in AFM patients, so have several other viruses including coxackie, West Nile and other viral agents, but causal relationship has not been established.   Sometimes no virus is found. It is not even clear if the cause is direct viral infection, or if a virus causes an immune or inflammatory response in the nervous system.  Clearly, a substantial degree of mystery remains here, but also a lot of ongoing research.

And how should parents view all this?  Most importantly, realize how uncommon  AFM is despite the extensive media attention, fewer than 100 cases a year in the whole country.  Next, follow common precautions the CDC recommends  including good handwashing, reasonable avoidance of individuals with viral infection, and seasonal mosquito repellent use.  Finally a word about immunization.  With so much anxiety and attention from a rare disease for which there is no vaccine available, how ironic and unfortunate it is that so many parents fear and even avoid immunization for more likely illnesses with clearly recognized and essentially preventable infections, and  potentially severe, even lethal outcome.  Just doesn’t make sense. 

A footnote.  With memories of polio reawakening with the appearance of AFM, it is worth recalling the history of polio in the country, and of an environment when a particular vaccine was desperately sought and awaited, and accepted by parents with the enthusiasm it deserved.  You can appreciate this in a fine video production from the American Experience series,  at https://www.amazon.com/My-Lai/dp/B004AUMAAY/ref=sr_1_1?s=instant-video&ie=UTF8&qid=1543207048&sr=1-1&keywords=american+experience+documentaries.  Not sure this is free without Amazon Prime, but it’s worth watching.