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Is There A New Polio? Acute Flaccid Myelitis

By: Suzan Miller-Hoover DNP, RN, CCNS, CCRN-K

Acute Flaccid Myelitis

Acute flaccid myelitis (AFM) is a rare disease that affects the spinal cord. AFM presents as acute flaccid weakness with spinal cord gray matter lesions on imaging, or evidence of spinal cord motor neuron injury on electrodiagnostic testing (National Institutes of Health (NIH), 2018, & Messacar et al., 2016).

In 2018, the Centers for Disease Control and Prevention (CDC) confirmed 62 cases of AFM across the United States, bringing the total number of cases since 2014 to 537. Most of these cases were children, however, AFM can also occur in adults (Centers for Disease Control and Prevention (CDC), 2019).

The cause of AFM is currently under review, however, there is epidemiological evidence and biological plausibility to support enterovirus D68 (EV-D68) as a causative factor (Messacar, et al., 2016; & Cassidy, et al., 2018). Enterovirus D68 has many similarities with the poliovirus, provoking discussions that EV-D68 might be the polio of the 21st century (Cassidy, et al., 2018).

The virus was first identified in 1962 and was originally considered a respiratory pathogen causing mild respiratory disease. However, it is suspected that a change in pathogenicity has produced a virus capable of causing AFM (Cassidy, et al., 2018).

AFM can be difficult to diagnose. Symptoms often mimic other neurological diseases such as Guillain-Barre syndrome, acute disseminated encephalomyelitis and transverse myelitis (NIH, 2018).

Symptoms of AFM include sudden (acute) weakness in the extremities, along with loss of muscle tone and decreased or absent reflexes. Some people with AFM report pain, facial weakness, drooping of the eyelids, difficulty swallowing, speaking or moving the eyes. The most serious complication of AFM is respiratory failure (NIH, 2018, & Messacar, et al., 2016).

Diagnosis
EV-D68 does not present in fecal samples the way that other enteroviruses do. Therefore, if the patient presents with a respiratory illness and neurological symptoms, the recommended laboratory tests should include stool, blood, respiratory and spinal fluid samples (Cassidy, et al., 2018). In addition, an MRI should be done to assess if there are lesions in the gray matter along the spinal cord (Cassidy, et al., 2018).

Treatment
Currently, there is no specific treatment or preventative vaccine. Treatments that have been utilized include immunoglobin, corticosteroids, plasma exchange and antiviral therapy. Unfortunately, these treatments show no evidence they effect the patient’s recovery. Physical and occupational therapy are important factors to reduce long-term effects.
Research continues to pursue a treatment modality and vaccine (NIH, 2018).

Mortality and Morbidity
To date there has been one death from AFM; however, many cases go undiagnosed and unreported.
Most patients recover fully, some have residual effects for up to a year, while others have a permanent functional impairment.

Prevention
Like any other viral infection, hand washing is tantamount to prevention.

Is acute flaccid myelitis (ACM) the new polio?
Only time will tell. Due to the relative recent emergence of this disease, it is important that all healthcare workers have AFM on their radar when admitting children during the flu and virus season. While there is no effective treatment to-date, symptom relief and physical therapy continue to provide some relief and decrease in long-term impairments.


References
Cassidy, H., Poelman, R., Knoester, M., Van Leer-Buter, C. C., & Niesters, H. G. M. (2018). Enterovirus D68 -The new polio. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6243117/

Centers for Disease Control and Prevention (CDC). AFM investigation. (2019). Retrieved from: https://www.cdc.gov/acute-flaccid-myelitis/afm-surveillance.html

National Institutes of Health. (2018). Acute flaccid myelitis. Retrieved from: https://rarediseases.info.nih.gov/diseases/13142/acute-flaccid-myelitis

Messacar, K., Schreiner, T.L., Van Haren, K., Yang, M., Glaser, C.A., Tyler, K.L., & Dominguez, S.R. (2016). Acute flaccid myelitis: A clinical review of US cases 2012-2015. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5098271/

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