Acute flaccid myelitis associated with enterovirus D68 in a non-epidemic setting

Emerging trends and insights in acute flaccid myelitis: a comprehensive review of neurologic manifestations

Acute Flaccid Myelitis (AFM) is a neurological condition in the anterior portion of the spinal cord and can be characterised as paraplegia (paralysis of the lower limbs), and cranial nerve dysfunction. These lesions are caused by the infection due to Enterovirus 68 (EV-D68); a member of the Enterovirus (EV) family belongs to the Enterovirus species within the Picornavirus family and a Polio-like virus. In many cases, the facial, axial, bulbar, respiratory, and extraocular muscles were affected, hence reducing the overall quality of the patient's life. Moreover, severe pathological conditions demand hospitalisation and can cause mortality in a few cases. The data from previous case studies and literature suggest that the prevalence is high in paediatric patients, but careful clinical assessment and management can decrease the risk of mortality and paraplegia. Moreover, the clinical and laboratory diagnosis can be performed by Magnetic resonance imaging (MRI) of the spinal cord followed by Reverse transcription polymerase chain reaction (rRT-PCR) and VP1 seminested PCR assay of the cerebrospinal fluid (CSF), stool, and serum samples can reveal the disease condition to an extent. The primary measure to control the outbreak is social distancing as advised by public health administrations, but more effective ways are yet to discover. Nonetheless, vaccines in the form of the whole virus, live attenuated, sub-viral particles, and DNA vaccines can be an excellent choice to treat these conditions. The review discusses a variety of topics, such as epidemiology, pathophysiology, diagnosis/clinical features, hospitalisation/mortality, management/treatment, and potential future developments.

Acute Flaccid Myelitis: Review of Clinical Features, Diagnosis, and Management with Nerve Transfers

BACKGROUND

Acute flaccid myelitis (AFM) is a devastating neurologic condition in children, manifesting as acute limb weakness and/or paralysis. Despite increased awareness of AFM following initiation of U.S. surveillance in 2014, no treatment consensus exists. The purpose of this systematic review was to summarize the most current knowledge regarding AFM epidemiology, cause, clinical features, diagnosis, and supportive and operative management, including nerve transfer.

METHODS

The authors systematically reviewed the literature based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using multiple databases to search the keywords ("acute flaccid myelitis"), ('acute flaccid myelitis'/exp OR 'acute flaccid myelitis'), and (Acute AND flaccid AND myelitis). Included articles reported on (1) AFM diagnosis and (2) patient-specific data regarding epidemiology, cause, clinical features, diagnostic features, or management of AFM.

RESULTS

Ninety-nine articles were included in this review. The precise cause and pathophysiologic mechanism of AFM remain undetermined, but AFM is strongly associated with nonpolio enterovirus infections. Clinical presentation typically comprises preceding viral prodrome, pleocytosis, spinal cord lesions on T2-weighted magnetic resonance imaging, and acute onset of flaccid weakness/paralysis with hyporeflexia in at least one extremity. Supportive care includes medical therapy and rehabilitation. Early studies of nerve transfer for AFM have shown favorable outcomes for patients with persistent weakness.

CONCLUSIONS

Supportive care and physical therapy are the foundation of a multidisciplinary approach to managing AFM. For patients with persistent limb weakness, nerve transfer has shown promise for improving function in distal muscle groups. Surgeons must consider potential spontaneous recovery, patient selection, donor nerve availability, recipient nerve appropriateness, and procedure timing.

Acute flaccid myelitis a review of the literature

Acute flaccid myelitis (AFM) is a rare neurological disorder that first rose to national attention in 2014. This neurological disorder has a biennial presentation with every other even year being a peak year. Most patients present in childhood 5 days after a prodromal infection. Patients usually present with muscle weakness and hypo or areflexia in the summer or fall months. Clinical outcomes are variable however most patients do not improve. Currently there are no definitive prognostic factors or etiologies found. However, it is thought that enterovirus-D68 (EV-D68) could be a potential component in the pathobiology of AFM. Treatment options are limited with variable options and no consensus. Supportive therapy has been shown to be the most effective thus far. With our review of the literature, we highlight the recent growing evidence of a possible relationship between EV-D68 and AFM. Additionally, we identify the knowledge gaps in AFM with treatment and prognostic factors.

Characteristics of Patients with Acute Flaccid Myelitis, United States, 2015-2018

Differences between years with and without increased activity suggest differences in viral etiologies.

Observed peaks of acute flaccid myelitis (AFM) cases have occurred biennially since 2014 in the United States. We aimed to determine if AFM etiology differed between peak and nonpeak years, considering that clinical features of AFM differ by virus etiology. We compared clinical and laboratory characteristics of AFM cases that occurred during peak (2016 and 2018, n = 366) and nonpeak (2015 and 2017, n = 50) years. AFM patients in peak years were younger (5.2 years) than those in nonpeak years (8.3 years). A higher percentage of patients in peak years than nonpeak years had pleocytosis (86% vs. 60%), upper extremity involvement (33% vs. 16%), and an illness preceding limb weakness (90% vs. 62%) and were positive for enterovirus or rhinovirus RNA (38% vs. 16%). Enterovirus D68 infection was associated with AFM only in peak years. Our findings suggest AFM etiology differs between peak and nonpeak years.

Enterovirus-Associated Hand-Foot and Mouth Disease and Neurological Complications in Japan and the Rest of the World

Enteroviruses (EVs) are responsible for extremely large-scale, periodic epidemics in pediatric cohorts, particularly in East and Southeast Asia. Clinical presentation includes a diverse disease spectrum, including hand-foot and mouth disease (HFMD), aseptic meningitis, encephalitis, acute flaccid paralysis, and acute flaccid myelitis. HFMD is predominantly attributable to EV-A types, including the major pathogen EV-A71, and coxsackieviruses, particularly CV-A6, CV-A16, and CV-A10. There have been multiple EV-A71 outbreaks associated with a profound burden of neurological disease and fatal outcomes in Asia since the early 1980s. Efficacious vaccines against EV-A71 have been developed in China but widespread pediatric vaccination programs have not been introduced in other countries. Encephalitis, as a consequence of complications arising from HFMD infection, leads to damage to the thalamus and medulla oblongata. Studies in Vietnam suggest that myoclonus is a significant indicator of central nervous system (CNS) complications in EV-A71-associated HFMD cases. Rapid response in HFMD cases in children is imperative to prevent the progression to a CNS infection; however, prophylactic and therapeutic agents have not been well established internationally, therefore surveillance and functional studies including development of antivirals and multivalent vaccines is critically important to reduce disease burden in pediatric populations.