Science News: Acute Flaccid Myelitis: Long-Term Outcomes Recorded in the CAPTURE Study Compared With Paediatric Transverse Myelitis

Submitted by: Hristelina Ilieva, MD, PhD
Edited by: Pritikanta Paul, MD

Greenberg B, Plumb P, Cutter G, et al. Acute flaccid myelitis: long-term outcomes recorded in the CAPTURE study compared with paediatric transverse myelitis. BMJ Neurol Open. 2021;3(1):e000127. Published 2021 May 19. doi:10.1136/bmjno-2021-000127

Summary: This is a prospective, multicenter, non-randomized, observational cohort study of children with myelitis seen at academic centers in North America. The study lasted 5 years and the length of follow-up was 1 year. Pediatric patients diagnosed with myelitis were eligible for enrollment in the study within 6 months of onset of symptoms. Patients were classified as transverse myelitis (TM) or the acute flaccid myelitis (AFM) variant based on clinical and radiographic findings.

Out of 113 patients who were screened, 51 AFM and 39 TM patients were included with complete data. A majority of patients reported a preceding illness, with respiratory samples testing positive for at least half of AFM cases. More than half of AFM patients had weakness of the upper extremities at onset as compared to a third of TM patients (p=0.03), sensory symptoms and bowel or bladder symptoms at onset were not uncommon. MRI in AFM cases showed predilection for mid-cervical region involvement; two clinically relevant patterns were identified-  a grey matter restricted form of AFM and a cohort with concomitant white matter involvement that could explain lower extremity motor deficits in patients with lesions restricted to the cervical spine. Patients were initially treated with IVIG or steroids and sometimes additional treatment with plasma exchange. The improvement in deficits with the use of corticosteroids was comparable in AFM and TM groups (p=0.97) and no difference in outcome between initial treatment with IVIG vs steroids.

Comments:
This prospective study provides a detailed information on clinical, laboratory, radiographic, and treatment response in pediatric AFM patients. While there is often concern for use of corticosteroids or PLEX in AFM cases potentiating infectious etiology and worsening outcomes, this study did not identify such specific risk and warrants need for further such studies. The non-randomized nature of the study and lack of baseline clinical data (initial 3 months from symptom onset) in many cases, are some of the limitations of this study.

Similar Article: 
Acute flaccid myelitis in childhood: a retrospective cohort study. Andersen EW, Kornberg AJ, Freeman JL, Leventer RJ, Ryan MM.Eur J Neurol. 2017 Aug;24(8):1077-1083. doi: 10.1111/ene.13345. Epub 2017 Jun 22.PMID: 28639345