AFP is a potentially severe neurological condition characterized by rapid onset of limb weakness with spinal cord gray matter abnormalities on MRI.  The etiology and optimal treatment remain unclear.

To describe results of a Canadian national survey of acute flaccid paralysis (AFP) cases in 2018, and the clinical and magnetic resonance imaging (MRI) features of a cluster of these cases that occurred in Toronto (Canada) in 2018.

A national survey of neurologists/ID specialists across Canada was conducted.  In addition, chart review of children diagnosed with suspected AFP at a single Canadian pediatric tertiary care center between August 7, 2018 and October 20, 2018 was performed.  

 Across the nation, 28 AFP cases were reported: Ontario (n=17), Manitoba (n=6), Quebec (n=4) and Alberta (n=1).  Chart review was performed for 12/12 cases at the Hospital for Sick Children (Toronto).  Their median age was 6.0 years (range 2.8-16.3); 7 were female. Median time of presentation was 5 days post-onset of weakness.  Presenting features included prodromal febrile respiratory illness (n=9), CSF lymphocytic pleocytosis (n=11), neck/back pain (n=8), elevated CSF protein (n=8), cervical cord lesion on MR imaging (n=10), brainstem lesion (n=7), and facial weakness (n=5).  Two required ICU admission.  Nasopharyngeal swab testing revealed enterovirus/rhinovirus in 4/12 patients.  No specific serotype has been identified to date. Acute therapies (pulse intravenous methylprednisolone (n=10), plasmapheresis (n=7), intravenous immunoglobulin (IVIG; n=2)), and fluoxetine (n=8)) were well tolerated.  Improvement of motor strength was seen in all but one patient within 23 days of symptom onset. Of the 5 patients who had been discharged from hospital, two returned to baseline. 

The current cluster of AFP cases share many similar clinical features with that of the Canadian cohort during the 2014 pandemic.  Further investigations are needed to uncover the etiology of and evaluate treatment for pediatric AFP.