Isolated Sixth Nerve Palsy and COVID-19: A Recurrent Case in a 7-Month-Old Child and Analysis of Reported Cases

Abstract

Background: With the SARS-CoV-2 pandemic (COVID-19), data on central and peripheral nervous system involvement, including those causing cranial nerve 6 (CN6) palsy, have been limited to case reports. To extract clinically relevant features of COVID-19–related CN6 palsy, we report on a recurrent pediatric case and analysis of reported cases associated with infection or immunization. Methods: A PubMed search revealed 18 cases of isolated CN6 palsy in addition to the index case (n = 19). Clinical characteristics, workup, and temporal associations between systemic symptoms onset or vaccination, symptoms onset, and resolution were compiled and analyzed. Results: The median age of CN6 onset was 43 years (interquartile range [IQR]: 28–52). Sixteen cases (84.2%) were associated with COVID-19 illness and 3 (15.8%) were associated with COVID-19 vaccination. Four cases (23.5%) had positive neuroimaging findings. The median latency from first COVID-19 symptoms or vaccination to onset of CN6 palsy was 6 days (IQR: 2.3–16), and the median time from onset to resolution was 30 days (IQR: 14–60). Latency to onset of CN6 palsy was significantly and directly associated with time to resolution (R2 = 0.401, P = 0.010). Patients who had a positive SARS-CoV-2 antibody test had significantly longer days from symptoms to onset (6.0 vs 24.5, P = 0.030), and patients with a positive SARS-CoV-2 polymerase chain reaction test had a significantly shorter time to resolution (17.50 vs 90, P = 0.042). Conclusions: Isolated CN6 palsy from COVID-19 is rare, can occur in infants as young as 7 months, and can be recurrent. Longer latency from systemic symptoms onset portends greater recovery times, and this relationship may reflect multiple mechanisms by which COVID-19 (and/or an immune response thereto) causes cranial neuropathies with direct clinical relevance.