Ultrasound-based neuropathy diagnosis in COVID-19 patients in post-intensive care rehabilitation settings: a retrospective observational study

Objectives: Using ultrasound (US) scanning to examine the correlation between increase of common fibular nerve's (CFN) cross sectional area (CSA) and functional impairment of foot dorsiflexor muscles as an early sign of peripheral neuropathy. Design: Retrospective observational study. Setting: In-patient rehabilitation unit between November 2020 and July 2021. Participants: Twenty-six inpatients who underwent prolonged hospitalization in intensive care units (ICUs) and were diagnosed with critical illness myopathy and polyneuropathy after SARS-COV-2 infection (N=26). Physical examination and US scanning of the CFN and EMG/ENG were carried out on each patient. Interventions: Not applicable. Main Outcome Measure(s): CFN's CSA at the peroneal head. Results: We verified a significant increase in the CSA of the CFN measured at the peroneal head in more than 90% of the nerves tested. A cut off value of CFN's CSA of 0.20 cm was used to identify pathologic nerves. No correlations with other variables (body mass index, ICU days) were found. Conclusion: US scanning of the CFN appears to be an early and specific test in the evaluation of CPN's abnormalities in post COVID-19 patients. US scanning is a reproducible, cost effective, safe, and easily administered bedside tool to diagnose a loss of motor function when abnormalities in peripheral nerves are present.