Recognition of phrenic paralysis as atypical presentation during CT chest examination of COVID-19 infection and its correlation with CT severity scoring: a local experience during pandemic era

BACKGROUND: Coronavirus disease 2019 (COVID-19) was declared a global pandemic by the World Health Organization on March 11, 2020. COVID-19 infection is considered a multi-system disease with neurological, digestive, and cardiovascular symptoms and complications. It can trigger acute and diffuse endothelial dysfunction, resulting in a cytokine storm, most likely induced by the interleukin-6 (IL-6) amplifier. The peripheral and central neurological complications may explain some clinical manifestations such as vagus nerve palsy. The known main CT chest findings of COVID-19 pneumonia include ground glass patches, pulmonary consolidations, inter-lobar septal thickening, crazy paving appearance, and others. We presented our experience in the incidental discovery of phrenic nerve paralysis as atypical chest finding in patients with a known history of COVID-19-associated pneumonia, proved by RT-PCR and coming for evaluation of the lung changes. Patients with evidence of diaphragmatic paralysis underwent close follow-up with a re-evaluation of the phrenic nerve palsy at their routine follow-up for COVID-19 pneumonia. The association of the phrenic nerve palsy was correlated with the CT chest severity score. RESULTS: Among 1527 scanned patients with known COVID-19 pneumonia, we had recognized 23 patients (1.5%) with unilateral diaphragmatic paralysis, accidentally discovered during CT chest examination. Twenty-one patients had shown complete recovery of the associated diaphragmatic paralysis during their follow-up CT chest with regression or the near-total resolution of the pulmonary changes of COVID-19- pneumonia. No significant correlation between the incidence of unilateral diaphragmatic paralysis and CT severity score with p value = 0.28. CONCLUSION: Phrenic paralysis is considered a serious but rare neurological complication of COVID-19 pneumonia. No significant correlation between the CT severity score and the incidental discovery of unilateral diaphragmatic paralysis. The majority of the cases show spontaneous recovery together with the improvement of the pulmonary changes of COVID-19 pneumonia. The association of phrenic paralysis with anosmia and dysgeusia could suggest a direct viral attack on the nerve cells.