Object: To improve the understanding of osmotic demyelination syndrome (ODS) after coronavirus disease 2019 (COVID-19) infection.

Method: The clinical manifestations and imaging features of 4 patients with ODS after COVID-19 infection were retrospectively described, and the related literatures were reviewed and analyzed.

Results: All 4 patients suffered from severe hyponatremia and overcorrection after COVID19 infection, with clinical manifestations including fever, vomiting, disturbance of consciousness, convulsions and movement disorders. No abnormalities were found in head MRI examination the early stage of the disease, and extrapontine lesions with or without pontine involvement appeared after 2-3 weeks. The patients were treated with gammaglobulin, steroids and plasmapheresis. Two patients achieved favorable outcomes, while the other two had poor prognoses.

Conclusion: Patients with COVID-19 infection are at high risk of ODS, which may be related to overly rapid sodium supplementation within 24 hours in the context of pre-existing hyponatremia. Other contributing factors include hypertension and hypovolemia induced by diuretic use. Close monitoring of serum sodium levels is essential during sodium supplementation. If the patient exhibits symptoms such as altered consciousness or head MRI suggests lesions involving the cortex, more aggressive immunotherapy and appropriate nursing measures should be taken.