ABSTRACT
Introduction Diabetes mellitus patients are a vulnerable group of people who are prone to getting infected with severe acute respiratory syndrome corona virus 2 (SARS-CoV-2). The virus has a high binding affinity to angiotensin-converting enzyme 2 receptor, which allows efficient host cell entering, prolonged virus retention, and a possibility of insulin resistance and ketoacidosis development. Case outline We describe a case of a 20-year-old patient with a past medical history of type 1 diabetes mellitus who presented with bilateral COVID-19 pneumonia. Initially, treatment with polyvitamin therapy, corticosteroids, tocilizumab, and convalescent plasma did not improve the patient's condition, but might have led to the worsening of the underlying disease, high blood glucose level, and ketoacidosis. Patient developed a rapid progression of the disease and severe pneumonia that required intubation and mechanical ventilation. Intravenous immunoglobulin (IVIg) was administrated in order to suppress a hyperactive immune response through its immunomodulatory effect. Forty-eight hours later, respiratory gas exchange was improved, almost complete regression of changes in the lungs was seen, normalization of metabolic and gas exchange parameters was detected. After 14 days of hospitalization, the patient was discharged in good general condition. Conclusion COVID-19 complicated by diabetes mellitus leads to a poor outcome of the disease, but antiviral and anti-inflammatory activity of IVIg suggests that it may be a useful therapeutic agent in cases of COVID-19. In the presented case, the application of IVIg led to a rapid improvement in the patient's condition.