Introduction. Diabetes mellitus patients represent 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 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 condition, but might have led to the worsening
of 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) has been administrated in order to suppress a hyperactive immune
response through its immunomodulatory effect. Forty-eight hours later
respiratory gas exchange had been improved, almost complete regression of
changes in the lungs have been seen, normalization of metabolic and gas
exchange parameters have been detected. After 14 days in the hospital the
patient was discharged home 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 they may be
useful therapeutic agent and in the case of COVID-19. In the presented case,
the application of IVIg very fast led to an improvement in the patient?s
condition.