The Gaisbock syndrome after COVID-19 pneumonia.

In 1905, Felix Gaisbock, MD, described a syndrome in patients with hypertension, elevated hematocrit levels, plethoric appearances, and no splenomegaly. He postulated this relative erythrocytosis was due to stress. In this case report, a 40-year-old Caucasian man with obesity was admitted with recurrent deep vein thrombosis and increasing oxygen requirements 2 weeks after hospitalization with COVID-19 pneumonia. This patient had a 10-year history of untreated hypertension and erythrocytosis. He had a ruddy appearance, a normal erythropoietin level, and a negative JAK2 V617 mutation. In this case, Gaisbock syndrome was suspected.