Gaisbock's Syndrome: A Case Study.

A 73-year-old hypertensive was found to have new-onset polycythemia during his routine health check up. A workup revealed no evidence of polycythemia rubra vera or a secondary cause of his polycythemia (his erythropoietin level was normal, he had no splenomegaly, and a test for JAK2 v617F mutation was negative). Over the next year of follow up, his hematological profile returned to normal levels. We conclude that this patient had Gaisbock's syndrome, a relative polycythemia that occurs when there is clinically evident contraction of the intravascular fluid space (plasma volume) in smokers and people who received diuretics.