Gaisbock Syndrome: A Review of Contemporary Studies, Pathogenesis, Complications, and Possible Treatment.

Gaisbock syndrome is the term ascribed to several conditions initially observed by Felix Gaisbock, MD, (from Innsbruck, Tyrol, Austria) in 1905 when he described a group of hypertensive male patients who had high hematocrit levels, normal leukocyte counts, and no splenomegaly. These patients had an overweight, stocky habitus, a plethoric appearance with suffusion of the eyes, tense and anxious personalities, a cigarette smoking habit, vascular disease, headaches, and facial rubor. Later studies identified alcoholism, diuretic therapy, and physical or emotional stress as additional risk factors that might contribute to the onset of this syndrome. This review revisits Gaisbock syndrome based on recent literature, and will highlight contemporary studies that have established an association between erythrocytosis and hypertension and associated risk factors. Several mechanisms help explain the pathophysiology underlying Gaisbock's observations, and these include psychiatric disorders resulting in chronic stress, volume contraction secondary to diuretics and hypertension, and obstructive sleep apnea with nocturnal hypoxemia and erythropoietin production. Complications associated with this syndrome include the formation of microthrombi with cerebral infarction; treatment should focus on the management of hypertension and a reduction in risk factors, such as obesity, cigarette smoking, and alcohol use. Gaisbock syndrome involves several clinical disorders, has a complex pathogenesis, and leads to a better understanding of the causes of erythrocytosis during patient evaluation.