Gaisböck's syndrome, first described by Félix Gaisböck in 1905, refers to the association of high blood pressure with an elevated hematocrit level in male patients, with a normal white blood cell count and in the absence of splenomegaly. We report the case of a young diabetic and smoking male who presented with severe hypertension and polycythemia. After ruling out other causes, a diagnosis of Gaisböck's syndrome was made. Antihypertensive treatment and lifestyle changes normalized his parameters. RésuméLe syndrome de Gaisböck, décrit pour la première fois par Félix Gaisböck en 1905, désigne l’association d’une hypertension artérielle et d’un hématocrite élevé chez les patients de sexe masculin. Cette pathologie se caractérise par un nombre normal de globules blancs et une absence de splénomégalie. Nous rapportons le cas d’un jeune homme, fumeur et diabétique, qui a été admis avec une hypertension sévère et une polyglobulie. Après avoir éliminé les autres causes possibles, le diagnostic de syndrome de Gaisböck a été posé. Un traitement antihypertenseur et des modifications de son mode de vie ont permis de normaliser ses paramètres.

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.

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.

The role of smoking, in particular hookah smoking, in the development of hypoxia and, as its consequence, - polycythemia with subsequent development of hypertension is often underestimated; modification of this risk factor can lead to the normalization of blood pressure, hemoglobin and hematocrit levels, as well as red blood cell count. A case of a 31 years old man, Caucasian, applied to the General Therapeutic Clinic of the National Military Medical Clinical Center "Main Military Clinical Center" (Kyiv, Ukraine), with hypertension and secondary polycythemia associated with cigarette and hookah smoking is presented.

Polycythemia is characterized by increased blood viscosity and a chronic inflammatory state possibly giving rise to excessive thromboembolic events and hypertensive cardiovascular disease. We aimed to study the relationship between polycythemia and cardiac risk factors using a large national registry. Patients more than 18 years with a diagnosis of polycythemia were identified from the National Inpatient Sample 2009-2010 database using International Classification of Diseases; Ninth Edition (ICD-9) code 238.4. Demographics, cardiac risk factors, and cardiovascular events were identified. Polycythemia was present in 0.1% (n = 37 922) of hospital-discharged patients. Patients with polycythemia had a significantly increased prevalence of all cardiac risk factors and events, except for diabetes mellitus and chronic kidney disease. Hypertension was more prevalent in polycythemia compared to controls (61 vs. 46%; P < 0.0001). After adjusting for age, sex, race, diabetes mellitus, hyperlipidemia, tobacco use, obesity, coronary artery disease, heart failure, and chronic kidney disease, polycythemia was still a determinant of hypertension [1.37 (1.28-1.45); P < 0.001]. Polycythemia had high prevalence of all cardiac risk factors and was independently associated with increased prevalence of hypertension even after adjusting. Our findings from the National Inpatient Sample provide an epidemiological correlate of Gaisböck's original observation of the association of polycythemia and hypertension more than a century ago.