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Abstract: TH-PO595

Gaisbock Syndrome: A Rare Etiology of Secondary Hypertension

Session Information

Category: Hypertension and CVD

  • 1501 Hypertension and CVD: Epidemiology‚ Risk Factors‚ and Prevention


  • Greene, Taylor, The University of Oklahoma - Tulsa, Tulsa, Oklahoma, United States

Gaisbock syndrome is an unusual clinical disorder first described in 1905 by Dr. Felix Gaisbock as hypertension in males attributed to elevated hematocrit levels without splenomegaly or abnormal leukocyte counts. The underlying pathophysiology for this syndrome was explained as psychiatric disorders that result in chronic stress, extracellular volume depletion due to diuresis, and hypoxemia due to obstructive sleep apnea as these conditions lead to relative and absolute polycythemias.

Case Description

17-year-old Caucasian male without significant medical history was referred to nephrology clinic for new onset of hypertension with associated headache. He was initially seen by his family physician and evaluation revealed polycythemia with hemoglobin (Hb) of 20 g/dl, hematocrit of 57%, and hypertensive urgency with blood pressure of 160/110 mmHg. Physical exam was within normal limits with normal BMI. Secondary etiologies for hypertension evaluating for renal artery stenosis, Coarctation of the aorta, hyperaldosteronism, and Pheochromocytoma were all unrevealing. Hematological evaluation revealed negative JAK2 mutation and further genetic testing revealed a P50 mutation consistent with familial polycythemia. With other secondary causes ruled out, the patient’s hypertension was attributed to Gaisbock syndrome due to familial polycythemia. The patient was initially treated with an Ace-inhibitor and Calcium channel blocker to control hypertension. Eventually one year after starting serial phlebotomy and attaining Hb of 15 -16 g/dl, the patient was able to come off antihypertensive medications and remained normotensive while continuing phlebotomy.


While rare, Gaisbock syndrome is a known phenomenon due to increased intravascular pressure from relative and absolute polycythemia. It can be difficult to differentiate, if hypertension is a consequence or its own diagnosis in some cases. It is important to consider other causes of secondary hypertension especially in patients with atypical presentations, such as this patient who was only 17 years old at onset of hypertension. Notably, Gaisbock syndrome does not have one singular etiology and thus treatment strategies may vary from patient to patient. In our patient, phlebotomy has proven to be an effective treatment in controlling hypertension. It is important to control hypertension as hyper viscosity poses an increased risk for thromboembolic complications.