The Overlooked Diagnosis: Unraveling a Case of Gaisböck Syndrome

Abstract

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.

INTRODUCTION

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, patients who have a normal white blood cell count and without a splenomegaly.

It is a diagnosis of exclusion which is considered after ruling out classical causes of polycythemia and/or high blood pressure. Psychological stress and smoking play a contributing role in etiopathogenesis of this syndrome.

. Treatment particularly relies on sympathetic nervous system blockers, blood pressure control, smoking cessation, and avoidance of mental stress.

We report the case of a patient whose investigations for high blood pressure led us to conclude that he has Gaisböck’s syndrome.

CASE REPORT

A 28-year-old male was admitted to the emergency department for diabetic ketoacidosis decompensation of his type 1 diabetes mellitus, which had been evolving for 2 years. His medical history included epilepsy since the age of 10 years, treated with phenobarbital, and active smoking at a rate of 6 pack-years. He was not taking any substances known to be hypertensive. His father had diabetes, but there was no history of hypertension in his family.

After an examination in the emergency department; we found a systolic-diastolic hypertensive peak at 24/10 cmHg, a heart rate of 74 bpm, an overweight (BMI: 29 kg/m²), and a plethoric appearance, in addition to hyperglycemia and positive ketonuria. Furthermore, the cardiovascular examination found no abnormalities, there were no signs of Cushing’s syndrome, Ménard’s triad was absent, and there was no splenomegaly.

After stabilizing the emergency, the patient was transferred to our department for further management, and an etiological investigation was conducted. After ruling out renovascular causes, the hormonal blood tests included: TSH: 2.5 IU/L (0.4-4),also a 1mg dexamethasone suppression test ruled out the diagnosis of hypercorticism, and an aldosterone/renin ratio came out normal.

The presence of snoring and daytime sleepiness led us to suspect obstructive sleep apnea syndrome, but polysomnography data were unremarkable.

The complete blood test, however, revealed polycythemia at 19.6 g/dL[13-17] and a hematocrit of 54.2% (42-54); which was confirmed repeatedly, with values varying in parallel with blood pressure readings [Table 1], in the presence of a normal erythropoietin level. The search for the c.1849G>T-p. Val617Phe mutation of the JAK2 gene was negative. This ultimately led to the conclusion of Gaisböck’s syndrome.

Table 1.

The changes in hemoglobin, hematocrit, and blood pressure in our patient

	11/2024	12/2024	01/2025	Normal Range
Hemoglobin level (g/dl)	19	17	20	[13-17]
Hematocrit (%)	56	47	57	[42-54]
Blood pressure (cmHg)	21/10	15/08	23/11	<14/09

As part of the assessment of the impact of hypertension, the fundus examination revealed vascular abnormalities secondary to hypertension, the electrocardiogram showed a rhythm disturbance, and the transthoracic echocardiogram showed left ventricular hypertrophy.

The patient was placed on quadruple antihypertensive therapy and advised to stop smoking and adopt a healthy lifestyle, which normalized his hematological parameters and blood pressure readings.

DISCUSSION

First described by Félix Gaisböck in 1905, Gaisböck’s syndrome refers to the association of arterial hypertension with an elevated hematocrit level in male patients, with a normal leukocyte count and in the absence of splenomegaly.[1]

These patients are characterized by being overweight, having a plethoric appearance, congested eyes, smoking habits, as well as an anxious and tense personality.

Gaisböck syndrome is also known to asa relative polycythemia, stress polycythemia, pseudopolycythemia, or false polycythemia.[2]

The pathophysiology of this syndrome, since its description, remains poorly explained. According to Gaisböck, people with this syndrome have anxious and tense personalities, suggesting a central role of mental stress. In fact, stress leads to a rapid and reversible secretion of, on the one hand, catecholamines (adrenaline and noradrenaline) which induce an elevation of hematocrit, and on the other hand, atrial natriuretic peptide, which in turn leads to a leakage of fluid from the intracellular space to the extracellular space and/or induces a natriuretic effect.[3]

These effects were studied by Kitahara et al. in 21 hypertensive patients[4] who underwent a 10-minute arrhythmic stress test, which increased their blood pressure from 129±2/80±2mm Hg to 167±5/98±3mm. In parallel, an elevation of the hematocrit level was observed, and this elevation was significantly correlated with that of their blood pressure.

Hyperviscosity, a consequence of elevated hematocrit levels, can be responsible for a reduction in blood flow and, ipso facto, the thrombotic complications observed in these patients.

In the same context, El Youssef and Bekwel,[5] studied the cases of two patients suffering from chronic psychiatric disorders with elevated hematocrit levels and arterial hypertension, associated with nocturnal hypotonic polyuria, then suggested the role of chronic stress in reducing the nocturnal activity of ADH and consequently, hemoconcentration.

Psychological stress is not the only factor involved in Gaisböck’s syndrome; Emery et al.[6] studied 13 patients with arterial hypertension and elevated hematocrit – these patients had a normal red blood cell count and a decreased plasma volume. After the introduction of antihypertensive treatment, the investigators observed a decrease in hematocrit parallel to the reduction in blood pressure, along with an increase in plasma volume. They concluded that the elevated hematocrit was due to plasma volume contraction, resulting from blood leakage from the vascular compartment into the extracellular space under the effect of intravascular hypertension.

The same observation was made in our patient, whose hematocrit level returned to the normal range after blood pressure control.

Smoking is also a factor involved in the genesis of Gaisböck’s syndrome. Indeed, carbon monoxide from cigarette smoke reduces oxygen-carrying capacity and induces vasoconstriction; this can lead to a slight increase in hematocrit and polycythemia if the patient starts with a high normal value.[7]

This factor is also present in our patient, who smoked 1 pack/day; the restabilization of his blood pressure readings and hematological parameters after quitting cigarettes is an argument in favor of this observation.

Before confirming the diagnosis of this syndrome, it is necessary to eliminate first two etiologies: Vaquez’s polycythemia and secondary polycythemia; an erythropoietin assay helps in guiding the diagnostic approach towards the first diagnosis when it is normal or low, in which case it is completed by a search for the JAK2 mutation, or towards a secondary polycythemia when it is elevated.[8,9]

Arguments in favor of stress polycythemia are hypertension itself, reduced activity of antidiuretic hormone at night, nocturnal hypoxemia, and heavy smoking.

Regarding arterial hypertension, early onset and severity should prompt investigation for secondary arterial hypertension. Approximately 90% of these are renovascular, while the remaining 10%; about 90% are endocrine in origin.[10] All these causes must be excluded before attributing hyperviscosity to Gaisböck’s syndrome.

Gaisböck’s syndrome can lead to several complications, including microthrombi formation; Ishikawa et al. reported 43 cases of Gaisböck’s syndrome associated with thrombotic strokes, 12 of these patients had QT prolongation and left ventricular hypertrophy.[11] The former authors suggest that these patients had developed stress polycythemia due to hyperfunction of the sympathetic nervous system. The latter can contribute to the complications of hypertension, such as left ventricular hypertrophy and cardiac arrhythmias.

These cardiac abnormalities were present in our patient.

Therapeutic options for Gaisböck’s syndrome depend on the pathogenesis; the mental stress hypothesis may suggest that the administration of sympatholytics such as beta-blockers could contribute to the treatment of polycythemia in these patients.

Some authors suggest that treatment should focus on good control of arterial hypertension and encouraging patients to stop smoking; phlebotomy can be used to reduce hematocrit levels when symptoms such as lethargy, dizziness, or headaches persist.[12]

According to Manolis et al., the use of central sympathetic nervous system inhibitors, such as α2-adrenergic receptor blockers and beta-blockers, can successfully treat conditions of sympathetic overactivity observed in Gaisböck’s syndrome.[13]

CONCLUSION

Gaisböck’s syndrome is characterized by the simultaneous presence of erythrocytosis and hypertension. The onset of these two conditions varies depending on their underlying cause. Erythrocytosis can be either secondary to hypoxemia or relative to a decrease in plasma volume. It is crucial for physicians to determine the cause of erythrocytosis to better understand the mechanism of this association.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.