Gaisbock syndrome is a condition characterized by hypertension and erythrocytosis (increased red blood cell count) in the absence of splenomegaly (enlarged spleen), leukocytosis (increased white blood cell count), or thrombocytosis (increased platelet count). It's often associated with mild obesity and increased blood viscosity, contributing to cardiovascular complications.
Key Characteristics of Gaisbock Syndrome:
- Hypertension: Elevated blood pressure.
- Erythrocytosis: Increased red blood cell mass, leading to a higher hematocrit.
- Absence of Splenomegaly: The spleen is not enlarged, differentiating it from other causes of erythrocytosis.
- Normal White Blood Cell and Platelet Counts: Leukocyte and thrombocyte numbers remain within normal ranges.
- Association with Obesity: Often seen in individuals with mild obesity.
- Increased Blood Viscosity: The increased red blood cell count thickens the blood, making it harder to pump.
Pathophysiology:
The exact cause of Gaisbock syndrome is not fully understood, but it is thought to be related to decreased plasma volume. This leads to a relative increase in red blood cell concentration, even though the absolute red blood cell mass may be normal or only slightly elevated. Factors contributing to reduced plasma volume can include:
- Diuretic use: Medications that increase urine production.
- Chronic stress: Leading to dehydration and decreased plasma volume.
- Obesity: Alterations in fluid balance.
Clinical Significance:
The increased blood viscosity associated with Gaisbock syndrome increases the risk of:
- Cardiovascular events: Such as heart attack and stroke.
- Thrombosis: Blood clot formation.
- Peripheral vascular disease: Reduced blood flow to the extremities.
Diagnosis:
Diagnosis typically involves:
- Complete blood count (CBC): Showing elevated hematocrit and red blood cell count.
- Physical examination: Ruling out splenomegaly.
- Exclusion of other causes of erythrocytosis: Such as polycythemia vera or secondary erythrocytosis due to hypoxia.
Treatment:
Treatment focuses on:
- Addressing underlying causes: Such as obesity and stress.
- Phlebotomy: Removing blood to reduce red blood cell mass and blood viscosity.
- Managing hypertension: With lifestyle modifications and/or medications.
- Low-dose aspirin: May be considered to reduce the risk of thrombosis.
