Gaisböck syndrome

Overview

Gaisböck syndrome, also known as stress polycythemia or spurious polycythemia, is a rare hematological condition characterized by an apparent increase in red blood cell mass without a true elevation in total red cell volume. It is primarily seen in middle-aged men and is associated with a decrease in plasma volume rather than an actual increase in erythrocyte production. This results in elevated hemoglobin and hematocrit levels despite normal or reduced total red cell mass. The syndrome was first described by Austrian physician Hans Gaisböck in the 20th century.

Causes

The exact cause of Gaisböck syndrome is not fully understood, but it is often linked to lifestyle and physiological factors that lead to reduced plasma volume. These may include:

• Chronic stress: Emotional or occupational stress may contribute to vascular changes and volume contraction.

• Hypertension: Many patients present with high blood pressure, which is a common association.

• Obesity: Excess body weight may influence blood volume regulation and plasma concentration.

• Diuretic use: Use of diuretics for hypertension or other conditions can reduce plasma volume.

• Smoking: Nicotine use is associated with hemoconcentration and vascular changes.

Symptoms

Gaisböck syndrome is often asymptomatic and detected incidentally during routine blood work. However, when symptoms do occur, they may include:

• Headaches

• Facial redness (plethora)

• Dizziness or lightheadedness

• Fatigue

• Blurred vision

• Mild hypertension-related symptoms

Diagnosis

Diagnosing Gaisböck syndrome requires careful exclusion of true polycythemia, such as polycythemia vera. The diagnostic process includes:

• Complete blood count (CBC): Elevated hemoglobin and hematocrit levels.

• Red cell mass measurement: Often normal, helping differentiate from true polycythemia.

• Plasma volume studies: Typically decreased, confirming hemoconcentration.

• Serum erythropoietin levels: Usually normal.

• JAK2 mutation testing: Negative, ruling out polycythemia vera.

Treatment

Treatment of Gaisböck syndrome is mainly focused on addressing underlying causes and improving lifestyle factors. Therapeutic strategies may include:

• Discontinuation or adjustment of diuretics if appropriate

• Weight loss and dietary modifications

• Stress management and lifestyle changes

• Smoking cessation

• Blood pressure control through alternative medications

Phlebotomy is generally not recommended unless hematocrit levels are significantly elevated with symptoms.

Prognosis

The prognosis for patients with Gaisböck syndrome is generally favorable when lifestyle factors are modified and contributing conditions like hypertension are managed effectively. Since it does not involve true polycythemia, complications such as thrombotic events are less common, although they can still occur if the condition is left unrecognized and untreated. Regular monitoring and follow-up care are important to ensure long-term health and to distinguish this benign condition from more serious hematologic disorders.