Transient erythrocytosis due to hemoconcentration (Gaisböck syndrome)

Specialty: Hematology.

• Spurious polycythemia
• relative erythrocytosis
• Gaisböck stress syndrome

Why it occurs

• Severe or prolonged dehydration (due to loss of extracellular water volume due to gastroenteritis, excessive use of loop diuretics or uncompensated profuse sweating, decreasing total plasma volume with relative elevation of erythrocyte concentration)
• Gaisböck syndrome (classic clinical entity characterized by relative erythrocytosis predominantly in middle-aged men with obesity, severe arterial hypertension, active smoking and significant psychophysical stress)
• Extensive second and third degree burns (massive loss of plasma through the injured skin surface)
• Chronic alcohol abuse or heavy smoking (associated with peripheral vasoconstriction and elevation of carbon monoxide that shifts the oxygen dissociation curve)
• Systemic capillary leak syndrome.

Initial workup

Serial complete blood count to monitor the hemoglobin level and critically the hematocrit (transiently elevated values ​​above 52% in men or 48% in women); determination of the volume of total erythrocyte mass and plasma volume by isotopic labeling with chromium-51 (gold standard to confirm relative erythrocytosis, showing normal erythrocyte mass in the presence of decreased plasma volume); complete lipid profile, uric acid (frequently elevated in Gaisböck syndrome), and serum creatinine levels to assess general hydration status; abdominal ultrasound (to actively rule out splenomegaly, which is absent in relative erythrocytosis but typically present in polycythemia vera); determination of JAK2 mutation and serum erythropoietin levels (to conclusively rule out myeloproliferative neoplasms).

Standard management

• 0.9% isotonic saline solution or Lactated Ringer's — physiological intravenous hydration to restore circulating intravascular volume in a controlled manner; Adequate rehydration directly and progressively decreases the relative hematocrit levels in the control blood count
• Losartan or Enalapril — oral antihypertensives indicated for the control of concomitant arterial hypertension in Gaisböck syndrome; Losartan also has a slight hematocrit-lowering effect by blocking angiotensin II receptors in the bone marrow.
• Statins / Atorvastatin — for the management of the lipid profile and elevated global cardiovascular risk in these patients
• Absolute cessation of smoking and control of psychophysical stress factors.