Learning objectives

• Define polycythemia
• Describe the classification of polycythemia
• Anesthetic management of a patient with polycythemia

Definition and mechanisms

• Polycythemia or erythrocytosis is an increase in red blood cell mass, and is associated with an increase in hemoglobin concentration (Hb) and hematocrit (Hct)
• The condition increases blood viscosity and can reduce cerebral blood flow

Classification

• Absolute polycythemia (increased red cell mass)
  • Primary (polycythemia vera; PV)
  • Secondary 
  • Idiopathic
• Apparent polycythemia (normal red cell mass)
  • Reduced plasma volume

Primary polycythemia

• PV is characterized by the clonal proliferation of myeloid cells
• >95% of patients have a genetic mutation of JAK2 → stimulates overproduction of erythrocytes, platelets, and granulocytes
• JAK2 mutation is not specific for PV, also found in patients with primary thrombocytosis and primary myelofibrosis
• Clinical manifestations result from thrombotic episodes secondary to increased blood viscosity
• Production of immature platelets with variable function and acquired von Willebrand’s disease (vWD) are thought to be behind the bleeding tendency
• Associated laboratory findings
  • Thrombocytosis
  • Leukocytosis
  • Elevated lactate dehydrogenase
• Clinical features
  • Hypertension (46%)
  • Splenomegaly (36%)
  • Pruritus (36%)
  • Erythromelalgia (29%)
  • Arterial thrombosis (16%)
  • Venous thrombosis (7%)
  • Hemorrhage (4%)
  • Facial plethora
  • Hepatomegaly
  • Gout

Secondary polycythemia

• Increased red cell mass is due to increased erythropoietin (EPO) production
• Compensatory mechanism in response to chronic tissue hypoxia or inappropriate production of EPO by the kidneys
• Causes include
  • Chronic obstructive pulmonary disease (COPD)
  • Obstructive sleep apnea (OSA)
  • Cyanotic heart disease
  • Altitude
  • Renal artery stenosis
  • Renal tumors
  • Transplanted kidneys

Idiopathic polycythemia

• Increased red cell mass without an identifiable cause
• Patients are more commonly male and >50% present with vascular occlusive complications

Apparent polycythemia

• Reduced plasma volume results in an increased Hct and Hb on laboratory tests, but the red cell mass is normal
• Associated with the following clinical conditions
  • Obesity
  • Hypertension
  • Smoking
  • Excessive alcohol intake
  • Diuretic use

Signs and symptoms

• Fatigue
• Headaches
• Dizziness
• Episodic blurred vision
• Red skin (particularly on the face, hands, and feet)
• Peripheral tingling, or burning and itching
• Hypertension
• Mucosal cyanosis
• Bruising
• Petechiae
• Unusual bleeding, nosebleeds
• Enlarged spleen or liver

Complications

• Pulmonary embolism
• Deep vein thrombosis
• Increased risk of heart attack and stroke

Diagnosis

Treatment

Management

Suggested reading

• Pollard BJ, Kitchen G. Handbook of Clinical Anaesthesia. 4th ed. Taylor & Francis group; 2018. Chapter 7 The blood, Duncan A.

Clinical updates

Tremblay et al. (2025, JAMA) reaffirm that polycythemia vera (PV) is almost universally driven by JAK2 mutations (> 95%) and carries substantial risks of arterial and venous thrombosis as well as bleeding, particularly with extreme thrombocytosis and acquired von Willebrand disease. The review reinforces that all PV patients should undergo therapeutic phlebotomy targeting a hematocrit < 45% and receive low-dose aspirin, while cytoreductive therapy (hydroxyurea, interferon, or ruxolitinib) is indicated for those ≥ 60 years or with prior thrombosis.