2. Polycythemia
Polycythemia or erythrocytosis is characterized by an increase in the red cell mass,
measured as increased hemoglobin and hematocrit above the normal level.
Polycythemia is classified into:
Absolute polycythemia- red cell mass (volume) is raised, which is subdivided
into primary and secondary polycythemia.
Relative or pseudopolycythemia -red cell volume is normal but the plasma
volume is reduced.
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3. Secondary Polycythemia
• Secondary polycythemia is an increase in red cell mass which can occur because of many
conditions. It resolves when the underlying cause is treated.
• It is due to increased erythropoietin effect
• Causes of secondary polycythemia:
High altitudes
Pulmonary disease and alveolar hypoventilation
Cardiovascular disease , especially congenital with the cyanosis
Increased affinity haemoglobin (familial polycythaemia)
Heavy cigarette smoking
Renal cancer
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5. Polycythaemia rubra vera (PRV), also known as polycythaemia vera and is a
myeloproliferative disorder in which there is increased production of red cells,
granulocytes and platelets.
In PRV, the increase in red cell volume is caused by a clonal malignancy of marrow stem
cell.
Polycythaemia vera is a rare chronic disease diagnosed in an estimated 2 to 3 people per
100,000 population.
Although it can occur at any age, polycythaemia vera usually affects older people, with
most patients diagnosed over the age of 55 years.
Polycythaemia vera is rare in children and young adults. It occurs more commonly in males
than in females.
PRIMARY POLYCYTHEMIA
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6. Relative polycythemia
Relative polycythemia is an apparent rise of the erythrocyte level in the blood; however,
the underlying cause is reduced blood plasma.
A specific type of relative polycythemia is Gaisböck syndrome.
In this syndrome, primarily occurring in obese men, hypertension causes a reduction in
plasma volume, resulting in a relative increase in red blood cell count.
Causes of relative polycythemia:
Stress
Cigarette smoking
Dehydration: water deprivation, vomiting
Plasma loss: burns, enteropathy
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8. Clinical Findings
SYMPTOMS
Headaches, dyspnea, numbness or tingling in the fingers.
Blurred vision
Sweating during nights.
Redness of the skin especially the face, may look red, ruddy cyanosis.
Weight loss.
Hypertension.
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9. ComplicationsPossible complications of polycythemia vera include:
Blood clots - Polycythemia vera causes an increase in blood thickness and decrease in
blood flow, as well as abnormalities in the platelets, and this increase the risk of blood
clots.
Blood clots can cause a stroke, a heart attack, or blockage of an artery in the lungs
(pulmonary embolism) or in a vein deep within a muscle (deep vein thrombosis).
It is the major cause of death in 10-40% of patients.
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