Polycythemia

Question 1

What is Polycythemia?

Answer 1

Polycythemia is an abnormally high total red blood cell mass with a hematocrit greater than 54% in men and greater than 47% in women.

Question 2

What can a hematocrit of greater than 50% cause?

Answer 2

cardiac dysfunction and vascular obstruction.

Question 3

What can a hematocrit of greater than 60% lead to?

Answer 3

hypoxia.( a state in which oxygen is not available in sufficient amounts at the tissue level to maintain adequate homeostasis)

Question 5

What is Polycythemia categorized as?

Answer 5

relative or absolute.

Question 6

What occurs in relative polycythemia?

Answer 6

-also called Gaisbock syndrome.
-the hematocrit rises because of a loss of plasma volume without a corresponding decrease in red cells.

Question 7

Why may relative polycythemia occur?

Answer 7

this may occur with water deprivation, excessive diuretic usage, or gastrointestinal losses.

Question 8

How would you correct relative polycythemia?

Answer 8

corrected by increasing the vascular fluid volume.

Question 9

What is absolute polycythemia?

Answer 9

a rise in hematocrit because of an increase in total red cell mass and is classified as primary or secondary.

Question 10

What is absolute PRIMARY polycythemia or polycythemia vera?

Answer 10

a proliferative disease of the bone marrow with an absolute increase in total red blood cell mass accompanied by elevated white cell and platelet counts.

Question 11

Polycythemia vera: clinical manifestations are related to what?

Answer 11

the clinical manifestations are variable and are related to an increase in the red cell count, hemoglobin level, and hematocrit with increased blood volume and viscosity.

Question 12

Polycythemia vera: clinical manifestations explained.

Answer 12

-Viscosity rises exponentially with the hematocrit and can interfere with cardiac output and blood flow.
-Hypertension is common, and there may be complaints of headache, dizziness, inability to concentrate, and sometimes difficulty with hearing and vision because of decreased cerebral blood flow.
-Venous stasis gives rise to a plethoric appearance of dusky redness, even cyanosis, particularly of the lips, fingernails, and mucous membranes.
-Because of the increased concentration of blood cells, the person may experience itching and pain in the fingers or toes, and the hypermetabolism may induce night sweats and weight loss.
-Thromboembolism and hemorrhage, because of platelet abnormalities, are common complications that can be prevented by phlebotomy.

Question 13

What is the goal of treatment in primary polycythemia?

Answer 13

Reduce blood viscosity. Withdrawing blood by periodic phlebotomy to reduce red cell volume can do this.

Question 14

What is absolute SECONDARY polycythemia?

Answer 14

results from increased erythropoietin levels caused by hypoxic conditions such as chronic heart and lung disease.

Question 15

What are the manifestations of polycythemia related to?

Answer 15

increased blood volume and viscosity that lead to hypertension and stagnation of blood flow.

Question 16

Concept Mastery Alert: Symptoms associated with polycythemia vera (review)

Answer 16

headache, hearing difficulty, dusky red appearance, and cyanosis of the lips, fingernails, and mucous membranes.

Question 17

Concept Mastery Alert: possible complications in polycythemia vera

Answer 17

possible complications associated with the increased number of red blood cells include blood clots because of increased blood thickness, enlarged spleen associated with work to remove extra red blood cells, hypertension because of increased viscosity and increased oxygen consumption, and chest pain because of oxygen-rich blood not reaching organs, especially the heart.

Question 18

What does secondary polycythemia result from?

Answer 18

physiologic increase in the level of erythropoietin, commonly as a compensatory response to hypoxia.

Question 19

What are conditions that could cause hypoxia?

Answer 19

living at high altitudes, chronic heart and lung disease, and smoking.

Question 20

What causes secondary polycythemia?

Answer 20

-the resultant release of erythropoietin by the kidney causes the increased formation of red blood cells in the bone marrow.
-Neoplasms that secrete erythropoietin may also cause a secondary polycythemia.
-Kidney disease such as hydronephrosis or renal cysts may obstruct blood flow, cause hypoxia, and lead to an increase in erythropoietin.

Question 21

What is the focus of treatment of secondary polycythemia?

Answer 21

focuses on relieving hypoxia.
-ex: continuous low-flow oxygen therapy can be used to correct the severe hypoxia that occurs in some people with chronic obstructive pulmonary disease.
-this form of treatment is thought to relieve the pulmonary hypertension and polycythemia and to delay the onset of cor pulmonale.