haemoglobin

Question 1

define polycythaemia

Answer 1

too many red cells in circulation (erythrocytosis)

Question 2

in polycythaemia, what are all increased vs normal subjects of same age and gender

Answer 2

Hb, RBC and Hct/PCV

Question 3

2 types of polycythaemia

Answer 3

psuedo (apparent) and true

Question 4

what is pseudo (apparent) polycythaemia

Answer 4

reduced plasma volume (e.g. dehydration)

Question 5

what is true polycythaemia

Answer 5

increase in total volume of red cells in circulation

Question 6

4 causes of true polycythaemia

Answer 6

blood doping/overtransfusion (too much blood), appropriately increased erythopoietin, inappropriate erythropoietin synthesis or use, independent of erythropoietin

Question 7

how is polycythaemia evaluated

Answer 7

clinical history -> physical examination -> compare with appropriate normal range

Question 8

when evaluating polycythaemia, what 3 things could be relevant in physical examination

Answer 8

splenomegaly, abdominal mass, cyanosis

Question 9

Hb, RBC and HCT: neonate vs other; children vs adults; women vs men

Answer 9

higher in neonate vs other; lower in children vs adults; lower in women vs men

Question 10

blood sample in polycythaemia vera vs normal when centrifuged

Answer 10

much higher Hct and much less plasma

Question 11

polycythaemia: causes of too much blood

Answer 11

doping, medical negligence. (e.g. look at weight of patient as multiple transfusions can cause polycythaemia and hypertension)

Question 12

polycythaemia: cause of appropriately high levels of erythropoietin

Answer 12

hypoxia (kidney cells that make erythropoietin sensitive to low O2 so secrete more e.g. altitude)

Question 13

polycythaemia: why is erythropoietin production at very high altitudes in response to hypoxia reduced due to mutation

Answer 13

if Hct rises largely, blood viscosity increases, so more likely to suffer CVD

Question 14

polycythaemia: causes of inappropriately high levels of erythropoietin

Answer 14

erythropoietin adminsistered causing high Hct in doping, or when a renal or other tumour inappropriately secretes erythropoietin (renal not surprising as normal site of erythropoietin production)

Question 15

polycythaemia: cause of abnormal function of bone marrow causing increased erythropoiesis independent of erythropoietin

Answer 15

intrinsic bone marrow disorder (polycythaemia vera) causing increased production of red cells

Question 16

what is polycythaemia vera classified as

Answer 16

myeloproliferative neoplasm

Question 17

what can polycythaemia vera lead to, and what can this cause

Answer 17

thick blood (hyperviscosity), causing vascular obstruction and gangrene

Question 18

treatment of polycythaemia if no physiological need for high Hb or if extreme hyperviscosity

Answer 18

blood removed to thin blood

Question 19

treatment of polycythaemia if intrinsic bone marrow disease

Answer 19

drugs to reduce bone marrow production of red cells

Question 20

clinical context when interpreting FBC showing polycythaemia: young healthy athlete

Answer 20

very suspicious (doping or using erythropoietin)

Question 21

clinical context when interpreting FBC showing polycythaemia: breathless cyanosed patient

Answer 21

probably due to hypoxia

Question 22

clinical context when interpreting FBC showing polycythaemia: abdominal mass

Answer 22

could be carcinoma of kidney

Question 23

clinical context when interpreting FBC showing polycythaemia: splenomegaly

Answer 23

polycythaemia vera