Lecture 6 - Erythrocytosis "polycythemia"

Question 1

__ is an increased PCV, RBC ct, Hgb

Answer 1

erythrocytosis (polycythemia is a misnomer, this normally refers to neoplastic proliferation of RBC)

Question 2

3 types of erythrocytosis

Answer 2

1. relative
2. transient
3. absolute

Question 3

What is the most common erythrocytosis caused by dehydration

Answer 3

relative erythrocytosis

Question 4

what erythrocytosis is common in horses and is normally due to splenic contraction

Answer 4

transient erythrocytosis

Question 5

__ normally have higher PCV’s (above reference interval) can be misinterpreted for erythrocytosis

Answer 5

sighthounnds (greyhouns)

Question 6

__ causes relative erythrocytosis due to decreased plasma volume producing an increase in number of circulating RBCs

Answer 6

hemoconcentration

Question 7

hemoconcentration (relative erythrocytosis) caused by

Answer 7

1. dehydration (water loss - diarrhea, vomit, sweat, fever, decreased drinking)
2. fluid shifts out of blood (edema, colic)

Question 8

if both PCV and TP are high after exercise and there is evidence of __ during PE what do you suspect

Answer 8

dehydration, dehydration (must have observed dehydration too)

Question 9

__ erythrocytosis is the redistribution of RBC in vascular sapce due to excitement, fear, exercise, pain, epinephrine, etc.

Answer 9

redistribution

Question 10

redistribution erythrocytosis is caused by transient __ in response to epinephrine

Answer 10

splenic contraction (can mask an anemia!)

Question 11

If have a post exercise increase in PCV but TP remains THE SAME

Answer 11

due to splenic contraction/redistribution

Question 12

___ erythrocytosis is increased production of RBC with marrow erythroid hyperplasia

Answer 12

absolute

Question 13

absolute erythrocytosis causes exercise intolerance, brick red mm, very high PCV (80%) with normal TP. Why?

Answer 13

blood is so thick it can’t deliver O2; sludges in capillaries and is prone to clots in small BV

Question 14

what determines if absolute erythrocytosis is primary or secondary

Answer 14

erythropoietin

Question 15

__ erythrocytosis is outside the control of EPO (normal or decreased EPO), it is characterized by uncontrolled RBC production due to myeloproliferative dz (cancer) and is uncommon

Answer 15

Primary absolute

Question 16

primary absolute erythrocytosis is also known as

Answer 16

primary polycythemia, polychythemia ruba vera, or polycythemia vera

Question 17

With primary absolute erythrocytosis or primary polycythemia there is __ EPO in circulation

Answer 17

normal (or decreased)

Question 18

If primary polycythemia is suspected what should you check to rule out/ddx

Answer 18

PaO2, if there is normal blood O2 concentration then it is not “polycythemia” caused by hypoxemia

Question 19

Is a p with primary polycythemia hypoxemic?

Answer 19

no, normal PaO2

Question 20

what is the most uncommon erythrocytosis

Answer 20

absolute

Question 21

increased __ production with secondary absolute erythrocytosis (can be hypoxemic or non-hypoxemic)

Answer 21

erythropoietin

Question 22

increased __ production with primary absolute erythrocytosis

Answer 22

RBC

Question 23

__ secondary erythrocytosis has a low PaO2 which stimulates normal EPO release. This can be seen in high altitudes and chronic cardio/pulmonary dz (things that effect O2 carrying capacity)

Answer 23

Hypoxemic (more common)

Question 24

__ secondary erythrocytosis has a normal PaO2 but inappropriate EPO release due to poor renal flow (kidney things body is hypoxic when it’s not) or paraneoplastic syndrome

Answer 24

non-hypoxemic (uncommon)

Question 25

__ (in this case) is due to tumor secreting EPO causing non-hypoxemic secondary erythrocytosis

Answer 25

paraneoplastic syndrome

Question 26

A calf has signs or hypoxia and right sided CHF, there is an increased PCV and normal TP and no dehydration seen on PE. What are you thinking?

Answer 26

1. Polycythemia (high PCV).
2. Normal TP and PE, rules out relative (calf is not dehydrated)
3. Bovides DO NOT have a contractile spleen, rules out transient
4. Must be absolute, know it is secondary bc the PaO2 is low (if primary PaO2 would be normal).
5. Now is it secondary due to hypoxemia or non-hypoxemia? Hypoxemia (has low PaO2, non-hypoxemia would have normal PaO2)
6. ANSWER: Secondary absolute erythrocytosis due to hypoxemia