September 23, 2015 - Polycythemia Flashcards Preview

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Flashcards in September 23, 2015 - Polycythemia Deck (15):
1

Polycythemia

Many "cytes" 

High RBC, high platelets, and high WBC

2

Erythrocytosis

High RBC or high hemoglobin

Often confused with polycythemia.

3

Relative Polycythemia

Caused by burns, diarrhea, or dehydration.

Blood plasma levels are decreased, so RBC occupy a higher percentage and appear elevated, even though they are not.

4

High EPO Without Hypoxia

Any decrease in oxygen delivery to the kidney.

- Renal artery stenosis

- High affinity hemoglobin

- Carboxy-HGB (carbon monoxide)

5

High EPO With Hypoxia

Any decrease in oxygenation of arterial blood will cause an increase in EPO. Common causes include...

- High altitude

- Sleep apnea

- Chronic lung disease

- Cyanotic heart diseases

6

Autonomous Bone Marrow Production

Will result in a production of blood cells with a corresponding low EPO.

Bone marrow is highly active. This can be from familial forms (congenital) or can be from polycythemia vera (acquired).

7

JAK-2

Mutated in polycythemia vera.

JH2 no longer inhibits JH1, and the receptor is activated in the absence of EPO binding. This causes it to continuously produce blood cells.

8

Polycythemia Vera

A neoplasm in which the bone marrow makes too many blood cells. Caused by a JAK-2 mutation which causes the receptor to be activated, even in the absence of EPO (which is normally needed for proliferation).

Most of the health concerns occur as a result of the thicker blood.

9

Consequences of Erythrocytosis

- Blood viscosity increase

- Decreased blood flow which results in decreased oxygen delivery which can manifest as headache, confusion, or chest pain

- Vascular dilation which can cause redness or hemorrhage

- Significantly increased risk of thrombosis

10

Clinical Presentation of Polycythemia Vera

Non-specific symptoms such as headache, weakness, dizziness, sweating, gouty arthritis.

Pruritis (particularly aquagenic - feel VERY itchy after getting out of the shower)

Thrombosis

Erythromelagia (burning in hands)

11

Physical Examination of PV

Splenomegaly (mild/moderate)

Facial plethora (redness)

Hepatomegaly

12

PV Lab Features

Elevated Hct - 95%

Thrombocytosis - 60%

Leukocytosis - 40%

Hypercellular bone marrow - 90%

Low/absent iron stores in marrow - 94%

Low EPO - 95%

JAK-2 mutation - 95%

13

PV Treatment

+ Phlebotomy to keep Hct < 0.45

+ Low-dose ASA

+ Hydroxyurea (if platelets >1000 or 60+ years old)

14

Prognosis of PV

6-18 months if untreated

13.5 years if treated

15

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