Erythrocytosis Flashcards
What is erythrocytosis?
increased RBC and PCV/Hct
What is the difference between absolute and relative erythrocytosis?
ABSOLUTE - true increase in red cell mass (increased RBCs in circulation)
RELATIVE - RBC mass doesn’t increase in volume, but PCV and RBC count (hemoconcentration due to decreased fluid volume)
What’s the difference between primary and secondary absolute erythrocytosis?
PRIMARY - in the abscence of increased EPO (polycythemia vera)
SECONDARY - increased EPO activity
What care causes of appropriate and inappropriate secondary absolute erythrocytosis?
APPROPRIATE = decreased tissue oxygenation
- pulmonary disease
- R to L CV shunts
- heart failure
- high altitude
- hyperthyroidism
INAPPROPRIATE = normal tissue oxygenation
- hyperadrenocorticism
- renal masses that produce EPO
- neoplasm
What is the most common cause of relative erythrocytosis? What other bloodwork values are typically increased?
hemoconcentration caused by dehydration or splenic concentration
TS/TP
When are clinical signs seen with erythrocytosis? What are 7 signs?
> 70-80% PCV
- increased blood viscosity
- decreased perfusion to the CNS = acute neurologic abnormalities (depressed)
- spastic tetraparesis, seizures, ataxia, paraparesis, collapse
- behavioral changes
- PU/PD
- paroxysmal sneezing (polycythemia vera)
What is most commonly seen on physical exams in patients with erythrocytosis?
- bright red MM
- erythema
- splenomegaly
- renal masses
How can dehydration be ruled out as a cause of erythrocytosis?
- high TP
- (lack of) signs of dehydration of examination
- response of PCV to flud therapy
What are the 3 most common secondary causes of erythrocytosis? How can it be diagnosed?
- respiratory disease - hypoxia (appropriate secondary)
- cardiac disease - hypoxia (appropriate secondary)
- renal masses - EPO production (inappropriate secondary)
How is primary erythrocytosis diagnosed?
(polycythemia vera)
- bone marrow biopsy to look for neoplasia
- EPO concentrations usually low or normal
What 2 treatments are recommended for primary erythrocytosis?
- therapeutic phlebotomy - removing RBCs and replaces with crystalloids to decrease blood viscosity
- hydroxyurea - chemotherapy stops bone marrow from producing RBCs