Lecture 3: Anemia I Flashcards
Why do females generally have a lower Hb?
Lower EPO stimulation due to more dilated kidneys from estrogen.
What anemias are classified as microcytic?
Iron deficiency
Thalassemias
Anemia of chronic disease
Lead toxicity
Zinc deficiency
What anemias are classified as normocytic?
Kidney disease
Non-thyroid endocrine heart failure
Copper deficiency
Mild form of most acquired microcytic or macrocytic etiologies of anemia
What anemias are macrocytic, specifically megaloblastic?
B12 deficiency
Folate deficiency
DNA synthesis inhibitors
What anemias are macrocytic, specifically non-megaloblastic?
Myelodysplasia
Liver disease
Reticulocytosis
Hypothyroidism
Bone marrow failure state (aplastic anemia, marrow infiltrative disorders, etc)
Copper deficiency
What does it mean if a hemolytic anemia is intravascular?
RBCs are being lysed within the BLOOD VESSELS.
Why is it significant if a hemolytic anemia is intravascular?
It is significant because large amts of Hgb are being released into circulation.
This will appear as a decrease in iron and haptoglobin.
This may appear as hemoglobinuria.
Iron will NOT be recycled.
Schistocytes will form.
What is a schistocyte?
A tripolar, popped balloon RBC.
It is like a shredded RBC.
Why does haptoglobin decrease in intravascular anemia?
A serum haptoglobin test measures FREE haptoglobin, so if there is a lot of Hgb circulating, then the FREE haptoglobin gets used up.
What does it mean if a hemolytic anemia is extravascular?
RBCs are being lysed within ORGANS.
Why is it significant if a hemolytic anemia is extravascular?
Minimal Hgb released into circulation.
This means little to no decrease in haptoglobin.
Iron should remain almost unchanged.
Spherocytes will form.
What is a spherocyte?
It is a smaller, darker, denser, hyperchromic cell.
It is essentially the formation of a damaged RBC repairing itself by collecting excess Hgb.
Excess Hgb = smaller RBC.
They are NOT biconcave and LACK central pallor.
Why does Iron remain unchanged in extravascular anemia?
Generally, the spleen is where most RBCs get caught, and it is able to recycle the Hgb from the lysed cells.
What is a key PE finding that may differentiate extravascular hemolytic anemia from intravascular?
Red-dark urine in intravascular anemia.
If I have a hemolytic anemia, what lab changes would I expect on:
Hgb
MCV
Reticulocyte count
Hgb would be normal or reduced.
MCV are often increased.
Reticulocytes are often increased.
Note:
Hgb changes little because bone marrow can up the production of RBCs.
Upping RBC production means increasing retic count and generally MCV.
Retic count can remain unchanged if it is a chronic anemia and the bone marrow is exhausted.
If I have a hemolytic anemia, what lab changes would I expect on:
Bilirubin
LDH
Haptoglobin
Bilirubin would increase, esp. unconjugated.
LDH would increase.
Haptoglobin would only markedly decrease in intravascular anemia.
Haptoglobin MAY decrease in extravascular anemia.
Note:
Haptoglobin changes are dependent on the severity of the anemia.
What can falsely elevate haptoglobin?
Chronic inflammation.
Which hemolytic anemia is structural?
Hereditary spherocytosis
What hemolytic anemias are related to Hgb pathologies?
Thalassemias
Sickle cell disease (SCD)
What hemolytic anemia is metabolic?
G6PD deficiency
What hemolytic anemias are immune-related?
Autoimmune hemolytic anemia (AIHA)
Paroxysmal nocturnal hemoglobinuria (PNH)
Hemolytic disease of the newborn (HDN)
What is hereditary spherocytosis and what causes it?
Abnormal formation of proteins in the RBC membrane.
It is a result of improper cytoskeleton formation and is mainly AUTOSOMAL DOMINANT inheritance.
Is hereditary spherocytosis intravascular or extravascular? What does that mean?
Extravascular.
The spherocytes commonly get stuck in red pulp fenestrations in the spleen, so the spleen will bite them.
Describe the clinical presentation of spherocytosis.
Varying degrees…
It can go undetected for years but:
PE:
Jaundice
Splenomegaly
+/- gallstones in 50% of pts
Presents acutely after infection or stress.