Flashcards in Buzzwords For Heme/Lymph Final Deck (68)
This Oxidative state of Fe is required both for heme function and Fe absorption in the gut. (Where does it get absorbed?)
Fe2+ - absorbed by DMT-1 in the Duodenum
Fe3+ on Hb is Methemoglobin, which does not carry O2
What is the Committing enzyme of Heme synthesis?
Aminolevulinate Synthase (ALAS)
What is the difference between ALAS 1 and ALAS 2?
ALAS 1 is found in the liver and is subjected to feedback inhibition by heme (transcription, translation, and translocation into the mitochondria)
ALAS 2 is not inhibited by heme and is found in reticulocytes.
Name 3 things cause increased sickling?
1) Increased Deoxygenation
2) Increased HbS
3) Decreased HbF
5) Cold Temperature and infections
How do you treat those who are sickling?
1) Give suppplemental O2, fluids, and antipyretics
2) Hydroxyurea - stimulate increased HbF production
What are the two types of anemias that produce spherocytes?
What test do you use to differentiate the two?
1) Hereditary Spherocytosis
2) Autoimmune Hemolytic Anemia
Use the Coomb's (Direct Antibody Test) -
Hereditary Spherocytosis (-)
Autoimmune Hemolytic Anemia (+)
What is the Direct Coomb's test
It tests to see if there are anti-bodies DIRECTLY on the surface of RBCs.
Where would you see RBC fragments / Schistocytes
Microangiopathic Hemolytic Anemia:
1) TTP - ADAMTS13
2) HUS - E. Coli or Shiga toxin
3) H.EL.LP - High BP during pregnancy
4) Malignant HTN
5) DIC - oozing from injection site
Double Bite Cells
Splenic macrophages removing heinz bodies from RBC.
What is are Heinz Bodies
Precipitated Globins with ROS damage
Most important parameter for assessing O2 carrying capacity of the blood
What measures the "chromicity" of an RBC?
MCHC - Mean Corpuscular Hb Concentration
In acute blood loss, a CBC will often not show anemia. Why is this and when is anemia shown?
Blood loss is whole blood, anemia develops when tissue fluid enters the vascular space to restore blood volume.
Reticulocytes will increase after 2-3 days and peak at 7-10 days
Symptoms of Porphoryias with defect EARLY in the biosynthesis pathway
Neurological defects - Build up of ALA -> producing ROS
Symptoms of porphoryias with defect in the LATE biosynthesis pathway
How long after birth are Sickle Cell Symptoms usually seen? Why?
10-12 Weeks - It's the amount of time for a baby's HbF to go down. HbF is protective against HbS
What is the major cause of death in adults with Sickle Cell Disease?
Acute Chest Syndrome
Acute Chest Syndrome
Lung clots that arrise from Infection or fat emolism from infarcted marrow; the cycle goes: sluggish flow --> sickling --> vasocclusion* --> more slugish flow
In lungs hypoxia causes constriction to shunt blood away, causing more vasocclusion
Most common cause of death in Sickle cell children?
Infection! Children will die because of autoslenectomy, allowing encapsulated bacteria (Strep pneumoniae and Haemophilus influenza).
Alpastic Crisis due to a drop in RBC precursors, is typically due to this?
Where diseases do you see Aplastic Crisis?
Sickle Cell Anemia, Hereditary Spherocytosis
Percentages of Hb types in Sickle Cell TRAIT
HbA 60%, HbS 40% (If you see HbS x > 50% then there will be sickling) unless you look at the kidneys (Renal medulla) which are already hypertonic.
Thalassemia's complication are directly related to what?
Deletions (alpha thalassemias) or Mutations (Beta thalassemias) that cause a decrease or absence of globin units.
Excess normal flobin chains accumulate and cause intracellular RBC cell death (ineffective erythropoiesis) or decreased survival (hemolytic anemia)
What genetic change causes Beta Thalassemia?
Mutation (Splicing error) in the B gene on chromosome 11?
What genetic change causes Alpha Thalassemia?
Deletion of the alpha gene on chromosome 16?
What is the hall mark lab finding for Beta Thalassemia Minor?
HbA2 increases to about 5% (from 2.5%)
What is the chemical marker of hemolysis due to its binding of free hemoglobin
What does Haptoglobin bind to? What is it cleared by
Haptoglobin binds to Hb
Haptoblobin-Hb is cleared by CD 163 - a scavenger receptor on monocytes/macrophages
What happens when CD163 binds its ligand? What is its ligand?
When CD163 binds Haptoglobin-Hb it causes receptor mediated endocytosis via clatherin coated pits;
Haptoglobin is then degraded and CD163 is recycled back to the membrane