Anemia Flashcards
In warm autoimmune hemolytic anemia, what antibody coats the RBCs?
IgG
What happens to the IgG-coated RBCs?
they get either get competely eaten by the macrophages in the spleen or they’re nibbled at in such a way that the cells become spherocytes
What is the main diagnostic factor for warm autoimmune hemolytic anemia?
DAT
What are the treatment options for warm autoimmune hemolytic anemia?
steroids and splenectomy if necessary
What antibody coats the RBCs in cold autoimmune hemolytic anemia?
IgM (plus complement)
How is cold autoimmune hemolytic anemia temperature dependent?
IgM falls off the cells in warm body parts - so it affects the periphery
What does the IgM coat cause the RBCs to do? WHat does the complement coat cause?
they form bridges with each other, causing agglutination
the complement causes the intravascular hemolysis
What will a presentation of cold autoimmune hemolytic anemia look like?
general pallor, but cyanosis in cold body parts - aggragated by cold temperatures
What is the most important hemoglobinopathy (qualitative Hb abnormality)?
sickle cell anemia
What’s the best lab test to look for hemoglobinopathies?
hemoglobin electrophoresis (HbS won’t travel as far as HbA - normal)
What’s the mutation for sickle cell anemia?
it’s a point mutation in the beta chain gene (valine for glutamate) yielding HbS
What does HbS do upon deoxygenation?
It aggregates and polymerizes in the RBC, causing it to form a sickle shape - very fragile
this clogs up vessels
Which ethicity has sickle cell anemia most often?
african americans
What is the treatment for sickle cell anemia?
you prevent the trigger (like infection, fever, dehydration, etc)
blood transfusions
bone marrow transplantation
While sickle cell was a qualitative Hb abnormality, what is a general example of quantitative Hb abnormalities?
thalassemias
Are thalassemias normochromic or hypochromic. normocytic, microcytic or macrocytic?
hypochromic microcytic
Do you have a increased or decreased RBC count in thalassemia? What other anemia does this differentiate thalassemia from?
increased! - this is how you can differentiate thalassemia from IDA
What are the two general types of thalasemias?
beta thalassemia and alpha thalassemia
What are the genotypes/phenotypes in beta thalassemias? Is it a defect or an absence of the gene?
A defect in the gene!
B gene = norma, B+ = make some beta chains, B- = make no beta chains
B thalassemia minor: B0/B or B+/B
B thalassemia intermedia: B0/B or B+/B+
B thalassemia major: B0/B0 or B0/B+
WHat are the genotypes/phenotypes in alpha thalassemias? Defect or absence of the gene?
An absence of the gene! -a/aa = silent --/aa or -a/-a = a-thal trait aa/-a = HbH disease --/-- = hydrops faetalis
Part of the issue in alpha thalassemias is that you have excess unpaired Hb chains. What do you see regarding this in newborns vs. adults?
newborns: gamma tetramers of Hb (Hb barts)
adults; beta tetramers of Hb
What morphology will you see on smear in a thalassemia?
hypochromatic, microcytic anemia
varying anisocytosis and poikilocytosis
target cells
basophilic stippling
Which ethnic groups typically have alpha thalassemia? beta thalassemia?
alpha = asians and blacks beta = mediterraneans, blacks, asians
Why do G6PD deficient red cells die?
they can’t reduce ROS, so the ROS attacks the Hb
The heme breaks away from the globin and the globin denatures, sticking to the red cell membrane to form Heinz bodies. THe spleen then bites out the Heinz bodies (bite cells) or just destroys them period
