RBC Disorders Flashcards
What is the most common cause of iron-deficiency anemia in older patients?
Colon cancer and polyps (lower GI bleeds)
A physician suspects their patient has iron-deficiency anemia. They run an iron study. What are the expected results?
Serum iron - decreased
Serum ferritin - decreased
TIBC - increased
Transferrin saturation - decreased
What is the most accurate laboratory measure of total body iron?
Total iron binding capacity
Anemia of chronic disease is due to an inability to use iron and decreased response to EPO. What is the classic laboratory presentation?
Serum iron - decreased
Serum ferritin - increased
Transferrin saturation - decreased
Increased hepcidin release triggered by cytokines is most associated with what type of anemia?
Anemia of chronic disease - this causes iron to remain within cells, thus low serum iron but high ferritin
What are the primary causes of megaloblastic anemia?
Folate and/or Vitamin B12 deficiency
True/False. Vitamin B12 deficiency will cause folate deficiency, if untreated.
True - Vitamin B12 is needed to regenerate folate from 5-methyl-THF
Why do RBCs increase in size due to Folate/B12 deficiency?
Folate and B12 play a role in DNA synthesis and repair. Deficiency causes unbalanced cell growth and division, resulting in large RBCs
A patient is diagnosed with megaloblastic anemia. How can folate/B12 deficiency be differentiated as the cause?
Folate Deficiency - High homocysteine, normal methylmalonic acid
B12 Deficiency - High homocysteine and methylmalonic acid
What is pernicious anemia?
Anemia caused be defective secretion of IF due to autoantibodies
What is thalassemia?
A quantitative decrease in the production of alpha/beta globin chains that causes excess globin to precipitate within the RBC
Two alpha globin genes are present on both chromosomes. What is the the result of deletion of three of these genes?
Hemoglobin H disease - due to the precipitation of four beta globin chains
Two alpha globin genes are present on both chromosomes. What is the the result of deletion of all four of these genes?
Hemoglobin Bart’s - incompatible with life, causing hydrops fetalis
Thalassemia is associated with what type of anemia?
Hemolytic, microcytic anemia
One beta globin gene is located on each chromosome. What alleles are possible at this locus?
B - Normal
B+ - some beta producing
B0 - no beta producing
Sickle cell disease affects which RBC globin chain?
Beta chain - point mutation of glutamate to valine
How does sickle cell anemia differ from sickle cell trait?
Sickle cell anemia is due to two abnormal (ss) sickle genes, whereas sickle cell trait is inheritance of only one abnormal gene (Ss)
Sickle cell anemia is what type of anemia?
Normocytic, hemolytic anemia
What is paroxysmal nocturnal hemoglobinuria?
A type of hemolytic anemia due to the absence of the GPI anchor protein to which complement inhibitory proteins bind
What complement inhibitory proteins are absent on RBCs of patients with paroxysmal nocturnal hemoglobinuria?
CD55 & CD59 - they bind to the GPI anchor protein, which is absent in PNH
G6PD is an X-linked recessive disorder that prevents regeneration of NADPH. What type of anemia does this cause?
Normocytic, hemolytic anemia
Warm autoimmune hemolytic anemia involves what class of antibodies against what RBC antigen?
IgG antibodies against the Rh antigen
Cold autoimmune hemolytic anemia involves what class of antibodies against what RBC antigen?
IgM antibodies against the I antigen
What is Haptoglobin?
Protein made by the liver that binds to free hemoglobin for excretion
