Anemia and Thalassemia Flashcards
What are 3 ways to think about anemias and thalassemias?
- decreased production
- increased destruction
- blood loss
How should you approach a pt with suspected anemia/thalassemia?
- H&P
- CBC
- RBC indices
- peripheral blood smear
What should you think if you see a decrease in WBCs on the CBC?
bone marrow suppression, B12/folate deficiency, hypersplenism, or DIC/TTP/sepsis
What should you think if you see an elevated platelet count?
iron deficiency, inflammation/infection (due to platelets acting as acute phase reactant), myeloproliferative disorder
***What if you see an elevated mean corpuscular volume (MCV; >95)?
MACROcytosis (large RBCs):
- increased red cell distribution width/increased reticulocytes (immature RBCs).
- B12/folate deficiency
- drugs interfering with nucleic acid synthesis
- myelodysplastic syndrome (disease of elderly that causes ineffective hematopoiesis).
- EtOH, liver disease
- hypothyroidism (mild macrocytic anemia).
- multiple myeloma (malignant tumor of bone marrow)
***What if you see a low mean corpuscular volume (MCV)?
MICROcytosis (small RBCs):
- iron deficiency (very pale RBCs; increased central pallor)
- copper deficiency
- decreased heme (from lead poisoning)
- decreased globin (thalassemia)
What could cause a person with an anemia to present with a normocytic MCV?
- early micro or macro (because MCV is an average)
- myelodysplastic syndrome
- anemia of chronic disease
What labs do we order for someone whom we suspect is iron deficient?
- total iron
- % saturation
- total iron binding capacity (TIBC) *2nd most important
- ferritin (what stores the iron) *most important
What is anemia?
reduction in circulating red blood cell mass
What is thalassemia?
inherited autosomal recessive blood disorder (also called Mediterranean anemia) due to decreased synthesis of the globin chains of hemoglobin.
Minor= no worries and asymptomatic bc they can make Hgb A.
Major= transfusions required (BAD; flat nose and big cheeks) Will see target cells.
Does anemia affect men or women more?
WOMEN
How are the white count, hemoglobin, and platelets depicted?
white count> hemoglobin
What most often causes an extremely high MCV?
B12 deficiency (will see hypersegmentation of the neutrophils as well).
What will an elevated methylmalonic acid (MMA) level tell you?
B12 deficiency
Will homocysteine levels be high or low in B12 deficiency?
high
Why do you order an intrinsic factor antibody test?
bc this is required for B12 absorption
What do we start to think about if the reticulocyte count is hight?
hemolysis
If MMA level is normal but homocysteine is high, what may you have?
folate deficiency
What could cause B12 deficiency?
pernicious anemia= autoimmune disorder that destroys stomach parietal cells, which are required for producing intrinsic factor.
How do we treat B12 deficiency?
IM or PO B12 supplementation
Will MCV be high or low with iron deficiency?
LOW
Will MCV be high or low with B12 deficiency?
HIGH
What else could cause B12 or iron deficiency?
malabsorption (celiac or crohn’s disease)
What makes up the total protein value?
albumin and globulin.
What is pancytopenia?
red cells, white cells, and platelets low
If your hemoglobin is low, what should your body want to produce?
reticulocytes (immature RBCs) to attempt to increase the hemoglobin
What is a megaloblastic anemia?
anemia (of macrocytic classification) that results from inhibition of DNA synthesis during red blood cell production.
What is aplastic anemia?
rare disease in which the bone marrow and the hematopoietic stem cells that reside there are damaged and thus don’t produce enough cells; pancytopenia.
What is pure red cell aplasia?
maturation arrest of RBCs. You will have an isolated profound anemia with NO RETICULOCYTES.
What virus can most commonly cause pure red cell aplasia?
parvovirus (pts who are susceptible are those with HIV and sickle cell anemia).
How does myelodysplastic syndrome normally present?
with anemia
What is a microcytic anemia?
anemia with MCV
What is a macrocytic anemia
anemia with MCV>100
What is a Myelophthisic process?
bone marrow is infiltrated by something else (ex. breast cancer).
What could cause a low erythropoietin state?
anything affecting the kidneys (anemia of chronic kidney disease) because the kidneys produce erythropoietin
What is a key molecule in ACD (anemia of chronic disease)?
Hepcidin= acute phase reactant produced in the liver during chronic inflammation. It sequesters iron in storage sites by limiting iron transfer from macrophages to erythroid precursors, and by suppressing EPO production in the kidneys. The aim is to prevent bacteria from accessing iron, which is necessary for their survival.
What are the inherited hemolytic anemias?
- sickle cell
- spherocytosis
- thalassemia
What will you see in the setting of hemolysis?
- elevated LDH, elevated indirect bilirubin, and elevated reticulocyte count.
- you will also see decreased haptoglobin (because it is binding free hemoglobin in the blood that was leaked from the lysed RBCs).
What will you see in extravascular hemolysis (RBC destruction by the reticuloendothelial system (macrophages, liver, spleen, and lymph nodes)?
spherocytes (round with no central pallor; all red).
Will see high MCHC (mean corpuscular hemoglobin concentration).
Treat with folic acid, NOT iron.
What will you see in intravascular hemolysis (RBC destruction within vessels)?
shistocytes= sheering of the RBCs
What is a warm antibody?
IgG binds to RBC membrane antigens at >37 degrees. This indicates autoimmune hemolytic anemia, due to the spleen removing sections of the RBC membrane causing spherocytes (extravascular hemolysis).
What test is used to look for autoimmune hemolytic anemia?
direct coombs test
How do you treat autoimmune hemolytic anemia?
- prednisone (steroid)
- IVIg
- splenectomy
What is a cold antibody?
IgM binds to RBC membrane antigens at
What is G6PD deficiency?
x linked recessive disorder characterized by a deficiency of the enzyme glucose 6 phosphate dehydrogenase, which supplies reducing substances via the PPP pathway by converting NADP to NADPH. This causes hemolytic anemia and characteristic heinz bodies and bite cells.
Fava beans and primaquine make it worse!
What specific pathogens does beta-thalassemia put you at risk for?
siderophoric organisms (iron loving): Yersinia and Mucor
How do we diagnose hemoglobinopathies (thalassemias)?
electrophoresis
