Anemias

Question 1

diamond-blackfan anemia description

Answer 1

rapid-onset anemia within 1st year of life due to intrinsic defect in erythroid progenitor cells

Question 2

diamond-blackfan anemia findings

Answer 2

increase % HbF (but decrease total Hb)

short stature, craniofacial abnormalities, and upper extremity malformations (triphalangeal thumbs) in up to 50% cases

Question 3

hereditary spherocytosis description

Answer 3

extravascular hemolysis due to defect in proteins interacting with RBC membrane skeleton and plasma membrane (eg, ankyrin, band 3, protein 4.2, spectrin)
mostly AD inheritance

Question 4

hereditary spherocytosis peripheral smear

Answer 4

results in small, round RBCs with less surface area and no central pallor (increase MCHC) -> premature removal by spleen

Question 5

GCPD deficiency description

Answer 5

most common enzymatic disorder of RBCs causes extravascular and intravascular hemolysis
X-linked recessive

defect in G6PD -> decrease reduced glutathione -> increase RBC susceptibility to oxidant stress

Question 6

G6PD deficiency presentation

Answer 6

hemolytic anemia following oxidant stress (sulfa drugs, antimalarials, infections, fava beans)

Question 7

hereditary spherocytosis findings

Answer 7

splenomegaly, aplastic crisis (parvovirus B19 infection)

Question 8

hereditary spherocytosis labs:

Answer 8

increase fragility test

normal to decrease MCV with abundance of cells

Question 9

hereditary spherocytosis treatment

Answer 9

splenectomy

Question 10

G6PD deficiency findings

Answer 10

back pain, hemoglobinuria a few days after oxidant stress

Question 11

G6PD deficiency labs:

Answer 11

blood smear shows RBCs with Heinz bodies and bite cells

Question 12

pyruvate kinase deficiency description

Answer 12

autosomal recessive pyruvate kinase defect -> decrease ATP -> rigid RBCs -> extravascular hemolysis
increases levels of 2,3-BPG -> decrease hemoglobin affinity for O2

Question 13

pyruvate kinase deficiency findings

Answer 13

hemolytic anemia in a newborn

Question 14

paroxysmal nocturnal hemoglobinuria description

Answer 14

increase complement-mediated intravascular RBC lysis (acquired mutation in PIGA gene -> impaired synthesis of GPI anchor for decay-accelerating factor [DAF/CD55] and membrane inhibitor of reactive lysis [MIRL/CD59] that protects RBC membrane from complement)
acquired mutation in a hematopoietic stem cell
increase incidence of acute leukemias

Question 15

paroxysmal nocturnal hemoglobinuria findings

Answer 15

associated with aplastic anemia
triad: Coombs negative hemolytic anemia, pancytopenia, venous thrombosis
patients may report red or pink urine (from hemoglobinuria)

Question 16

paroxysmal nocturnal hemoglobinuria labs

Answer 16

CD55/59 negative RBCs on flow cytometry

Question 17

paroxysmal nocturnal hemoglobinuria treatment

Answer 17

eculizumab (inhibits terminal complement formation)