Pathology Notes

Hemolytic disease of the fetus and new born Updated: 07/24/2025 © Jun Wang, MD, PhD   General features Caused by maternal antibodies (IgG) against fetal RBCs Most common anti-D (Rh), A, B Anti-D RhD-negative mother, RhD-positive child Usually not first pregnancy (IgM does not cross placenta) Caused by fetal RBCs entered maternal circulation Anti-A or B Group O mother, group A or B child Associated with maternal IgG against A or B antigen  May affect first pregnancy Usually mild (levels of anti-A and anti-B IgG are low, and IgM does not cross placenta) Clinical features Lead to fetal anemia, hydrops fetalis and death in utero Lead to neonatal anemia, hyperbilirubinemia and kernicterus Extramedullary hematopoiesis, hepatosplenomegaly Laboratory findings Positive direct antiglobulin test ABO mismatch: antibody screening might be negative Identification of maternal antibodies against child RBCs Anemia with reticulocytosis, spherocytes, polychromasia, and nucleated RBCs Hyper...

Practice Question Answers Anemia VII © Jun Wang, MD, PhD   Abbreviations: Hb: hemoglobin HCT: hematocrit MCV: Mean Corpuscular Volume MCH: Mean Corpuscular Hemoglobin RDW: Red Cell Distribution Width TIBC: total iron binding capacity   1. A. This patient has a few conditions that may cause fatigue. However, dark urine and jaundice are commonly seen with hemolysis . Her low hemoglobin and elevated reticulocyte count and bilirubin are consistent with hemolytic anemia . Positive DAT is consistent with immune hemolytic anemia . Depression, hypothyroidism, liver disease and Prozac seldom cause hemolysis . 2. E. The peripheral blood smear reveals many spherocytes (RBCs without central pallor area). Warm auto-immune antibodies cause spherocytic changes in immune hemolytic anemia . Cold agglutinin disease is characterized by recurrent painful episodes of fingers and toes and bluish discoloration inv...

Practice questions Anemia VII © Jun Wang, MD, PhD   Abbreviations: Hb: hemoglobin HCT: hematocrit MCV: Mean Corpuscular Volume MCH: Mean Corpuscular Hemoglobin RDW: Red Cell Distribution Width TIBC: total iron binding capacity   1. Use this case for the next four questions . A 45-year-old woman presents to the clinic with fatigue, dyspnea, dark-colored urine and jaundice for the past month. She has a history of Hashimoto thyroiditis for 10 years. She was diagnosed with depression three years ago is current taking Prozac. Physical examination reveals pallor and splenomegaly. Laboratory tests show the following: Hemoglobin: 7.5 g/dL (12-16 g/dL) MCV: 85 fL (80-100 fL) Reticulocyte count: 7% (0.5-2.5%) Total bilirubin: 3.2 mg/dL (0.3-1.2 mg/dL) Direct Coombs test: positive for IgG and C3  Her white cell and platelet count, and TSH are within normal range. An image of her peripher...

Practice Question Answers Anemia VI © Jun Wang, MD, PhD   Abbreviations: Hb: hemoglobin HCT: hematocrit MCV: Mean Corpuscular Volume MCH: Mean Corpuscular Hemoglobin RDW: Red Cell Distribution Width TIBC: total iron binding capacity   1. A. This case is characterized by sudden onset of jaundice and dark urine after medication, consistent with a drug induced hemolysis , further supported by elevated indirect bilirubin and LDH, and presence of bite cells (semicircular portion loss) and blister cells (submembrane vesicle/peripheral vacuole) in peripheral blood. He has had similar episodes. These features are highly suspicious of G6PD deficiency . Eosin-5-maleimide binding assay and osmotic fragility test is used to diagnose hereditary spherocytosis . Flow-cytometry for RBC bound CD55 and CD59 is used to diagnose paroxysmal nocturnal hemoglobinuria . Hemoglobin analysis by electrophoresis of H...