Exam 17: Hemolytic Anemia: Membrane Defects

Complete the following table:

Select the best statement from the following choices to describe the pathogenesis of PNH.

Which of these disorders has a defective vertical protein interaction between RBC skeleton and the membrane?

Mary, a 7-year-old, was admitted to the hospital after experiencing severe anemia following a respiratory infection. Her father has a history of RBC membrane abnormality and recently underwent a splenectomy to help alleviate the problem. Upon examination, it was revealed that Mary had hepatosplenomegaly and slight bruising on her forearms. A CBC was ordered, with the following results: HGB 10.8 g/dL HCT 29.2% WBC 11 × 10⁹/L RBC 3.8 × 10¹²/L MCV 77 fl MCH 28 pg MCHC 37% PLT 275 × 10⁹/L Peripheral smear: moderate polychromasia and spherocytes Which of the following is most consistent with a presumptive diagnosis in this case?

Which of the following disorders has an abnormal erythrocyte membrane that is abnormally permeable, resulting in the loss of K+ and water and decreased deformability?

The characteristic "fish-mouth" central pallor seen in overhydrated hereditary stomatocytosis is caused by an excessive influx of what in the RBCs?

The screening sucrose hemolysis (sugar-water) test is useful in identifying PNH cells by what mechanism?

What is the principal confirmation test in the diagnosis of HS?

Laboratory findings on a stained blood smear exhibit striking erythrocyte morphologic abnormalities. The MCV is decreased, osmotic fragility is abnormal, and the thermal sensitivity test demonstrates an increase in erythrocyte fragmentation. Autohemolysis in increased and is not corrected with glucose. What disorder is associated with these findings?

The laboratory professional notes about 20% spherocytes on a peripheral blood smear of a 4-year-old boy. An osmotic fragility test is performed. The control shows initial hemolysis at 0.50% NaCl and complete hemolysis at 0.35% NaCl. The patient sample has initial hemolysis 0.60% NaCl and complete hemolysis at 0.45% NaCl. What does this indicate?

A 5-year-old boy is admitted to the pediatric unit with a fractured tibia. Routine blood work is ordered. His PB smear shows moderate spherocytosis. An osmotic fragility is also ordered, and the test result indicates an increased osmotic fragility. Based on these findings, what is the most likely defect?

Immunophenotyping is performed on a patient suspected of having PNH. What monoclonal antibody specificity should be ordered?

A patient is suspected of having HS. However, there appear to be <1% spherocytes on the peripheral blood smear, and the osmotic fragility test is normal. What test could be performed to increase the sensitivity of testing for HS?

Which of the following causes horizontal interactions of skeletal protein abnormalities?

Which of the following disorders is characterized by both a deficiency in spectrin and the presence of a mutant spectrin protein?

In PNH, cells are susceptible to complement-induced lysis. This is thought to result from the lack of what two regulating factors?

Defects in integral proteins, band 4.1, and spectrin are associated with which of the following disorders?

Which of the following subtypes of PNH is characterized by moderate hemolysis and intermediate GPI expression?

Differentiate between the three different subtypes of HE based on PB smear morphology.

In hereditary spherocytosis, the erythrocytes become trapped in the splenic cords and run out of ATP to pump out excessive ions. What is the ion involved?