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Difficulty: MediumHematology and Oncology

Match the following patient presentations with the most likely underlying pathophysiologic mechanism of their hematologic abnormality.

  • A 32-year-old woman presents with altered mental status, fever, and petechiae. Labs show hemoglobin 7.5 g/dL, platelets 22,000/mm³, and creatinine 2.4 mg/dL. Peripheral smear shows schistocytes. PT and PTT are normal.Severely reduced activity of a von Willebrand factor-cleaving metalloprotease
  • A 48-year-old man admitted for gram-negative sepsis develops diffuse oozing from his intravenous catheter sites. Labs show platelets 35,000/mm³, prolonged PT and PTT, and decreased fibrinogen.Uncontrolled generation of thrombin and widespread consumption of coagulation factors
  • A 24-year-old healthy woman presents with heavy menstrual bleeding and petechiae on her lower extremities. Labs show hemoglobin 11.8 g/dL, platelets 15,000/mm³, and normal PT and PTT. Peripheral smear shows large platelets without schistocytes.Destruction of platelets mediated by anti-glycoprotein IIb/IIIa autoantibodies
  • A 62-year-old woman with chronic lymphocytic leukemia presents with new-onset fatigue and scleral icterus. Labs show hemoglobin 8.2 g/dL, elevated indirect bilirubin, and elevated LDH. Peripheral smear shows spherocytes.Macrophage-mediated destruction of red blood cells coated with IgG autoantibodies

Answer

The correct matches are: the patient with the TTP pentad matches with ADAMTS13 deficiency; the patient with DIC matches with consumption of coagulation factors; the patient with ITP matches with anti-glycoprotein IIb/IIIa autoantibodies; and the patient with AIHA matches with IgG-coated red blood cell destruction.
Each vignette represents a distinct hematologic pathophysiology. TTP results from ADAMTS13 deficiency, allowing large von Willebrand factor multimers to shear red blood cells and consume platelets. DIC involves systemic activation of the coagulation cascade, depleting clotting factors and causing prolonged PT/PTT. ITP is an autoimmune destruction of platelets mediated by anti-glycoprotein IIb/IIIa antibodies without affecting the coagulation cascade. Warm AIHA is the antibody-mediated destruction of red blood cells, often producing spherocytes on a peripheral smear, and is frequently associated with lymphoid malignancies like CLL.

Step-by-Step Solution

1
Analyze the first clinical vignette for diagnostic clues.
Identified the presence of microangiopathic hemolytic anemia (MAHA), thrombocytopenia, renal impairment, and altered mental status with normal coagulation times.
These findings represent the classic pentad of Thrombotic Thrombocytopenic Purpura (TTP), which is caused by a deficiency in the ADAMTS13 protease.
2
Analyze the second clinical vignette for diagnostic clues.
Identified thrombocytopenia accompanied by prolonged PT and PTT, and low fibrinogen in the setting of severe infection (sepsis).
These laboratory derangements indicate consumption of coagulation factors, confirming the diagnosis of Disseminated Intravascular Coagulation (DIC).
3
Analyze the third clinical vignette for diagnostic clues.
Identified isolated thrombocytopenia without hemolysis and with normal coagulation studies in an otherwise healthy young adult.
This presentation is characteristic of Immune Thrombocytopenic Purpura (ITP), where autoantibodies target platelet surface antigens.
4
Analyze the fourth clinical vignette for diagnostic clues.
Identified extravascular hemolysis (jaundice, indirect hyperbilirubinemia, spherocytes) in a patient with underlying chronic lymphocytic leukemia.
These findings point to Warm Autoimmune Hemolytic Anemia (AIHA), caused by IgG autoantibodies binding to red blood cell surface antigens.

Key Concept

Differentiation of bleeding and hemolytic disorders based on peripheral smear findings and coagulation panels.
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Topics

Hematology and Oncology

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