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Difficulty: MediumHematology and Oncology

Match each clinical and laboratory presentation to the most likely hematologic diagnosis.

  • Microangiopathic hemolytic anemia, severe thrombocytopenia, acute kidney injury, and normal coagulation times (PT/aPTT).Thrombotic thrombocytopenic purpura (TTP)
  • Prolonged aPTT that does not correct with a mixing study, associated with recurrent venous or arterial thrombosis.Antiphospholipid syndrome (APS)
  • Macrocytic anemia, hypersegmented neutrophils, glossitis, and elevated methylmalonic acid levels.Vitamin B12 deficiency
  • Marked leukocytosis predominantly consisting of mature small lymphocytes, with smudge cells seen on peripheral smear.Chronic lymphocytic leukemia (CLL)

Answer

The presentations match as follows: MAHA and normal coags with TTP; prolonged aPTT failing to correct with APS; macrocytic anemia and elevated MMA with Vitamin B12 deficiency; and mature lymphocytosis with smudge cells with CLL.
Each presentation contains classic defining features for its respective disease: TTP has microangiopathic hemolytic anemia and strictly normal coags; APS has a paradoxically prolonged aPTT that fails to correct with a mixing study; B12 deficiency has megaloblastic changes with uniquely elevated methylmalonic acid; and CLL has mature lymphocytosis with fragile smudge cells.

Step-by-Step Solution

1
Analyze the first clinical presentation: Microangiopathic hemolytic anemia, thrombocytopenia, acute kidney injury, and normal coagulation times.
Identified as Thrombotic thrombocytopenic purpura (TTP).
TTP is characterized by the formation of microthrombi consuming platelets and shearing RBCs, but without consuming coagulation factors, which keeps PT and aPTT normal.
2
Evaluate the second presentation: Prolonged aPTT that does not correct with a mixing study in a patient with recurrent thrombosis.
Identified as Antiphospholipid syndrome (APS).
The lupus anticoagulant in APS interferes with phospholipid-dependent coagulation tests in vitro, causing a prolonged aPTT that does not correct with normal plasma, despite being strongly prothrombotic in vivo.
3
Review the third presentation: Macrocytic anemia, hypersegmented neutrophils, glossitis, and elevated methylmalonic acid.
Identified as Vitamin B12 deficiency.
Vitamin B12 is required for DNA synthesis (leading to megaloblastic changes) and for the conversion of methylmalonyl-CoA to succinyl-CoA (leading to elevated MMA levels).
4
Assess the fourth presentation: Marked leukocytosis predominantly consisting of mature small lymphocytes, with smudge cells.
Identified as Chronic lymphocytic leukemia (CLL).
CLL involves the proliferation of incompetent, mature-appearing B lymphocytes that are fragile and easily broken during the preparation of a peripheral blood smear, resulting in characteristic smudge cells.

Key Concept

Identifying key hematologic disorders based on pathognomonic clinical and laboratory findings.
Estimated Time:1m 30s
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Topics

Hematology and Oncology

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