Examkin

Question

Difficulty: MediumHematology and Oncology

Match each peripheral blood smear description or characteristic laboratory finding with the most likely underlying hematologic disorder.

  • Hypersegmented neutrophils and macro-ovalocytesMegaloblastic anemia
  • Schistocytes, elevated lactate dehydrogenase, and normal PT/aPTTThrombotic thrombocytopenic purpura
  • Spherocytes, reticulocytosis, and a positive direct antiglobulin testAutoimmune hemolytic anemia
  • Teardrop cells (dacrocytes), nucleated red blood cells, and a left shift in granulocytesPrimary myelofibrosis

Answer

Hypersegmented neutrophils match with Megaloblastic anemia; Schistocytes with normal PT/aPTT match with Thrombotic thrombocytopenic purpura; Spherocytes with a positive DAT match with Autoimmune hemolytic anemia; Teardrop cells match with Primary myelofibrosis.
Each peripheral smear finding represents a distinct pathophysiologic mechanism. Megaloblastic anemia impairs DNA synthesis, causing macro-ovalocytes and hypersegmented neutrophils. TTP causes mechanical shearing of red blood cells in microthrombi, resulting in schistocytes without consuming coagulation factors. Autoimmune hemolytic anemia involves splenic macrophage removal of antibody-coated red blood cell membrane, producing spherocytes with a positive DAT. Primary myelofibrosis distorts red blood cells as they squeeze through fibrotic marrow, yielding teardrop cells.

Step-by-Step Solution

1
Analyze the first peripheral smear finding: Hypersegmented neutrophils and macro-ovalocytes.
Identified as a defect in DNA synthesis affecting all cell lines.
These specific morphological changes are highly sensitive and specific for megaloblastic hematopoiesis.
2
Analyze the second finding: Schistocytes with normal PT/aPTT.
Identified as a primary thrombotic microangiopathy.
Schistocytes indicate intravascular hemolysis from mechanical shearing. Normal coagulation distinguishes it from Disseminated Intravascular Coagulation (DIC).
3
Analyze the third finding: Spherocytes and a positive direct antiglobulin test.
Identified as an antibody-mediated hemolytic process.
The positive DAT specifically confirms the presence of antibodies or complement on the red blood cell surface, defining autoimmune hemolytic anemia.
4
Analyze the fourth finding: Teardrop cells and nucleated red blood cells.
Identified as a leukoerythroblastic picture due to bone marrow replacement.
Marrow fibrosis forces hematopoietic cells into the periphery prematurely and causes mechanical distortion (teardrop shape) of red cells as they exit.

Key Concept

Interpretation of peripheral blood smears is crucial for differentiating mechanisms of anemia and underlying hematologic disorders.
Rate this question

Topics

Hematology and Oncology

More questions from this topic