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Difficulty: MediumHematology and Oncology

Match each patient's clinical presentation with the most likely corresponding finding on a peripheral blood smear.

  • A 24-year-old man develops dark urine and fatigue three days after starting trimethoprim-sulfamethoxazole. Laboratory evaluation shows elevated unconjugated bilirubin and reduced haptoglobin.Degmacytes and blister cells
  • A 38-year-old woman presents with confusion, fever, and petechiae. Laboratory evaluation shows severe thrombocytopenia, normal prothrombin and activated partial thromboplastin times, and elevated creatinine.Fragmented erythrocytes (schistocytes)
  • A 65-year-old man presents with severe back pain, fatigue, and constipation. Laboratory evaluation shows normocytic anemia, hypercalcemia, and an elevated total protein gap.Erythrocytes appearing as stacked coins
  • A 45-year-old strict vegan presents with progressive fatigue, impaired proprioception, and a smooth, red tongue. Laboratory evaluation shows a mean corpuscular volume of 115 fL.Neutrophils with six or more nuclear lobes

Answer

Patient 1 matches with degmacytes; Patient 2 matches with schistocytes; Patient 3 matches with stacked erythrocytes; Patient 4 matches with hypersegmented neutrophils.
Each clinical scenario presents hallmark signs of a distinct hematologic disorder that is definitively linked to a specific peripheral blood smear abnormality. G6PD deficiency results in oxidative red blood cell damage, leading to degmacytes (bite cells). TTP causes mechanical shearing of red blood cells in microthrombi, resulting in schistocytes. Multiple myeloma produces excess monoclonal proteins that alter red blood cell electrical charge, causing them to stack (Rouleaux formation). Vitamin B12 deficiency disrupts nuclear maturation in myeloid cell lines, leading to hypersegmented neutrophils.

Step-by-Step Solution

1
Evaluate the first vignette to identify the underlying condition.
The patient has sulfa-induced hemolytic anemia, highly suggestive of Glucose-6-phosphate dehydrogenase (G6PD) deficiency.
Identifying the disease allows for correlation with its hallmark peripheral smear finding, which is degmacytes (bite cells).
2
Evaluate the second vignette to identify the underlying condition.
The patient presents with the classic pentad of Thrombotic Thrombocytopenic Purpura (TTP): thrombocytopenia, microangiopathic hemolytic anemia, neurologic signs, renal impairment, and fever, with normal coagulation studies.
TTP is a microangiopathic hemolytic anemia that mechanically destroys red blood cells, leading to schistocytes.
3
Evaluate the third vignette to identify the underlying condition.
The patient has hypercalcemia, bone pain, and a high protein gap, which are classic signs of Multiple Myeloma.
Excess paraproteins in Multiple Myeloma neutralize red blood cell surface charges, leading to Rouleaux formation (stacked coins).
4
Evaluate the fourth vignette to identify the underlying condition.
The patient has dietary Vitamin B12 deficiency causing macrocytic anemia and subacute combined degeneration of the spinal cord.
Vitamin B12 deficiency impairs DNA synthesis, leading to megaloblastic changes such as hypersegmented neutrophils on the peripheral smear.

Key Concept

Peripheral blood smear findings are highly specific diagnostic clues for various hematologic disorders, reflecting underlying pathophysiology such as oxidative damage (G6PD), microangiopathy (TTP), paraproteinemia (Multiple Myeloma), or impaired DNA synthesis (B12 deficiency).
Estimated Time:1m 30s
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Topics

Hematology and Oncology

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