Hypersegmented neutrophils

A 41-year-old woman with no significant medical history presents complaining of fatigue and lightheadedness. Physical exam is notable for conjunctival pallor, bilateral brisk patellar reflexes, slightly ataxic gait, and impaired position and vibration sense in the feet bilaterally. Her hematocrit is 23%. Serologic studies are positive for anti-parietal cell antibodies. What would you expect to see on peripheral blood smear?
Burr cells
Hypersegmented neutrophils
Howell-Jolly bodies
Schistocytes
Spur cells

Correct answer
Hypersegmented neutrophils
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correct answer: B

This patient has pernicious anemia, autoimmune attack on parietal cells causing decreased production of intrinsic factor and resultant vitamin B12 deficiency. B12 deficiency causes a megaloblastic anemia (with hypersegmented neutrophils on blood smear), stomatitis, glossitis, and subacute combined degeneration of peripheral nerves and spinal cord (which can cause ataxia, hyperreflexia, and impaired position/vibration sense). Burr cells (A) and spur cells (E) are types of poikilocytes - burr cells suggest renal disease and spur cells (acanthocytes) suggest liver disease or lipid abnormalities. Howell-Jolly bodies © are clusters of DNA within RBC cytoplasm indicative of asplenia or hyposplenia. Schistocytes (D) are fragmented red blood cells that are seen in microangiopathic diseases such as disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura (TTP), and hemolytic uremic syndrome (HUS).