Differential Diagnosis for Normocytic Anemia with Elevated WBC

Given the presentation of normocytic anemia on peripheral smear with an elevated white blood cell (WBC) count, normal hemoglobin, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RDW), and normal platelets, the differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis

  • Chronic Disease: The presence of normocytic anemia in the context of an elevated WBC count can suggest a chronic inflammatory or infectious process. Conditions like chronic infections, autoimmune diseases, or chronic kidney disease can lead to normocytic anemia due to the body's inflammatory response and subsequent impact on erythropoiesis. The elevated WBC count supports the presence of an underlying inflammatory or infectious process.

• Other Likely Diagnoses

  • Anemia of Chronic Kidney Disease: Although the hemoglobin and hematocrit are currently normal, early stages of chronic kidney disease can sometimes present with normocytic anemia due to decreased erythropoietin production. The elevated WBC could be coincidental or related to another process.
  • Hemolysis: Although the RDW is normal, some forms of hemolysis (especially if compensated) could present with normocytic anemia. The elevated WBC could be a response to the hemolytic process.
  • Bone Marrow Disorders: Early stages of bone marrow disorders (e.g., myelodysplastic syndromes) could potentially present with normocytic anemia and an elevated WBC count due to the bone marrow's attempt to compensate for ineffective erythropoiesis.

• Do Not Miss Diagnoses

  • Leukemia: Although less likely given the normal platelet count and the absence of blasts on the peripheral smear, leukemia (especially chronic forms like chronic lymphocytic leukemia or chronic myeloid leukemia) could present with an elevated WBC count and normocytic anemia. Missing this diagnosis could have significant implications.
  • Sepsis: An elevated WBC count can be a sign of sepsis, which can also cause normocytic anemia due to the acute inflammatory response and potential hemolysis. Sepsis is a medical emergency and must not be missed.

• Rare Diagnoses

  • Paroxysmal Nocturnal Hemoglobinuria (PNH): A rare cause of hemolytic anemia that could potentially present with normocytic indices if the hemolysis is compensated. The elevated WBC could be part of the disease process or a response to hemolysis.
  • Myeloproliferative Neoplasms: Rare conditions like polycythemia vera, essential thrombocytosis, or primary myelofibrosis could potentially present with an elevated WBC count and normocytic anemia, especially in early stages or in the context of another complicating factor.

Each of these diagnoses requires careful consideration of the patient's clinical presentation, additional laboratory tests, and sometimes bone marrow examination to confirm the diagnosis.