Differential Diagnosis for Elevated RDW and LDH

Elevated Red Cell Distribution Width (RDW) and Lactate Dehydrogenase (LDH) can be indicative of various conditions affecting the blood and other systems. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Iron Deficiency Anemia: This condition often presents with an elevated RDW due to the variation in red blood cell size (anisocytosis) and elevated LDH as a result of increased red blood cell turnover. It's a common cause of these lab abnormalities and should be considered first.

• Other Likely Diagnoses

  • Vitamin Deficiency Anemias (B12 or Folate Deficiency): These deficiencies can lead to elevated RDW due to ineffective erythropoiesis and variable red cell size. Elevated LDH can also occur due to increased cell turnover.
  • Chronic Diseases (e.g., Chronic Kidney Disease): Chronic diseases can lead to anemia of chronic disease, which may present with elevated RDW and LDH due to the body's response to chronic inflammation and possible renal impairment affecting erythropoietin production.
  • Hemolytic Anemias: Conditions like autoimmune hemolytic anemia can cause elevated LDH due to red blood cell destruction and elevated RDW due to the release of reticulocytes (immature red blood cells) into the circulation, which are larger and more variable in size.

• Do Not Miss Diagnoses

  • Paroxysmal Nocturnal Hemoglobinuria (PNH): A rare, acquired, life-threatening disease of the blood characterized by the destruction of red blood cells, activation of the coagulation system, and impairment of bone marrow function. Elevated LDH is a hallmark due to intravascular hemolysis.
  • Myeloproliferative Neoplasms: Conditions like Polycythemia Vera, Essential Thrombocythemia, or Primary Myelofibrosis can sometimes present with elevated RDW and LDH, especially if there's associated anemia or hemolysis.

• Rare Diagnoses

  • Myelodysplastic Syndromes (MDS): A group of disorders caused by poorly formed or dysfunctional blood cells, which can lead to elevated RDW due to dysplastic erythropoiesis and variable cell size, and elevated LDH due to ineffective hematopoiesis.
  • Sickle Cell Disease: While primarily known for its hemoglobinopathy, sickle cell disease can also present with elevated RDW and LDH, particularly during crises due to hemolysis and variable red cell size.
  • Wilson's Disease: A genetic disorder that leads to copper accumulation in the body, potentially causing hemolytic anemia with elevated LDH and RDW due to the toxic effects of copper on red blood cells.