Differential Diagnosis for Anemia with High MCV and MCH

• Single most likely diagnosis
  • Vitamin B12 or Folate Deficiency Anemia: This is the most common cause of macrocytic anemia (high MCV) and increased MCH (mean corpuscular hemoglobin), as both vitamin B12 and folate are essential for DNA synthesis and red blood cell production. A deficiency in either leads to the production of larger, but fewer, red blood cells.
• Other Likely diagnoses
  • Alcohol-Related Anemia: Chronic alcohol consumption can lead to macrocytosis due to its toxic effects on the bone marrow and the potential for associated nutritional deficiencies, including folate and vitamin B12.
  • Hypothyroidism: This condition can cause macrocytic anemia, possibly due to decreased production of erythropoietin or other metabolic effects.
  • Reticulocytosis: An increase in reticulocytes (immature red blood cells) can elevate MCV and MCH due to their larger size compared to mature red blood cells.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Bone Marrow Failure Syndromes: Conditions like aplastic anemia or myelodysplastic syndromes can present with macrocytosis and require prompt diagnosis and treatment to prevent severe complications.
  • Paroxysmal Nocturnal Hemoglobinuria (PNH): A rare, acquired, life-threatening disease of the blood characterized by the destruction of red blood cells, which can sometimes present with macrocytic anemia.
• Rare diagnoses
  • Ornithine Transcarbamylase Deficiency: A rare genetic disorder that can lead to macrocytic anemia due to its impact on the urea cycle and subsequent effects on folate metabolism.
  • Congenital Dyserythropoietic Anemias: A group of rare genetic disorders characterized by ineffective erythropoiesis, which can result in macrocytic anemia among other types of anemia.