Question

Fatima is a 36-year-old female with a megaloblastic anemia. An initial diagnosis of moderate anemia, jaundice, and neurological complications was made. Based on the patient’s laboratory test results, she was diagnosed as having a vitamin B12 deficiency. Her CBC results showed MCV of 87 fl. The Schilling test demonstrated that the deficiency was due to the absence of intrinsic factor. This patient can be diagnosed with a megaloblastic anemia due to a lack of intrinsic factor. The patient is suffering from the adult form of pernicious anemia with demonstrated anti-intrinsic factor antibodies. Still, the doctor was not definite of the final diagnosis. In order to help understanding the case:

1. What is the morphologic classification of the patient’s anemia?

2. What abnormal morphological findings on a stained blood smear comprise the triad in megaloblastic anemia?

3. What further testing can be done to obtain a definitive diagnosis?

4. What would you predict this patient’s reticulocyte count to be?

5. What you expect other CBC indices of WBC and platelets?

Answer 1

1.Megaloblastic anemia is a macrocytic anemia that is characterized by large RBC precursors (megaloblasts) in the bone marrow and that is usually caused by nutritional deficiencies of either folic acid (folate) or vitamin B₁₂ (cobalamin).

2.Megaloblastic anemia is characterized by morphological abnormalities of hemopoietic cells that include the formation of abnormally large erythrocyte precursors (megaloblasts) and giant metamyelocytes in the bone marrow, and abnormally large (macrocytic) erythrocytes and hypersegmented neutrophils in the blood.

3.A diagnosis of megaloblastic anemia is made based upon a thorough clinical evaluation, a detailed patient history, identification of characteristic findings and a variety of blood tests. Blood tests may reveal the abnormally large, misshapen red blood cells that characterize megaloblastic anemia.

4.Reticulocyte counts are inappropriately low, representing lack of production of RBCs due to massive intramedullary hemolysis. These findings are characteristics of ineffective hematopoiesis that occurs in megaloblastic anemia

5.Hypersegmented neutrophils and macro-ovalocytes strongly suggest megaloblastic anemia. Nucleated RBCs, teardrop cells, decreased or large platelets, and immature WBCs are often present