A 70-year-old female presents to your office complaining of easy fatigability, exertional dyspnea and weight loss. She also complains of frequent falls. Physical examination reveals symmetrically decreased vibratory sensation to the lower extremities. Her hemoglobin is 7.8 g/dL and a peripheral blood smear shows hypersegmented neutrophils. Which of the following is the best treatment for this patient?

Question

A 70-year-old female presents to your office complaining of easy fatigability, exertional dyspnea and weight loss.  She also complains of frequent falls.  Physical examination reveals symmetrically decreased vibratory sensation to the lower extremities.  Her hemoglobin is 7.8 g/dL and a peripheral blood smear shows hypersegmented neutrophils.  Which of the following is the best treatment for this patient?

Quizplus · Accepted Answer

Deficiencies of folic acid and vitamin B12 are the most important causes of megaloblastic anemia. Both of these vitamins are required for DNA synthesis in erythropoiesis. When there is a deficiency of either of these vitamins, cell division is delayed, though the cytoplasm develops normally. Thus, the cells enlarge (megaloblasts) but do not divide. The bone marrow is hypercellular in megaloblastic anemia, but the megaloblastic erythroid precursor cells are rapidly destroyed in the bone marrow and few differentiated large RBCs are released into the circulation. In severe megaloblastic anemia, 90% of erythroid precursors are destroyed without ever entering the circulation. Vitamin B12 and folic acid deficiencies cause similar hematological pictures. However, neurological dysfunction is only seen in patients with vitamin B12 deficiency. This is because B12 deficiency also causes axonal demyelination and degeneration. In late disease, the neurological dysfunction may be irreversible. The main sites of neurological involvement include the peripheral nerves, spinal cord (posterior and lateral columns), and the cerebrum. Decreased vibratory and position sense are early signs of vitamin B12 deficiency. Patients experience ataxia and recurrent falls because of compromised proprioception. Importantly, neurologic abnormalities can occur in vitamin B12 deficiency in the absence of frank anemia. Treating megaloblastic anemia due to vitamin B12 deficiency with folate alone could worsen the neurological dysfunction. An RBC mean corpuscular volume (MCV) of more than 100 fL is suggestive of megaloblastic anemia. However, RBC macrocytosis can also occur in liver disease, hypothyroidism, and alcohol-induced liver disease. MCVs greater than 110 fL are typically seen only with vitamin B12 and folic acid anemias. On peripheral blood smear, there is macrocytosis (large RBCs), hypersegmented neutrophils, and large bizarrely shaped platelets. The presence of even a single neutrophil with more than 6 lobes should raise the suspicion of megaloblastic anemia. The medications listed in the other answer choices are not used for the treatment of megaloblastic anemia. Educational Objective: Vitamin B12 and folic acid deficiencies cause similar hematological pictures. However, neurological dysfunction is only seen in patients with vitamin B12 deficiency. If megaloblastic anemia due to vitamin B12 deficiency is mistakenly treated with folate alone, the neurologic dysfunction can worsen.

A 70-Year-Old Female Presents to Your Office Complaining of Easy