Vitamin B12 (and folate) deficiency impairs DNA synthesis in all rapidly dividing cells, including red and white blood cell precursors in the bone marrow. In red cell precursors, this causes a maturation defect where the cells grow large but cannot divide properly, resulting in large, oval-shaped red blood cells called macro-ovalocytes. In the white cell lineage, the same DNA defect affects neutrophil nuclei, causing them to have an abnormally high number of segments (5 or more lobes). This is called neutrophil hypersegmentation. Therefore, the combination of macrocytic anemia (large red cells) and hypersegmented neutrophils on a blood film is highly characteristic of megaloblastic anemia caused by B12 or folate deficiency.

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Zambia

• loveness Phiri – 1084 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies