Snapshot A 68-year-old man presents to his primary care physician with complaints of weakness and fatigue over the past half year. His medical history is significant for poorly-controlled diabetes. His family history is notable for type II diabetes in both of his parents and colon cancer in his father and older brother. A fecal occult blood test is performed and is shown to be positive for blood in the stool. A peripheral blood smear shows the following. Introduction Overview iron deficiency anemia is a microcytic anemia that occurs when loss of iron exceeds intake may occur with insufficienty dietary intake of iron or in the setting of chronic blood loss treatment is usually with supplemental iron Epidemiology incidence most common anemia worldwide over 12% of the world's population are affected demographics most commonly seen in adolescent girls and women of childbearing age due to blood loss from menstruation and childbirth risk factors pregnancy menorrhagia occult bleeding (i.e., gastrointestinal blood loss) gastrointestinal parasites (i.e., hookworm), particularly in developing countries celiac disease Pathophysiology iron deficiency causes decrease in heme synthesis decreased iron in the body may be due to chronic or occult bleeding colon cancer until proven otherwise in elderly dietary deficiency in children high cow's milk intake in infants cow's milk is low in iron and causes poor absorption of iron malabsorption gastrointestinal surgery Presentation Symptoms fatigue weakness pica (craving for non-nutritious substances, such as ice, metal, hair, and paint) Physical exam conjunctival pallor tachycardia glossitis brittle nails restless leg syndrome Studies Serum labs iron studies ↓ serum iron ↓ serum ferritin reflects low stores of iron in the body confirms the diagnosis of iron deficiency ↑ transferrin and total iron binding capacity (TIBC) complete blood count ↓ RBC count ↓ hemoglobin and hematocrit ↓ absolute reticulocyte count due to decreased production of RBCs Histology peripheral blood smear hypochromic and microcytic RBCs ↑ red cell distribution width (RDW) Differential Thalassemia key distinguishing factors normal or ↑ RBC production normal or ↑ RBC count on CBC ↑ iron stores due to ineffective erythropoiesis and/or excessive blood transfusions Sideroblastic anemia key distinguishing factors presence of ringed sideroblasts on iron stain of a bone marrow aspirate ↑ iron stores Treatment Lifestyle supplementation with replacement iron antacids may decrease iron absorption avoid cow's milk before 12 months of age and limit intake in patients 1-5 years old