Microcytic Anemias

1. Fe deficiency anemia
   

1. The most common type of anemia and iron deficiency is the most prevalent deficiency state on a worldwide basis.

2. Caused when the dietary intake or absorption of iron is insufficient.
   

3. United States, 20% of all women of childbearing age have iron deficiency anemia. The principal cause of iron deficiency anemia in pre-menopausal women is blood lost during menses. In older patients, iron deficiency anemia is often due to bleeding lesions of the gastrointestinal tract
   

2. Anemia of Chronic Disease

1. usually normocytic, normochromic, and relatively mild, however, when severe, the MCV becomes reduced

2. conditions often associated are inflammatory conditions, malignancy, congestive heart failure, thrombosis, chronic pulmonary disease, diabetes, trauma

3. mechanism of disease is thought that chronic inflammation prevents iron from being released and or RBCs have a shortened life span
   

3. Thalassemias

1. inherited anemias characterized by defects in the synthesis of one or more of the globin chain subunits of the hemoglobin tetramer.
2. quantitative disorder = α or β chains are defective so not enough hemoglobin for RBCS
3. common in patients with Mediterranean backgrounds. 3 type α, β, δ.
   

4. Sideroblastic anemia

1. can be hereditary (x-linked) or acquired (alcohol, isonaizid, chloramphenicol)

2. diagnosed by finding ring sideroblasts in the bone marrow with Prussian blue staining
   

3. X-linked forms of hereditary sideroblastic anemia generally exhibit low activity of ALAS (5-aminolevulinate synthase)

5. Lead poisoning

1. inhibits heme synthesis (delta-ALA dehydratase and ferrochelatase)
2. finger, wrist, foot drop from neurotoxicity
3. gingival lead lines can be seen
4. tx with EDTA

6. Sickle cell disease

1. structurally abnormal hemoglobin (point mutation Val->Glutamic acid)
2. primarily seen in African-Americans
3. sickle cell crisis: deformed RBCs clog blood vessels (very painful), leads to organ infarction (autosplenectomy), strokes
   
4. susceptible to encapsulated bacteria (S. pneumo, H. flu, N. meningitis) and Salmonella for osteomyelitis

Category: Pathology Notes