Anemia [Low Hemoglobin]
Anemia (in Greek an means “negative” and haima = blood). In medicine, it is a reduction below normal in the quantity of hemoglobin or in the volume of packed red cells per 100 ml of blood. Associated words: aplastic, autoimmune hemolytic, pernicious, blood loss, chronic disease, congenital, hypochromic, spherocytosis, iatrogenic, iron deficiency, macrocytic, megaloblastic, normocytic, normochromic, nosocomial, aplastic and others.
Damage to the red cell is called hemolytic anemia (lysis is dissolution in Greek). Red cell walls can be destroyed by a misdirected immunologic process, by unusually rigid red cells, by an unusual response to a drug, or by bashing against artificial heart valves. Sometimes this can be associated with jaundice and an enlarged spleen. The clue here is a positive test for antibody on the surface of red cells – a positive Coomb’s test. This test might be done when small round red cells or blue tinged red blood cells appear in the blood smear.
If the red cells in anemia are normal sized with normal pigmentation (normocytic normochromic), the doctor must think of chronic disease like rheumatoid arthritis, chronic infection, kidney failure, or a bone marrow problem such as multiple myeloma. Anemia with organ enlargement such as liver, spleen or lymph nodes or a low or very high white blood or platelet count may indicate leukemia (a white blood cell cancer reducing the space for red cell production in the marrow). This requires a bone marrow examination from the crest of the hip bone using local anesthesia.
Cells containing abnormal hemoglobin live less long than normal ones. A familial anemia of families of Mediterranean origin is called thalassemia (sea anemia) or of African Americans is called sickle cell disease (from the curved red cells) and both need electrophoretic (electrical migration) measurement of specific abnormal hemoglobins. Eight percent of African Americans and 30% of Nigerians carry the “trait” of sickle cell disease. A trait from both parents will lead to the disease. Rigid sickle cells block capillaries and cause acutely painful crisis. Parvovirus (parvus: small) infection can also produce a crisis.
Finally the bone marrow red cell production factory can shut down, perhaps after a drug insult such as gold salts or chloromycetin or exposure to a poison like benzene. If the entire bone marrow becomes empty, it is called aplastic or “no growth anemia.“
Treatment with iron for most anemias works. In response evaluation, young red cells are looked for to judge the response to treatment. These new cells still have an internal blue staining network and are called reticulocytes. Hemoglobin should rise 1-2 gm weekly for a proper response. Treatable anemias like iron deficiency and pernicious anemia are by far the most common.
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