hypochromic anemia

anemia

[ah-ne´me-ah] a condition in which there is reduced delivery of oxygen to the tissues; it is not actually a disease but rather a symptom of any of numerous different disorders and other conditions. The World Health Organization has defined anemia as a hemoglobin concentration below 7.5 mmol/L (12 g/dL) in women and below 8.1 mmol/L (13 g/dL) in men.

Peripheral blood smears from a patient with megaloblastic anemia (left) and from a normal subject (right), both at the same magnification. The smear from the patient shows variation in the size and shape of erythrocytes and the presence of macro-ovalocytes. From Goldman and Bennett, 2000.
Some types of anemia are named for the factors causing them: poor diet (nutritional anemia), excessive blood loss (hemorrhagic anemia), congenital defects of hemoglobin (hypochromic anemia), exposure to industrial poisons, diseases of the bone marrow (aplastic anemia and hypoplastic anemia), or any other disorder that upsets the balance between blood loss through bleeding or destruction of blood cells and production of blood cells. Anemias can also be classified according to the morphologic characteristics of the erythrocytes, such as size (microcytic, macrocytic, and normocytic anemias) and color or hemoglobin concentration (hypochromic anemia). A type called hypochromic microcytic anemia is characterized by very small erythrocytes that have low hemoglobin concentration and hence poor coloration. Data used to identify anemia types include the erythrocyte indices: (1) mean corpuscular volume (MCV), the average erythrocyte volume; (2) mean corpuscular hemoglobin (MCH), the average amount of hemoglobin per erythrocyte; and (3) mean corpuscular hemoglobin concentration (MCHC), the average concentration of hemoglobin in erythrocytes. adj., adj ane´mic.Symptoms. Mild degrees of anemia often cause only slight and vague symptoms, perhaps nothing more than easy fatigue or a lack of energy. As the condition progresses, more severe symptoms may be experienced, such as shortness of breath, pounding of the heart, and a rapid pulse; these are caused by the inability of anemic blood to supply the body tissues with enough oxygen. Pallor, particularly in the palms of the hands, the fingernails, and the conjunctiva (the lining of the eyelids), may also indicate anemia. In very advanced cases, swelling of the ankles and other evidence of heart failure may appear.Common Causes of Anemia. Loss of Blood (Hemorrhagic Anemia): If there is massive bleeding from a wound or other lesion, the body may lose enough blood to cause severe and acute anemia, which is often accompanied by shock. Immediate transfusions are generally required to replace the lost blood. Chronic blood loss, such as excessive menstrual flow, or slow loss of blood from an ulcer or cancer of the gastrointestinal tract, may also lead to anemia. These anemias disappear when the cause has been found and corrected. To help the blood replenish itself, the health care provider may prescribe medicines containing iron, which is necessary to build hemoglobin, and foods with high iron content, such as kidney and navy beans, liver, spinach, and whole wheat bread.
Dietary Deficiencies and Abnormalities of Red Blood Cell Production (Nutritional Anemia, Aplastic Anemia, and Hypoplastic Anemia): Anemia may develop if the diet does not provide enough iron, protein, vitamin B₁₂, and other vitamins and minerals needed in the production of hemoglobin and the formation of erythrocytes. The combination of poor diet and chronic loss of blood makes for particular susceptibility to severe anemia. Anemias associated with folic acid deficiency are very common.
Excessive Destruction of Red Blood Cells (hemolytic anemia): Anemia may also develop related to hemolysis due to trauma, chemical agents or medications (toxic hemolytic anemia), infectious disease, isoimmune hemolytic reactions, autoimmune disorders, and the paroxysmal hemoglobinurias.Patient Care. Assessment of patients with some form of anemia will depend to some extent on the specific type of blood dyscrasia presented. In general, these patients do share some common problems requiring special assessment skills and interventions. Anemia can affect many different body systems (see table). Although pallor of the skin is a sign of anemia, it is not the most reliable sign; many other factors can affect complexion and skin color. Jaundice of the skin and sclera can occur as a result of hemolysis and the release of bilirubin into the blood stream, where it eventually finds its way into the skin and mucous membranes. (See also jaundice.) Bleeding under the skin and bruises in response to the slightest trauma often are present in anemic and leukemic patients. A bluish tint to the skin (cyanosis) can indicate hypoxia due to inadequate numbers of oxygen-bearing erythrocytes.
Activity intolerance is a common problem for patients with anemia. Physical activity increases demand for oxygen, but if there are not enough circulating erythrocytes to provide sufficient oxygen, patients become physically weak and unable to engage in normal physical activity without experiencing profound fatigue. This can result in some degree of deficit" >self-care deficit as the fatigue interferes with the patient's ability to carry on regular or enjoyable activities.acute posthemorrhagic anemia hemorrhagic anemia.aplastic anemia see aplastic anemia.autoimmune hemolytic anemia (AIHA) an acquired disorder characterized by hemolysis due to the production of autoantibodies against one's own red blood cell antigens.Blackfan-Diamond anemia congenital hypoplastic anemia (def. 1).congenital hypoplastic anemia idiopathic progressive anemia occurring in the first year of life, without leukopenia and thrombocytopenia; it is due to an isolated defect in erythropoiesis and is unresponsive to hematinics, requiring multiple blood transfusions to sustain life. For those responding to steroid therapy the prognosis is good. Called also Blackfan-Diamond anemia or syndrome, Diamond-Blackfan anemia or syndrome, and erythrogenesis imperfecta.Fanconi's syndrome (def. 1).Cooley's anemia tthalassemia major.deficiency anemia nutritional anemia.Diamond-Blackfan anemia congenital hypoplastic anemia (def. 1).drug-induced hemolytic anemia (drug-induced immune hemolytic anemia) a form of immune hemolytic anemia induced by the taking of drugs, involving one of four different mechanisms:
Immune complex problems: Ingestion of any of a large number of drugs is followed by immunization and the formation of a soluble drug–anti-drug complex that adsorbs nonspecifically to the erythrocyte surface.
Drug absorption: Drugs bind firmly to erythrocyte membrane proteins, inducing the formation of specific antibodies; the drug most commonly associated with this mechanism is penicillin.
Membrane modification: A nonimmunologic mechanism whereby the drug involved is able to modify erythrocytes so that plasma proteins can bind to the membrane.
Autoantibody formation: Methyldopa (Aldomet) induces the production of autoantibodies that recognize erythrocyte antigens and are serologically indistinguishable from those seen in patients with warm autoimmune hemolytic anemia.Fanconi's anemia (Fanconi's hypoplastic anemia) Fanconi's syndrome (def. 1).hemolytic anemia see hemolytic anemia.hemorrhagic anemia anemia caused by the sudden and acute loss of blood; called also acute posthemorrhagic anemia.hypochromic anemia anemia in which the decrease in hemoglobin is proportionately much greater than the decrease in number of erythrocytes.hypochromic microcytic anemia any anemia with microcytes that are hypochromic (reduced in size and in hemoglobin content); the most common type is iron deficiency anemia.hypoplastic anemia anemia due to incapacity of blood-forming organs.immune hemolytic anemia an acquired hemolytic anemia in which a hemolytic response is caused by isoantibodies or autoantibodies produced on exposure to drugs, toxins, or other antigens. See also anemia" >autoimmune hemolytic anemia, anemia" >drug-induced immune hemolytic anemia, and erythroblastosis fetalis.iron deficiency anemia a type of hypochromic microcytic anemia that results from the presence of greater demands on stored iron than can be met, usually because of chronic blood loss, dietary deficiency, or defective absorption; it is characterized by low or absent iron stores, low serum iron concentration, low transferrin saturation, elevated transferrin (total iron-binding capacity), and low hemoglobin concentration or hematocrit. Iron deficiency anemia is the most common nutritional disorder in the United States.macrocytic anemia anemia characterized by macrocytes" >macrocytes (erythrocytes much larger than normal).Mediterranean anemia thalassemia major.megaloblastic anemia any of various anemias characterized by the presence of megaloblasts" >megaloblasts in the bone marrow or blood; the most common type is pernicious anemia" >pernicious anemia.microangiopathic hemolytic anemia thrombotic thrombocytopenic purpura.microcytic anemia anemia characterized by microcytes" >microcytes (erythrocytes smaller than normal); see also hypochromic microcytic anemia and microcythemia.myelopathic anemia (myelophthisic anemia) leukoerythroblastosis.normochromic anemia that in which the hemoglobin content of the red blood cells is in the normal range.normocytic anemia anemia characterized by proportionate decrease in hemoglobin, packed red cell volume, and number of erythrocytes per cubic millimeter of blood.nutritional anemia anemia due to a deficiency of an essential substance in the diet, which may be caused by poor dietary intake or by malabsorption; called also deficiency anemia.pernicious anemia see pernicious anemia.sickle cell anemia see sickle cell anemia.sideroachrestic anemia (sideroblastic anemia) any of a heterogenous group of acquired and hereditary anemias with diverse clinical manifestations, commonly characterized by large numbers of sideroblasts in the bone marrow, ineffective erythropoiesis, variable proportions of hypochromic erythrocytes in the peripheral blood, and usually increased levels of tissue iron.spur cell anemia anemia in which the erythrocytes are acanthocytes (spur cells) and are destroyed prematurely, primarily in the spleen; it is an acquired form occurring in severe liver disease in which there is increased serum cholesterol and increased uptake of cholesterol into the erythrocyte membrane, causing the abnormal shape.