microangiopathic hemolytic anemia


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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 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.
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 autoimmune hemolytic 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 (erythrocytes much larger than normal).
Mediterranean anemia thalassemia major.
megaloblastic anemia any of various anemias characterized by the presence of megaloblasts in the bone marrow or blood; the most common type is pernicious anemia.
microangiopathic hemolytic anemia thrombotic thrombocytopenic purpura.
microcytic anemia anemia characterized by 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.

mi·cro·an·gi·o·path·ic he·mo·lyt·ic a·ne·mi·a

hemolysis due to intravascular fragmentation of red blood cells; may be due to microcirculatory lesions or the insertion of cardiac or intravascular prosthetic devices.

mi·cro·an·gi·o·path·ic he·mo·lyt·ic a·ne·mi·a

(MAHA) (mī'krō-an-jē-ō-path'ik hē'mō-lit'ik ă-nē'mē-ă)
Hemolysis attributed to narrowing or obstruction of small blood vessels usually due to inflammation; causes fragmentation and distortion in the shape of red blood cells.
References in periodicals archive ?
Early diagnosis of pernicious anemia and treatment with vitamin [B.sub.12] in a patient presenting with microangiopathic hemolytic anemia are associated with fewer complications and significant clinical improvement compared to plasma exchange for presumed thrombotic thrombocytopenic purpura.
The diagnosis is made by clinical and laboratory findings of microangiopathic hemolytic anemia, thrombocytopenia and acute renal damage and demonstration of the disruption in regulation of the complement system.
Diagnosis is made by evidence of microangiopathic hemolytic anemia (anemia, thrombocytopenia, and schistocytes/helmet cells seen on blood smear) with some evidence of renal insufficiency.
TTP is a one of the thrombotic microangiopathies, conditions characterized by thrombosis in arterioles and capillaries that manifest clinically with thrombocytopenia and microangiopathic hemolytic anemia (3).
ABBREVATIONS: ADAMTS = a disintegrin-like and metalloprotease domain with thrombospondin type motifs; HUS = hemolytic-uremic syndrome; LD = lactate dehydrogenase; MAHA = microangiopathic hemolytic anemia; PT = prothrombin times; PTT = partial thromboplastin times; TMA = thrombotic microangiopathy; TT = thrombin times; TTP = thrombotic thrombocytopenic purpura; ULVWF = ultralarge VWF; VTEC = verotoxin-producing Ecoli; VWF = Von Willebrand factor; VWF-cp = VWF-cleaving protease.
Silva, "Sunitinib-induced microangiopathic hemolytic anemia with fatal outcome," The American Journal of Therapeutics, vol.
HUS was defined as a case of microangiopathic hemolytic anemia (hematocrit <30% with peripheral evidence of intravascular hemolysis), thrombocytopenia (platelet count <150,000/[mm.sup.3]), and renal insufficiency (serum creatinine concentration greater than the upper limit of normal for age) (11).
Both thrombocytopenic thrombotic purpura (TTP) and hemolytic uremic syndrome (HUS) present with microangiopathic hemolytic anemia. Which set of features best represents TTP?
A 54-year-old male is admitted with a 2-day history of frontal headache, blurred vision, nausea/vomiting, malignant hypertension, witnessed grand mal seizure activity, microangiopathic hemolytic anemia, and acute renal failure.
Lysis of red blood cells with release of their membrane lipids is a possible pathogenetic factor.[1] Microangiopathic hemolytic anemia and thrombocytopenia have been reported in association with primary pulmonary hypertension, and the consumption of erythrocytes and platelets was attributed to their destruction in plexiform lesions.[6,7] In this case, plexiform lesions most likely developed secondary to long-standing pulmonary hypertension, causing hemolysis and thrombocytopenia.
Clinically they are characterized by thrombocytopenia, microangiopathic hemolytic anemia (MAHA), and extremely elevated serum lactate dehydrogenase (LDH) levels with or without signs of end-organ damage [1, 2].