hemolytic anemia (redirected from Anemia, hemolytic)

Hemolytic Anemia 

Definition

Red blood cells have a normal life span of approximately 90-120 days, at which time the old cells are destroyed and replaced by the body's natural processes. Hemolytic anemia is a disorder in which the red blood cells are destroyed prematurely. The cells are broken down at a faster rate than the bone marrow can produce new cells. Hemoglobin, the component of red blood cells that carries oxygen, is released when these cells are destroyed.

Description

As a group, anemias (conditions in which the number of red blood cells or the amount of hemoglobin in them is below normal) are the most common blood disorders. Hemolytic anemias, which result from the increased destruction of red blood cells, are less common than anemias caused by excessive blood loss or by decreased hemoglobin or red cell production.

Since a number of factors can increase red blood cell destruction, hemolytic anemias are generally identified by the disorder that brings about the premature destruction. Those disorders are classified as either inherited or acquired. Inherited hemolytic anemias are caused by inborn defects in components of the red blood cells—the cell membrane, the enzymes, or the hemoglobin. Acquired hemolytic anemias are those that result from various other causes. With this type, red cells are produced normally, but are prematurely destroyed because of damage that occurs to them in the circulation.

Causes and symptoms

Inherited hemolytic anemias involve conditions that interfere with normal red blood cell production. Disorders that affect the red blood cell membrane include hereditary spherocytosis, in which the normally disk-shaped red cells become spherical, and hereditary elliptocytosis, in which the cells are oval, rather than disk-shaped. Other hereditary conditions that cause hemolytic anemia include disorders of the hemoglobin, such as sickle cell anemia and thalassemia, and red blood cell enzyme deficiencies, such as G6PD deficiency.

The causes of acquired hemolytic anemias vary, but the most common are responses to certain medications and infections. Medications may cause the body to develop antibodies that bind to the red blood cells and cause their destruction in the spleen. Immune hemolytic anemia most commonly involves antibodies that react against the red blood cells at body temperature (warm-antibody hemolytic anemia), which can cause premature destruction of the cells. About 20% of hemolytic anemias caused by warm antibodies come from diseases such as lymphocytic leukemia, 10% from an autoimmune disease, and others are drug-induced. Cold-antibody hemolytic anemia is a condition in which the antibodies react with the red blood cells at a temperature below that of normal body temperature. Red blood cells can also receive mechanical damage as they circulate through the blood vessels. Aneurysms, artificial heart valves, or very high blood pressure can cause the red cells to break up and release their contents. In addition, hemolytic anemia may be caused by a condition called hypersplenism, in which a large, overactive spleen rapidly destroys red blood cells.

Major symptoms of hemolytic anemias are similar to those for all anemias, including shortness of breath; noticeable increase in heart rate, especially with exertion; fatigue; pale appearance; and dark urine. A yellow tint, or jaundice, may be seen in the skin or eyes of hemolytic anemia patients. Examination may also show an enlarged spleen. A more emergent symptom of hemolytic anemia is pain in the upper abdomen. Severe anemia is indicated if there are signs of heart failure or an enlarged liver.

Diagnosis

In order to differentiate hemolytic anemia from others, physicians will examine the blood for the number of young red blood cells, since the number of young cells is increased in hemolytic anemia. The physician will also examine the abdominal area to check for spleen or liver enlargement. If the physician knows the duration of hemolysis, it may also help differentiate between types of anemia. There are a number of other indications that can be obtained from blood samples that will help a physician screen for hemolytic anemia. An antiglobulin (Coomb's) test may be performed as the initial screening exam after determining hemolysis. In the case of immune hemolytic anemia, a direct Coomb's test is almost always positive.

Treatment

Treatment will depend on the cause of the anemia, and may involve treatment of the underlying cause. If the hemolytic anemia was brought on by hereditary spherocytosis, the spleen may be removed. Corticosteroid medications, or adrenal steroids, may be effective, especially in hemolytic anemia due to antibodies. If the cause of the disorder is a medication, the medication should be stopped. When anemia is severe in conditions such as sickle cell anemia and thalassemia, blood transfusions may be indicated.

Prognosis

Hemolytic anemias are seldom fatal. However, if left untreated, hemolytic anemia can lead to heart failure or liver complications.

Prevention

Hemolytic anemia due to inherited disorders can not be prevented. Acquired hemolytic anemia may be prevented if the underlying disorder is managed properly.

Resources

Organizations

American Autoimmune Related Diseases Association, Inc. Focus: A quarterly newsletter of the AARDA. Detroit, MI. (313) 371-8600. http://www.aarda.org.

The American Society of Hematology. 1200 19th Street NW, Suite 300, Washington, DC 20036-2422. (202) 857-1118. http://www.hematology.org.

National Heart, Lung and Blood Institute. PO Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.

Key terms

Antibody — Antibodies are parts of the immune system which counteract or eliminate foreign substances or antigens.

Erythrocyte — The name for red blood cells or red blood corpuscles. These components of the blood are responsible for carrying oxygen to tissues and removing carbon dioxide from tissues.

Hemolysis — The process of breaking down of red blood cells. As the cells are destroyed, hemoglobin, the component of red blood cells which carries the oxygen, is liberated.

Thalassemia — One of a group of inherited blood disorders characterized by a defect in the metabolism of hemoglobin, or the portion of the red blood cells that transports oxygen throughout the blood stream.

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anemia /ane·mia/ (ah-ne´me-ah) reduction below normal of the number of erythrocytes, quantity of hemoglobin, or the volume of packed red cells in the blood; a symptom of various diseases and disorders.ane´mic

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achrestic anemia  any of various types of megaloblastic anemia resembling pernicious anemia but unresponsive to therapy with vitamin B12.

aplastic anemia  a diverse group of anemias characterized by bone marrow suppression with replacement of the hematopoietic cells by fat, which causes pancytopenia, often accompanied by granulocytopenia and thrombocytopenia.

autoimmune hemolytic anemia  AIHA; a general term covering a large group of anemias involving autoantibodies against red cell antigens; they may be idiopathic or may have any of a number of causes, including autoimmune disease, hematologic neoplasms, viral infections, or immunodeficiency disorders.

aregenerative anemia  anemia characterized by bone marrow failure, so that functional marrow cells are regenerated slowly or not at all.

Blackfan-Diamond anemia  congenital hypoplastic a. (1).

congenital hypoplastic anemia 

1. a progressive anemia of unknown etiology seen in the first year of life, with deficiency of red cell precursors in an otherwise normally cellular bone marrow; it is unresponsive to hematinics.

2. Fanconi's syndrome (1).

congenital nonspherocytic hemolytic anemia  any of a heterogeneous group of inherited anemias characterized by shortened red cell survival, lack of spherocytosis, and normal osmotic fragility with erythrocyte membrane defects, multiple intracellular enzyme deficiencies or other defects, or unstable hemoglobins.

Cooley's anemia  thalassemia major.

drug-induced immune hemolytic anemia  immune hemolytic anemia produced by drugs, classified as the penicillin type, in which the drug induces the formation of specific antibodies; the methyldopa type, in which the drug induces the formation of anti-Rh antibodies; and the stibophen type, in which circulating drug-antibody complexes bind to red cells.

equine infectious anemia  a viral disease of equines, with recurring malaise and abrupt temperature rises, weight loss, edema, and anemia; transmission to humans has been suggested, in whom it causes anemia, neutropenia, and relative lymphocytosis.

Fanconi's anemia  Fanconi's syndrome (1).

hemolytic anemia  any of a group of acute or chronic anemias, inherited or acquired, characterized by shortened survival of mature erythrocytes and inability of bone marrow to compensate for the decreased life span.

hereditary iron-loading anemia  hereditary sideroblastic a.

hereditary sideroachrestic anemia  hereditary sideroblastic a.

hereditary sideroblastic anemia  an X-linked anemia characterized by ringed sideroblasts, hypochromic, microcytic erythrocytes, poikilocytosis, weakness, and later by iron overload.

hookworm anemia  hypochromic microcytic anemia resulting from infection with Ancylostoma or Necator; see also under disease.

hypochromic anemia  that characterized by a disproportionate reduction of red cell hemoglobin and an increased area of central pallor in the red cells.

hypoplastic anemia  that due to varying degrees of erythrocytic hypoplasia without leukopenia or thrombocytopenia.

iron deficiency anemia  a form characterized by low or absent iron stores, low serum iron concentration, low transferrin saturation, elevated transferrin, low hemoglobin concentration or hematocrit, and hypochromic, microcytic red blood cells.

macrocytic anemia  a group of anemias of varying etiologies, marked by larger than normal red cells, absence of the customary central area of pallor, and an increased mean corpuscular volume and mean corpuscular hemoglobin.

Mediterranean anemia  thalassemia major.

megaloblastic anemia  any anemia characterized by megaloblasts in the bone marrow, such as pernicious a.

microcytic anemia  that marked by decrease in size of the red cells.

myelopathic anemia , myelophthisic anemia leukoerythroblastosis.

normochromic anemia  anemia in which the hemoglobin content of the red cells as measured by the MCHC is in the normal range.

normocytic anemia  that marked by a proportionate decrease in the hemoglobin content, the packed red cell volume, and the number of erythrocytes per cubic millimeter of blood.

pernicious anemia  megaloblastic anemia, most commonly affecting older adults, due to failure of the gastric mucosa to secrete adequate and potent intrinsic factor, resulting in malabsorption of vitamin B12.

polar anemia  an anemic condition that occurs during exposure to low temperature; initially microcytic, but subsequently becoming normocytic.

pure red cell anemia  anemia characterized by absence of red cell precursors in the bone marrow; the congenital form is called congenital hypoplastic a.

refractory normoblastic anemia  refractory sideroblastic a.

refractory sideroblastic anemia  a sideroblastic anemia clinically similar to the hereditary sideroblastic form but occurring in adults and often only slowly progressive. It is unresponsive to hematinics or to withdrawal of toxic agents or drugs and may be preleukemic.

sickle cell anemia  an autosomal dominant type of hemolytic anemia, seen primarily in those of West African descent, and less often in the Mediterranean basin and a few other areas; it is caused by hemoglobin S with abnormal erythrocytes (sickle cells) in the blood. Homozygous individuals have the full-blown syndrome with accelerated hemolysis, increased blood viscosity and vaso-occlusion, arthralgias, acute attacks of abdominal pain, and ulcerations of the lower limbs; some have periodic attacks of sickle cell crises. The heterozygous condition is called sickle cell trait and is usually asymptomatic.

sideroachrestic anemia  sideroblastic a.

sideroblastic anemia  any of a group of anemias that may have diverse clinical manifestations; commonly characterized by large numbers of ringed sideroblasts in the bone marrow, ineffective erythropoiesis, variable proportions of hypochromic erythrocytes in the peripheral blood, and usually increased levels of tissue iron.

sideropenic anemia  a group of anemias marked by low levels of iron in the plasma; it includes iron deficiency anemia and the anemia of chronic disorders.

spur cell anemia  anemia in which the red cells have a bizarre spiculated shape and are destroyed prematurely, primarily in the spleen; it is an acquired form occurring in severe liver disease and represents an abnormality in the cholesterol content of the red cell membrane.

toxic hemolytic anemia  that due to toxic agents, including drugs, bacterial lysins, and snake venoms.

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hemolytic anemia

n.

Anemia resulting from the abnormal destruction of red blood cells, as in response to certain toxic or infectious agents and in certain inherited blood disorders.

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hemolytic anemia

[-lit′ik]

Etymology: Gk, haima + lysis + a, without, + haima, blood

a disorder characterized by chronic premature destruction of red blood cells. Anemia may be minimal or absent, reflecting the ability of the bone marrow to increase production of red blood cells. The condition may be associated with some infectious diseases, certain inherited red cell disorders, or neoplastic diseases. It may be a response to drugs or other toxic agents. Also spelled haemolytic anemia. Compare aplastic anemia, congenital nonspherocytic hemolytic anemia, iron deficiency anemia, myelophthisic anemia. See also anemia, hemolysis, spherocytosis.

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anemia (nē´mē),

n a term indicating that the concentration of hemoglobin or the number of red blood cells is below the accepted normal value with respect to age and gender. In true anemia the total concentration of hemoglobin, or the total number of erythrocytes, is below normal regardless of concentration values. Symptoms, which may not be evident, include weakness, pallor, anorexia, and those related to the cause of the anemia.

anemia, Addison-Biermer,

n.pr See anemia, pernicious.

anemia, aplastic,

n a type characterized by a decrease in all marrow elements, including platelets, red blood cells, and granulocytes.

anemia, Biermer's,

n.pr See anemia, pernicious.

anemia, Cooley's,

n.pr See thalassemia major.

anemia, displacement,

n See anemia, myelophthisic.

anemia, erythroblastic,

n See thalassemia major.

anemia, hemolytic,

n a type characterized by an increased rate of destruction of red blood cells, reticulocytosis, hyperbilirubinemia, and/or increased urinary and fecal urobilinogen, and, generally, splenic enlargement. Hereditary ones include congenital hemolytic jaundice, sickle cell anemia, oval cell anemia, and thalassemia. Included are paroxysmal nocturnal hemoglobinuria and those caused by immune mechanisms (erythroblastosis fetalis), transfusions of incompatible blood, infections, drugs, and poisons. Autoimmune ones are acquired hemolytic anemias associated with antibody-like substances that may not be true autoantibodies or even antibodies; they may be primary (idiopathic), or they may be secondary to lymphoma, lymphatic leukemia, disseminated lupus erythematosus, or sensitization to drugs and pollens.

anemia, hemorrhagic

n a type due to deficiency in red blood cells and/or hemoglobin resulting from excessive bleeding.

anemia, hyperchromic,

n a type in which the erythrocytes are larger than normal so that the content but not the concentration of hemoglobin is increased.

anemia, hypochromic,

n a type caused by impaired hemoglobin synthesis resulting from a deficiency of iron or pyridoxine and from chronic lead poisoning.

anemia, iron deficiency,

n a type resulting from a deficiency of iron, characterized by hypochromic microcytic erythrocytes and a normoblastic reaction of the bone marrow. Iron deficiency may result from an increased demand during growth or re-peated pregnancies; chronic or recurrent hemorrhage such as from menstrual abnormalities, hemorrhoids, or peptic ulcer; a low intake of iron; or impaired absorption, as often occurs with chronic diarrhea.

anemia, macrocytic normochromic

n a type related to a failure of nucleoprotein synthesis caused by a deficiency of vitamin B₁₂, folic acid, or related substances.

anemia, Mediterranean,

n See thalassemia major.

anemia, megaloblastic,

n a type characterized by hyperplastic bone marrow changes and maturation arrest resulting from a dietary deficiency, impaired absorption, impaired storage and modification, or impaired use of one or more hematopoietic factors. Included are pernicious anemia, nutritional macrocytic anemias associated with gastrointestinal disturbances, anemias associated with impaired liver function (e.g., macrocytic anemia of pregnancy), hypothyroidism, leukemia, and achrestic anemia.

anemia, microcytic hypochromic,

n a type in which the mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) content, and mean corpuscular hemoglobin concentration (MCHC) are all low (e.g., iron deficiency anemia, hereditary leptocytosis, hemoglobin C anemia, and anemias resulting from pyridoxine deficiency and chronic lead poisoning).

anemia, myelophthisic

n (displacement anemia), a type resulting from displacement or crowding out of erythropoietic cells of the bone marrow by foreign tissue, as in leukemia, metastatic carcinoma, lymphoblastoma, multiple myeloma, osteoradionecrosis, and xanthomatosis.

anemia, normocytic normochromic

n a type associated with disturbances of red cell formation and related to endocrine deficiencies, chronic inflammation, and carcinomatosis.

anemia, nutritional macrocytic,

n macrocytic normochromic type occurring as a result of a deficiency of substances necessary for deoxyribonucleic acid synthesis; e.g., vitamin B₁₂ and folic acid deficiency may result from a lack of intrinsic factors, sprue, or regional enteritis or with chronic alcoholism, as a result of a diet deficient in meats and vegetables, and in diseases causing intestinal malabsorption.

anemia, oval cell,

n See elliptocytosis.

anemia, pernicious

n (Addison-Biermer anemia), a macrocytic normochromic (megaloblastic) type associated with achlorhydria and lack of a gastric intrinsic factor necessary for the binding and absorption of vitamin B₁₂, which is an erythrocyte maturing factor. In addition to hematologic findings, atrophic glossitis and gastrointestinal and nervous disorders occur.

Pernicious anemia.

anemia, physiologic,

n a type characterized by lowered blood values resulting from an increase in plasma volume that occurs most markedly during the sixth and seventh months of pregnancy.

anemia, sickle cell,

n (drepanocythemia, sicklemia), a hereditary hemolytic type in which the presence of an abnormal hemoglobin (hemoglobin S) results in distorted, sickle-shaped erythrocytes. Manifestations include episodic crises of muscle, joint, and abdominal pain; neurologic symptoms; and leg ulcers. Sickle cell anemia occurs almost exclusively in African Americans. See also trait, sickle cell.

anemia, spherocytic

n See jaundice, congenital hemolytic.

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anemia

a reduction below normal in the number or volume of erythrocytes or in the quantity of hemoglobin in the blood. Clinically it is manifested by weakness, exercise intolerance, hyperpnea which is only moderate, pallor of mucosae, tachycardia and a large increase in the intensity of the heart sounds. There are often accompanying signs related to the site of blood or hemoglobin loss.

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aplastic anemia

a form of anemia generally unresponsive to specific antianemia therapy. It is often chronic, accompanied by granulocytopenia and thrombocytopenia, in which the bone marrow is usually acellular or hypoplastic. It may, however, be rapidly fatal. The term is actually all-inclusive and most probably encompasses several clinical syndromes. See pure red cell aplasia.

autoimmune hemolytic anemia

immune-mediated hemolytic anemia, which occurs in many species, particularly dogs, in which autoantibodies directed against red blood cells are produced. Different classes of immunoglobulins may be involved giving rise to differing clinical syndromes. Signs include pallor, lethargy, splenomegaly, and sometimes icterus, bilirubinuria and hemoglobinuria. There may also be an accompanying thrombocytopenia with bleeding tendencies. Diagnosis is based on a positive Coombs test.

avian infectious anemia

see chicken anemia.

blood loss anemia

see hemorrhagic anemia (below).

anemia of chronic disease

see anemia of inflammatory disease (below).

cold antibody anemia

an immune-mediated hemolytic anemia in which the antibody is maximally active at temperatures below 98.6°F (37°C). See also cold agglutinin disease.

cold (or cold water) anemia

a disease of cattle, especially calves, housed in warm barns and given near freezing water to drink. Dyspnea and the passage of red urine occur several hours after a large drink.

Coombs-positive anemia

immunoglobulin-mediated anemia that gives a positive reaction to Coombs tests, indicating the presence of immunoglobulins on the red cell surface. See also autoimmune hemolytic anemia (above), alloimmune hemolytic anemia of the newborn.

deficiency anemia

nutritional anemia.

drug-induced hemolytic anemia

some drugs such as quinine, quinidine, para-aminosalicylic acid, phenacetin, penicillin, insecticides, chlorpromazine, sulfonamides and dipyrone may be directly injurious to red cells or act to initiate an immune response in which red cells are destroyed.

familial nonspherocytic anemia of Basenji dogs

an inherited pyruvate kinase deficiency causes a hemolytic anemia with shortened red cell life span. In early stages, the disease is characterized by very active erythropoiesis but eventually, usually by the second or third year of life, a terminal myelofibrosis and osteosclerosis develops. The disease is inherited as an autosomal recessive trait.

feline infectious anemia

see feline infectious anemia.

fragmentation anemia

see microangiopathic anemia (below).

Heinz body anemia

hemolytic anemia resulting from oxidation of globin and formation of Heinz bodies, which are seen in blood smears as dark refractile intracytoplasmic bodies and stain with new methylene blue. Some common causes are ingestion of onions and plants in the Brassicaeae family, phenazopyridine, methylene blue and acetaminophen (paracetamol). Cats are particularly susceptible to Heinz body formation.

hemolytic anemia

see hemolytic anemia.

hemorrhagic anemia

is caused by loss of whole blood. If this is very rapid hypovolemic shock develops. At a slower rate there is anemic anoxia and the animal is suffering from anemia. Called also blood loss anemia.

hypochromic anemia

anemia in which the decrease in hemoglobin is proportionately much greater than the decrease in number of erythrocytes.

hypoplastic anemia

anemia due to incapacity of blood-forming organs, i.e. inactivity of the bone marrow. See also aplastic anemia (above).

idiopathic immune anemia

see autoimmune hemolytic anemia (above).

infectious equine anemia

see equine infectious anemia.

anemia of inflammatory disease

a nonregenerative, usually mild, anemia that occurs in association with malignancy or chronic infection. Although other causes of anemia such as hemolysis and blood loss may also occur with these conditions, there is altered iron metabolism with decreased serum iron and iron-binding capacity but with increased iron storage that results in decreased erythropoiesis.

iron-deficiency anemia

a form characterized by low or absent iron stores, low serum iron concentration, low transferrin saturation, elevated transferrin (iron-binding capacity), low hemoglobin concentration or hematocrit, and hypochromic, microcytic red blood corpuscles, and thrombocytosis. See also iron.

isoimmune hemolytic anemia

see alloimmune hemolytic anemia of the newborn.

lizard viral anemia

produces inclusion bodies in erythrocytes, commonly mistaken for protozoan parasites.

macrocytic anemia

anemia in which the erythrocytes are much larger than normal. The MCV (mean corpuscular volume) and MCH (mean corpuscular hemoglobin) are increased and the MCHC (mean corpuscular hemoglobin concentration) is normal.

megaloblastic anemia

anemia characterized by the presence of megaloblasts in the bone marrow and macrocytic erythrocytes. It occurs in vitamin B₁₂, cobalt and folic acid deficiencies and in some myeloproliferative disorders in cats.

microangiopathic anemia

anemia due to fragmentation of erythrocytes in blood vessels whose endothelium has been badly damaged, usually by an infectious disease such as septicemias, disseminated intravascular coagulation and salmonellosis. Called also fragmentation anemia.

microcytic anemia

anemia characterized by decrease in size of the erythrocytes.

myelopathic anemia, myelophthisic anemia

anemia due to destruction or crowding out of hematopoietic tissues by space-occupying lesions, neoplasms and fibrosis.

nonregenerative anemia

one occurring without an appropriate erythropoietic response by the bone marrow.

normochromic anemia

that in which the hemoglobin content of the red cells as measured by the MCHC and MCH is within the normal range.

normocytic anemia

the anemia in which the red blood cells are normal in size.

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. See also pyridoxine, vitamin b12, folic acid, copper, iron.

parasitic anemia

hemorrhagic anemia due to blood loss caused by blood-sucking parasites such as fleas, hookworms and Haemonchus contortus.

pernicious anemia

see pernicious anemia.

physiological anemia

the anemia which occurs as part of a natural event, e.g. in neonates.

piglet anemia

see iron nutritional deficiency.

primary immune anemia

see autoimmune hemolytic anemia (above).

regenerative anemia, responsive anemia

associated with active erythropoiesis with increased numbers of reticulocytes, nucleated red blood cells, anisocytosis and polychromasia in the peripheral blood.

spur-cell anemia

anemia in which the red cells have a bizarre spiculated shape and are destroyed prematurely, primarily in the spleen; it is an acquired form occurring in severe liver disease, and represents an abnormality in the cholesterol content of the red cell membrane.

unresponsive anemia

see nonregenerative anemia (above).

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hemolytic

pertaining to, characterized by, or producing hemolysis.

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hemolytic anemia

anemia caused by the increased destruction of erythrocytes which may occur in the vascular system—intravascular hemolysis, or due to phagocytosis by the monocyte-macrophage system—extravascular or intracellular hemolysis. It may result from incompatibility (see alloimmune hemolytic anemia of the newborn), from mismatched blood transfusions, from poisons such as copper, organic agents in plants such as kale, from nutritional deficiencies such as phosphorus and from protozoan infections such as babesiosis. Hemolytic anemia may also occur as a result of a disorder of the immune response in which B cell-produced antibodies fail to recognize erythrocytes that are 'self' and directly attack and destroy them. In addition to the usual signs of anemia, the patient may also exhibit jaundice.

hemolytic component

a degree of extravascular hemolysis in association with other types of anemia.

hemolytic disease of the newborn

see alloimmune hemolytic anemia of the newborn.

hemolytic enterotoxemia

a little reported disease recorded mostly in Australia in sheep, cattle and foals; a highly fatal hemolytic anemia associated with a heavy population of Clostridium perfringens type A in the intestines.

hemolytic plaque assay

see plaque assay.

hemolytic-uremic syndrome

a microangiopathic hemolytic anemia with thrombocytopenia and severe involvement of renal vasculature which leads to acute renal failure. In humans associated with verocytoxin-producing bacteria such as Escherichia coli, Shigella and some Salmonella; usually associated with the ingestion of poorly cooked meat. A similar clinical syndrome has been reported in cows, horses and dogs.

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hemolytic anemia

Hematology Anemia which occurs when more RBCs are lysed than are produced; HA may be immune-mediated or non-immune, due to intrinsic or extrinsic RBC defects. See Nonimmune hemolytic anemia Immunology Immune hemolysis is alloimmune, autoimmune, and drug-induced, and may be intravascular or extravascular Microbiology Hemolysis is characteristic of certain strains of streptococci and is divided into α- and β-hemolysis; γ 'hemolysis' is a complete misnomer. See Gamma-hemolysis, Innocent bystander hemolysis.