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
, 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
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.
autoimmune hemolytic anemia (AIHA) an acquired disorder characterized by hemolysis due to the production of autoantibodies against one's own red blood cell antigens.
congenital hypoplastic anemia 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.
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.
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.
anemia characterized by macrocytes
(erythrocytes much larger than normal).
any of various anemias characterized by the presence of megaloblasts
in the bone marrow or blood; the most common type is pernicious anemia
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.
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
) 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.
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
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.
anemia characterized by bone marrow failure
, so that functional marrow cells are regenerated slowly or not at all.
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.
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.
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.
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 sideroblastic anemia an X-linked anemia characterized by ringed sideroblasts, hypochromic, microcytic erythrocytes, poikilocytosis, weakness, and later by iron overload.
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.
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.
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 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.
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.
anemia (a-ne'me-a) [ ¹an- + -emia]
A reduction in the mass of circulating red blood cells. People are considered anemic when their hemoglobin levels are more than two standard deviations below the mean level in their hospital's laboratory. The diagnosis of anemia is influenced by variables such as the patient's age (neonates are anemic at levels of hemoglobin that would be considered polycythemic in some adults), gender (men have higher hemoglobin levels than women), pregnancy status (hemodilution in pregnancy lowers measured hemoglobin), residential altitude, and ethnic or racial background. anemic
Symptomatic anemia exists when hemoglobin content is less than that required to meet the oxygen-carrying demands of the body. If anemia develops slowly, however, there may be no functional impairment even though the hemoglobin is less than 7 g/100/dL of blood.
Anemia is not a disease but rather a symptom of other illnesses. It is classified on the basis of mean corpuscular volume as microcytic (80), normocytic (80–94), and macrocytic (> 94); on the basis of mean corpuscular hemoglobin as hypochromic (27), normochromic (27–32), and hyperchromic (> 32); and on the basis of etiological factors.
Anemia may be caused by bleeding, e.g., from the gastrointestinal tract or the uterus; vitamin or mineral deficiencies, esp. vitamin B12, folate, or iron; decreases in red blood cell production, e.g., bone marrow suppression in kidney failure or bone marrow failure in myelodysplastic syndromes; increases in red blood cell destruction as in hemolysis due to sickle cell anemia; or increases in red blood cell sequestration by the spleen (as in portal hypertension), or administration of toxic drugs (as in cancer chemotherapy).
Anemic patients may experience weakness, fatigue, lightheadedness, breathlessness, palpitations, angina pectoris, and headache. Signs of anemia may include a rapid pulse or rapid breathing if blood loss occurs rapidly. The chronically anemic may have pale skin, mucous membranes, or nail beds and fissures at the corners of the mouth.
Treatment of anemia must be specific for the cause. The prognosis for recovery from anemia is excellent if the underlying cause is treatable.
Anemia due to excessive blood loss: For acute blood loss, immediate measures should be taken to stop the bleeding, to restore blood volume by transfusion, and to combat shock. Chronic blood loss usually produces iron-deficiency anemia.
Anemia due to excessive blood cell destruction: The specific hemolytic disorder should be treated.
Anemia due to decreased blood cell formation: For deficiency states, replacement therapy is used to combat the specific deficiency, e.g., iron, vitamin B12, folic acid, ascorbic acid. For bone marrow disorders, if anemia is due to a toxic state, removal of the toxic agent may result in spontaneous recovery.
Anemia due to renal failure, cancer chemotherapy, HIV, and other chronic diseases: Erythropoietin injections are helpful.
The patient is evaluated for signs and symptoms, and the results of laboratory studies are reviewed for evidence of inadequate erythropoiesis or premature erythrocyte destruction. Prescribed diagnostic studies are scheduled and carried out. Rest: The patient is evaluated for fatigue; care and activities are planned and regular rest periods are scheduled. Mouth care: The patient's mouth is inspected daily for glossitis, mouth lesions, or ulcers. A sponge stick is recommended for oral care, and alkaline mouthwashes are suggested if mouth ulcers are present. A dental consultation may be required. Diet: The patient is encouraged to eat small portions at frequent intervals. Mouth care is provided before meals. The nurse or a nutritionist provides counseling based on type of anemia. Medications: Health care professionals teach the patient about medication actions, desired effects, adverse reactions, and correct dosing and administration. Patient education: The cause of the anemia and the rationale for prescribed treatment are explained to the patient and family. Teaching should cover the prescribed rest and activity regimen, diet, prevention of infection, including the need for frequent temperature checks, and the continuing need for periodic blood testing and medical evaluation.
A hypochromic, microcytic anemia associated with a lack of free hydrochloric acid in gastric juice.
APLASTIC ANEMIA: (×200)
Anemia caused by a severe decrease in the number of stem cells and/or white blood cell ancestors. See: illustration
Many patients can be treated effectively with bone marrow transplantation or immunosuppressive drugs.
The patient and family are educated about the cause and treatment of the illness. Measures to prevent infection are explained, and the importance of adequate rest is emphasized. In the acute phase, prescribed treatment is carried out; side effects of drugs and transfusions are explained, and a restful environment for the patient is ensured. If the patient's platelet count is low (less than 20,000/cu mm), the following steps are taken to prevent hemorrhage: avoiding parenteral injections, suggesting the use of an electric razor, use of humidifying oxygen to prevent dry mucous membranes, and promoting regular bowel movements with stool softeners and dietary measures. Pressure is applied to all venipuncture sites until bleeding has stopped, and bleeding is detected early by checking for occult blood in urine and stools and by assessing the skin for petechiae and ecchymoses. Standard precautions and careful handwashing (and protective isolation if necessary) are used; a diet high in vitamins and protein is provided, and meticulous oral and perianal care are provided. The patient is assessed for life-threatening hemorrhage, infection, adverse effects of drug therapy, or blood transfusion reactions. Throat, urine, and blood cultures are performed when indicated to identify infection. See: protective isolation
autoimmune hemolytic anemia Abbreviation: AIHA
Anemia caused by antibodies produced by the patient's own immune system that destroy red blood cells. They are classified by the thermal properties of the antibody involved; the warm form is most common and may be associated with viral infections. Drug-induced hemolytic anemias are clinically indistinguishable from AIHA and are therefore classified with this disorder.
anemia of chronic inflammationInflammatory anemia.
congenital hemolytic anemia
Any of a group of inherited chronic diseases marked by disintegration of red blood cells, jaundice, splenomegaly, and gallstones. Hereditary spherocytosis is the most common of these hemolytic diseases. Other such anemias include congenital elliptocytosis, hereditary stomatocytosis, and hemolytic anemias caused by enzymatic defects of the red cell, of which glucose-6–phosphate dehydrogenase and pyruvate kinase deficiency are the most important. Synonym: hemolytic icterus
; hemolytic jaundice
See: glucose-6-phosphate dehydrogenase
congenital hypoplastic anemiaDiamond-Blackfan anemia.
Cooley anemia See: Cooley anemia
Anemia due to lack of an essential ingredient such as iron or vitamins in the diet or the inability of the intestine to absorb them. Synonym: nutritional anemia
Diamond-Blackfan anemia See: Diamond-Blackfan anemia
Anemia resulting from inheritance of a recessive trait responsible for interference with hemoglobin synthesis. Synonym: thalassemia major
folic acid deficiency anemia
Anemia resulting from a deficiency of folic acid. It is a cause of megaloblastic anemia and is common in patients with nutritional deficiencies, e.g., alcoholics, patients with malabsorption, and during hemolysis or pregnancy. Folate deficiency during pregnancy increases the risk of thrombocytopenia, hemorrhage, infection, and fetal neural tube defects.
Fluid and electrolyte balance is monitored, particularly in the patient with severe diarrhea. The patient can obtain daily folic acid requirements by including an item from each food group in every meal; a list of foods rich in folic acid (green leafy vegetables, asparagus, broccoli, liver and other organ meats, milk, eggs, yeast, wheat germ, kidney beans, beef, potatoes, dried peas and beans, whole-grain cereals, nuts, bananas, cantaloupe, lemons, and strawberries) is provided. The rationale for replacement therapy is explained, and the patient is advised not to stop treatment until test results return to normal. Periods of rest and correct oral hygiene are encouraged.
Anemia resulting from the destruction of erythrocytes by drugs, artificial heart valves, toxins, snake venom, infections, and antibodies. Drugs may either destroy the erythrocyte membrane directly or stimulate production of autoantibodies that lyse the erythrocytes. Children may develop hemolytic anemia in response to destruction of erythrocytes by viral and bacterial organisms. Artificial valves cause physical damage to the erythrocyte membrane during the circulation of blood through the heart. See: hemolytic uremic syndrome
Anemia in which mean corpuscular hemoglobin concentration is higher than normal. The red blood cells are darker staining than normal.
Anemia in which hemoglobin is deficient and mean corpuscular hemoglobin concentration is lower than normal.
A term for aplastic anemia. If anemia caused by failure of formation of red blood cells is meant, pure red blood cell aplasia is the proper term.
Anemia due to chronic disease. Synonym: anemia of chronic inflammation
iron-deficiency anemia Abbreviation: IDA
Anemia resulting from a greater demand on stored iron supplies than can be provided. The erythrocyte count may sometimes be normal, but there is insufficient hemoglobin. Erythrocytes are hypochromic and show poikilocytosis. IDA is present in about 8% of men and 14% of women ages 3 to 74 years in the U.S.
IDA is caused by inadequate iron intake, malabsorption of iron, blood loss, pregnancy and lactation, intravascular hemolysis, or a combination of these factors.
Chronically anemic patients often complain of fatigue and dyspnea on exertion. Iron deficiency resulting from rapid bleeding, may produce palpitations, orthostatic dizziness, or syncope.
Laboratory studies reveal decreased iron levels in the blood, with elevated iron-binding capacity and a diminished transferrin saturation. Ferritin levels are low. The bone marrow does not show stainable iron.
Additional Diagnostic Studies
Adult nonmenstruating patients with IDA should be evaluated to rule out a source of bleeding in the gastrointestinal tract.
Dietary iron intake is supplemented with oral ferrous sulfate or ferrous gluconate (with vitamin C to increase iron absorption). Oral liquid iron supplements should be given through a straw to prevent staining of the teeth. Iron preparations cause constipation; laxatives or stool softeners should be considered as concomitant treatment. When underlying lesions are found in the gastrointestinal tract, e.g., ulcers, esophagitis, cancer of the colon, they are treated with medications, endoscopy, or surgery.
Parents should be warned to keep iron preparations away from children because three or four tablets may cause serious poisoning.
Anemia marked by abnormally large erythrocytes.
Mediterranean anemia See: thalassemia
Anemia in which megaloblasts are found in the blood. Synonym: Zuelzer-Ogden syndrome
In a young child, iron-deficiency anemia caused by consistent consumption of milk in amounts greater than 1 qt daily. This excessive milk intake displaces iron-rich foods in the diet.
anemia of the newborn
Hemoglobin levels less than 14 g/dL in term newborns. Common causes include peripartum bleeding, hemolytic disease of the newborn, twin-to-twin transfusion (15% to 30% of all monochorionic twins with abnormalities of placental blood vessels), and impaired red cell manufacture caused by glucose-6-phosphate dehydrogenase deficiency.
Anemia in which the red blood cells contain the normal amount of hemoglobin.
Anemia in which the size and hemoglobin content of red blood cells remain normal (the mean corpuscular volume is 80–100 fL).
nutritional anemiaDeficiency anemia.
A chronic, macrocytic anemia marked by achlorhydria. It occurs most often in 40- to 80-year-old northern Europeans with fair skin but has been reported in other races and ethnic groups. It is rare in Africans and Asians.
Pernicious anemia is an autoimmune disease. The parietal cells of the stomach lining fail to secrete enough intrinsic factor to ensure intestinal absorption of vitamin B12, the extrinsic factor. This is the result of atrophy of the glandular mucosa of the fundus of the stomach and is associated with absence of hydrochloric acid.
Symptoms include weakness, sore tongue, paresthesias (tingling and numbness) of the extremities, and gastrointestinal symptoms such as diarrhea, nausea, vomiting, and pain; in severe anemia, there may be signs of cardiac failure.
Vitamin B12 is given parenterally or, in patients who respond, intranasally or orally.
physiological anemia of pregnancy
Pseudoanemia of pregnancy due to an increase of plasma that exceeds the production of red blood cells. See: pseudoanemia of pregnancy
anemia of prematurity
Anemia that gradually develops in the first months of life in an infant born before the 37th week of gestation. It is caused by insufficient production of erythropoietin. Treatment may include red blood cell transfusions to increase iron stores and/or recombinant human erythropoietin.
Mild hemolysis with hematuria, hemoglobinemia, and hemoglobinuria produced by strenuous exercise, including running. The anemia may be caused by the destruction of red blood cells during repeated striking of the ground by the runner’s feet, by plasma volume expansion, and by intestinal blood loss. Blood may be lost in the feces, presumably due to transient ischemia of the gut during vigorous exercise.
Anemia due to severe infection.
sickle cell anemia
An autosomal recessive disorder that causes an abnormality of the globin genes in hemoglobin. The frequency of the genetic defect responsible for this chronic anemia disorder is highest among African-American, native African, and Mediterranean populations. The disease also affects people from the Caribbean and Central and South America. Approximately 75,000 people in the U.S. have sickle cell anemia. The illness affects one of every 500 African-American babies. Roughly 8% of the African-American population carry the sickle cell trait. Sickle cell anemia during pregnancy increases the risk of crisis, preeclampsia, urinary tract infection, congestive heart failure, and pulmonary infarction. Use of supplemental oxygen during labor is recommended.hemoglobin S disease
When both parental genes carry the same defect, the person is homozygous for hemoglobin S, i.e., HbSS, and manifests the disorder. When exposed to a decrease in oxygen, hemoglobin S becomes viscous. This causes the red cells to become crescent-shaped (sickled), rigid, sticky, and fragile, increasing red-cell destruction (hemolysis). When sickled red blood cells clump together, circulation through the capillaries is impeded, causing obstruction, tissue hypoxia, and further sickling. In infants younger than 5 months old, high levels of fetal hemoglobin inhibit the reaction of the hemoglobin S molecule to decreased oxygen.
The shortened life span of the abnormal red cells (10–20 days) results in a chronic anemia; pallor, weakness, and fatigue are common. Jaundice may result from hemolysis of red cells. Crisis may occur as a result of sickling, thrombi formation, vascular occlusion, tissue hypoxia, and infarction. People with sickle cell anemia are at increased risk of bacterial infections relative to the general population. Specific risks include osteomyelitis, meningitis, pneumonia, and sepsis from agents such as Streptococcus pneumoniae, Mycoplasma, and Chlamydia. Sickle cell patients with fever, cough, and/or regional pain should begin antibiotic therapy immediately after cultures for blood and urine and diagnostic x-rays are obtained. Sickle cell anemia also increases the risk for ischemic organ and tissue damage. Intensely painful episodes (crises) affecting the extremities, back, chest, and abdomen can last from hours to weeks and are the most frequent cause of hospitalization. Crises can be triggered by hypoxemia, infection, dehydration, and worsening anemia. Sickle cell crisis should be suspected in the sickle cell patient with pale lips, tongue, palms, or nail beds; lethargy; listlessness; difficulty awakening; irritability; severe pain; or temperature over 104°F (37.8°C) lasting at least 2 days. Life-threatening complications may arise from damage to specific internal organs, including splenic infarcts, myocardial infarction, acute chest syndrome, liver injury, aplastic anemia, and multiorgan dysfunction syndrome. See: sickle cell crisis
Supportive therapy includes supplemental iron and blood transfusion. Administration of hydroxyurea stimulates the production of hemoglobin F and decreases the need for blood transfusions and painful crises. Prophylactic daily doses of penicillin have demonstrated effectiveness in reducing the incidence of acute bacterial infections in children. Life-threatening complications require aggressive transfusion therapy or exchange transfusion, hydration, oxygen therapy, and the administration of high doses of pain relievers. Bone marrow transplantation, when a matched donor is available, can cure sickle cell anemia.
During a crisis, patients are often admitted to the hospital to treat pain and stop the sickling process. Adequate pain control is vital. Morphine is the opioid of choice to manage pain because it has flexible dosing forms, proven effectiveness, and predictable side effects. It should be administered using patient-controlled analgesia, continuous low-dose intravenous infusions, or sustained release pain relievers to maintain consistent blood levels. Supplemental short-acting analgesics may be needed for breakthrough pain. Side effects of narcotic pain relievers should be treated with concurrent administration of antihistamines, antiemetics, stool softeners, or laxatives. When administering pain relievers, care providers should assess pain using a visual analog scale to evaluate the effectiveness of the treatment. Other standard pain reduction techniques, such as keeping patients warm, applying warm compresses to painful areas, and keeping patients properly positioned, relaxed, or distracted may be helpful. Patients and families are to be advised never to use cold applications for pain relief because this treatment aggravates sickling. If transfusions are required, packed red blood cells (leukocyte-depleted and matched for minor antigens) are administered, and the patient is monitored for transfusion reactions. Scheduled deep breathing exercises or incentive spirometry helps to prevent atelectasis, pneumonia, and acute chest syndrome. During remission, the patient can prevent some exacerbations with regular medical checkups; the use of medications such as hydroxyurea; consideration of bone marrow transplantation; avoiding hypoxia (as in aircraft or at high altitudes); excessive exercise; dehydration; vasoconstricting drugs; and exposure to severe cold. The child must avoid restrictive clothing, strenuous exercise and body-contact sports but can still enjoy most activities. Additional fluid should be consumed in hot weather to help prevent dehydration. Patients and families should be advised to seek care at the onset of fevers or symptoms suggestive of infectious diseases. Annual influenza vaccination and periodic pneumococcal vaccination may prevent these common infectious diseases. Affected families should be referred for genetic counseling regarding risks to future children and for psychological counseling related to feelings of guilt. Screening of asymptomatic family members may determine whether some are heterozygous carriers of the sickling gene. Families affected by sickle cell anemia may gain considerable support in their communities or from national associations such as the American Sickle Cell Anemia Association, www.ascaa.org.
Enlargement of the spleen due to portal or splenic hypertension with accompanying anemia, leukopenia, thrombocytopenia, and gastric hemorrhage. See: Banti syndrome
; congestive splenomegaly
Anemia for which the only effective therapy is repeated blood transfusions.
CAUTION!Iron overload may be a complication of therapy, esp. after the transfusion of over 10 units of blood.
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.
n.pr See anemia, pernicious.
n a type characterized by a decrease in all marrow elements, including platelets, red blood cells, and granulocytes.
n.pr See anemia, pernicious.
n See anemia, myelophthisic.
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.
n a type due to deficiency in red blood cells and/or hemoglobin resulting from excessive bleeding.
n a type in which the erythrocytes are larger than normal so that the content but not the concentration of hemoglobin is increased.
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.
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).
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, 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.
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
(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.
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.
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.
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
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.
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.
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.
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
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.
anemia in which the decrease in hemoglobin is proportionately much greater than the decrease in number of erythrocytes.
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).
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.
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 lizard viral anemia
produces inclusion bodies in erythrocytes, commonly mistaken for protozoan parasites.
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.
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.
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.
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.
one occurring without an appropriate erythropoietic response by the bone marrow.
that in which the hemoglobin content of the red cells as measured by the MCHC and MCH is within the normal range.
the anemia in which the red blood cells are normal in size.
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
hemorrhagic anemia due to blood loss caused by blood-sucking parasites such as fleas, hookworms and Haemonchus contortus.
see pernicious anemia.
the anemia which occurs as part of a natural event, e.g. in neonates.
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.
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.
see nonregenerative anemia (above).