Items in AFP with MESH term: Hemoglobins
Anemia in Children - Article
ABSTRACT: Anemia in children is commonly encountered by the family physician. Multiple causes exist, but with a thorough history, a physical examination and limited laboratory evaluation a specific diagnosis can usually be established. The use of the mean corpuscular volume to classify the anemia as microcytic, normocytic or macrocytic is a standard diagnostic approach. The most common form of microcytic anemia is iron deficiency caused by reduced dietary intake. It is easily treatable with supplemental iron and early intervention may prevent later loss of cognitive function. Less common causes of microcytosis are thalassemia and lead poisoning. Normocytic anemia has many causes, making the diagnosis more difficult. The reticulocyte count will help narrow the differential diagnosis; however, additional testing may be necessary to rule out hemolysis, hemoglobinopathies, membrane defects and enzymopathies. Macrocytic anemia may be caused by a deficiency of folic acid and/or vitamin B12, hypothyroidism and liver disease. This form of anemia is uncommon in children.
ABSTRACT: The prevalence of nutritional iron deficiency anemia in infants and toddlers has declined dramatically since 1960. However, satisfaction with this achievement must be tempered because iron deficiency anemia in infants and toddlers is associated with long-lasting diminished mental, motor, and behavioral functioning. Additionally, the prevalence of iron deficiency anemia in one- to three-year-old children seems to be increasing. The exact relationship between iron deficiency anemia and the developmental effects is not well understood, but these effects do not occur until iron deficiency becomes severe and chronic enough to produce anemia. At that point, treatment with iron can reverse the anemia and restore iron sufficiency, yet the poorer developmental functioning appears to persist. Therefore, intervention should focus on the primary prevention of iron deficiency. In the first year of life, measures to prevent iron deficiency include completely avoiding cow's milk, starting iron supplementation at four to six months of age in breastfed infants, and using iron-fortified formula when not breastfeeding. Low-iron formula should not be used. In the second year of life, iron deficiency can be prevented by use of a diversified diet that is rich in sources of iron and vitamin C, limiting cow's milk consumption to less than 24 oz per day, and providing a daily iron-fortified vitamin. All infants and toddlers who did not receive primary prevention should be screened for iron deficiency. Screening is performed at nine to 12 months, six months later, and at 24 months of age. The hemoglobin/hematocrit level alone detects only patients with enough iron deficiency to be anemic. Screening by erythrocyte protoporphyrin or red-cell distribution width identifies earlier stages of iron deficiency. A positive screening test is an indication for a therapeutic trial of iron, which remains the definitive method of establishing a diagnosis of iron deficiency.
Alpha and Beta Thalassemia - Article
ABSTRACT: The thalassemias are a group of inherited hematologic disorders caused by defects in the synthesis of one or more of the hemoglobin chains. Alpha thalassemia is caused by reduced or absent synthesis of alpha globin chains, and beta thalassemia is caused by reduced or absent synthesis of beta globin chains. Imbalances of globin chains cause hemolysis and impair erythropoiesis. Silent carriers of alpha thalassemia and persons with alpha or beta thalassemia trait are asymptomatic and require no treatment. Alpha thalassemia intermedia, or hemoglobin H disease, causes hemolytic anemia. Alpha thalassemia major with hemoglobin Bart's usually results in fatal hydrops fetalis. Beta thalassemia major causes hemolytic anemia, poor growth, and skeletal abnormalities during infancy. Affected children will require regular lifelong blood transfusions. Beta thalassemia intermedia is less severe than beta thalassemia major and may require episodic blood transfusions. Transfusion-dependent patients will develop iron overload and require chelation therapy to remove the excess iron. Bone marrow transplants can be curative for some children with beta thalassemia major. Persons with thalassemia should be referred for preconception genetic counseling, and persons with alpha thalassemia trait should consider chorionic villus sampling to diagnose infants with hemoglobin Bart's, which increases the risk of toxemia and postpartum bleeding. Persons with the thalassemia trait have a normal life expectancy. Persons with beta thalassemia major often die from cardiac complications of iron overload by 30 years of age.
Evaluation of Anemia in Children - Article
ABSTRACT: Anemia is defined as a hemoglobin level of less than the 5th percentile for age. Causes vary by age. Most children with anemia are asymptomatic, and the condition is detected on screening laboratory evaluation. Screening is recommended only for high-risk children. Anemia is classified as microcytic, normocytic, or macrocytic, based on the mean corpuscular volume. Mild microcytic anemia may be treated presumptively with oral iron therapy in children six to 36 months of age who have risk factors for iron deficiency anemia. If the anemia is severe or is unresponsive to iron therapy, the patient should be evaluated for gastrointestinal blood loss. Other tests used in the evaluation of microcytic anemia include serum iron studies, lead levels, and hemoglobin electrophoresis. Normocytic anemia may be caused by chronic disease, hemolysis, or bone marrow disorders. Workup of normocytic anemia is based on bone marrow function as determined by the reticulocyte count. If the reticulocyte count is elevated, the patient should be evaluated for blood loss or hemolysis. A low reticulocyte count suggests aplasia or a bone marrow disorder. Common tests used in the evaluation of macrocytic anemias include vitamin B12 and folate levels, and thyroid function testing. A peripheral smear can provide additional information in patients with anemia of any morphology.
ABSTRACT: Anemia is a prevalent condition with a variety of underlying causes. Once the etiology has been established, many forms of anemia can be easily managed by the family physician. Iron deficiency, the most common form of anemia, may be treated orally or, rarely, parenterally. Vitamin B12 deficiency has traditionally been treated with intramuscular injections, although oral and intranasal preparations are also available. The treatment of folate deficiency is straightforward, relying on oral supplements. Folic acid supplementation is also recommended for women of child-bearing age to reduce their risk of neural tube defects. Current research focuses on folate's role in reducing the risk of premature cardiovascular disease.