Anemia
Friday, March 6, 2009
Unlike many Chapters of this handbook that deal with a specific surgical condition, this short Chapter touches on a physiologic state that has great importance to the surgeon. Anemia denotes a state in which a patient has less than normal hemoglobin. In this situation, decreased oxygen transport may decrease wound healing, may increase cardiac stress during or after surgical event, and may predispose to a variety of postoperative complications. Fortunately, all these anemia problems are less likely in the pediatric patient, but still one must consider carefully the presence of anemia, its probable cause, whether it should be corrected (how and how quickly), and its chance of seriously affecting surgical outcome.
Definition
Generally, anemia is defined as hemoglobin less than 10 grams/deciliter. The normal value for adults and older children is 12-16 grams/deciliter. However, this value may be higher in the newborn and will characteristically fall below this normal range during the first 1-2 months of life.
Physiologic Anemia
Babies rapidly lower their hemoglobin in the neonatal period. Values often fall to the 9-10 g/dl level with corresponding hematocrits of 25-30%. This change is normal and reflects a slow initiation of hematopoesis by the neonatal bone marrow. If surgery is necessary during this period, the surgical and anesthesiological staff must decide whether the transfusion of blood outweighs risks of transfusion and delay of hematopoesis onset.
Iron Deficiency
Iron supplies are transferred to a neonate late in intrauterine life. These supplies may be low in preterm children, just as the supply of other nutrients, vitamins, minerals are low in early children. If there is no compelling reason to correct the anemia quickly, the infant is given iron orally. This is absorbed in the duodenum and proximal jejunum and nicely corrects the problem. Parental iron or transfusion are the alternatives if this deficiency must be corrected quickly.
Hereditary Spherocytosis
This is an autosomal dominant disease process that prevents red cells from assuming their characteristic biconcave shape. The elliptical red blood cells do not move easily through the capillary bed or the pulp of the spleen. Red cells thus entrapped are more rapidly destroyed, resulting in splenomegaly, jaundice, and anemia. The presence of a family history consistent with this disease and the observation of spherocytes and reticulocytes on a peripheral blood smear confirm the diagnosis. Further confirmation involves demonstration of increased cellular fragility in the osmotic fragility test. These children are highly prone to the development of gallstones and concomitant biliary tract disease. Thus, they need full evaluation of those structures if they are coming to splenectomy to control the spherocytosis.
Sickle Cell Anemia
This is the most common inherited disorder of the African American population. Up to 10% of this population is affected. This disease is an autosomal recessive trait and requires the homozygous state for expression of the full-blown disease. Most of these patients have anemia, leukocytosis, jaundice, and perhaps splenomegaly early. By teenage years, the spleen usually shrinks from progressive infarction and fibrosis. However, these children by then often also have biliary stones and biliary tract disease.
In severe forms of this disease, children have painful crises that involve bone pain, severe right and left upper abdominal pain, strokes, and pulmonary infarctions. Many of these children develop osteomyelitis and leg ulcers.
A peripheral smear demonstrates sickle shaped red blood cells, especially when crisis is occurring. However, today most of these children are quickly diagnosed at the time of birth through mandated state screening programs. Hemoglobin electrophoresis confirms the presence of hemoglobin S and indicates the zygosity. Prenatal diagnosis is possible through amniocentesis and DNA analysis.
Although surgeons are not generally asked to manage children with this disease, they are frequently asked to consult for abdominal pain. When surgery is necessary for appendicitis, biliary problems, etc., it is important that the surgeon know how to manage these children to optimize outcome. Preoperative suppressive transfusions, exchange transfusions, meticulous hydration and prevention of hypoxia all are important aspects of preoperative, intraoperative, and postoperative care.
Other Anemias
Diverse other anemic states more rarely come to the attention of pediatric surgeons. Generally, the request is to assist with a complication of the anemia, most often splenomegaly or biliary complications such as cholelithiasis. Care should be used to correct the anemia to the degree possible before operation. If this is not possible, the surgeon must try to optimize care to prevent postoperative complications associated with low red blood volume and decreased oxygen transport.
Definition
Generally, anemia is defined as hemoglobin less than 10 grams/deciliter. The normal value for adults and older children is 12-16 grams/deciliter. However, this value may be higher in the newborn and will characteristically fall below this normal range during the first 1-2 months of life.
Physiologic Anemia
Babies rapidly lower their hemoglobin in the neonatal period. Values often fall to the 9-10 g/dl level with corresponding hematocrits of 25-30%. This change is normal and reflects a slow initiation of hematopoesis by the neonatal bone marrow. If surgery is necessary during this period, the surgical and anesthesiological staff must decide whether the transfusion of blood outweighs risks of transfusion and delay of hematopoesis onset.
Iron Deficiency
Iron supplies are transferred to a neonate late in intrauterine life. These supplies may be low in preterm children, just as the supply of other nutrients, vitamins, minerals are low in early children. If there is no compelling reason to correct the anemia quickly, the infant is given iron orally. This is absorbed in the duodenum and proximal jejunum and nicely corrects the problem. Parental iron or transfusion are the alternatives if this deficiency must be corrected quickly.
Hereditary Spherocytosis
This is an autosomal dominant disease process that prevents red cells from assuming their characteristic biconcave shape. The elliptical red blood cells do not move easily through the capillary bed or the pulp of the spleen. Red cells thus entrapped are more rapidly destroyed, resulting in splenomegaly, jaundice, and anemia. The presence of a family history consistent with this disease and the observation of spherocytes and reticulocytes on a peripheral blood smear confirm the diagnosis. Further confirmation involves demonstration of increased cellular fragility in the osmotic fragility test. These children are highly prone to the development of gallstones and concomitant biliary tract disease. Thus, they need full evaluation of those structures if they are coming to splenectomy to control the spherocytosis.
Sickle Cell Anemia
This is the most common inherited disorder of the African American population. Up to 10% of this population is affected. This disease is an autosomal recessive trait and requires the homozygous state for expression of the full-blown disease. Most of these patients have anemia, leukocytosis, jaundice, and perhaps splenomegaly early. By teenage years, the spleen usually shrinks from progressive infarction and fibrosis. However, these children by then often also have biliary stones and biliary tract disease.
In severe forms of this disease, children have painful crises that involve bone pain, severe right and left upper abdominal pain, strokes, and pulmonary infarctions. Many of these children develop osteomyelitis and leg ulcers.
A peripheral smear demonstrates sickle shaped red blood cells, especially when crisis is occurring. However, today most of these children are quickly diagnosed at the time of birth through mandated state screening programs. Hemoglobin electrophoresis confirms the presence of hemoglobin S and indicates the zygosity. Prenatal diagnosis is possible through amniocentesis and DNA analysis.
Although surgeons are not generally asked to manage children with this disease, they are frequently asked to consult for abdominal pain. When surgery is necessary for appendicitis, biliary problems, etc., it is important that the surgeon know how to manage these children to optimize outcome. Preoperative suppressive transfusions, exchange transfusions, meticulous hydration and prevention of hypoxia all are important aspects of preoperative, intraoperative, and postoperative care.
Other Anemias
Diverse other anemic states more rarely come to the attention of pediatric surgeons. Generally, the request is to assist with a complication of the anemia, most often splenomegaly or biliary complications such as cholelithiasis. Care should be used to correct the anemia to the degree possible before operation. If this is not possible, the surgeon must try to optimize care to prevent postoperative complications associated with low red blood volume and decreased oxygen transport.
0 comments:
Post a Comment