Anemia - Blood Disease Disorders
Anemia Caused by Blood Loss
Blood loss can also cause anemia - whether it's because of excessive bleeding due to injury, surgery, or a problem with the blood's clotting mechanism. Slower, long-term blood loss, such as intestinal bleeding due to inflammatory bowel disease, can also cause anemia. Anemia can also result from heavy menstrual periods in teen girls and women. Any of these factors will also increase the body's need for iron because iron is needed to make new red blood cells.
Anemia Caused by Inadequate RBC Production
Infants are born with high levels of hemoglobin and RBCs in their blood. This occurs in the fetus to help fetal blood carry enough oxygen while the developing baby is in the relatively oxygen-poor environment inside the uterus. After birth, when more oxygen is available, the baby's hemoglobin level normally drops to a low point at about 2 months of age, a condition known as physiologic anemia of infancy. After this occurs, the infant's body gets the signal to increase RBC production. This temporary and expected drop in the blood count is considered normal and no treatment is needed. Anemia also occurs when the body isn't able to produce enough healthy red blood cells. This can happen because of a deficiency of iron or certain other substances in the body or from inherited defects or diseases that interfere with the production of red blood cells.
Aplastic anemia occurs when the bone marrow is unable to produce sufficient numbers of blood cells. More often, aplastic anemia is caused by a virus infection or exposure to certain toxic chemicals, radiation, or medications, such as antibiotics, antiseizure medications, or cancer medications. Some childhood cancers can cause anemia of this type, such as with certain types of leukemia in which abnormal cells crowd out the bone marrow cells needed to produce blood cells. Chronic diseases of other organs can result in anemia. For example, the kidneys and thyroid gland make hormones that are needed by the bone marrow to produce blood cells.
Autoimmune hemolytic anemia
Autoimmune hemolytic anemia, the immune system mistakes red blood cells for foreign invaders and begins destroying them. Other children inherit defects in the red blood cells (RBC’s), which may involve the RBC's structure or the production of hemoglobin or RBC enzymes. Common forms of inherited hemolytic anemia include sickle cell anemia, thalassemia, and glucose-6-phosphate dehydrogenase deficiency.
Iron is essential for the production of hemoglobin in red blood cells. Poor dietary iron intake (or excessive loss of iron from the body) leads to iron-deficiency anemia, the most common cause of anemia in children. Iron-deficiency anemia can affect children at any age, but it is most commonly seen in children under 2 years of age, and in teens, particularly in adolescent girls who have started menstruating.
During the first 6 months of life, babies are usually protected against developing iron deficiency due to the stores of iron built up in their bodies while they are in the uterus. However, by the second half of the first year of life, as infants continue to undergo significant growth, often they do not take in enough iron through breast milk alone or regular cow's milk (which contains less iron than fortified infant formula) to meet their iron needs. Regular cow's milk can also cause some infants to lose iron from their intestines, and drinking lots of it can make an infant less interested in eating other foods that are better sources of iron. For these reasons, regular cow's milk is not recommended for children until they reach 1 year of age and are eating an iron-rich diet.
The growth spurt that occurs during puberty is also associated with an increased risk of iron-deficiency anemia. Girls are at particularly high risk because of the onset of menstruation; the monthly blood loss increases the need for dietary iron. In a recent report on iron deficiency in the United States, the Centers for Disease Control and Prevention (CDC) noted that, according to a 1996 survey, less than half of 1- to 2-year-olds and just over one fourth of teen girls were meeting the recommended daily intake of iron.
Anemia can be caused by deficiency in the nutrients folic acid and vitamin B12, both of which are necessary for normal blood production. Pernicious anemia is a type of anemia that occurs when a person lacks a substance that is necessary to absorb and process vitamin B12. However, these forms anemia are rarely found in babies and young children.
Sickle Cell Anemia
Sickle cell anemia is an inherited blood disease. That means individuals are born with it and it lasts a lifetime. Sickle cell anemia affects the red blood cells. Normal red blood cells are smooth and round like doughnuts. They move easily through blood vessels to carry oxygen to all parts of the body. In sickle cell anemia, the red blood cells become hard, sticky, and shaped like sickles or crescents. When these hard and pointed red cells go through the small blood vessels, they tend to get stuck and block the flow of blood. This can cause pain, damage, and a low blood count or anemia. Anemia is a shortage of red blood cells in your blood. In sickle cell anemia, this shortage of red blood cells occurs because sickle cells do not last very long. It is hard for your body to make new red blood cells fast enough to keep up. Normal red blood cells last about 120 days in the bloodstream. Sickle cells die after only about 10 to 20 days. Sickle cell trait is different from sickle cell anemia. A person with sickle cell trait does not have the disease but carries the gene that causes the disease. Persons with sickle cell trait can pass the gene to their children.
Sickle cell anemia is a serious disease and there is no universal cure. Bone marrow transplantation offers a cure, but very few patients have matched donors. Some patients also do not want bone marrow transplants because of the risks involved. Over the past 30 years, doctors have learned a great deal about the disease. They know what causes it, what it does to your body, and how to treat many of the complications.
People with sickle cell anemia inherit two genes, one from each parent, that are variant (different from normal). The variant genes are call sickle cell genes. The sickle cell genes tell the body to make the variant hemoglobin (hee-muh-glow-bin) that results in deformed red blood cells. Hemoglobin is the protein in red blood cells that carries oxygen to all parts of the body.
Children who inherit sickle cell genes from both parents will have sickle cell anemia. Children who inherit the sickle cell gene from only one parent will not have the disease. They will have sickle cell trait. Persons with sickle cell trait: Generally have no symptoms, live normal lives, and can pass the sickle cell gene on to their children.
People with thalassemia have an inherited blood disorder that causes mild or severe anemia (uh-NEE-me-uh). The anemia is due to reduced hemoglobin (he-mo-GLOBE-in) and fewer red blood cells than normal. Hemoglobin is the protein in red blood cells that carries oxygen to all parts of the body.
In people with Thalassemia, the genes that code for hemoglobin are missing or variant (different than the normal genes). Severe forms of thalassemia are usually diagnosed in early childhood and are lifelong conditions.
The two main types of thalassemia, alpha and beta, are named for the two protein chains that make up normal hemoglobin. The genes for each type of thalassemia are passed from parents to their children. There are mild and severe forms of the disease, the latter often called Cooley's anemia. Cooley's anemia is the most common severe form of thalassemia seen in the U.S.
Alpha thalassemia occurs when one or more of the four genes needed for making the alpha globin chain of hemoglobin are variant or missing. Moderate to severe anemia results when more than two genes are affected. Alpha thalassemia major can result in miscarriages.
Beta thalassemia occurs when one or both of the two genes needed for making the beta globin chain of hemoglobin are variant. The severity of illness depends on whether one or both genes are affected, and the nature of the abnormality. If both genes are affected, anemia can range from moderate to severe.Thalassemia, which usually affects people of Mediterranean, African, and Southeast Asian descent, is marked by abnormal and short-lived red blood cells. Thalassemia major, also called Cooley's anemia, is a severe form of anemia in which red blood cells are rapidly destroyed and iron is deposited in the skin and vital organs. Thalassemia minor involves only mild anemia and minimal red blood cell changes.
Hemophilia is the oldest known hereditary bleeding disorder. There are two types of hemophilia, A and B (Christmas Disease). Both are caused by low levels or complete absence of a blood protein essential for clotting. Patients with hemophilia A lack the blood clotting protein, factor VIII, and those with hemophilia B lack factor IX. There are about 20,000 hemophilia patients in the United States. Each year, about 400 babies are born with this disorder. Approximately 85% have hemophilia A and the remainder have hemophilia B.. The severity of hemophilia is related to the amount of the clotting factor in the blood. About 70% of hemophilia A patients have less than one percent of the normal amount and, thus, have severe hemophilia. A small increase in the blood level of the clotting factor, up to five percent of normal, results in mild hemophilia with rare bleeding except after injuries or surgery. Enormous strides made in assuring the safety of the blood supply and in the genetic aspects of hemophilia research allow us now to focus on issues which will improve the quality of life of the hemophilia patient and, ultimately, develop a cure.
Von Willebrand Disease
Von Willebrand disease is an inherited bleeding disorder. Children born with the disease have one or both of the following: (1) low levels of a protein that helps the blood to clot and/or (2) the protein does not work as it should. This clotting protein is called von Willebrand factor. When some of this factor is missing or defective it can cause prolonged bleeding after an injury or accident.
Links to Blood Disorders
- Understanding your complete blodcount - Pdf file: A very good explanation of what is involved and how to understand blood counts and blood test results.
- Blood and blood disorders: A complete overview of every aspect of blood, blood diseases, specific conditions and much more.
- Blood disorders: 18 specific blood disorders are discussed with links and other information.
- Blood disorders and diseases - A Bloodbook Guide: This site discusses numerous blood disorders and diseases in depth with excellent links to other sites on the same topic.