Anemia

Anemia (American English) or anaemia (Commonwealth English), which literally means "without blood," is a deficiency of red blood cells and/or hemoglobin. This results in a reduced ability of blood to transfer oxygen to the tissues. Hemoglobin (the oxygen-carrying protein in the red blood cells) has to be present to ensure adequate oxygenation of all body tissues and organs.

Differential diagnosis

Anemia is classified by the size of the red blood cells; this is either done automatically or on microscopic examination of a peripheral blood smear. The size is reflected in the mean corpuscular volume (MCV). If the cells are smaller than normal (under 80 fl), the anemia is said to be microcytic; if they are normal size (80-100 fl), normocytic; and if they are larger than normal (over 100 fl), the anemia is classified as macrocytic. Other characteristics visible on the peripheral smear may provide valuable clues about a more specific diagnosis; for example, abnormal white blood cells may point to a cause in the bone marrow.

Related Topics:
Mean corpuscular volume - Fl - White blood cell - Bone marrow

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Microcytic anemia

The most common type of anemia overall is iron deficiency anemia, which is most often microcytic. Much rarer causes (apart from communities where these conditions are prevalent) are hemoglobinopathies such as sickle-cell disease and thalassemia.

Related Topics:
Iron deficiency anemia - Hemoglobinopathies - Sickle-cell disease - Thalassemia

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Iron deficiency anemia is caused when the dietary intake or absorption of iron is insufficient. Iron is an essential part of hemoglobin, and low iron levels result in decreased incorporation of hemoglobin into red blood cells. In the United States, 20% of all women of childbearing age have iron deficiency anemia, compared with only 2% of adult men. The principal cause of iron deficiency anemia in premenopausal women is blood lost during menses. Studies have shown that iron deficiency without anemia causes poor school performance and lower IQ in teenage girls. In older patients, iron deficiency anemia is often due to bleeding lesions of the gastrointestinal tract; fecal occult blood testing, upper and lower endoscopy are often performed to identify bleeding lesions, which can be malignant.

Related Topics:
Iron - Menses - IQ - Gastrointestinal tract - Fecal occult blood test - Upper - Lower endoscopy - Malignant

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Iron deficiency is the most prevalent deficiency state on a worldwide basis. Iron deficiency affects women from different cultures and ethnicities. In countries where meat consumption is not as common, iron deficiency anemia is six to eight times more prevalent than in North America and Europe. This is due to the importance of meat in the diets of North Americans and Europeans.

Related Topics:
Culture - Ethnicities

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Normocytic anemia

Normocytic anemia can be caused by acute blood loss, chronic disease ("anemia of chronic disease") or failure to produce enough red blood cells (as opposed to hemoglobin, which causes microcytic anemia). Chronic renal failure or liver failure cause normocytic anemia; in renal failure this is due to decreased production of the hormone erythropoietin.

Related Topics:
Blood loss - Chronic renal failure - Liver failure - Erythropoietin

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Certain hormonal deficiencies, like testosterone deficiency (hypogonadism), can cause normocytic anemia. Lastly, sideroblastic anemia is caused by abnormal production of red blood cells as part of myelodysplastic syndrome, which can evolve into hematological malignancies (especially acute myelogenous leukemia).

Related Topics:
Testosterone deficiency - Hypogonadism - Sideroblastic anemia - Myelodysplastic syndrome - Hematological malignancies - Acute myelogenous leukemia

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Aplastic anemia (bone marrow failure) is anemia caused by the inability of the bone marrow to produce blood cells. Aplastic anemias are much rarer than dietary deficiency or genetic defect anemias, and progess rapidly.

Related Topics:
Aplastic anemia - Bone marrow

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Macrocytic anemia

• The most common cause of macrocytic anemia is megaloblastic anemia due to a deficiency of either vitamin B12 or folic acid (or both) due either to inadequate intake or insufficient absorption. Folate deficiency normally does not produce neurological symptoms, while B12 deficiency does. Pernicious anemia is an autoimmune condition where the body lacks intrinsic factor, required to absorb vitamin B12 from food.
• Alcoholism can cause macrocytic anemia.
• Drugs that inhibit DNA replication, such as methotrexate, can also cause macrocytic anemia. This is the most common etiology in nonalcoholic patients.

The treatment for vitamin B12-deficient macrocytic and pernicious anemias was first devised by William Murphy who bled dogs to make them anemic and then fed them various substances to see what (if anything) would make them healthy again. He discovered that ingesting large amounts of liver seemed to cure the disease. George Minot and George Whipple then set about to chemically isolate the curative substance and ultimately were able to isolate the vitamin B12 from the liver. For this, all three shared the 1934 Nobel Prize in Medicine.

Related Topics:
William Murphy - George Minot - George Whipple - Vitamin B12 - 1934 - Nobel Prize in Medicine

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Dimorphic Anemia

Here there are 2 types of anemia simultaneously, e.g., Macrocytic Hypochromic, due to hookworm infestation leading to deficiencey of both iron and vitamin B12 or folic acid http://www.mercksource.com/pp/us/cns/cns_hl_dorlands.jspzQzpgzEzzSzppdocszSzuszSzcommonzSzdorlandszSzdorlandzSzdmd_a_37zPzhtm or following a blood transfusion.

Related Topics:
Iron - Vitamin B12 - Folic acid

~ ~ ~ ~ ~ ~ ~ ~ ~ ~