Megaloblastic anemia definition

What is folate-deficiency anemia? Folate-deficiency anemia is the lack of folic acid in the blood. Folic acid is a B vitamin that helps your body make red blood cells. If you don’t have enough red blood cells, you have anemia. Red blood cells carry oxygen to all parts of your body. When you have anemia, your blood can’t bring enough oxygen to all your tissues and organs. Without enough oxygen, your body can’t work as well as it should. Low levels of folic acid can cause megaloblastic anemia. With this condition, red blood cells are larger than normal. There are fewer of these cells. They are also oval-shaped, not round. Sometimes these red blood cells don’t live as long as normal red blood cells. What causes folate-deficiency anemia? You can develop folate-deficiency anemia if: • You don’t eat enough foods that have folic acid. These include green leafy vegetables, fresh fruits, fortified cereals, yeast, and meats (including liver). • You drink too much alcohol • You have certain diseases of the lower digestive tract, such as celiac disease. This type of anemia also occurs in people with cancer. • You take certain medicines, such as some used for seizures. • You are pregnant. This is because the developing baby needs more folic acid. Also, the mother absorbs it more slowly. A lack of folate during pregnancy is linked to major birth defects that affect the brain, spinal cord, and spine (neural tube defects). Some babies are born unable to absorb folic acid. This can lead to...

Sitemap USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.

Wikipedia Rate this definition: 0.0 / 0 votes • Megaloblastic anemia Megaloblastic anemia is a type of macrocytic anemia. An anemia is a red blood cell defect that can lead to an undersupply of oxygen. Megaloblastic anemia results from inhibition of DNA synthesis during red blood cell production. When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis (M) stage. This leads to continuing cell growth without division, which presents as macrocytosis. Megaloblastic anemia has a rather slow onset, especially when compared to that of other anemias. The defect in red cell DNA synthesis is most often due to hypovitaminosis, specifically vitamin B12 deficiency or folate deficiency. Loss of micronutrients may also be a cause. Megaloblastic anemia not due to hypovitaminosis may be caused by antimetabolites that poison DNA production directly, such as some chemotherapeutic or antimicrobial agents (for example azathioprine or trimethoprim). The pathological state of megaloblastosis is characterized by many large immature and dysfunctional red blood cells (megaloblasts) in the bone marrow and also by hypersegmented neutrophils (defined as the presence of neutrophils with six or more lobes or the presence of more than 3% of neutrophils with at least five lobes). These hypersegmented neutrophils can be detected in the peripheral blood (using a diagnostic smear of a blood sample). Freebase Rate this definition: 0.0 / 0 votes • Megaloblastic an...

Vitamin B 12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms, and other clinical manifestations. Screening average-risk adults for vitamin B 12 deficiency is not recommended. Screening may be warranted in patients with one or more risk factors, such as gastric or small intestine resections, inflammatory bowel disease, use of metformin for more than four months, use of proton pump inhibitors or histamine H 2 blockers for more than 12 months, vegans or strict vegetarians, and adults older than 75 years. Initial laboratory assessment should include a complete blood count and serum vitamin B 12 level. Measurement of serum methylmalonic acid should be used to confirm deficiency in asymptomatic high-risk patients with low-normal levels of vitamin B 12. Oral administration of high-dose vitamin B 12 (1 to 2 mg daily) is as effective as intramuscular administration for correcting anemia and neurologic symptoms. Intramuscular therapy leads to more rapid improvement and should be considered in patients with severe deficiency or severe neurologic symptoms. Absorption rates improve with supplementation; therefore, patients older than 50 years and vegans or strict vegetarians should consume foods fortified with vitamin B 12 or take vitamin B 12 supplements. Patients who have had bariatric surgery should receive 1 mg of oral vitamin B 12 per day indefinitely. Use of vitamin B 12 in patients with elevated serum homocysteine levels and cardiovascular...