What is megaloblastic anemia?
Megaloblastic anemia is a type of anemia characterized by very large red blood cells. In addition to the large cells, the internal contents of each cell are not fully developed. This malformation causes the bone marrow to produce fewer cells, and sometimes the cells die earlier than the expected life span of 120 days. Rather than being round or disc-shaped, the red blood cells are oval in shape.
Megaloblastic anemia is a macrocytic anemia caused by vitamin B12 or folic acid deficiency that results in impaired cellular deoxyribonucleic acid (DNA) synthesis, usually seen in infants and pregnant women. In recent years, with the advent of an aging society and the increase of chronic diseases in the elderly, the prevalence of megaloblastic anemia in the elderly is on the rise. Because of the lack of specificity in its clinical manifestations, it can be easily delayed or misdiagnosed and therefore requires special vigilance for early detection and treatment.
Causes for having megaloblastic anemia
There are many causes for megaloblastic anemia, but the most common cause is a vitamin deficiency of folic acid or vitamin B-12. Other sources of megaloblastic anemia include the following
Causes for megaloblastic anemia from digestive disorders - Certain disorders of the lower gastrointestinal tract can lead to megaloblastic anemia. These disorders include celiac disease, chronic infectious enteritis and intestinal fistulas. Pernicious anemia is a form of megaloblastic anemia in which vitamin B-12 is not absorbed due to a lack of intrinsic factors in gastric secretions. intrinsic factors enable the absorption of vitamin B-12.
Causes for megaloblastic anemia due to malabsorption - Hereditary congenital malabsorption of folic acid, a genetic problem in which the intestine is unable to absorb folic acid, can lead to megaloblastic anemia. This requires early intensive treatment to prevent long-term problems such as mental retardation.
Causes for megaloblastic anemia due to drug-induced folate deficiency - Certain medications, especially those that prevent seizures, such as phenytoin, primidone and phenobarbital, can interfere with the absorption of folic acid. This deficiency can usually be treated with dietary supplements.
Causes for megaloblastic anemia due to folic acid deficiency - Folic acid is a B vitamin needed to produce normal red blood cells. Folic acid is found in foods such as green vegetables, liver and yeast. It can also be produced synthetically and added to many foods.
Clinical data show that the main cause of megaloblastic anemia in the elderly is vitamin B12 deficiency. Many elderly people are on a long-term vegetarian diet because of high blood lipids, which may lead to insufficient intake of vitamin B12; some elderly people suffer from chronic digestive system diseases, such as chronic gastritis, gastric ulcer, inflammatory bowel disease, chronic cholecystitis, or post-gastrectomy, which lead to reduced absorption of folic acid and vitamin B12 in the gastrointestinal tract, and if accompanied by internal factor deficiency, it will increase the prevalence of pernicious anemia in the elderly.
In addition, some elderly people have chronic alcoholism, chronic infection or long-term use of antibiotics, which may affect the absorption of folic acid and vitamin B12, or cause intestinal flora disorders that reduce the synthesis of vitamin B12, thus becoming an important cause of megaloblastic anemia.
Almost all elderly patients with megaloblastic anemia have different degrees of dizziness, movement, palpitations, shortness of breath and aggravation after activity, as well as general signs such as facial pallor, mirror tongue, edema, xanthogranuloma, etc. Some patients also have neurological signs such as numbness and abnormal sensation in the hands and feet. However, in general, the symptoms lack specificity.
Therefore, to make a definitive diagnosis, laboratory tests are necessary to obtain evidence.
1. peripheral blood picture macrocytic anemia with increased erythrocyte volume, which may be accompanied by a decrease in whole blood cells;
2. Bone marrow picture shows active proliferation, with the most active proliferation in the erythrocyte system and the appearance of various stages of juvenile erythrocytes;
3. Serum folate level <6.81 mmol/L, or vitamin B12 serum level <74 picomoles/L. Therefore, elderly people with general anemia symptoms and anemic appearance should go to the hospital promptly in order to obtain sufficient evidence for early and definite diagnosis.
The principles of treatment for megaloblastic anemia in the elderly include control of the primary disease, dietary modification and pharmacological treatment. Dietary modification includes correcting poor dietary habits, eating more fresh vegetables, and increasing the intake of protein foods, such as fish, eggs, milk and meat.
Treatment of the causes for megaloblastic anemia
How you and your doctor decide to treat megaloblastic anemia depends on the cause for the megaloblastic anemia. Your treatment plan also depends on your age and overall health, as well as how well you respond to treatment and the severity of your disease.
Treatment to control anemia is usually ongoing.
Causes for megaloblastic anemia with vitamin B12 deficiency
If the cause for megaloblastic anemia is due to vitamin B12 deficiency, you may need monthly injections of vitamin B12. You may also be given oral supplements.
Adding more vitamin B12-containing foods to your diet can help. Other foods that contain vitamin B12 include
- Chicken
- Fortified grains, especially wheat bran
- Red meats
- Shellfish
Some people have a genetic mutation in the methylenetetrahydrofolate reductase (MTHFR) gene. This gene is responsible for converting certain B vitamins (including B12 and folic acid) into usable forms in the body.
Methylcobalamin supplementation is recommended for individuals with MTHFR mutations.
Regular intake of vitamin B12-rich foods, vitamins or fortified products is unlikely to prevent deficiency or its health consequences in people with this gene mutation.
Causes for megaloblastic anemia due to folic acid deficiency
Megaloblastic anemia caused by folic acid deficiency can be treated with oral or intravenous folic acid supplements. Dietary changes can also help boost folic acid levels.
Additional foods to include in the diet include
- Green leafy vegetables
- Peanuts
- Lentils
- Grains in abundance
As with vitamin B12, people with MTHFR mutations are encouraged to take methylfolate to prevent folic acid deficiency and its complications.
The key to medication is to supplement folic acid or vitamin B gamma. It is recommended to take folic acid orally under the guidance of a doctor, 5 mg each time, 3~4 times a day for 2~4 weeks; vitamin B12 0.1 g each time, 1 intramuscular injection daily: or 0.5 g each time, 1 intramuscular injection every other day or 3 days, and after 2 weeks, change to oral vitamin B12. 0.5 g once a day until the anemia is corrected.
To prevent megaloblastic anemia in the elderly.
1. To mix meat and vegetables, avoid long-term vegetarian diet
2. Actively prevent and treat various digestive system diseases
3. Limit alcohol consumption and avoid long-term alcohol abuse
4. Use antibiotics reasonably and avoid long-term abuse of antibiotics.
References:
1. Megaloblastic Anemia | Children's Hospital of Philadelphia
2. Megaloblastic Anemia: Symptoms, Causes, Treatment & More
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