Megaloblastic anemia is a type of anemia in which the bone marrow produces larger than normal red blood cells and smaller white blood cells and platelets. It is mainly caused by a deficiency of vitamin B12 or B9 in the blood.
This type of anemia can cause symptoms such as excessive fatigue, paleness, weakness and difficulty breathing in some cases, however symptoms can vary from one person to another.
It is important for cases of megaloblastic anemia to be identified and treated as advised by a general practitioner or hematologist, who may recommend a change in eating habits or supplementation with vitamin B12 or B9, depending on the underlying.
Main symptoms
The common symptoms of megaloblastic anemia are:
- Excessive fatigue
- Paleness
- Weakness
- Muscle pain
- Difficulty breathing
- Hair loss
- Loss of appetite with weight loss
- Changes in intestinal transit, with diarrhea or constipation
- Abdominal pain or nausea
- Tingling in the hands or feet
Megaloblastic anemia caused by a vitamin B12 deficiency can also lead to neurological symptoms, such as tingling in the hands or feet, loss of sensation or muscle weakness.
Over time, other symptoms may gradually start to appear, such as problems with balance or walking, vision loss, mental confusion or memory loss.
Confirming a diagnosis
Megaloblastic anemia is diagnosed by the general practitioner or hematologist, initially, by evaluating the patient's presenting symptoms.
To confirm a diagnosis, the doctor will order a complete blood count and also order a B12 and B9 blood test. Read more about the anemia blood tests your doctor may order and what they evaluate.
Possible causes
Megaloblastic anemia is mainly related to reduced levels of vitamin B12 or B9:
1. B12 deficiency
Vitamin B12 deficiency typically occurs due to decreased intake of foods that are rich in this vitamin. It is more common in vegetarians and vegans, since sources of vitamin B12 are usually of animal origin.
Low levels of intrinsic factor can also cause a type of megaloblastic anemia, called pernicious anemia. Intrinsic factor is a protein that binds to vitamin B12 in the stomach so that it can be absorbed in the intestine, and low levels of this protein and lead to low B12 levels.
Other conditions such as pancreatic insufficiency, intestinal resection or the use of certain medications can also cause vitamin B12 deficiency and, consequently, megaloblastic anemia.
2. Folic acid deficiency
Folic acid (vitamin B9) deficiency can occur due to excessive alcohol consumption, as alcohol can reduce the absorption of folic acid in the intestines. Low levels of B9 can also be the result of reduced intake of foods that contain this micronutrient.
Other possible causes of a folic acid deficiency are conditions that increase the demand for this vitamin, such as pregnancy and hemodialysis. Low levels can also be the result of malabsorption due to Crohn's disease or intestinal surgeries, or the use of anticonvulsant or carcinogenic medications that interfere with folic acid metabolism.
3. Use of certain medications
The use of certain medications can cause changes in the bone marrow, and affect the formation of red blood cells. Examples of medications that have this effect include allopurinol, methotrexate, fluorouracil, azathioprine, among others.
Treatment options
Treatment of megaloblastic anemia should be carried out as advised by your doctor, and may vary depending on the cause of it.
Cases of pernicious anemia may be treated with daily or oral supplementation, either with B12 injections or tablets, until B12 and hemoglobin levels are back to normal levels.
Cases of megaloblastic anemia caused by B12 deficiency can be treated by improving eating habits. Ideally, you should increase your intake of foods with vitamin B12, like fish, cheese, milk and brewer's yeast, for example. Read more about vitamin B12 foods that you can include in your diet. Supplementation may also be necessary.
Megaloblastic anemia that is caused by a vitamin B9 deficiency may be treated with oral B9 supplementation or the intake of foods rich in folic acid, such as spinach, broccoli, nuts and beans, for example. Check-out a list of foods with folic acid that can be included in your diet.