What Is Megaloblastic Anemia?
Megaloblastic anemia is a type of anemia, a
blood disorder in which the number of red blood cells is lower than normal. Red
blood cells transport oxygen through the body. When your body doesn’t have
enough red blood cells, your tissues and organs don’t get enough oxygen.
There are many types of anemia with different
causes and characteristics. Megaloblastic anemia is characterized by red blood
cells that are larger than normal. There also aren’t enough of them. It’s known
as vitamin B-12 or folate deficiency anemia, or macrocytic anemia, as well.
Megaloblastic anemia is caused when red blood
cells aren’t produced properly. Because the cells are too large, they may not
be able to exit the bone marrow to enter the bloodstream and deliver oxygen.
Causes of Megaloblastic Anemia
The two most common causes of megaloblastic
anemia are deficiencies of vitamin B-12 or folate. These two nutrients are
necessary for producing healthy red blood cells. When you don’t get enough of
them, it affects the makeup of your red blood cells. This leads to cells that
don’t divide and reproduce the way they should.
Vitamin B-12 Deficiency
Vitamin B-12 is a nutrient found in some
foods like meat, fish, eggs, and milk. Some people can’t absorb enough vitamin
B-12 from their food, leading to megaloblastic anemia. Megaloblastic anemia
caused by vitamin B-12 deficiency is referred to as pernicious anemia.
Vitamin B-12 deficiency is most often caused
by the lack of a protein in the stomach called “intrinsic factor.” Without
intrinsic factor, vitamin B-12 can’t be absorbed, regardless of how much you eat.
It’s also possible to develop pernicious anemia because there isn’t enough
vitamin B-12 in your diet.
Folate is another nutrient that’s important
for the development of healthy red blood cells. Folate is found in foods like
beef liver, spinach, and Brussels sprouts. You can also find it in fortified
cereals. Folate is often mixed up with folic acid — technically, folic acid is
the artificial form of folate, found in supplements.
Your diet is an important factor in making
sure you have enough folate. Folate deficiency can also be caused by chronic
alcohol abuse, since alcohol interferes with the body’s ability to absorb folic
acid. Pregnant women are more likely to have folate deficiency, because of the
high amounts of folate needed by the developing fetus.
What Are the Symptoms of Megaloblastic Anemia?
The most common symptom of megaloblastic
anemia is fatigue. Symptoms can vary from person to person. Common symptoms
- shortness of breath
- muscle weakness
- abnormal paleness of the skin
- glossitis (swollen tongue)
- loss of appetite/weight loss
- fast heartbeat
- smooth or tender tongue
- tingling in hands and feet
- numbness in extremities
Diagnosing Megaloblastic Anemia
One test used to diagnose many forms of
anemia is the complete blood count (CBC). This test measures the different parts
of your blood. Your doctor can check the number and appearance of your red
blood cells. They will appear larger and underdeveloped if you have
megaloblastic anemia. Your doctor will also gather your medical history and
perform a physical exam to rule out other causes of your symptoms.
Your doctor will need to do more blood tests
to figure out if vitamin deficiency is causing your anemia. These tests will
also help them find out whether it’s a vitamin B-12 or folate deficiency that’s
causing the condition.
One test that your doctor may use to help
diagnose you is the Schilling test. The Schilling test is a blood test that
evaluates your ability to absorb vitamin B-12. After you take a small supplement
of radioactive vitamin B-12, you’ll collect a urine sample for your doctor to
analyze. You will then take the same radioactive supplement in combination with
the “intrinsic factor” protein that your body needs to be able to absorb vitamin
B-12. Then you’ll provide another urine sample so it can be compared to the
It’s a sign that you don’t produce intrinsic
factor of your own if the urine samples show that you only absorbed the B-12
after consuming it along with the intrinsic factor. This means that you’re
unable to absorb vitamin B-12 naturally.
How Is Megaloblastic Anemia Treated?
How you and your doctor decide to treat megaloblastic
anemia depends on what’s causing it. Your treatment plan can also depend on
your age and overall health as well as your response to treatments and how
severe the disease is. Treatment to manage anemia is often ongoing.
Vitamin B-12 Deficiency
In the case of megaloblastic anemia caused by
vitamin B-12 deficiency, you may need monthly injections of vitamin B-12. Oral
supplements may also be given. Adding more foods with vitamin B-12 to your diet
can help. Foods that have vitamin B-12 in them include:
- fortified cereals (especially
- red meats (especially beef)
Megaloblastic anemia caused by a lack of folate
may be treated with oral or intravenous folic acid supplements. Dietary changes
also help boost folate levels. Foods to include in your diet include:
- leafy green vegetables
- enriched grains
Living with Megaloblastic Anemia
In the past, megaloblastic anemia was
difficult to treat. Today, people with megaloblastic anemia due to either vitamin
B-12 or folate deficiency can manage their symptoms and feel better with
ongoing treatment and nutrient supplements.
Vitamin B-12 deficiency can lead to other
problems. These can include nerve damage, neurological problems, and digestive
tract problems. These complications can be reversed if you get diagnosed and
treated early. People who have pernicious anemia also may be at higher risk for
weakened bone strength and stomach cancer. For these reasons, it’s important to
catch megaloblastic anemia early. Talk to your doctor if you see any signs of
anemia so you and your doctor can come up with a treatment plan and help
prevent any permanent damage.
Different types of anemia