Pernicious Anemia

What Is Pernicious Anemia? 

Anemia is a common blood disorder in which the body does not have enough healthy red blood cells, which provide body tissues with oxygen. Many different forms of anemia exist, including vitamin B12 anemia. When red blood cells decrease because the intestines are unable to absorb vitamin B12 properly, the condition is called pernicious anemia.

What Causes Pernicious Anemia?

Your body needs vitamin B12 to make red blood cells. You get this essential vitamin from many foods, including meat, poultry, dairy products, eggs, and shellfish. When you eat these foods, a protein called intrinsic factor (IF) binds to vitamin B12, making it possible for the intestines to absorb it. But when the stomach fails to produce enough IF, the intestines cannot properly absorb the vitamin.

Why does this happen? Pernicious anemia is often caused by an autoimmune condition in which the immune system mistakenly attacks the IF protein or the cells in the stomach lining that create it. It can also be caused by a weakened stomach lining (known as atrophic gastritis), which is genetic in rare cases.

Certain medical conditions can also raise your risk for pernicious anemia. These include Addison disease, Graves’ disease, hypothyroidism, Type 1 diabetes and celiac disease.

What Are the Symptoms of Pernicious Anemia

Symptoms of pernicious anemia may not show in adults until after age 30. Those symptoms may present as:

  • bleeding gums or a swollen, red tongue
  • diarrhea or constipation
  • fatigue
  • heartburn
  • lightheadedness with exertion or when standing up
  • loss of appetite
  • nausea and vomiting
  • pale skin
  • shortness of breath during exercise

Over time, low levels of vitamin B12 can lead to nervous system damage. Symptoms include:

  • confusion
  • delusions
  • depression
  • hallucinations
  • loss of balance
  • numbness and tingling in hands and feet
  • optic nerve damage
  • short-term memory loss
  • trouble concentrating

Diagnosis and Treatment

If your doctor suspects you might have pernicious anemia, they will perform a physical exam and a complete blood count, which is a blood test that measures red blood cells and other blood features. Doctors might also do other blood tests to measure the amount of vitamin B12 in your blood, levels of antibodies against IF and other parts of the blood.

If you are diagnosed with pernicious anemia, your doctor will start you on treatment right away to increase your vitamin B12 levels. Doctors may prescribe one of the following:

  • a shot of B12 monthly (or more if your levels are severely low in the beginning)
  • large doses of vitamin B12 supplements taken by mouth

Permanent nerve damage can occur if treatment does not start within six months of the onset of symptoms. It is very important to visit your doctor if you have symptoms of vitamin B12 deficiency. Other complications can include:

  • bone marrow failure
  • fractures of the upper leg, forearm, and back
  • gastric polyps and gastric cancer

Prompt treatment can help prevent complications, and most people who receive treatment do well and live a full, healthy life.