Pernicious anemia

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at March 21, 2016
StartDiseasesPernicious anemia

Anemia occurs when the body lacks enough healthy red blood cells. Because the red blood cells provide oxygen to the body tissues, anemia causes many problems. There are many types of anemia, and among them is pernicious anemia, which is also called vitamin B12 deficiency anemia.


Definition & Facts

Pernicious anemia is an autoimmune disease in which the body cannot make enough healthy red blood cells. This is normally due to the fact that it cannot absorb enough vitamin B12. It was named ‘pernicious’ which means having harmful effects, especially in a gradual way, since it was considered deadly due to lack of available treatment. That is however not the case today since research has made it easier to treat it. If left untreated, pernicious anemia can lead to brain damage, nerve damage, heart problems, chronic anemia and even stomach cancer.

Symptoms & Complaints

Because pernicious anemia progresses very slowly, it can be difficult for one to recognize the symptoms since one may have grown accustomed to feeling unwell. Some of the most common symptoms which are normally overlooked are weakness, headaches, chest pains and unexplained weight loss.

Other symptoms include pica - the desire to eat non-food things, diarrhea, or constipation, fatigue, loss of appetite, difficulty concentrating, shortness of breath especially when exercising, and swollen, red tongue, or bleeding gums.

In very rare occasions, pernicious anemia causes neurological symptoms such as: loss of memory, unsteady gait, progressive lesions of the spinal cord, peripheral neuropathy (numbness in the arms and legs), spasticity (stiffness and tightness in the muscles).


Vitamin B12 is an essential ingredient for the formation of red blood cells. When one is deficient in B12, the body produces large red blood cells, which may not leave the bone marrow, resulting in a decrease in oxygen-carrying red blood cells in the bloodstream. Vitamin B12 can be obtained from eating foods such as poultry, meats, eggs, shellfish, dairy products, fortified soy, nut and rice milk, as well as nutritional supplements, so diets low in these items may cause vitamin B12 deficiency anemia.

The intrinsic factor (IF) released by cells in the stomach helps the intestines absorb vitamin B12. Sometimes, the stomach lining can be weakened, thus failing to produce enough intrinsic factor and making it difficult for the intestines to absorb vitamin B12.

In other cases, pernicious anemia can be caused by an autoimmune condition. Here, the body’s immune system attacks the intrinsic factor protein or the cells in the stomach lining which make it, resulting in reduced absorption of vitamin B12.

Pernicious anemia can also be congenital, passed down through families. One is at a high risk of suffering from pernicious anemia if one suffers from Addison's disease, Hashimoto's thyroiditis, Graves' disease, hypoparathyroidism, hypopituitarism, myasthenia gravis, amenorrhea, diabetes mellitus type 1, testicle dysfunction, or vitiligo.

Diagnosis & Tests

Once in hospital, the doctor runs a number of tests before diagnosing one with pernicious anemia. These tests include:

There are other tests that can raise a red flag for pernicious anemia since it affects their results. These tests include bilirubin, cholesterol test, gastrin, leukocyte alkaline phosphatase, peripheral smear and TIBC (total iron-binding capacity).

Treatment & Therapy

Pernicious anemia is usually treated in two phases. First, a patient will be treated for any existing vitamin B12 deficiency and also for iron deficiency. Secondly, he or she will have lifelong monitoring to reduce long-term consequences. Treatment begins with:

  • Vitamin B12 injections, which are decreased over time normally starting with once a month. However, people with severely low levels of vitamin B12 can be given more shots at the beginning. In addition to the shots, patients may be given vitamin B12 supplements which are taken orally. There is a certain type of vitamin B12 supplement which may be given through the nose.
  • Complete blood count tests are carried out to measure the levels of vitamin B12 and iron in the blood serum.
  • Further blood tests are carried out to monitor replacement treatments. The doctor may also advise on proper diet to the patient.

When the levels of vitamin B12 in the blood have been raised to acceptable levels, phase two of the treatment begins where the doctor monitors the patient for any symptoms of long-term damage. These include difficulty swallowing, weight loss, iron deficiency and upset stomach.

Monitoring on a long-term basis focuses on identifying possible serious consequences of pernicious anemia. The most serious complication is gastric cancer, which can be checked through biopsies during subsequent visits to the hospital.

Prevention & Prophylaxis

One can avoid getting pernicious anemia by eating a healthy diet. Since pernicious is caused by low levels of vitamin B12, eating foods high in vitamin B12 such as meat, eggs and dairy products can keep pernicious anemia at bay.

Vegetarians and vegans should have their vitamin B12 levels checked regularly or obtain B12 from multivitamins, and B-complex vitamin supplements. Since the elderly naturally have trouble absorbing vitamin B12, they can eat foods fortified with vitamin B12 or take vitamin B12 supplements.

Pernicious anemia that is caused by lack of intrinsic factor is not preventable since lack of intrinsic factor automatically means that vitamin B12 will not be absorbed, no matter how abundant it is. It is best to see a doctor as soon as one thinks he or she may have symptoms of pernicious anemia. This is because early diagnosis and treatment help prevent further complications.