Pernicious anemia
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Pernicious anemia is one of the most common causes of Vitamin B12 deficiency in adults. It is also known as Biermer’s anaemia, Macrocytic achylic anemia, and Addison’s anaemia.


It is a form of megaloblastic anemia, which is a disorder of the blood where a person's red blood cells become abnormally larger. Pernicious Anemia is indicated by the malabsorption of cobalamin (Vitamin B12), a vitamin needed for red blood cells to form and enable the nervous system to work normally.

The body cannot produce Vitamin B12 by itself, and so it must be derived from food intake, especially from eggs, fish, meat, milk and other dairy products. A Vitamin B12 deficiency can result when the body lacks a protein known as intrinsic factor, which is produced by parietal cells in the stomach's lining.


This inability to absorb Vitamin B12 from the gastrointestinal tract is caused by atrophic gastritis (chronic inflammation of the stomach’s innermost layer) which results in a loss of parietal cells (stomach cells that produce gastric acid). When these cells are impaired as a result of a compromised immune system or because of stomach surgery, intrinsic factor protein is not produced and the stomach is unable to absorb Vitamin B12.

A Vitamin B12 deficiency can also be caused by an inadequate or purely vegetarian diet, aging, alcoholism, certain intestinal disorders like Crohn's disease, and infections of the intestine.

Pernicious Anemia most often affects older adults around age 60, and it is a common ailment in regions with a temperate climate. There are also rare cases of congenital Pernicious Anemia in infants born with the inability to produce the intrinsic factor protein.


Other factors that increase the risk for developing the disease include a family history of Pernicious Anemia, people descended from Scandinavian or other Northern European stock, and those who have had previous autoimmune endocrine disorders like type 1 diabetes, Addison's disease (an endocrine disorder), hypoparathyroidism (decreased function of the thyroid), testicular dysfunction, and chronic thyroiditis (thyroid gland inflammation).

People who have Pernicious Anemia will experience fatigue and weakness due to the lack of oxygen in the body. As the heart will be working twice as hard to pump blood in order to distribute oxygen to all the organs and tissues, it can incur stress which can cause heart murmurs, arrhythmia (irregular heartbeat), heart enlargement, or congestive heart failure.

Pernicious Anemia also causes tingling and numbness in the hands and feet (paresthesias), difficulty walking and inability to balance. The lack of Vitamin B12 changes a person’s sense of taste, smell, and even eyesight. It can also take a toll on mental health, causing confusion and loss in memory.


The surface of the tongue may become red, sore and may shrink, and the stomach lining thins. These symptoms of Pernicious Anemia increase the risk for stomach cancer, gastric polyps and gastric carcinoid tumors.

Other symptoms include anemia, loss of appetite and weight, constipation and diarrhea, abdominal pain, fever, bleeding gums, muscle spasms, chest pains, and jaundice or pallor. The sufferer may also incur Babinski’s reflex, where the big toe becomes bent toward the upper part of the foot while the rest of the toes spread out. Eventually, Pernicious Anemia causes a loss of deep tendon reflexes, neurological problems, and personality changes known as “megaloblastic madness”
pernicious anemia
Image: Pernicious anemia


To diagnose Pernicious Anemia, the doctor will order a complete blood count to check for any sign of megaloblastic anemia and to measure Vitamin B12 levels in the blood. In a diagnostic procedure known as the Schillings test, the patient drinks radiolabeled Vitamin B12 and receives an intramuscular injection of unlabeled Vitamin B12 at the same time. The results of the test will be found in the patient’s urine where the absorbtion of the B vitamin is assessed. The urine of patients with Pernicious Anemia will only show 5% of the radiolabeled B12, attesting to their inability to absorb the vitamin.


The doctor may order a gastrocopy, an examination and biopsy of the esophagus, stomach and duodenum with the use of an endoscope. In patients with Pernicious Anemia, 90% will be positive for parietal cell antibodies.

Other tests may include a bone marrow examination (through biopsy or aspiration); reticulocyte count (bone marrow’s production rate of red blood cells); serum LDH (platelet count measurement), and determining the hemoglobin (protein in blood cells which carry oxygen) and hematocrit (red blood cell count) levels.

Since Pernicious Anemia is caused by a Vitamin B12 deficiency, treatment will involve taking Vitamin B12 supplements. In patients who exhibit malabsorption, higher doses of the supplements are given, either orally, intravenously via injection, or through a preparation given through the nose.

The B12 supplements will eventually correct symptoms like anemia and neurological complications if therapy is started at an early stage of the disease. With elderly patients also suffering from gastric atrophy, doctors usually recommend oral supplements as well as a monthly injection.


There is still no known method to prevent the immune system from destroying the stomach’s parietal cells which produce intrinsic factor protein, a lack of which leads to Pernicious Anemia. However, symptoms and complications of the disease can be controlled and managed with early diagnosis of Vitamin B12 deficiency.

Eating a well-balanced diet rich in Vitamin B12 and folic acid can prevent this deficiency, especially eggs, poultry, meat, milk and other dairy products, cereals, rice or barley, nuts, sprouts, asparagus, green leafy vegetables, peas, beans and lentils. Multivitamins and B-complex vitamins in supplement form also help.


With adequate treatment, the prognosis for Pernicious Anemia is excellent. In some rare cases, sufferers are afflicted with permanent nerve damage before the disease has been diagnosed and treated. However, some of the damage may be reversed with prolonged therapy. While Pernicious Anemia increases the risk for the occurrence of stomach cancer, patients will be advised to have regular tests for cancer while undergoing treatment.

The USDA Nutrition Research Center has recently found that having high folate and Vitamin B12 levels in elderly patients, not only lowered the risk for anemia, but also encouraged better mental functions in people 60 years and older, substantiating the study published in the American Journal of Clinical Nutrition in January 2007, which stated that low levels of Vitamin B12 contributed to cognitive impairment.
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