Anemia, Pernicious

Pernicious anemia refers to a type of autoimmune anemia. Antibodies are directed against intrinsic factor or parietal cells which produce intrinsic factor. Intrinsic factor is required for vitamin B12 absorption, so impaired absorption of vitamin B12 can result. more...

The term pernicious anemia is sometimes used more loosely to include non-autoimmune causes of vitamin B12 deficiency.

Diagnosis

Blood testing typically shows a macrocytic anemia, and low levels of serum vitamin B12. A Schilling test can then be used to distinguish between pernicious anemia, vitamin B12 malabsorption, and vitamin B12 deficiency. Approximately 90% of individuals with pernicious anemia have antibodies for parietal cells, however only 50% of individuals with these antibodies have the disease.

History

The treatment for pernicious anemia was first devised by William Murphy who bled dogs to make them anemic and then fed them various substances to see what (if anything) would make them healthy again. He discovered that ingesting large amounts of liver seemed to cure the disease. George Minot and George Whipple then set about to chemically isolate the curative substance and ultimately were able to isolate the vitamin B12 from the liver. For this, all three shared the 1934 Nobel Prize in Medicine. As a result, pernicious anemia is now treated with either vitamin B12 injections (hydroxocobalamin or cyanocobalamin), or large oral doses of vitamin B12, typically between 2 and 4 mg daily.

Maurice Beddow Bayly, an anti-vaccinationist and anti-vivisectionist, campaigned against the use of liver therapy, having failed to recognise the nature of the disease (despite reciting the necessary information) .

Symptoms

Pernicious anemia may cause inflammation of the tongue (glossitis). It is also associated with premature greying, blue eyes, vitiligo, and blood group A.

Treatment

Treatment is with vitamin B12 (hydroxycobalamin or cyanocobalamin) injected intramuscularly. Body stores (in the liver) are refilled with half a dozen injections in the first couple of weeks and then maintenance with monthly to quarterly injections throughout the life of the patient.

B12 has traditionaly been given parenterally to ensure absorption. Alternatively, since it has become appreciated that when B12 given orally in sufficient quantity is absorbed regardless of intrinsic factor or the ileum, oral replacement has emerged as an accepted route. Generally 1000 to 2000 mcg daily is required . By contrast, the typical Western diet contains 5-7 mcg of B12.

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