Pernicious anaemia

2007 Schools Wikipedia Selection. Related subjects: Health and medicine

Pernicious anaemia refers to a type of autoimmune anaemia. 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. An anaemia is a deficiency of the blood cells, but in addition to blood cells, many other cells in the body need vitamin B₁₂, including nerve cells.

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

Diagnosis

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

Pernicious anaemia is more common among women (1.6 : 1) with a peak occurrence at the age of sixty. It has a hereditary component, and it is notably more common in persons of Northern European ancestry.

Symptoms

Symptoms may include weakness, an abnormally rapid heartbeat ( tachycardia), shortness of breath, chest pains, an upset stomach including diarrhea, difficulty walking, numbness and tingling in the extemities, lack of color (pallor) in the lips, gum, and tongue, and/or depression. Pernicious anaemia may cause inflammation of the tongue ( glossitis). It is also associated with premature greying, blue eyes, vitiligo, and blood group A.

It is also associated with unpredictable periods of fatigue and an inability to concentrate. Irreversible Central Nervous System (CNS) damage may have occurred prior to treatment. Scissors gait can appear as a late sign of unchecked anaemia.

Some sufferers also report mouth ulcers, joint pain and tinnitus as associated with the onset of pernicious anaemia. see intrisnic factor

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 traditionally been given parenterally to ensure absorption. However, oral replacement is now an accepted route, as it has become increasingly appreciated that sufficient quantities of B₁₂ are absorbed when large doses are given. This absorption does not rely on the presence of intrinsic factor or an intact ileum. Generally 1 to 2 mg daily is required as a large dose . By contrast, the typical Western diet contains 5–7 µg of B₁₂ ( Food and Drug Administration (FDA) Daily Value ).

History

The treatment for pernicious anaemia was first devised by George Whipple who bled dogs to make them anaemia 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 William Murphy 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 anaemia 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).

Synonyms

• Addison's anaemia
• Addison-Biermer Anaemia
• Addisonian Pernicious Anaemia
• Primary Anaemia