Pernicious Anemia Health Article

Diagnosis

Diagnosis of pernicious anemia is suggested when a blood test reveals abnormally large red blood cells. Many of these will also be abnormally shaped. The earliest, least mature forms of red blood cells (reticulocytes) will also be low in number. White blood cells and platelets may also be decreased in number. Measurements of the quantity of B₁₂ circulating in the bloodstream will be low.

Once these determinations are made, it will be important to diagnose the cause of the anemia. True pernicious anemia means that the parietal cells of the stomach are atrophied, resulting in decreased production of intrinsic factor. This diagnosis is made by the Schilling test. In this test, a patient is given radioactive B₁₂ under two different sets of conditions: once alone, and once attached to intrinsic factor. Normally, large amounts of B₁₂ are absorbed through the intestine, then circulate through the blood, and enter the kidneys, where a certain amount of B₁₂ is then passed out in the urine. When a patient has pernicious anemia, the dose of B₁₂ given by itself will not be absorbed by the intestine, so it will not pass into the urine. Therefore, levels of B₁₂ in the urine will be low. When the B₁₂ is given along with intrinsic factor, the intestine is able to absorb the vitamin. Urine levels of B₁₂ will therefore be higher.

Treatment

Treatment of pernicious anemia requires the administration of lifelong injections of B₁₂. Vitamin B₁₂ given by injection enters the bloodstream directly, and does not require intrinsic factor. At first, injections may need to be given several times a week, in order to build up adequate stores of the vitamin. After this, the injections can be given on a monthly basis. Other substances required for blood cell production may also need to be given, such as iron and vitamin C.

Prognosis

Prognosis is generally good for patients with pernicious anemia. Many of the symptoms improve within just a few days of beginning treatment, although some of the nervous system symptoms may take up to 18 months to improve. Occasionally, when diagnosis and treatment have been delayed for a long time, some of the nervous system symptoms may be permanent.

Because an increased risk of stomach cancer has been noted in patients with pernicious anemia, careful monitoring is necessary, even when all the symptoms of the original disorder have improved.