Symptoms and Complications

In most cases, there are no early signs of pernicious anemia. As the disorder progresses, there may be shortness of breath and less endurance during exercise. A rapid noticeable heartbeat may also be evident. People with pernicious anemia often have very low hemoglobin but few symptoms of low hemoglobin, such as fatigue. Because the hemoglobin has decreased slowly over time, the person's body has gotten used to it. In contrast, with iron deficiency anemia, the hemoglobin level drops more quickly and people are more likely to notice symptoms of low hemoglobin. Other symptoms that may develop include:

• pale skin
• a sore tongue
• poor appetite and loss of weight
• tingling and numbness of hands and feet
• disturbed walking gait and balance (especially in the dark)
• mental changes, including memory loss, irritability, mild depression, and dementia
• yellow-blue color blindness

If left untreated, the lack of vitamin B12 may gradually affect the sensory and motor nerves and cause neurological effects. The anemia can also affect the gastrointestinal system and cardiovascular systems, result in tongue problems, impair the sense of smell, and cause bleeding gums and the loss of deep tendon reflexes. In very advanced cases, paranoia, delirium, and confusion may also occur.

Pernicious anemia is a chronic disease that progresses slowly and steadily. In the past, before much was known about the disease and there was no treatment, it would eventually cause death after many years of suffering. Today, the prognosis is excellent. Replacement therapy with adequate amounts of vitamin B12 will correct the deficiency and allow a person to lead a normal life.

If the condition progresses for a long time before it's detected, it may damage certain parts of the body, primarily the nervous and digestive systems. Gastric polyps may develop, which leads to a greater chance of developing gastric cancer. Vitamin B12 deficiency will affect the appearance of epithelial cells on the cervix, and an untreated woman may get a false positive result on a Pap test.

Making the Diagnosis

The basic symptoms will probably lead a doctor to perform various tests for anemia. One of these tests will measure the amount of vitamin B12 in the blood. The blood will be examined under a microscope to assess the size and shape of the red blood cells. In cases of pernicious anemia, these cells will be larger and there will be fewer of them.

A bone marrow test may also be done. A sample of the bone marrow will be examined to determine whether antibodies to intrinsic factor are present. This is an indirect way to tell whether intrinsic factor itself is present.

A doctor may order a Schilling test to see whether the vitamin B12 deficiency is due to a lack of intrinsic factor, or whether there's a failure to absorb the vitamin for some other reason. The test measures the amount of vitamin B12 excreted in the urine after ingestion of a dose of vitamin B12. A one-stage Schilling test (without intrinsic factor) or a two-stage Schilling test (with intrinsic factor) may be used. A second test will be conducted about one week after the first stage if the two-stage Schilling test is given. A third Schilling test may be performed after a course of antibiotics if overgrowth of intestinal bacteria is suspected as the cause of inadequate vitamin B12 absorption.

The Schilling test requires that urine samples be supplied over a 24-hour period, and certain drugs that may interfere with the test may have to be discontinued for the duration.

People with pernicious anemia have an increased incidence of stomach cancer. The doctor will need to follow up on any clinical findings (e.g., symptoms, positive test for traces of blood in the stool) that suggest a problem with the digestive system, and further tests such as X-rays may be ordered or endoscopy (inspecting the inside of the body with a small viewer on a flexible tube) may be necessary.

Treatment and Prevention

The amount of B12 stored in the body is directly related to the amount that is taken in. The main treatment for pernicious anemia is injections of vitamin B12. Calculating the required amount of vitamin B12 needed can be difficult, because it must also replace the B12 stored in the liver.

At first there may be five to seven injections in a short span of time. This therapy usually makes a difference within 48 hours to 72 hours, so there shouldn't be any need for a blood transfusion. Eventually, injections can be given once a month and will probably continue indefinitely. Recently it has been found that vitamin B12 can be given by mouth in very large doses (0.5 mg to 2 mg per day) for maintenance treatment, making injections unnecessary.

Pernicious anemia cannot be treated without the help of a doctor. However, a well-balanced diet is essential to provide other components for healthy blood cell development, such as folic acid, iron, and vitamin C.

Vitamin B12 therapy must be maintained for life unless the underlying cause of the deficiency is corrected.

The key to prevention is in finding out if you have a family history of pernicious anemia. It's possible to prevent this condition if you know that you have a relative with the illness, which allows you to work with a doctor to develop a plan for early detection. In this case, your doctor can test your blood every few years without waiting for symptoms to appear. Also, people with other types of anemia (such as macrocytic anemia and folic acid deficiency) should be tested for vitamin B12 deficiency.