Pernicious anemia is a rare chronic type of anemia characterized by the body’s inability to produce healthy red blood cells due to the lack of vitamin B12. It is usually caused by the lack of Intrinsic Factor that is produced by the cells in the stomach’s lining which is essential in absorbing vitamin B12 from food through the intestines.
The symptoms of pernicious anemia are insidious, slow, and steady and they develop over many years. Most of these symptoms can be linked to other conditions which makes it more difficult to diagnose the disease.
Pernicious anemia is diagnosed through a thorough clinical evaluation of the patient which includes a physical examination, a detailed patient history based on the patient’s family and medical histories, and specialized laboratory tests.
In diagnosing pernicious anemia, the doctor also checks for the primary cause of the disease. The doctor wants to know whether the disease is caused by the lack of Intrinsic Factor or it is caused by something else. He/she also wants to know how severe the condition is to be able to give the proper treatment needed by the patient.
Family and Medical Histories
The doctor usually asks about the symptoms that the patient is experiencing. The doctor also asks about the following:
- The diet and the medicines being taken
- History of intestinal or stomach surgeries
- History of digestive disorders like Crohn’s disease or celiac disease
- Family history of pernicious anemia or other types of anemia
- Family history of autoimmune endocrine disorders such as type 1 diabetes, Addison’s disease, vitiligo, or Graves’ disease
The doctor does a physical test for possible symptoms of pernicious anemia. The doctor may look for the following signs of pernicious anemia:
- yellowish or pale skin
- enlarged liver
- irregular or rapid heartbeats or heart murmur
- signs of damage to the nerves
The doctor wants to see how well the patient’s senses, muscles, reflexes, and eyes work. He/she may also ask questions or perform tests to check for coordination, walking ability, and mental status.
Complete Blood Count
A CBC or complete blood count is normally the first test to diagnose most types of anemia. The CBC checks the hematocrit and hemoglobin levels. A low level of hematocrit or hemoglobin is a sign that an individual has anemia.
CBC checks the number of platelets, red blood cells, and white blood cells in the blood. Unusual results can be a sign of anemia, an infection, other blood disorders, or another problem or condition.
CBC also looks at MCV or mean corpuscular volume which measures the average size of red blood cells. MCV can serve as a clue to what’s causing anemia. Red blood cells are usually larger than usual in pernicious anemia.
- Vitamin B12 deficiency test: A blood test can help the doctor assess the vitamin B12 levels of a patient. Low levels of vitamin B12 indicate a deficiency.
- Intrinsic Factor deficiency test: A blood sample is needed in order to test Intrinsic Factor deficiency. The blood is tested to check for antibodies that are against Intrinsic Factor and the stomach’s cells.
- Reticulocyte count: This test counts the number of new red blood cells present in the blood. This test shows whether the bone marrow produces red blood cells at the proper or correct rate. Reticulocyte counts are usually low for individuals with pernicious anemia.
- Iron, iron-binding capacity, and serum folate tests: These tests can help detect if an individual has pernicious anemia or other types of anemia. Some patients with vitamin B12 deficiency can have a coexisting folate deficiency which can cause the same blood changes.
If Intrinsic Factor antibodies are not present after doing a blood test, a Schilling Test is performed. This test measures the intestine’s ability to absorb vitamin B12. The patient is asked to take oral doses of vitamin B12 labeled with radioactive cobalt with and without an active Intrinsic Factor preparation. This test shows the distinction between stomach problems and intestinal causes. Intrinsic Factor corrects the absorption of vitamin B12 in pernicious anemia and other stomach lesions but it does not do the same for intestinal disorders. X-ray studies can determine if the body is properly absorbing vitamin B12.
Bone Marrow Tests
The doctor may recommend bone marrow biopsy or aspiration if he/she suspects bone marrow disorders. These tests can show if the bone marrow is producing the right amount of red blood cells and is healthy.
In bone marrow biopsy, the doctor extracts a little amount of bone marrow tissue using a larger needle. In bone marrow aspiration, the doctor extracts a little amount of fluid bone marrow by using a needle. The samples are microscopically examined.
The bone marrow cells that develop into blood cells are usually larger than the normal in pernicious anemia.
The doctor may also want to know if there has been any damage to the stomach walls which can be done through biopsy. A sample of the stomach’s cells is removed and examined under a microscope to check for any damage.
Gastroscopy is done to check for possible cancers in the stomach especially for patients who have symptoms such as pain and bleeding from the bowel and unexplained weight loss after treatment.