Pernicious anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are many types of anemia.
Anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Different type...
Read Article Now Book Mark ArticlePernicious anemia is a decrease in red blood cells that occurs when the intestines cannot properly absorb vitamin B12.
Causes
Anemia - Animation
Do you feel tired and listless? Do you find your mind drifting during the day? Do you get dizzy or short of breath whenever you climb the stairs? There are a few possible reasons for the way you feel, but you could have anemia. You could even have anemia without noticing any symptoms at all. Anemia is a problem with hemoglobin, a substance in red blood cells that carries oxygen throughout your body. Without enough hemoglobin, your heart and other organs can't get the oxygen they need to work. When your organs slow down, you slow down and you start feeling tired and listless. Many different health conditions can cause anemia, from heavy blood loss during a woman's period, to pregnancy, to an underactive thyroid gland. Healthy red blood cells are made in your bone marrow, the soft tissue in the middle of your bones. Any disease that damages blood marrow, such as lymphoma or leukemia, can also affect your red blood cell production. Anemia can also be caused by an immune system problem that damages red blood cells, or surgery to the stomach or intestines. How do you know if you have anemia? You may feel tired, dizzy, and have trouble concentrating. You may get sick more often. People with anemia often complain of chest pain, headaches, or shortness of breath. Your skin might look pale, like you haven't seen the sun for months. Because these can also be symptoms of other conditions, your doctor will confirm that you have anemia by taking a blood test to check your red blood cell count and hemoglobin level. Blood tests can also look for problems that may be causing your anemia, such as a vitamin or iron deficiency. If you are anemic, it's very important to treat it. When your body isn't getting enough oxygen, it can starve vital organs like your heart. This can lead to a heart attack. How you treat anemia really depends on the cause. If the problem is with your bone marrow, you may take a medicine called erythropoietin, which will help your bone marrow make more red blood cells. If the problem is a vitamin or mineral deficiency, your doctor may prescribe iron, vitamin B12, or folic acid supplements. Or, you may need a blood transfusion to replace damaged red blood cells with healthy ones. How well you do really depends on what's causing your anemia. Call your doctor if you have any symptoms like fatigue or shortness of breath. Once your doctor can find and treat the cause of your anemia, you should have more energy and start feeling like your old self again.
Pernicious anemia is a type of vitamin B12 anemia. The body needs vitamin B12 to make red blood cells. You get this vitamin from eating foods such as meat, poultry, shellfish, eggs, and dairy products.
A special protein, called intrinsic factor (IF), binds vitamin B12 so that it can be absorbed in the intestines. This protein is released by cells in the stomach. When the stomach does not make enough intrinsic factor, the intestine cannot properly absorb vitamin B12.
Common causes of pernicious anemia include:
- Weakened stomach lining (atrophic gastritis)
- An autoimmune condition in which the body's immune system attacks the actual intrinsic factor protein or the cells in the lining of your stomach that make it.
In rare cases, pernicious anemia is passed down through families. This is called congenital pernicious anemia. Babies with this type of anemia do not make enough intrinsic factor. Or they cannot properly absorb vitamin B12 in the small intestine.
In adults, symptoms of pernicious anemia are usually not seen until after age 30. The average age of diagnosis is age 60.
You are more likely to develop this disease if you:
- Are Scandinavian or Northern European
- Have a family history of the condition
Certain diseases can also raise your risk. They include:
- Addison disease
Addison disease
Addison disease is a disorder that causes the adrenal glands to not produce enough hormones.
Read Article Now Book Mark Article - Graves disease
Graves disease
Graves disease is an autoimmune disorder that leads to an overactive thyroid gland (hyperthyroidism). An autoimmune disorder is a condition that occ...
Read Article Now Book Mark Article - Hypoparathyroidism
Hypoparathyroidism
Hypoparathyroidism is a disorder in which the parathyroid glands in the neck do not produce enough parathyroid hormone (PTH).
Read Article Now Book Mark Article - Hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. This condition is often called underactive thyroid....
Read Article Now Book Mark Article - Myasthenia gravis
Myasthenia gravis
Myasthenia gravis is a neuromuscular disorder. Neuromuscular disorders involve the muscles and the nerves that control them.
Read Article Now Book Mark Article - Loss of normal function of ovaries before 40 years of age (primary ovarian failure)
- Type 1 diabetes
Type 1 diabetes
Type 1 diabetes is a lifelong (chronic) disease in which there is a high level of sugar (glucose) in the blood.
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- Vitiligo
Vitiligo
Vitiligo is a skin condition in which there is a loss of color (pigment) from areas of skin. This results in uneven white patches that have no pigme...
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Sjögren syndrome
Sjögren syndrome is an autoimmune disorder in which the glands that produce tears and saliva are destroyed. This causes dry mouth and dry eyes. The...
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Hashimoto disease
Chronic thyroiditis is caused by a reaction of the immune system against the thyroid gland. It often results in reduced thyroid function (hypothyroi...
Read Article Now Book Mark Article - Celiac disease
Celiac disease
Celiac disease is an autoimmune condition that damages the lining of the small intestine. This damage comes from a reaction to eating gluten. This ...
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Pernicious anemia can also occur after gastric bypass surgery.
Symptoms
Some people do not have symptoms. Symptoms may be mild.
They may include:
- Diarrhea or constipation
- Nausea
- Vomiting
- Fatigue, lack of energy, or lightheadedness when standing up or with exertion
Fatigue
Fatigue is a feeling of weariness, tiredness, or lack of energy.
Read Article Now Book Mark Article - Loss of appetite
Loss of appetite
A decreased appetite is when your desire to eat is reduced. The medical term for a loss of appetite is anorexia.
Read Article Now Book Mark Article - Pale skin (mild jaundice)
- Shortness of breath, mostly during exercise
Shortness of breath
Breathing difficulty may involve:Difficult breathing Uncomfortable breathingFeeling like you are not getting enough air
Read Article Now Book Mark Article - Heartburn
- Swollen, red tongue or bleeding gums
If you have a low vitamin B12 level for a long time, you can have nervous system damage. Symptoms may include:
- Confusion
Confusion
Confusion is the inability to think as clearly or quickly as you normally do. You may feel disoriented and have difficulty paying attention, remembe...
Read Article Now Book Mark Article - Short-term memory loss
- Depression
Depression
Depression may be described as feeling sad, blue, unhappy, miserable, or down in the dumps. Most of us feel this way at one time or another for shor...
Read Article Now Book Mark Article - Loss of balance
- Numbness and tingling in the hands and feet
- Problems concentrating
- Irritability
- Hallucinations
Hallucinations
Hallucinations involve sensing things such as visions, sounds, or smells that seem real but are not. These things are created by the mind.
Read Article Now Book Mark Article - Delusions
- Optic nerve atrophy
Optic nerve atrophy
Optic nerve atrophy is damage to the optic nerve. The optic nerve carries images of what the eye sees to the brain.
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Exams and Tests
Your health care provider will perform a physical exam. Tests that may be done include:
- Complete blood count (CBC)
Complete blood count (CBC)
A complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...
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Reticulocyte count
Reticulocytes are slightly immature red blood cells. A reticulocyte count is a blood test that measures the amount of these cells in the blood....
Read Article Now Book Mark Article - Lactate dehydrogenase (LDH) level
Lactate dehydrogenase (LDH)
Lactate dehydrogenase (LDH) is a protein that helps produce energy in the body. An LDH test measures the amount of LDH in the blood.
Read Article Now Book Mark Article - Serum bilirubin
Serum bilirubin
The bilirubin blood test measures the level of bilirubin in the blood. Bilirubin is a yellowish pigment found in bile, a fluid made by the liver. Bi...
Read Article Now Book Mark Article - Serum methylmalonic acid (MMA) level
Serum methylmalonic acid (MMA
The methylmalonic acid blood test measures the amount of methylmalonic acid in the blood.
Read Article Now Book Mark Article - Homocysteine level (amino acid found in blood)
Homocysteine level (amino acid found in...
Homocystinuria is a genetic disorder that affects the metabolism of the amino acid methionine. Amino acids are the building blocks of all proteins i...
Read Article Now Book Mark Article - Serum vitamin B12 level
Serum vitamin B12 level
The vitamin B12 level is a blood test that measures how much vitamin B12 is in your blood.
Read Article Now Book Mark Article - Levels of antibodies against IF or the cells that make IF
Treatment
The goal of treatment is to increase your vitamin B12 level:
- Treatment involves a shot of vitamin B12 once a month. People with severely low levels of B12 may need more shots in the beginning.
- Some people may be adequately treated by taking large doses of vitamin B12 supplements by mouth.
- A certain type of vitamin B12 may be given through the nose.
Outlook (Prognosis)
Most people often do well with treatment.
It is important to start treatment early. Nerve damage can be permanent if treatment does not start within 6 months of symptoms.
Possible Complications
People with pernicious anemia may have gastric polyps. They are also more likely to develop gastric cancer and gastric carcinoid tumors.
Gastric cancer
Stomach cancer is cancer that starts in the stomach.
Read Article Now Book Mark ArticlePeople with pernicious anemia are more likely to have fractures of the back, upper leg, and upper forearm.
Brain and nervous system problems may continue or be permanent if treatment is delayed.
A woman with a low B12 level may have a false positive Pap smear. This is because vitamin B12 deficiency affects the way certain cells (epithelial cells) in the cervix look.
When to Contact a Medical Professional
Contact your provider if you have symptoms of vitamin B12 deficiency.
Prevention
There is no known way to prevent this type of vitamin B12 anemia. However, early detection and treatment can help reduce complications.
Reviewed By
Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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Anusha V. Pernicious anemia/megaloblastic anemia. In: Kellerman RD, Rakel DP, Heidelbaugh JJ, Lee EM, eds. Conn's Current Therapy 2024. Philadelphia, PA: Elsevier; 2024:491-493.
Elghetany MT, Banki K. Erythrocytic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 33.
Means Jr. RT. Approach to the anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 144.
Stabler SP. Megaloblastic anemias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 150.