Pernicious anemia is an autoimmune disorder that causes improper absorption of vitamin B12 in your stomach. Not having enough vitamin B12 in your body can impact the process of red blood cell production, leading to the bone marrow producing unhealthy red blood cells that are too large.
Since red blood cells are responsible for carrying oxygen from your lungs to the rest of your body, not having enough healthy red blood cells will cause anemia. This may lead to serious health consequences if not treated. In addition to common anemia symptoms, such as dizziness, shortness of breath, and fatigue, some people report back pain.
Let’s take a closer look at pernicious anemia and back pain.
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Pernicious anemia is a subtype of megaloblastic macrocytic anemia, where the red blood cells are larger than normal and have an abnormal structure. Macrocytic comes from the word “macrocyte,” where “macro” means large and “cytes” means cells.
Pernicious anemia occurs when your intestines can’t absorb vitamin B12 properly. This might happen because your immune system attacks the stomach cells responsible for the secretion of a substance called intrinsic factor. This substance binds to the vitamin B12 you get from food and assists in its absorption in the small intestine.
The abnormally large and inefficient red blood cells cannot perform their functions properly and sometimes die unusually early. This will affect the oxygen transfer from your lungs to your other organs, leading you to start experiencing anemia symptoms.
The initial symptoms of pernicious anemia may be vague, making it difficult to diagnose. As the condition progresses, more symptoms manifest. These commonly include the following:¹
Swollen, smooth tongue
Pale or yellowish skin
Diarrhea or constipation
Loss of appetite
Shortness of breath when physically active
Not everyone experiences symptoms, and they can be mild in some cases. This means you may not notice signs of pernicious anemia for many years. The condition might not be diagnosed until it’s uncovered during routine blood tests.
It’s important to speak to your doctor as soon as possible if you notice the symptoms above, as early diagnosis and treatment are vital. Having an untreated vitamin B12 deficiency over a long period can result in nerve damage. Symptoms include the following:
Loss of balance
Short-term memory problems
Numbness in your hands and feet
Hallucinations and delusions
Optic nerve degeneration leading to vision issues
While back pain isn’t a common symptom of anemia, B12 deficiency may cause painful sensations or neurological pain in the body.²
A person with a balanced diet receives vitamin B12 from food, mainly from animal products. People who consume plant-based diets obtain vitamin B12 from fortified foods and supplements eaten to avoid deficiency.
When the vitamin enters the body, it is absorbed through the intestines. Before this can happen, a special protein called intrinsic factor binds to vitamin B12. Otherwise, the absorption is disturbed.
The intrinsic factor originates from the cells in your stomach. If your stomach doesn’t make enough of it, your intestines can’t absorb vitamin B12 properly. This leads to anemia.
Pernicious anemia can be caused by the following:³
Atrophic gastritis — this condition leads to the destruction of stomach lining cells and decreased production of intrinsic factors.
An autoimmune condition — you might have a condition that causes your body to attack the intrinsic factor or the cells that produce it.
Genetics — in rare cases, you can get pernicious anemia from your parents. This is called congenital pernicious anemia. The condition keeps the body from making a sufficient amount of intrinsic factors.
Some conditions can increase your risk of developing pernicious anemia. They include Addison’s disease, Graves’ disease, thyroid gland problems, loss of normal ovarian function before you turn 40, type 1 diabetes, Hashimoto’s disease, and celiac disease.
Back pain is not a typical symptom of pernicious anemia, but some people may face this problem. Most likely, the pain you experience is related to the underlying causes of your condition, other illnesses that commonly coexist with pernicious anemia, or complications of the condition.
Studies have found that people diagnosed with pernicious anemia are more likely to have other autoimmune disorders, such as type 1 diabetes, autoimmune thyroid disease, and vitiligo.⁴
You may also experience chronic back pain if you have diabetes. Hyperglycemia may cause this issue as it can lead to a cascade of chemical events that will eventually contribute to disc prolapse and the onset of mechanical back pain.⁵
Diabetes also affects the blood vessels responsible for providing nutrition to the intervertebral discs. This could potentially cause them to degenerate, resulting in back pain.
People with atrophic gastritis can experience stomach pain that radiates to the back. It’s important to share your symptoms with your doctor.⁶
People with pernicious anemia are reported to have a higher risk of developing stomach cancers later in life. Stomach cancers can cause severe abdominal pain that radiates to the lower back.⁷
If you have pernicious anemia and start experiencing gastric issues such as pain, nausea, vomiting, heartburn, indigestion, difficulty swallowing, or feeling full too quickly when eating, it is important to discuss your symptoms urgently with your doctor.
To alleviate the symptoms and prevent complications of pernicious anemia, you need to increase vitamin B12 levels in your body. For this, your doctor can prescribe the following:
Oral supplements — large daily doses of vitamin B12 supplements that you take by mouth
Shots — a shot of vitamin B12 once a month (if your vitamin B12 levels are low, you may need more than one shot during the first month)
Your doctor may change the approach to therapy depending on the results. If oral supplements don’t work, they may prescribe intramuscular shots. When shots improve your vitamin B12 levels, you may be able to switch back to oral supplements.
The earlier you start treatment, the more likely you are to avoid serious consequences. Getting treatment for pernicious anemia can help reduce lower back pain. Some studies show that vitamin B12 injections can be beneficial for treating back pain problems even in those who are not deficient in this vitamin.⁸
Pernicious anemia doesn’t usually cause back pain, but underlying issues and associated conditions or complications may do so. Getting diagnosed early is essential as it enables you to begin appropriate treatment.
If you experience symptoms of pernicious anemia and back pain, contact your doctor as soon as possible. When left untreated, this condition can lead to irreversible nerve damage.
In most cases, people respond well to pernicious anemia treatment. By diagnosing the condition on time, you can improve your quality of life faster and avoid serious health consequences.
Untreated vitamin B12 deficiency can cause subacute combined degeneration of the spinal cord. This can cause tingling, burning, and numbness in the hands and feet, but it doesn’t usually cause back pain.⁹
If left untreated, pernicious anemia can cause damage to the nervous system. This can manifest as memory loss, poor coordination, confusion, loss of balance, depression, and vision problems.
Pernicious anemia | MedlinePlus
Vitamin B12–deficiency anemia | National Heart, Lung, and Blood Institute
Pernicious anemia | MedlinePlus
Atrophic gastritis (2023)