Pernicious Anemia

• Pernicious Anemia is an autoimmune disease causing vitamin B12 deficiency due to a lack of intrinsic factor.
• Common symptoms include fatigue, weakness, neurological issues, and digestive problems.
• The primary cause is the immune system attacking stomach cells responsible for intrinsic factor production.
• Diagnosis involves blood tests to check B12 levels and specific antibodies.
• Treatment typically involves lifelong vitamin B12 injections to manage the deficiency.

What is Pernicious Anemia?

Pernicious Anemia is a type of vitamin B12 deficiency anemia that occurs when the body cannot make enough healthy red blood cells because it lacks vitamin B12. This deficiency is primarily due to the absence of intrinsic factor, a protein produced by the stomach lining that is necessary for the absorption of vitamin B12 in the small intestine. It is considered an autoimmune disease, meaning the body’s immune system mistakenly attacks its own healthy cells, in this case, the parietal cells in the stomach that produce intrinsic factor.

The condition can affect individuals of any age, though it is more commonly diagnosed in older adults. According to the National Institutes of Health, pernicious anemia affects approximately 0.1% of the general population and 1% of individuals over 60, highlighting its prevalence in the elderly demographic. Without sufficient vitamin B12, the body cannot produce enough healthy red blood cells, leading to anemia, and can also result in neurological damage.

Pernicious Anemia: Symptoms and Causes

Understanding pernicious anemia symptoms causes is crucial for early detection and management. The symptoms often develop gradually and can be subtle at first, making diagnosis challenging. They arise from both the anemia itself and the neurological impact of vitamin B12 deficiency.

Common symptoms include:

• Fatigue and weakness
• Pale or yellowish skin
• Shortness of breath and dizziness
• Numbness or tingling in the hands and feet (peripheral neuropathy)
• Difficulty walking and balance problems
• Memory loss, confusion, or other cognitive impairments
• Sore, red tongue (glossitis)
• Gastrointestinal issues like nausea, vomiting, diarrhea, or constipation

The primary cause of pernicious anemia is an autoimmune reaction where the immune system attacks the parietal cells of the stomach, which are responsible for producing intrinsic factor. Without intrinsic factor, dietary vitamin B12 cannot be absorbed. Less common causes include gastric surgery (such as gastrectomy or bariatric surgery), which can remove the parts of the stomach that produce intrinsic factor, and certain rare genetic disorders that affect B12 absorption.

Diagnosis and Treatment Options for Pernicious Anemia

Accurate and timely diagnosis is vital to prevent irreversible complications associated with vitamin B12 deficiency. The diagnostic process typically involves a combination of medical history, physical examination, and specific laboratory tests.

How to Diagnose Pernicious Anemia

Diagnosing pernicious anemia involves several blood tests. A complete blood count (CBC) will often show large, immature red blood cells (macrocytic anemia). Key diagnostic tests include measuring serum vitamin B12 levels, which will be low. Additionally, tests for specific antibodies, such as anti-intrinsic factor antibodies and anti-parietal cell antibodies, can confirm the autoimmune nature of the condition. These antibodies indicate that the immune system is attacking the cells necessary for B12 absorption. In some cases, a bone marrow biopsy may be performed, though it is less common now with the availability of specific antibody tests.

Once diagnosed, pernicious anemia treatment options primarily focus on replenishing vitamin B12 levels and managing the deficiency for life. Since the body cannot absorb B12 through the digestive system in these patients, oral supplements are ineffective. The standard treatment involves regular vitamin B12 injections, typically administered intramuscularly. Initially, injections may be given frequently (e.g., daily or weekly) to correct the deficiency, followed by maintenance doses, usually once a month, for the rest of the patient’s life. This lifelong treatment helps to alleviate symptoms, prevent further neurological damage, and ensure the body has sufficient B12 for red blood cell production and overall health. Regular monitoring of B12 levels and symptom assessment are part of ongoing care.