From the Guidelines
Pernicious anemia is an autoimmune condition where the body cannot properly absorb vitamin B12, leading to a decrease in healthy red blood cells, and requires immediate treatment with vitamin B12 replacement therapy to prevent serious neurological complications, as recommended by NICE guidelines 1. Pernicious anemia occurs when the stomach lacks intrinsic factor, a protein necessary for B12 absorption in the intestines. Without sufficient B12, the body produces abnormally large and fragile red blood cells that cannot function properly, resulting in symptoms such as fatigue, weakness, pale skin, shortness of breath, numbness or tingling in extremities, balance problems, cognitive changes, and glossitis (inflamed tongue).
- Key symptoms include:
- Fatigue and weakness
- Pale skin
- Shortness of breath
- Numbness or tingling in extremities
- Balance problems
- Cognitive changes
- Glossitis (inflamed tongue) Treatment typically involves lifelong vitamin B12 replacement therapy, usually through injections, with a common regimen including initial loading doses of hydroxocobalamin 1 mg intramuscularly on alternate days until there is no further improvement, then administer hydroxocobalamin 1 mg intramuscularly every 2 months for people with neurological involvement, as recommended by NICE guidelines 1.
- For people with no neurological involvement, the recommended treatment is hydroxocobalamin 1 mg intramuscularly three times a week for 2 weeks, followed by maintenance treatment with 1 mg intramuscularly every 2–3 months lifelong 1. Regular monitoring of B12 levels and complete blood counts is essential to ensure adequate treatment, and patients with possible neurological involvement should seek urgent specialist advice from a neurologist and haematologist 1.
From the FDA Drug Label
Pernicious anemia is associated with an increased incidence of carcinoma of the stomach, but this is believed to be related to the underlying pathology and not to treatment with cyanocobalamin. Patients with pernicious anemia should be informed that they will require monthly injections of vitamin B12 for the remainder of their lives. Pernicious anemia, both uncomplicated and accompanied by nervous system involvement.
Pernicious anemia is a condition that requires lifelong treatment with vitamin B12 injections. It is associated with an increased risk of stomach cancer, but this is thought to be related to the underlying disease process rather than the treatment itself. The condition can lead to permanent degenerative lesions of the spinal cord if left untreated or if treatment is delayed 2. Pernicious anemia can be caused by various factors, including dietary deficiency, malabsorption, and inadequate secretion of intrinsic factor 3. Key characteristics of pernicious anemia include:
- Increased risk of stomach cancer
- Requirement for lifelong vitamin B12 injections
- Potential for permanent nerve damage if left untreated
- Association with various underlying conditions, such as gastric atrophy and intestinal parasites 2 3
From the Research
Definition and Causes of Pernicious Anemia
- Pernicious anemia (PA) is an autoimmune disease characterized by the deficiency of intrinsic factor, leading to the malabsorption of vitamin B12 [(4,5,6)].
- It is the most common cause of vitamin B12 deficiency anemia worldwide 5.
- The disease is often insidious in onset and progression, and patients may not exhibit anemic symptoms until the disease has advanced 5.
Clinical Features and Diagnosis
- Pernicious anemia is characterized by severe anemia, gastrointestinal disturbances, and lesions of the spinal cord 6.
- The diagnosis of PA is based on the presence of classical immune gastritis and anti-intrinsic factor and/or antiparietal cell antibodies 4.
- Laboratory tests, such as total plasma vitamin B12, plasma homocysteine, and plasma methylmalonic acid (pMMA) concentration, can help diagnose PA 4.
- Diagnostic challenges remain due to the lack of reliable cobalamin assays and clinical mimics that simulate other hematological conditions 5.
Treatment and Management
- Oral vitamin B12 supplementation or intramuscular injections of vitamin B12 are indicated for the treatment of PA [(4,6,7)].
- A study found that oral supplementation with 1000 μg/d of cyanocobalamin improved vitamin B12 deficiency in PA 4.
- Timely diagnosis and treatment are essential to prevent misdiagnosis and ensure proper management 7.
Complications and Consequences
- Vitamin B12 deficiency can lead to a wide range of clinical symptoms, including hemolytic anemia, macrocytosis, and signs of hemolysis 7.
- If left untreated, PA can result in irreversible neurological sequelae 5.
- The consequences and severity of vitamin B12 deficiency are variable, depending on the degree and duration of the deficiency 8.