From the Guidelines
Pernicious anemia should be treated immediately with hydroxocobalamin 1 mg intramuscularly, with the treatment regimen depending on the presence of neurological involvement, as recommended by the British Obesity and Metabolic Surgery Society guidelines 1. The diagnosis of pernicious anemia is based on the presence of vitamin B12 deficiency, which can be caused by a lack of intrinsic factor, a protein produced by stomach cells.
Key Considerations
- The treatment of vitamin B12 deficiency requires immediate attention, especially in cases with possible neurological involvement, such as unexplained sensory and/or motor and gait symptoms 1.
- Hydroxocobalamin 1 mg intramuscularly should be administered on alternate days until there is no further improvement, then hydroxocobalamin 1 mg intramuscularly administered every 2 months for patients with neurological involvement 1.
- For patients with no neurological involvement, hydroxocobalamin 1 mg intramuscularly should be administered three times a week for 2 weeks, followed by maintenance treatment with 1 mg intramuscularly every 2–3 months for life 1.
- It is essential to seek urgent specialist advice from a neurologist and haematologist if there is possible neurological involvement 1.
Treatment Regimen
- The treatment regimen for pernicious anemia includes:
- Initial treatment with hydroxocobalamin 1 mg intramuscularly, with the frequency and duration depending on the presence of neurological involvement 1.
- Maintenance treatment with 1 mg intramuscularly every 2–3 months for life 1.
- Regular monitoring of B12 levels, complete blood counts, and neurological symptoms is essential to ensure the effectiveness of the treatment and to prevent long-term complications 1.
Important Considerations
- Folic acid deficiency may indicate non-adherence with the daily multivitamin and mineral supplement or malabsorption, and treatment with oral folic acid 5 mg daily should be given for a minimum of 4 months after excluding vitamin B12 deficiency 1.
- Patients with pernicious anemia should also be monitored for other autoimmune conditions and stomach cancer, which occur at higher rates in those with pernicious anemia.
From the FDA Drug Label
Pernicious Anemia Parenteral vitamin B12 is the recommended treatment and will be required for the remainder of the patient's life. A dose of 100 mcg daily for 6 or 7 days should be administered by intramuscular or deep subcutaneous injection. If there is clinical improvement and if a reticulocyte response is observed, the same amount may be given on alternate days for seven doses, then every 3 to 4 days for another 2 to 3 weeks. By this time hematologic values should have become normal This regimen should be followed by 100 mcg monthly for life. Folic acid should be administered concomitantly if needed.
The diagnosis of pernicious (vitamin B12 deficiency) anemia is typically made through laboratory tests, including:
- Hematocrit
- Reticulocyte count
- Vitamin B12 levels
- Folate levels
- Iron levels The treatment for pernicious anemia is parenteral vitamin B12, which is required for the remainder of the patient's life. The recommended dosage is:
- 100 mcg daily for 6 or 7 days, followed by
- 100 mcg on alternate days for seven doses, then
- 100 mcg every 3 to 4 days for another 2 to 3 weeks, and finally
- 100 mcg monthly for life. Folic acid should be administered concomitantly if needed 2. It is essential to note that folic acid may mask the symptoms of vitamin B12 deficiency, but it will not prevent the progression of subacute combined degeneration 2.
From the Research
Diagnosis of Pernicious Anemia
- Pernicious anemia is an autoimmune disease characterized by autoimmune chronic atrophic gastritis (CAG) and cobalamin deficiency (CD) 3
- The diagnosis of pernicious anemia is based on the presence of classical immune gastritis and of anti-intrinsic factor and/or antiparietal cell antibodies 4
- Diagnostic challenges remain tangible for many practicing clinicians, since there is a lack of reliable cobalamin assays to diagnose CD as well as clinical mimics, which simulate many other hematological conditions 3
Treatment of Pernicious Anemia
- Traditionally, intramuscular vitamin B12 injections were the standard treatment, bypassing the impaired absorption 4
- Oral vitamin B12 supplementation at 1000 μg daily has been shown to be an effective alternative to vitamin B12 IM injections 4, 5
- Oral supplementation with 1000 μg/d of cyanocobalamin has been shown to improve vitamin B12 deficiency in pernicious anemia, with significant improvement of plasma vitamin B12, plasma homocysteine, and plasma methylmalonic acid (pMMA) concentrations 4
- Treatment is based on the administration of parenteral vitamin B12, although other routes of administration (eg, oral) are currently under study 6
Management and Monitoring
- Patients should be offered oral vitamin B12 supplementation as an alternative to vitamin B12 IM injections after an informed discussion on the advantages and disadvantages of both treatment options 5
- Clinical and biological vitamin B12 deficiency related features should be prospectively and systematically assessed over the study duration 4
- The median time to reverse initial vitamin B12 deficiency abnormalities ranged from 1 mo for hemolysis to 4 mo for mucosal symptoms 4