Neurological Vitamin B12 Deficiency: When Lifelong Intramuscular Replacement Has Not Achieved Its Targets

This protocol applies when neurological manifestations of vitamin B12 deficiency persist or remain unresolved despite initial lifelong intramuscular vitamin B12 replacement — specifically in patients with malabsorption due to autoimmune gastritis, total gastrectomy, or complete terminal ileal resection.

Clinical Scenario

The relevant population includes patients with vitamin B12 deficiency where the underlying cause is autoimmune gastritis (confirmed or suspected), a history of total gastrectomy, or a history of complete terminal ileal resection. These conditions permanently impair the ability to absorb vitamin B12 through normal gastrointestinal mechanisms, making this population dependent on parenteral replacement.

Previous Treatment & Failure Condition

The first-line approach for this population is lifelong intramuscular vitamin B12 replacement. The goals of that line are symptom improvement — expected within 2 weeks to up to 3 months — and adequate increase in vitamin B12 concentrations. When those goals are not sufficiently met, escalation to the next step is indicated.

Next-Line Approach (Partial Overview)

The next step involves a specific adjustment to the intramuscular replacement regimen based on clinical response. The complete protocol — including the criteria that guide this adjustment and how they align with product guidance — is available via the link below.

Instant Access to Structured Evidence-Based Regimens

References

Offer lifelong intramuscular vitamin B12 replacement to people if: autoimmune gastritis is the cause, or suspected cause, of vitamin B12 deficiency or they have had a total gastrectomy, or a complete terminal ileal resection.
Increase the frequency of injections if needed, in line with the summary of product characteristics and

View source ↗