💊 Oral vs Intramuscular B12 Replacement Simulator

Finding the Root Cause of B12 Deficiency

Placeholder: different causes need different replacement strategies.

• ~30%: Metformin users (placeholder low B12 risk)
• ~10-30%: PPI long-term use (placeholder reduced absorption)
• IF loss: Pernicious anemia (placeholder autoimmune cause)
• Direct loss: Ileal resection (placeholder absorption site removed)

Common causes overview

Placeholder: metformin, PPIs, pernicious anemia, and ileal disease each reduce B12 differently.

Scoring Malabsorption Severity

Placeholder: severity score guides route choice.

• 0-3: Mild severity (placeholder oral usually fine)
• 4-6: Moderate severity (placeholder oral with monitoring)
• 7-10: Severe severity (placeholder IM preferred)
• ~8-12 wk: Reassessment (placeholder recheck levels)

Severity scoring basis

Placeholder: labs, symptoms, and cause combine into a severity score.

High-Dose Oral Cyanocobalamin — Passive Diffusion Route

Placeholder: high doses push enough B12 through passive diffusion.

• ~1%: Passive diffusion (placeholder of oral dose absorbed)
• 1000-2000 mcg: Typical dose (placeholder daily oral dose)
• Yes: IF-independent (placeholder bypasses IF gate)
• Mild-moderate: Best for (placeholder severity cases)

Oral pathway mechanism

Placeholder: high concentration gradient drives passive gut absorption.

Intramuscular Injection — Direct Reservoir Filling

Placeholder: IM injection bypasses gut entirely and fills the bloodstream.

• ~100%: Bioavailability (placeholder injected dose)
• 1mg IM: Typical schedule (placeholder loading then monthly)
• Severe cases: Best for (placeholder or neuro symptoms)
• High: Reliability (placeholder independent of gut)

IM pathway mechanism

Placeholder: injection deposits B12 directly into muscle then blood.

Choosing a Maintenance Therapy Route

Placeholder: maintenance route depends on response and cause reversibility.

• Oral ok: Reversible cause (placeholder e.g. metformin/PPI)
• IM ok: Irreversible cause (placeholder e.g. pernicious anemia)
• 3-6 mo: Monitoring interval (placeholder recheck levels)
• No response: Switch trigger (placeholder escalate to IM)

Maintenance decision summary

Placeholder: match maintenance route to severity trend and cause.

Placeholder: reassess route if levels fail to normalize.