Autoimmune Trigger Onset
Genetic and environmental factors break self-tolerance in the stomach.
- HLA-DR3/4: Genetic Link (placeholder association)
- ~2:1: Female Bias (placeholder ratio)
- >60 yrs: Peak Onset (placeholder age range)
- Thyroiditis: Comorbidity (placeholder overlap)
Loss of self-tolerance
Placeholder: regulatory T-cells fail to suppress autoreactive clones.
Placeholder key insight about tolerance breakdown triggers.
Genetic susceptibility
Placeholder: HLA haplotypes raise autoimmune gastritis risk.
Associated conditions
Placeholder: often co-occurs with other autoimmune endocrine disease.
Parietal Cell Destruction
Cytotoxic T-cells and autoantibodies destroy acid- and IF-producing cells.
- H+/K+ ATPase: Target Antigen (placeholder pump)
- Progressive: Cell Loss (placeholder course)
- CD4+/CD8+: Infiltrate (placeholder lymphocytes)
- Corpus/Fundus: Gland Zone (placeholder location)
Parietal cell antigen target
Placeholder: proton pump autoantigen drives cytotoxic attack.
Placeholder key insight about parietal cell loss mechanism.
Lymphocytic infiltration
Placeholder: gastric mucosa shows dense chronic inflammatory infiltrate.
Progressive cell loss
Placeholder: destruction accumulates silently over years.
Anti-Intrinsic Factor Antibodies
Blocking and binding antibodies neutralize remaining intrinsic factor.
- Blocking IgG: Antibody Type (placeholder class)
- ~50%: Sensitivity (placeholder detection)
- ~95%: Specificity (placeholder detection)
- B12 pocket: Binding Site (placeholder target)
Blocking antibodies
Placeholder: antibodies occupy the B12-binding site of IF.
Placeholder key insight about antibody-mediated IF blockade.
Binding antibodies
Placeholder: a second antibody type prevents ileal receptor binding.
Diagnostic relevance
Placeholder: anti-IF antibodies are a specific diagnostic marker.
Achlorhydria & Gastric Atrophy
The gastric mucosa thins and both acid and IF secretion collapse.
- Near zero: Acid Output (placeholder achlorhydria)
- Elevated: Gastrin Level (placeholder feedback)
- Atrophic: Mucosa (placeholder histology)
- Increased: Cancer Risk (placeholder association)
Achlorhydria
Placeholder: absent acid secretion impairs digestion broadly.
Placeholder key insight about atrophic gastritis progression.
Gastrin feedback loop
Placeholder: low acid drives compensatory hypergastrinemia.
Long-term consequences
Placeholder: chronic atrophy raises gastric neoplasia risk.
B12 Malabsorption & Anemia
Without intrinsic factor, B12 cannot be absorbed and anemia develops.
- Years: B12 Stores (placeholder depletion time)
- Megaloblastic: RBC Type (placeholder morphology)
- Possible: Neuro Signs (placeholder symptom)
- B12 injection: Treatment (placeholder therapy)
B12 absorption pathway
Placeholder: IF-B12 complex is required for ileal uptake.
Placeholder key insight about anemia onset timeline.
Megaloblastic changes
Placeholder: impaired DNA synthesis enlarges red cell precursors.
Clinical management
Placeholder: lifelong B12 replacement bypasses the defect.