OGD Scopy (EGD) in Anemia - A Comprehensive Guide

1. Why is OGD Needed in Anemia?

A. Blood Loss from Upper GI Tract

Cameron ulcers are particularly important: patients with large hiatal hernias and IDA should be examined in both normal and retroflexed positions during OGD to detect these lesions. - Goldman-Cecil Medicine

B. Malabsorption of Iron (Proximal GI)

"Duodenal biopsy specimens should be taken to look for evidence of celiac disease... H. pylori infection decreases iron absorption and may produce microerosions that bleed." - Goldman-Cecil Medicine

2. When is OGD an Alarm Indication in Anemia?

• Unexplained iron deficiency anemia or GI bleeding
• Age >55 years with new-onset dyspepsia + anemia
• Unintentional weight loss
• Progressive dysphagia
• Palpable abdominal mass or lymphadenopathy
• Family history of upper GI cancer

3. Investigative Algorithm in IDA - Where Does OGD Fit?

1. COLONOSCOPY first
   (designed to screen colorectal cancer - common cause of occult blood loss)
        |
        | If negative
        v
2. OGD (Upper Endoscopy) + PUSH ENTEROSCOPY
   - Inspect oesophagus, stomach, duodenum
   - Take duodenal biopsies for coeliac disease
   - Test/treat H. pylori
        |
        | If negative
        v
3. CAPSULE ENDOSCOPY
   (small bowel - angiectasias, tumours, Meckel's)
        |
        | If negative
        v
4. Non-GI causes (menorrhagia, haemolysis, IRIDA, etc.)

"GI evaluation of iron deficiency anemia is indicated in adult men, regardless of age, and postmenopausal women. Colonoscopy should be performed first, followed by upper endoscopy and push enteroscopy if colonoscopy is negative." - Goldman-Cecil Medicine

4. What OGD Can Diagnose in Anemia

5. Special Situations

• NSAIDs / Aspirin users with IDA: Upper GI complications (erosive gastritis, peptic ulcer) must be suspected and investigated by OGD.
• Refractory IDA in children: H. pylori testing during upper endoscopy is specifically indicated (Red Book, American Academy of Pediatrics).
• Post-gastrectomy / bariatric surgery: Reduced acid and bypass of the duodenum causes iron malabsorption - OGD evaluates anastomotic ulcers and the remnant.
• Pernicious anaemia (B12 deficiency): OGD can confirm atrophic gastritis (autoimmune), which also predisposes to gastric cancer surveillance.

6. What OGD Does That Other Tests Cannot

• Direct visualisation and localisation of bleeding sites
• Biopsy for histology (H. pylori, coeliac, gastric cancer, autoimmune gastritis)
• Therapeutic intervention in the same session - injection, clipping, banding of varices, argon plasma coagulation for angiodysplasia
• Detection of Cameron ulcers that are invisible on CT or barium studies
• Duodenal aspirate for giardiasis (another malabsorption cause)

7. Recent Evidence (2024-2026)

• A 2024 systematic review (PMID: 38227849) confirms that when OGD + colonoscopy are both negative in IDA, capsule endoscopy has a significant diagnostic yield for small bowel pathology.
• A 2026 meta-analysis (PMID: 41784434) found a high prevalence of non-malignant GI disease (peptic ulcers, gastritis, coeliac disease) in IDA patients - underlining that endoscopy reveals treatable pathology in the majority.
• Faecal immunochemical tests (FIT) can help triage for colonoscopy, but do not replace OGD for upper GI evaluation.

Summary

1. The upper GI tract is a leading source of occult chronic blood loss causing IDA
2. The duodenum is the primary site of iron absorption - diseases here cause IDA without any bleeding
3. Alarm features (older age, weight loss, dysphagia) demand cancer exclusion
4. OGD allows biopsy and simultaneous treatment in a single procedure
5. A negative OGD does not end the investigation - it guides the next step (capsule endoscopy or non-GI workup)