What is the appropriate management for a patient with iron deficiency anemia due to gastrointestinal bleeding?

Management of Iron Deficiency Anemia with Gastrointestinal Bleeding

This patient requires immediate initiation of oral iron supplementation AND urgent bidirectional endoscopy (both upper endoscopy with small bowel biopsies and colonoscopy) to identify the bleeding source, as the laboratory findings confirm severe iron deficiency anemia (ferritin 7.8, iron saturation 5%) with overt GI blood loss. 1, 2

Immediate Iron Replacement Therapy

• Start oral iron supplementation immediately without waiting for endoscopic evaluation, using 100-200 mg of elemental iron daily (equivalent to 324 mg ferrous sulfate tablets providing 65 mg elemental iron, taken 1-3 times daily). 1, 3, 4
• Continue iron therapy for three months after hemoglobin normalization to fully replenish iron stores. 1, 2
• If oral iron causes intolerable side effects (nausea, constipation, diarrhea) or proves ineffective, switch to intravenous iron therapy. 3, 4

Urgent Gastrointestinal Evaluation

Upper Endoscopy (First Priority)

• Perform upper GI endoscopy with mandatory small bowel biopsies even if the mucosa appears normal, as 2-3% of iron deficiency anemia patients have celiac disease as a non-bleeding cause. 1, 5
• Upper endoscopy identifies a bleeding source in 30-50% of cases, with common findings including peptic ulcers, gastric erosions, angiodysplasia, and malignancy. 1, 5
• Obtain serological celiac disease screening (tissue transglutaminase antibody with IgA level) if not already done. 5, 4

Lower Endoscopy (Mandatory Even if Upper Source Found)

• Colonoscopy must be performed regardless of upper endoscopy findings because dual pathology (lesions in both upper and lower GI tracts) occurs in 10-15% of patients. 1, 5
• Do not accept minor upper GI lesions (esophagitis, erosions, aphthous ulceration, or peptic ulcer alone) as the definitive cause without completing lower tract evaluation. 1
• Colonoscopy is superior to barium enema for detecting angiodysplasia and allows tissue biopsy. 1, 5

Additional Initial Workup

• Stop NSAIDs and aspirin immediately if the patient is taking them, as these are common culprits for occult GI bleeding. 1
• Perform urinalysis to exclude urinary tract bleeding as a rare cause of iron deficiency. 5
• Document family history of bleeding disorders, telangiectasia, or hematological disorders (thalassemia, sideroblastic anemia). 1

Further Investigation (If Initial Workup Negative)

• Small bowel evaluation is NOT routinely needed unless the patient becomes transfusion-dependent, has persistent visible blood loss, or fails to respond to iron therapy after correction of dietary deficiency and NSAID cessation. 1
• If further investigation is warranted, capsule endoscopy is the preferred modality for small bowel examination, with CT/MRI enterography as alternatives. 5, 4
• Enteroscopy may detect and treat small bowel angiodysplasia in transfusion-dependent cases. 1

Critical Pitfalls to Avoid

• Never assume dietary deficiency alone as the cause in a 56-year-old male with overt blood in stool—full GI investigation is mandatory even with positive dietary history. 1, 5
• Do not stop investigation after finding a single lesion on upper endoscopy; complete the lower tract evaluation due to high dual pathology rates. 1
• Fecal occult blood testing has no diagnostic value in this setting—it is insensitive and non-specific. 1
• Do not delay iron replacement while awaiting endoscopy unless colonoscopy is imminent and bowel preparation would be compromised. 5

Monitoring and Follow-up

• Monitor hemoglobin concentration regularly during treatment to ensure adequate response. 1
• If hemoglobin and MCV cannot be normalized and iron stores cannot be replenished, reconsider further evaluation including small bowel investigation. 1, 5
• Failure to respond to appropriate iron therapy after 3-6 months warrants small bowel investigation even if initial bidirectional endoscopy was negative. 4, 6