What is the best treatment approach for a patient with high iron binding capacity and low iron stores, indicating iron deficiency anemia?

Treatment of High Iron Binding Capacity with Low Iron Stores (Iron Deficiency Anemia)

Initiate oral iron supplementation with ferrous sulfate 200 mg three times daily to correct anemia and replenish iron stores, continuing for three months after hemoglobin normalization. 1

Diagnostic Confirmation

Before initiating treatment, confirm the diagnosis with:

• Serum ferritin <30 μg/L indicates low iron stores (or <45 μg/L if inflammation present) 1
• Elevated total iron-binding capacity with low serum iron and low transferrin saturation (<20%) confirms iron deficiency 1
• Microcytic, hypochromic anemia with reduced mean cell hemoglobin (MCH) and mean cell volume (MCV) 1

Identify and Treat Underlying Cause

Investigation is mandatory to identify the source of iron loss, as iron deficiency in adults typically indicates blood loss or malabsorption 1:

• Men and postmenopausal women: Perform upper gastrointestinal endoscopy with duodenal biopsies (to exclude celiac disease) AND colonoscopy or barium enema to exclude gastrointestinal malignancy 1
• Premenopausal women <45 years: Investigate only if upper GI symptoms present or if menstrual loss inadequately explains severity; check tissue transglutaminase antibody for celiac disease 1
• Premenopausal women ≥45 years: Full investigation as per men/postmenopausal women due to increasing cancer risk 1

First-Line Treatment: Oral Iron

Ferrous sulfate 200 mg three times daily is the preferred initial therapy 1:

• Alternative preparations (ferrous gluconate, ferrous fumarate) are equally effective if ferrous sulfate not tolerated 1
• Add ascorbic acid to enhance absorption when response is poor 1
• Expected response: Hemoglobin should rise by 2 g/dL after 3-4 weeks 1
• Duration: Continue for 3 months after hemoglobin normalization to replenish iron stores 1, 2

Common Pitfall to Avoid

Do not use enteric-coated or sustained-release preparations, as these reduce iron absorption 2. Taking tablets with meals can improve tolerance despite slightly reduced absorption 2.

Indications for Intravenous Iron

Switch to IV iron when oral therapy is inadequate 1, 3:

• Intolerance to at least two oral iron preparations 1
• Malabsorption (celiac disease, inflammatory bowel disease, post-bariatric surgery) 1, 3
• Active inflammatory bowel disease with compromised absorption 1
• Ongoing blood loss not responding to oral iron 1
• Chronic kidney disease patients, particularly those on dialysis 1, 4
• Pregnancy (second and third trimesters) 3
• Heart failure with iron deficiency 3

IV Iron Dosing

For hemodialysis patients: Iron sucrose 100 mg undiluted as slow IV injection over 2-5 minutes per consecutive hemodialysis session, with usual total course of 1000 mg 5

For non-dialysis patients: Iron sucrose 200 mg on 5 different occasions over 14 days 5

Monitoring and Follow-Up

Monitor hemoglobin and MCV every 3 months for one year, then annually 1:

• Failure to achieve expected hemoglobin rise after 3-4 weeks indicates: poor compliance, continued blood loss, malabsorption, or misdiagnosis 1, 6
• Target iron stores: Serum ferritin ≥100 ng/mL and transferrin saturation ≥20% 1, 4
• Additional oral iron should be given if hemoglobin or MCV falls below normal 1

Special Considerations

Inflammatory Bowel Disease

Treat active inflammation effectively to enhance iron absorption or reduce iron depletion 1. IV iron is first-line in patients with active inflammation 1.

Celiac Disease

Ensure strict gluten-free diet adherence to improve iron absorption 1. Oral iron may be added based on severity, but IV iron is indicated if villous atrophy is severe or oral iron fails 1.

Chronic Kidney Disease

Supplemental iron is required in the majority of CKD patients receiving erythropoiesis-stimulating agents 4. Administer IV iron when serum ferritin <100 mcg/L or transferrin saturation <20% 4.