Management of Iron Deficiency Anemia

Oral Iron Replacement – First‑Line Therapy

• Ferrous sulfate 200 mg three times daily (≈65 mg elemental iron per dose) is recommended for all patients to correct anemia and replenish iron stores. 1
• If ferrous sulfate is not tolerated, ferrous gluconate or ferrous fumarate are equally effective alternatives. 2, 3
• Liquid iron formulations may improve tolerability when tablets cause gastrointestinal side effects. 2
• Adding vitamin C (ascorbic acid) enhances iron absorption and should be considered when the hematologic response is suboptimal. 2, 3
• After hemoglobin normalizes, iron supplementation should be continued for an additional three months to fully restore body stores. 2, 4
• Expected hematologic response: hemoglobin should increase by ~2 g/dL within 3–4 weeks (or ≥10 g/L within 2 weeks). 2

Intravenous Iron – Indications & Limitations

• Parenteral iron is reserved for patients with documented intolerance to at least two different oral iron preparations or confirmed non‑compliance. 2, 3
• Intravenous iron (often administered intramuscularly) is painful, costly, carries a risk of anaphylaxis, and does not produce a faster rise in hemoglobin compared with oral therapy. 2, 3

Blood Transfusion – When to Use

• Transfusion should be limited to patients who are hemodynamically unstable or at risk of cardiovascular compromise due to severe anemia. 1
• Routine transfusion of stable patients, regardless of hemoglobin level, is not recommended. 1

Diagnostic Evaluation – Gastro‑Intestinal Investigation

• All post‑menopausal women and all men with confirmed iron‑deficiency anemia require both upper and lower gastrointestinal endoscopy unless a significant overt non‑GI source of blood loss is documented. 1
• Upper endoscopy with duodenal biopsies identifies the cause in 30–50 % of cases. 4
• Small‑bowel biopsies are mandatory to screen for celiac disease, which accounts for 2–5 % of iron‑deficiency anemia cases. 1, 4
• Colonoscopy must be performed even when upper endoscopy reveals a lesion because dual pathology (simultaneous upper and lower lesions) occurs in 10–15 % of patients. 1, 4
• Only advanced gastric cancer or confirmed celiac disease should preclude lower‑GI investigation. 1
• Universal celiac disease screening (serology plus duodenal biopsy) is advised for all patients with iron‑deficiency anemia. 1
• Additional small‑bowel imaging (enteroscopy or radiology) is unnecessary unless the anemia is transfusion‑dependent or hemoglobin cannot be restored/maintained with iron therapy. 1, 2, 4
• In transfusion‑dependent anemia, enteroscopy can detect and treat small‑bowel angiodysplasia. 2, 3, 4
• Small‑bowel radiologic studies are rarely useful unless there is a clinical suspicion of Crohn’s disease. 2, 4
• Faecal occult blood testing provides no diagnostic benefit for iron‑deficiency anemia because of low sensitivity and specificity. 1, 2, 4

Special Populations – Women

• All pre‑menopausal women with iron‑deficiency anemia should undergo celiac disease screening. 1
• Women aged > 45 years should receive full upper and lower GI investigation per standard guidelines. 2
• For women < 45 years, the decision to pursue endoscopic evaluation should be based on clinical judgment, considering family history, anemia severity, and alarm symptoms. 1, 2

Laboratory Diagnosis – Key Tests

• Serum ferritin is the single most powerful test for confirming iron deficiency. 1
• Red‑cell indices (MCV, MCH) are sensitive indicators of iron deficiency when chronic disease or hemoglobinopathies are absent. 1
• The lower the hemoglobin concentration, the greater the likelihood of serious underlying pathology and the more urgent the need for investigation. 1
• Hemoglobin electrophoresis is recommended in patients with microcytosis/hypochromia from appropriate ethnic backgrounds to avoid unnecessary GI work‑up. 1

Monitoring & Follow‑Up

• After normalization of hemoglobin, repeat hemoglobin and red‑cell indices every three months for one year, then once more after an additional year. 2, 4
• If hemoglobin or MCV falls below normal, resume oral iron therapy and consider checking ferritin in ambiguous cases. 2, 4
• Further diagnostic investigation is warranted only when hemoglobin and MCV cannot be maintained despite adequate iron supplementation. 2, 4
• In most patients whose cause remains unidentified after a comprehensive work‑up, iron deficiency does not recur. 2, 4

Addressing Underlying Causes

• Non‑steroidal anti‑inflammatory drugs (NSAIDs) are common, often unreported contributors to iron‑deficiency anemia; clinicians should explicitly inquire about all NSAID use. 1
• Discontinuation of NSAIDs is advised when they are identified as a contributing factor. 2, 4
• In patients with recurrent iron‑deficiency anemia and normal repeat endoscopies, eradication of Helicobacter pylori is recommended if the organism is detected. 1
• Dietary iron deficiency should be corrected when present, but it must not be assumed to be the sole cause; a full GI investigation remains mandatory. 2, 4

Clinical Pitfalls – What to Avoid

• Do not use parenteral iron as first‑line therapy; at least two different oral iron formulations must be trialed first. 2, 3
• Do not transfuse hemodynamically stable patients regardless of hemoglobin level. 1
• Do not cease investigation after identifying a single cause; multiple concurrent pathologies occur in 10–15 % of cases. 1
• Do not accept minor upper‑GI findings (e.g., mild esophagitis, erosions, aphthous ulcers, peptic ulcer) as the sole explanation without completing colonoscopy. 4
• Do not skip celiac disease screening in any patient with unexplained iron‑deficiency anemia. 1

Management of Iron Deficiency Anemia

Iron Replacement Therapy

• The standard treatment for iron deficiency anemia is ferrous sulfate 200 mg three times daily, equivalent to 65 mg elemental iron per dose, as recommended by the American Gastroenterological Association 5, 6
• Alternative oral formulations, such as ferrous gluconate and ferrous fumarate, are equally effective 5, 6
• Liquid preparations may be better tolerated when tablets cause side effects, and adding ascorbic acid (vitamin C) enhances iron absorption 5
• Iron supplementation should be continued for 3 months after hemoglobin normalizes to replenish body stores, with an expected response of hemoglobin rising by ≥10 g/L within 2 weeks, or 2 g/dL after 3-4 weeks 7, 5

Investigation of Underlying Cause

• All patients with iron deficiency anemia require investigation of the underlying cause, including bidirectional GI endoscopy (gastroscopy and colonoscopy) unless an obvious cause is identified, as recommended by the American Gastroenterological Association 7, 8
• Initial workup should include upper GI endoscopy with small bowel biopsy, colonoscopy or barium enema, urinalysis or urine microscopy, and serological screening for celiac disease 7, 9, 8
• Approximately one-third of men and postmenopausal women with iron deficiency anemia have underlying GI pathology, most commonly malignancy 7, 9

Monitoring and Follow-Up

• After achieving normal hemoglobin, patients should be monitored with hemoglobin and MCV every 3 months for 1 year, and rechecked after an additional year, with additional oral iron given if hemoglobin or MCV falls below normal 5, 9
• Failure to respond to oral iron indicates poor compliance, misdiagnosis, continued blood loss, or malabsorption 5, 9

Key Clinical Pearls

• Multiple causes of iron deficiency anemia may coexist, and finding one cause should not stop further investigation 9
• A good response to iron therapy strongly suggests absolute iron deficiency, even with equivocal iron studies 7
• Serum ferritin is the single most useful marker, but may be falsely normal in inflammatory conditions 7, 9
• NSAID use is a common contributing factor that must be addressed, and the target for audit is 90% of patients having both upper endoscopy with small bowel biopsy and colonoscopy/barium enema 5, 6, 9

Management of Iron‑Deficiency Anemia Presenting with Abdominal Pain and Dysgeusia

Diagnostic Priorities

• Confirm iron deficiency using serum ferritin together with a complete blood count, transferrin saturation, and red‑cell indices. Serum ferritin is the most powerful single test for detecting iron deficiency, but it can be falsely normal in inflammatory states; therefore, additional parameters are required for accurate diagnosis. 10

• A rapid hemoglobin rise (≥10 g/L within 2 weeks) after initiating iron therapy strongly confirms absolute iron deficiency when ferritin results are equivocal. This clinical response helps differentiate true deficiency from anemia of chronic disease. 10

Endoscopic Evaluation (Bidirectional Endoscopy)

• All adult males and post‑menopausal females with unexplained iron‑deficiency anemia should undergo both upper gastrointestinal endoscopy (gastroscopy) and colonoscopy, irrespective of the presence or absence of gastrointestinal symptoms. This comprehensive approach ensures that occult sources of blood loss are not missed. 10

• Approximately one‑third of this population harbor clinically significant gastrointestinal pathology, most frequently malignancy; colorectal cancer occurs about seven times more often than gastric cancer in these patients. The high prevalence of serious disease justifies the routine use of bidirectional endoscopy. 10

Small‑Bowel Investigation

• Wireless capsule endoscopy is valuable in cases of recurrent or refractory iron‑deficiency anemia to detect angiodysplasia or small‑bowel neoplasms when conventional endoscopic studies are nondiagnostic. This modality should be considered after standard upper and lower endoscopy have been completed and the anemia persists. 10