What is the appropriate management for a patient with iron deficiency anemia?

Management of Iron Deficiency Anemia with Low Ferritin

Start oral ferrous sulfate 200 mg three times daily immediately to correct the anemia and replenish iron stores, while simultaneously investigating the underlying cause of blood loss. 1

Interpretation of Laboratory Values

Your labs confirm iron deficiency anemia:

• Low ferritin (10 ng/mL) indicates depleted iron stores, despite normal-appearing iron and saturation levels 2
• The hemoglobin of 8.4 g/dL represents moderate anemia requiring treatment 1
• Normal iron and saturation can be misleading—ferritin is the definitive marker of iron stores 3

Immediate Iron Supplementation

All patients with iron deficiency anemia require iron supplementation regardless of underlying cause: 2, 1

• Ferrous sulfate 200 mg (containing 65 mg elemental iron) three times daily is the simplest and most cost-effective first-line treatment 2, 1, 4
• Alternative formulations include ferrous gluconate or ferrous fumarate if ferrous sulfate is not tolerated 2
• Add ascorbic acid (vitamin C) to enhance iron absorption if response is poor 2, 1
• Continue treatment for 3 months after hemoglobin normalizes to adequately replenish iron stores 2, 1

Expected Treatment Response

• Hemoglobin should rise by 2 g/dL after 3-4 weeks of treatment 2, 1
• Failure to achieve this response indicates: poor compliance, misdiagnosis, continued blood loss, or malabsorption 2, 1
• Resolution of anemia should occur within 6 months in 80% of patients 2, 1

Investigation Algorithm Based on Age and Gender

For patients over 45 years (regardless of gender): 1

• Perform both upper GI endoscopy with small bowel biopsy AND colonoscopy (or barium enema) unless a firm cause is identified with the first investigation 2, 1
• 90% of patients should complete bidirectional endoscopy 2

For premenopausal women under 45 years: 2, 1

• Upper GI endoscopy with small bowel biopsy only if upper GI symptoms present 2, 1
• Check antiendomysial antibodies (IgA type) and total IgA level to screen for celiac disease 2
• Colonoscopy only if specific indications exist 2
• Menstrual loss, menorrhagia, pregnancy, and breastfeeding are common causes in this population 2

For men under 45 years: 2

• Same approach as women under 45: investigate only if upper GI symptoms present, otherwise check celiac antibodies 2

Monitoring Schedule

• Check hemoglobin every 3 months for the first year, then again at 2 years 2, 1
• Check ferritin if hemoglobin or MCV falls below normal during follow-up 2, 1
• Further investigation is only necessary if hemoglobin and MCV cannot be maintained with intermittent iron supplementation 2, 1

When to Consider Intravenous Iron

Parenteral iron should only be used when: 2

• Intolerance to at least two oral iron preparations 2
• Non-compliance with oral therapy 2
• Malabsorption conditions (celiac disease, post-bariatric surgery) 5, 3
• Chronic inflammatory conditions (CKD, heart failure, IBD) 3
• Ongoing blood loss 3

Important caveat: Parenteral iron is painful when given intramuscularly, expensive, may cause anaphylactic reactions, and produces no faster hemoglobin rise than oral preparations 2

Common Pitfalls to Avoid

• Do not rely on normal serum iron or iron saturation to exclude iron deficiency—ferritin is the key diagnostic marker 2, 3
• Do not perform fecal occult blood testing—it is insensitive and non-specific 2
• Do not stop iron supplementation when hemoglobin normalizes—continue for 3 months to replenish stores 2, 1
• Do not skip investigation in men or postmenopausal women—they require full GI evaluation 6