What is the appropriate management for a 40-year-old woman with iron deficiency anemia, as indicated by low iron saturation and ferritin levels?

Management of Iron Deficiency Anemia in a 40-Year-Old Woman

Start oral iron supplementation immediately with ferrous sulfate 200 mg three times daily (or 325 mg daily if better tolerated) and investigate the underlying cause of blood loss. 1

Interpretation of Laboratory Values

Your patient's labs confirm iron deficiency anemia:

• Iron saturation of 5% (normal >20%) indicates severe iron deficiency 2
• Serum ferritin below 45 ng/mL meets diagnostic criteria for iron deficiency in anemic patients 1
• Low serum iron and elevated TIBC further support the diagnosis 2

Immediate Iron Replacement Therapy

All patients with iron deficiency anemia require iron supplementation to correct anemia and replenish body stores. 1

First-Line Treatment: Oral Iron

• Ferrous sulfate 200 mg (65 mg elemental iron) three times daily is the gold standard, being most effective and least expensive 1, 3
• Alternative ferrous salts (ferrous gluconate, ferrous fumarate) are equally effective if ferrous sulfate is not tolerated 1
• Continue iron for 3 months after anemia correction to replenish iron stores 1
• Expect hemoglobin to rise by 2 g/dL after 3-4 weeks of treatment 1

Optimizing Oral Iron Absorption

• Take on an empty stomach when possible for better absorption 1
• Add ascorbic acid (vitamin C) 500 mg if response is poor, as it enhances iron absorption 1
• If gastrointestinal side effects occur, consider taking with meals or alternate-day dosing 1, 4

When to Use Intravenous Iron

Reserve IV iron for specific situations: 1

• Intolerance to at least two oral iron preparations 1
• Non-compliance with oral therapy 1
• Malabsorption conditions (celiac disease, post-bariatric surgery) 2
• Ongoing blood loss not responding to oral iron 1
• Active inflammatory conditions compromising absorption 1

Mandatory Investigation for Blood Loss Source

Because this patient is 40 years old, investigation is essential even though she is premenopausal. 1

Age-Based Investigation Strategy

• Patients ≥45 years: Full gastrointestinal evaluation with upper endoscopy with small bowel biopsy AND colonoscopy or barium enema 1
• Patients <45 years (your patient): More selective approach 1

Specific Workup for Your 40-Year-Old Patient

First, assess menstrual blood loss: 1

• Menstrual loss (especially menorrhagia) is responsible for iron deficiency in 5-10% of premenopausal women 1
• History alone is unreliable for quantifying menstrual loss 1
• Consider pictorial blood loss assessment charts (80% sensitivity and specificity for menorrhagia) 1
• Gynecologic evaluation if menorrhagia is suspected 1

Gastrointestinal evaluation if: 1

• Upper GI symptoms present → perform upper endoscopy with small bowel biopsy 1
• No upper GI symptoms → check antiendomysial antibody (with IgA level to exclude IgA deficiency) to screen for celiac disease 1
• Colonoscopy only if specific indications present (changed bowel habit, rectal bleeding, family history) 1

Additional evaluation: 1

• Review dietary iron intake 1
• Assess for NSAID use 2
• Test for Helicobacter pylori infection 1
• Exclude hematuria (rare urinary tract tumors can cause iron deficiency) 1

Monitoring and Follow-Up

Check hemoglobin at 3-4 weeks: 1

• Should increase by 2 g/dL 1
• Failure to respond indicates: poor compliance, misdiagnosis, continued blood loss, or malabsorption 1

Long-term monitoring after correction: 1

• Monitor hemoglobin and MCV every 3 months for 1 year, then annually 1
• Recheck ferritin if hemoglobin or MCV falls 1
• Further investigation only needed if anemia cannot be maintained with oral iron 1

Common Pitfalls to Avoid

• Do not skip investigation in premenopausal women - while menstrual loss is common, gastrointestinal pathology still occurs and increases with age approaching 45 1
• Do not use faecal occult blood testing - it is insensitive and non-specific for investigating iron deficiency 1
• Do not stop iron when hemoglobin normalizes - continue for 3 months to replenish stores 1
• Do not rush to IV iron - oral iron is equally effective when tolerated, and IV iron carries risks of anaphylaxis and hypophosphatemia 1, 5