WHO Guidelines for Iron Deficiency Anemia
Note: The evidence provided does not contain actual WHO guidelines, but rather British Society of Gastroenterology and American Gastroenterological Association guidelines. I will provide recommendations based on the available guideline evidence.
First-Line Treatment: Oral Iron Supplementation
Start with ferrous sulfate 200 mg once daily, taken with vitamin C 500 mg to enhance absorption 1, 2. This simplified once-daily dosing improves compliance compared to traditional three-times-daily regimens 1. Recent evidence suggests alternate-day dosing (giving 120-200 mg every other day) may actually increase total iron absorption by avoiding hepcidin elevation that occurs with daily dosing 3.
Alternative Oral Formulations
- Use ferrous gluconate or ferrous fumarate if ferrous sulfate is not tolerated 1, 2
- Consider liquid preparations for patients with swallowing difficulties 1
- All ferrous salts are equally effective when given in equivalent elemental iron doses 2
Monitoring Treatment Response
Hemoglobin should rise by 2 g/dL after 3-4 weeks of treatment 4, 1, 2. If this target is not met, consider:
- Poor compliance (most common cause) 4, 2
- Misdiagnosis 4, 2
- Continued blood loss 4, 2
- Malabsorption 4, 2
Continue oral iron for 3 months after hemoglobin normalizes to replenish iron stores 1, 2. Monitor hemoglobin and ferritin every 3 months for the first year, then annually 1, 2.
When to Use Parenteral Iron
Reserve intravenous iron for patients with intolerance to at least two different oral iron preparations, non-compliance, or malabsorption 4, 1, 2.
Key Points About IV Iron:
- Intramuscular administration is painful and should be avoided 4
- Hemoglobin rise is no faster than with oral preparations 4
- True anaphylaxis is very rare; most reactions are complement activation-related pseudo-allergy (infusion reactions) 1
- Preferred formulations allow iron deficit replacement with 1-2 infusions rather than multiple infusions 1
- Available preparations include iron sucrose, ferric carboxymaltose, and iron dextran 2
Investigation for Underlying Cause
Age-Based Approach:
For patients >45 years old: Perform both upper GI endoscopy with small bowel biopsy AND colonoscopy or barium enema unless a firm cause is identified with the first investigation 4, 1. This age cutoff reflects increasing incidence of GI malignancy 4.
For patients <45 years old:
- Perform endoscopy with small bowel biopsy only if upper GI symptoms are present 4
- Screen for celiac disease with antiendomysial antibodies and IgA levels (to exclude IgA deficiency which makes the test unreliable) 4, 1
- Perform colonoscopy only if specific indications exist 4
Special Populations:
- Menstruating women: Iron deficiency occurs in 5-10% 4, 2. Screen for celiac disease in all premenopausal women with IDA 2. Investigate GI tract if symptoms present, family history of colorectal cancer, or persistent IDA after iron supplementation 2
- Young men: Investigation approach remains controversial and should be individualized based on risk factors 4
Common Pitfalls to Avoid
- Premature discontinuation: Stopping iron before stores are replenished (before 3 months post-normalization) leads to rapid recurrence 1
- Excessive dosing: Prescribing >200 mg elemental iron daily increases side effects and paradoxically reduces absorption due to hepcidin elevation 1
- Failing to investigate: Assuming dietary insufficiency alone in older patients without investigating for GI pathology, particularly malignancy 1, 2
- Ignoring continued blood loss: No amount of supplementation will correct anemia if ongoing blood loss exceeds absorption capacity 4, 1
- Using parenteral iron as first-line: This is expensive, carries unnecessary risks, and provides no faster hemoglobin response than oral therapy 4, 2