Management of Iron Deficiency Anemia in a 38-Year-Old Woman
Start oral ferrous sulfate 200 mg once daily on an empty stomach, add vitamin C 500 mg to enhance absorption, and investigate the underlying cause of iron deficiency while treating. 1
Immediate Treatment Strategy
Oral Iron Supplementation
- Initiate ferrous sulfate 200 mg once daily as first-line therapy, which is the most cost-effective and evidence-based approach 1
- Take on an empty stomach for optimal absorption, though taking with food is acceptable if gastrointestinal side effects occur 1
- Add ascorbic acid (vitamin C) 500 mg with each iron dose to enhance absorption, particularly critical given the severely low transferrin saturation of 5.2% 2, 1
- Alternative formulations (ferrous gluconate or ferrous fumarate) are equally effective if ferrous sulfate is not tolerated 2, 1
- Continue iron therapy for 3 months after hemoglobin normalizes to fully replenish iron stores 1, 3
Expected Response and Monitoring
- Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment 2, 1
- Repeat iron studies (ferritin, transferrin saturation, hemoglobin) after 8-10 weeks 3
- Monitor hemoglobin and red cell indices every 3 months for the first year, then every 6-12 months thereafter 3
Investigation of Underlying Cause
For This 38-Year-Old Premenopausal Woman
- Assess menstrual blood loss first, as menorrhagia, pregnancy, and breastfeeding are responsible for iron deficiency in 5-10% of menstruating women 2
- Consider pictorial blood loss assessment charts, which have 80% sensitivity and specificity for detecting menorrhagia 2
- Screen for celiac disease with antiendomysial antibody and IgA measurement, as this is a common cause of malabsorption in younger patients 2, 1
When to Pursue Gastrointestinal Investigation
- Since this patient is under 45 years old, gastrointestinal endoscopy is only indicated if she has upper GI symptoms 2
- Colonic investigation should only be performed if there are specific indications (e.g., rectal bleeding, family history of colon cancer, alarm symptoms) 2
- If celiac screening is negative and no obvious gynecologic cause is found, consider upper endoscopy with small bowel biopsy 2
When to Switch to Intravenous Iron
Specific Indications
- Intolerance to at least two different oral iron preparations 2, 1
- No hemoglobin response after 4 weeks of adequate oral therapy 1
- Documented malabsorption (celiac disease with ongoing gluten exposure, post-bariatric surgery, inflammatory bowel disease with active inflammation) 1, 3
- Ongoing gastrointestinal blood loss exceeding oral replacement capacity 1
IV Iron Administration
- Use formulations that can replace iron deficits with 1-2 infusions, such as ferric carboxymaltose 1 gram as a single dose over 15 minutes 1, 3
- Note that parenteral iron is painful (when given intramuscularly), expensive, and carries risk of anaphylactic reactions 2
- The rise in hemoglobin is no quicker than with oral preparations 2
Critical Pitfalls to Avoid
- Do not prescribe multiple daily doses (e.g., three times daily) as this increases side effects without improving efficacy and reduces compliance 1, 4
- Do not stop iron therapy when hemoglobin normalizes - continue for 3 months to replenish stores 1, 3
- Do not continue oral iron indefinitely without response - reassess after 4 weeks and switch to IV iron if hemoglobin fails to rise 1
- Do not overlook vitamin C supplementation when oral iron response is suboptimal, as ascorbic acid significantly enhances absorption 2, 1
- Do not fail to identify and treat the underlying cause while supplementing iron 2, 1
Failure to Respond
If No Improvement After 4 Weeks
- Verify patient adherence to therapy 1
- Assess for continued blood loss 2, 1
- Evaluate for malabsorption syndromes 2, 1
- Consider misdiagnosis (e.g., anemia of chronic disease, thalassemia trait) 2