Iron Deficiency Anemia: Diagnosis and Treatment
This patient has iron deficiency anemia (IDA) and requires oral iron supplementation along with mandatory gastrointestinal evaluation to identify the source of blood loss.
Diagnostic Confirmation
The laboratory values definitively establish iron deficiency anemia:
- Ferritin 37 ng/mL is below the diagnostic threshold of <45 μg/L for IDA, confirming depleted iron stores 1
- Transferrin saturation of 13% is well below the 16-20% threshold, indicating insufficient iron available for erythropoiesis 1
- Elevated TIBC of 508 reflects the body's compensatory attempt to capture more circulating iron 1
- Hemoglobin 10.7 g/dL confirms anemia in an adult female 2
- The microcytic pattern (low hematocrit 32.7) is characteristic of iron deficiency 1
Mandatory Gastrointestinal Investigation
Before or concurrent with iron therapy, this 53-year-old postmenopausal woman requires complete gastrointestinal evaluation because occult GI blood loss is the most common cause of IDA in this population and asymptomatic malignancy must be excluded 1, 2.
Required Endoscopic Procedures:
- Upper endoscopy with small bowel biopsies to exclude gastric cancer, peptic ulcer disease, angiodysplasia, and celiac disease (present in 2-3% of IDA patients) 1, 2
- Colonoscopy to exclude colonic cancer, polyps, inflammatory bowel disease, and other sources of occult bleeding 1, 2
- Upper endoscopy reveals a cause in 30-50% of IDA patients 1
Additional Evaluation:
- Stool guaiac testing for occult blood 1
- Medication review for NSAIDs, aspirin, and anticoagulants—these should be stopped when possible but should not delay investigation 1
- Dietary history to assess iron intake, though borderline deficient diets alone should not preclude full GI investigation 1
Treatment Approach
First-Line: Oral Iron Supplementation
Initiate oral ferrous sulfate 325 mg daily (containing 65 mg elemental iron) or on alternate days 3, 4.
- Oral iron is first-line therapy for most patients with IDA 1, 4
- Alternate-day dosing may improve tolerability while maintaining efficacy 4
- Common side effects include nausea, abdominal pain, and constipation 1, 5
- Monitor hemoglobin response after 3 weeks of therapy 1
When to Consider Intravenous Iron:
Switch to IV iron if the patient experiences:
- Intolerance to oral iron (gastrointestinal side effects) 1, 4
- Inadequate response after 3 weeks of oral therapy 1
- Ongoing blood loss that exceeds intestinal iron absorption capacity 5, 4
- Malabsorption conditions (celiac disease, post-bariatric surgery, atrophic gastritis) 1, 4
Treatment Goals:
- Replenish iron stores until ferritin reaches >30 ng/mL (ideally >100 ng/mL in presence of inflammation) 1
- Normalize hemoglobin to age- and sex-appropriate levels 2
- Address underlying cause identified during GI evaluation 1, 2
Critical Pitfalls to Avoid
- Never assume dietary insufficiency alone without complete GI evaluation in postmenopausal women—this delays diagnosis of potentially curable malignancies 1, 2
- Do not use ferritin alone in patients with inflammatory conditions, as ferritin is an acute-phase reactant and may be falsely elevated; transferrin saturation <16% with ferritin 30-100 ng/mL suggests combined iron deficiency and inflammation 1
- Avoid repeated phlebotomy if polycythemia is not present—this worsens iron deficiency 1
- Monitor compliance with oral iron, as gastrointestinal side effects frequently lead to discontinuation 1, 5