What is the best approach to manage low ferritin (iron deficiency) in a postmenopausal woman?

Management of Low Ferritin in Postmenopausal Women

In postmenopausal women with low ferritin, you must perform bidirectional endoscopy (both upper endoscopy and colonoscopy) to evaluate for gastrointestinal malignancy, while simultaneously initiating oral iron supplementation and screening for celiac disease. 1

Diagnostic Confirmation

Define Iron Deficiency

• Diagnose iron deficiency if ferritin is <45 ng/mL, which provides optimal sensitivity (85%) and specificity (92%) for detecting true iron deficiency 1
• If ferritin is 15-45 ng/mL and the patient has chronic inflammation or kidney disease, interpret cautiously as ferritin is an acute phase reactant 1
• A ferritin >150 ng/mL essentially excludes iron deficiency even with inflammation present 1

Determine if Anemia is Present

• Check if hemoglobin is <12 g/dL (defines anemia in non-pregnant women) 1
• Even without anemia, low ferritin in postmenopausal women warrants investigation if there are GI symptoms, family history of GI pathology, or other concerning features 1

Mandatory Gastrointestinal Evaluation

Bidirectional Endoscopy is Required

• Perform both esophagogastroduodenoscopy (EGD) and colonoscopy in all postmenopausal women with iron deficiency anemia - this is a strong recommendation based on the 8.9% risk of lower GI malignancy and 2.0% risk of upper GI malignancy in this population 1
• Complete both procedures at the same setting unless advanced gastric cancer or celiac disease is found on upper endoscopy 1
• Colonoscopy is preferred over CT colonography, but either is acceptable if colonoscopy is not feasible 1

Pre-Endoscopy Screening

• Test for celiac disease with serology (anti-endomysial or anti-tissue transglutaminase antibodies) before or during endoscopy, as celiac disease causes 3-5% of iron deficiency cases 1, 2
• Perform non-invasive testing for Helicobacter pylori (stool antigen or urea breath test) 1
• If H. pylori or celiac serology is positive, treat accordingly but still proceed with endoscopy in postmenopausal women 1

Endoscopy Biopsy Strategy

• Avoid routine gastric or small bowel biopsies 1
• Only biopsy for celiac disease if serology is positive or there is high clinical suspicion with negative serology 1
• Only biopsy for H. pylori if there is an endoscopic abnormality despite negative non-invasive testing 1

Iron Replacement Therapy

First-Line Treatment

• Start oral ferrous sulfate 324 mg (65 mg elemental iron) three times daily immediately - do not wait for endoscopy results 2, 3
• This dosing provides 362% of the recommended daily intake and is the standard first-line therapy 3
• Continue iron therapy for 3 months after hemoglobin normalizes to fully replenish body iron stores 2

Monitoring Response

• Recheck hemoglobin after 3-4 weeks, expecting a rise of 2 g/dL over this period 2
• Failure to achieve this increase suggests poor compliance, continued blood loss, malabsorption, or misdiagnosis 2
• Monitor hemoglobin and red cell indices every 3 months for one year, then annually 2

When to Use Intravenous Iron

• Consider IV iron if the patient cannot tolerate at least two different oral iron preparations 2
• IV iron is also appropriate for documented non-adherence to oral therapy 2
• Parenteral iron should not be used as first-line therapy due to risks and lack of superiority over oral preparations 1, 2

Further Investigation if Endoscopy is Negative

Small Bowel Evaluation

• If bidirectional endoscopy is unrevealing and hemoglobin cannot be restored or maintained with iron therapy, consider video capsule endoscopy to evaluate the small bowel 1
• This is particularly important in patients requiring antiplatelet or anticoagulant therapy 1
• Small bowel evaluation is also warranted if symptoms suggestive of small bowel disease develop 1, 2

Eradicate H. pylori if Present

• In patients with recurrent iron deficiency and normal endoscopies, eradicate H. pylori if detected 1

Common Pitfalls to Avoid

• Do not perform fecal occult blood testing - it provides no benefit in the diagnostic workup of iron deficiency 1, 2
• Do not delay endoscopy in postmenopausal women even if there is a plausible non-GI explanation, as dual pathology occurs in 1-10% of cases 1
• Do not use a ferritin cutoff of <15 ng/mL as this misses 41% of iron deficiency cases 1
• Do not skip lower endoscopy even if upper endoscopy reveals a lesion (unless it's advanced gastric cancer), as dual pathology is common 1
• Blood transfusions should be reserved only for patients with or at risk of cardiovascular instability 1