Workup for Anemia in the Elderly
In elderly patients with confirmed anemia, perform both upper and lower gastrointestinal tract evaluation regardless of symptoms, as dual pathology occurs in 10-15% of cases and investigation of the colon is particularly productive in this age group. 1
Initial Laboratory Assessment
Serum ferritin is the most powerful test for iron deficiency, with levels <30 μg/L confirming deficiency in the absence of inflammation. 1, 2
Essential first-line tests include:
- Complete blood count with red cell indices and reticulocyte count 2, 3
- Serum ferritin and transferrin saturation (<30% suggests deficiency) 1
- C-reactive protein to assess for inflammation 3
- Renal function (creatinine/GFR), as chronic kidney disease contributes to anemia in >50% of elderly patients 1
- Vitamin B12 and folate levels 3, 4
- Thyroid-stimulating hormone (TSH) 5
Critical Context for the Elderly Population
Iron deficiency is multifactorial in elderly patients, often involving poor diet, reduced absorption, occult blood loss, medications (especially aspirin/NSAIDs), and chronic disease. 1 More than 65% of elderly patients have two to four concomitant causes of anemia simultaneously. 5
Never assume anemia is "normal aging"—more than 75% of cases have a specific, treatable cause. 2, 6
Gastrointestinal Evaluation Protocol
When to Investigate
GI investigations should be performed in all patients with confirmed iron deficiency anemia unless there is documented significant non-GI blood loss. 1
Investigation Sequence
Prioritize colonoscopy in elderly patients, as colonic pathology is more likely to be productive than upper GI sources in this age group. 1
Upper GI endoscopy reveals a cause in 30-50% of patients and should include small bowel biopsies, as 2-3% of patients with iron deficiency anemia have celiac disease. 1
Lower GI tract examination (colonoscopy or CT colonography) must be performed even if upper endoscopy reveals findings like esophagitis, erosions, or peptic ulcer, as these should not be accepted as the sole cause until the colon is cleared. 1
Bidirectional endoscopy (same-session upper and lower) is efficient and addresses the high rate of dual pathology. 1
CT colonography may be a more attractive alternative to colonoscopy for frail elderly patients with significant comorbidities. 1
Special Considerations for Elderly Patients
Carefully weigh risks and benefits of invasive endoscopic investigation in patients with major comorbidities, limited performance status, or reduced life expectancy. 1 These considerations should be discussed with the patient and family, incorporating their preferences. 1
Further Evaluation for Persistent Anemia
Small bowel visualization (enteroscopy) is indicated only if:
- Anemia is transfusion-dependent 1
- There has been visible blood loss despite negative upper and lower GI evaluation 1
- Enteroscopy may detect and treat small bowel angiodysplasia in transfusion-dependent cases 1
Medication Review
Document and discontinue when possible:
- Aspirin and NSAIDs (major contributors to occult GI bleeding) 1
- Anticoagulants (though their use should not usually deter investigation) 1
Treatment Approach
Iron Deficiency Anemia
- Oral iron supplementation is first-line treatment 2, 4
- Parenteral iron is indicated for intolerance or malabsorption of oral preparations 2, 6
- Normalization of hemoglobin typically occurs by 8 weeks in most patients 4
Vitamin B12 Deficiency
- Intramuscular or deep subcutaneous cyanocobalamin 100 mcg daily for 6-7 days, then alternate days for seven doses, then every 3-4 days for 2-3 weeks, followed by 100 mcg monthly for life 2, 7
Folate Deficiency
- Oral folate supplementation, but avoid high-dose folic acid that may mask B12 deficiency symptoms 2, 3
Common Pitfalls to Avoid
- Do not accept a positive dietary history as the sole cause—full GI investigation is still required even with documented poor intake. 1
- Watch for combined deficiencies, especially in elderly patients with inflammatory conditions. 2
- Do not stop investigation at the first finding—proceed with lower GI evaluation even when upper GI pathology is identified. 1
- Monitor hemoglobin after correcting dietary deficiency and stopping NSAIDs to ensure response. 1