What is the next step in management for a 45-year-old male with iron deficiency anemia that has improved with iron supplementation?

Management of Iron Deficiency Anemia in a 45-Year-Old Male

In a 45-year-old male with iron deficiency anemia that has improved with iron supplementation, bidirectional endoscopy (upper GI endoscopy with small bowel biopsy and colonoscopy) is the essential next step to investigate the underlying cause, as gastrointestinal blood loss is the most common etiology in this demographic. 1, 2

Rationale for GI Investigation

• Men with iron deficiency anemia have approximately a 1/3 risk of underlying pathological abnormality, most commonly in the GI tract 1
• Asymptomatic colonic and gastric carcinomas may present with iron deficiency anemia, making exclusion of these conditions a priority 1
• The British Society of Gastroenterology guidelines specifically recommend urgent GI investigation for men with a new diagnosis of IDA 1

Recommended Investigation Algorithm

1. Upper GI Endoscopy with Small Bowel Biopsy

   • Essential to evaluate for:
     • Gastric/duodenal ulcers
     • Gastric cancer
     • Celiac disease (via small bowel biopsy)
     • Erosive gastritis/esophagitis
   • Small bowel biopsy is crucial even without overt GI symptoms 1, 2

2. Colonoscopy

   • Preferred method for lower GI evaluation as it allows direct visualization and biopsy of lesions 1
   • Alternative: Double contrast barium enema if colonoscopy facilities are limited 1

3. Additional Testing to Consider

   • Serum B12 and folate levels to rule out concurrent deficiencies 2
   • Celiac disease serology (if not already performed) 2
   • Renal function tests to assess for chronic kidney disease 2

Continuation of Iron Therapy

While investigating the underlying cause, iron supplementation should continue:

• Continue oral iron therapy for 3 months after normalization of hemoglobin to replenish iron stores 1, 2
• Standard dosing: Ferrous sulfate 200 mg three times daily (or equivalent) 1, 2
• Lower doses (100 mg daily) may be considered if GI side effects occur 2

Follow-up Monitoring

• Monitor hemoglobin and red cell indices at 3-month intervals for one year, then after a further year 1, 2
• Expect hemoglobin to rise by 2 g/dL after 3-4 weeks of adequate iron supplementation 2
• If no response is seen after 4 weeks, consider poor compliance, continued blood loss, or malabsorption 2

Important Caveats

• Further small bowel evaluation (enteroscopy) is generally not necessary unless the anemia is transfusion-dependent or there is visible blood loss 1
• If initial endoscopic investigations are negative but anemia persists or recurs despite adequate iron supplementation, consider additional investigations such as capsule endoscopy 1
• Faecal occult blood testing is not recommended as it is insensitive and non-specific for investigation of IDA 1

The urgency of investigation is justified by the need to exclude GI malignancy, which can present as iron deficiency anemia even in the absence of specific symptoms 1.