Is low iron (hypoferritemia) in a 48-year-old male with chronic normocytic anemia indicative of a colonoscopy as the next step?

Colonoscopy is Indicated, But Upper Endoscopy Should Also Be Performed

Yes, colonoscopy is indicated as the next step in a 48-year-old male with low iron and chronic normocytic anemia, but gastroscopy should be performed as well—ideally during the same session (bidirectional endoscopy). 1

Why Both Upper and Lower GI Tract Evaluation is Essential

The British Society of Gastroenterology strongly recommends that in men and postmenopausal women with newly diagnosed iron deficiency anemia (IDA), gastroscopy and colonoscopy should generally be the first-line GI investigations. 1 This applies even when the anemia appears normocytic, as iron deficiency can present with normal MCV values early in the disease course or when mixed with other causes of anemia. 2

The Risk of Dual Pathology

• Dual unrelated pathology (lesions in both upper and lower GI tracts) occurs in approximately 10-15% of patients with IDA. 1, 2
• Finding colon polyps or other lower tract lesions does not exclude significant upper tract pathology. 2
• Deferring colonoscopy should only occur if an upper GI cancer is found. 1

Critical Upper GI Lesions Frequently Missed Without Gastroscopy

Even in the absence of upper GI symptoms, several important bleeding sources are commonly overlooked without direct visualization:

• Cameron erosions in large hiatal hernias are commonly undetected without gastroscopy. 2
• Gastric or duodenal angiectasias represent up to 80% of occult bleeding cases and are often missed. 2
• Antral vascular ectasia, peptic ulcers (especially posterior duodenal bulb), and Dieulafoy lesions require direct visualization. 2
• Atrophic gastritis impairs iron absorption and contributes to IDA. 1

Malignancy Risk in This Age Group

• In men with confirmed IDA, the yield of pathology on GI tract examination is considerably higher than in women of the same age. 1
• Malignancy was found in 29% of asymptomatic IDA patients in one prospective study, predominantly right-sided colon carcinoma. 3
• Upper GI cancer occurs in approximately 1/7 the frequency of colon cancer in IDA patients. 4
• The risk factors for GI malignancies include male gender (OR 7.5), advanced age, and lower mean corpuscular volume. 5

Essential Pre-Endoscopy Workup

Before proceeding to endoscopy, confirm iron deficiency and screen for other causes:

• Serum ferritin is the single most useful marker of IDA, though transferrin saturation can help if false-normal ferritin is suspected. 1
• Screen for celiac disease serologically (anti-tissue transglutaminase or anti-endomysial antibodies), as it is found in 3-5% of IDA cases. 1, 2
• Perform urinalysis or urine microscopy to exclude renal tract pathology (particularly renal cell carcinoma) as a source of chronic blood loss. 1, 2
• Test for Helicobacter pylori (urea breath test or stool antigen) with treatment if positive. 2

Procedural Considerations During Endoscopy

• Perform random duodenal biopsies during gastroscopy to exclude celiac disease even if serology is negative, as 2-3% of IDA patients have this condition. 1, 2, 6
• Use an endoscope with a cap to examine blind areas (high lesser curvature, under the incisura angularis, posterior duodenal bulb) to increase diagnostic yield. 2
• Bidirectional endoscopy at the same session is more efficient and simplifies the decision to proceed with colonoscopy if upper tract findings are of uncertain relevance. 1

Common Pitfalls to Avoid

• Do not assume normocytic anemia excludes iron deficiency—iron studies are essential to confirm the diagnosis. 1
• Do not attribute anemia solely to medications (NSAIDs, PPIs) or minor findings without excluding structural lesions, as these may mask underlying pathology. 2, 6
• Do not skip gastroscopy even if colonoscopy reveals polyps or other lesions, as dual pathology is common. 2
• Do not ignore "mild" anemia (hemoglobin 118-129 g/L in men) without evident explanation, as it may signal significant pathology including early malignancies. 2
• The absence of upper GI symptoms does not exclude significant pathology, as many lesions (angiectasias, certain early cancers) are asymptomatic. 2, 6

Alternative if Colonoscopy Not Feasible

CT colonography is a reasonable alternative in patients not suitable for colonoscopy due to comorbidities, though it does not identify subtle mucosal pathology like vascular malformations and may require subsequent colonoscopy for histology or polypectomy. 1

Iron Replacement Therapy

Iron replacement therapy should not be deferred while awaiting investigations unless colonoscopy is imminent. 1 Start with one tablet daily of ferrous sulfate, fumarate, or gluconate, and monitor hemoglobin response within 4 weeks. 1