What could be causing morning bloating that improves throughout the day in a 15-year-old male with suspected gastrointestinal (G.I.)-related anemia?

Morning Bloating with GI-Related Anemia in a 15-Year-Old Male

This 15-year-old male with morning bloating that improves throughout the day and suspected GI-related anemia should be immediately tested for celiac disease with tissue transglutaminase (tTG) IgA antibody and total IgA levels, as celiac disease is a leading cause of iron deficiency anemia in adolescents and commonly presents with bloating as a primary symptom. 1, 2

Priority Diagnostic Approach

Immediate Celiac Disease Screening

• All patients with iron deficiency anemia should be screened for celiac disease regardless of whether GI symptoms are present or absent 2, 3
• Celiac disease is present in 2-6% of asymptomatic patients with iron deficiency anemia and is easily missed without systematic screening 2
• The combination of bloating and iron deficiency anemia represents alarm symptoms that warrant urgent investigation 1
• Iron deficiency occurs in celiac disease due to duodenal villous atrophy disrupting iron absorption at the duodenum, the primary site of iron uptake 2

Why Morning Bloating Pattern Matters

• Bloating that is worse upon waking and improves throughout the day suggests food intolerance or malabsorption rather than functional causes 1
• Patients with celiac disease, nonceliac gluten sensitivity, and gluten intolerance experience bloating with or without changes in bowel habits 1
• The pattern of improvement throughout the day may reflect overnight fasting followed by gradual symptom resolution as the bowel empties 1

Diagnostic Testing Algorithm

First-Line Testing

• Tissue transglutaminase IgA antibody and total IgA levels (to exclude IgA deficiency which would cause false-negative results) 1, 2
• Complete blood count with iron studies (ferritin, transferrin saturation, total iron-binding capacity) 1
• If tTG antibody is positive, proceed directly to upper endoscopy with duodenal biopsies for confirmation before starting treatment 1, 2

Critical Caveat About Dual Pathology

• Even if celiac disease is confirmed, do not stop the investigation if the patient has marked anemia (hemoglobin <12 g/dL in males) 1, 2
• Dual pathology (bleeding lesions in both upper and lower GI tracts) occurs in 1-10% of patients and increases with age 1
• In males with hemoglobin <12 g/dL, more urgent investigation is warranted as lower hemoglobin suggests more serious disease 1

If Initial Celiac Testing is Negative

• Consider carbohydrate intolerance testing (lactose, fructose) via 2-week dietary elimination trial first, as this is the most economically sound approach 1
• Hydrogen breath testing is reserved for patients refractory to dietary restrictions 1
• Upper endoscopy should still be performed to evaluate for other causes of iron deficiency, including gastric lesions, erosions, and to obtain duodenal biopsies if serology was not done initially 1

Additional Considerations for This Age Group

Adolescent-Specific Factors

• Inadequate dietary iron intake is particularly common during adolescence due to rapid growth and increased iron requirements 4
• However, GI blood loss remains the most common cause of iron deficiency anemia in males of any age, making investigation mandatory 1, 5
• The 6-year residence history is relevant for parasitic infections; consider testing for Giardia lamblia if diarrhea is present, though this is less common 1

Testing for H. pylori

• If celiac disease and colonoscopy are negative and anemia persists, test for Helicobacter pylori via non-invasive testing and eradicate if present 1
• H. pylori colonization may impair iron uptake and increase iron loss 1

Treatment Implications

If Celiac Disease is Confirmed

• Most patients will see anemia improve after initiation of a strict gluten-free diet even without iron supplementation, though response can be slow 2
• Oral iron supplementation (ferrous sulfate 200 mg twice daily) is less likely to be effective in patients with severe villous atrophy; intravenous iron may be indicated 1, 2
• Recovery from anemia usually occurs within 1 year after starting a gluten-free diet, but 6% of patients still have iron deficiency anemia after 1 year 2
• Continue oral iron for 3 months after iron deficiency is corrected to replenish stores 1

Common Pitfall to Avoid

• Do not accept findings of esophagitis, erosions, or peptic ulcer disease as the sole cause of iron deficiency anemia until lower GI investigations have been completed 1
• One-third of patients with potentially bleeding benign upper GI lesions have another lesion in the colon 5