What is the likely diagnosis and appropriate management for left upper quadrant abdominal pain about 8 inches below the axilla that worsens with oral iron supplementation and fatty/fried foods?

Left Upper Quadrant Pain Worsened by Iron Supplements and Fatty Foods

Most Likely Diagnosis

This clinical presentation strongly suggests iron pill-induced gastritis, potentially with underlying gastric pathology that is being exacerbated by oral iron supplementation. The location (8 inches below the armpit corresponds to the left upper quadrant/gastric region), worsening with iron supplements, and aggravation by fatty/fried foods creates a classic pattern for gastric mucosal injury 1, 2.

Understanding the Clinical Picture

Why Iron Supplements Cause This Pain

• Oral iron supplements directly damage gastric mucosa, causing erosions, hemorrhagic lesions, and inflammatory changes even at therapeutic doses 1, 2, 3.
• Iron-induced gastritis occurs in approximately 16% of patients taking oral iron tablets, making this a common but under-recognized complication 2.
• The mechanism involves direct mucosal injury from unabsorbed iron creating reactive oxygen species (Fenton reaction) and crystalline iron deposits that cause tissue inflammation 4.
• Symptoms typically include nausea, abdominal pain, and heartburn—the most discriminating symptoms for iron-related GI injury 5.

Why Fatty Foods Worsen the Pain

• Fatty and fried foods delay gastric emptying and increase gastric acid secretion, which exacerbates existing gastric inflammation 1.
• The combination of iron-induced mucosal damage plus dietary irritants creates a synergistic inflammatory response 2, 3.

Immediate Management Algorithm

Step 1: Stop Oral Iron Immediately

Discontinue oral iron supplementation right away 1, 2, 3. The gastric mucosa needs time to heal from the iron-induced injury.

Step 2: Obtain Upper Endoscopy

• Upper GI endoscopy is essential to visualize the extent of gastric injury and rule out other pathology (ulcers, malignancy, H. pylori) 1, 2, 3.
• Endoscopic findings typically show: multiple brown/black deposits on gastric mucosa, hemorrhagic erosions (especially in the antrum), and reactive gastritis 1, 2.
• Biopsy with histopathology confirms diagnosis by demonstrating iron deposits in the gastric mucosa with associated erosive gastritis 1, 2, 3.

Step 3: Treat the Gastritis

• Initiate proton pump inhibitor therapy to reduce gastric acid and promote mucosal healing 1, 3.
• Test for and eradicate H. pylori if present 3.
• Advise dietary modifications: avoid fatty, fried, and spicy foods during the healing phase 1.

Step 4: Address Iron Deficiency with Alternative Route

Switch to intravenous iron rather than attempting different oral formulations 4, 6. The rationale:

• Intravenous iron is first-line therapy for patients with active gastritis or previous intolerance to oral iron 4, 6.
• IV ferric carboxymaltose is the preferred formulation, allowing rapid iron repletion without gastric exposure 4, 6.
• All oral iron formulations can cause gastric injury, so switching from ferrous sulfate to ferrous gluconate or other oral forms will not solve the problem 4, 2.

Critical Pitfalls to Avoid

Don't Continue Oral Iron "With Food"

• While taking iron with food reduces absorption and may slightly decrease symptoms, it does not prevent iron-induced gastric mucosal injury 4, 6.
• Unabsorbed iron still contacts inflamed gastric surfaces causing direct mucosal harm 4.

Don't Assume This is Just "Normal Iron Side Effects"

• Iron pill-induced gastritis is distinct from simple GI intolerance (nausea, constipation) 1, 2, 3.
• This represents actual mucosal injury with erosions and hemorrhagic lesions, not just functional symptoms 1, 2.
• Without endoscopy, serious complications can be missed, including significant bleeding or progression to ulceration 1, 3.

Don't Try Multiple Oral Iron Formulations

• Switching between ferrous sulfate, ferrous gluconate, ferrous fumarate, or even ferric maltol will not prevent gastric injury in a patient with established iron-induced gastritis 4, 2.
• The issue is iron contact with damaged gastric mucosa, not the specific formulation 2, 3.

Long-Term Iron Repletion Strategy

Once gastritis heals (typically 4-8 weeks after stopping oral iron):

• Continue IV iron therapy until iron stores are repleted (ferritin >100 μg/L, transferrin saturation >20%) 4.
• Monitor hemoglobin and iron parameters every 4 weeks during repletion 7, 6.
• Investigate the underlying cause of iron deficiency (GI blood loss, malabsorption, dietary insufficiency) 4, 7.
• Do not restart oral iron if the patient had documented iron-induced gastritis; continue periodic IV iron infusions as needed 4, 6.

When to Consider Alternative Diagnoses

While iron-induced gastritis is most likely, also consider:

• Gastric ulcer or gastritis from other causes (H. pylori, NSAIDs, stress) if symptoms preceded iron supplementation 3.
• Splenic pathology (splenomegaly, splenic infarct) if pain is more lateral and doesn't correlate with meals 4.
• Pancreatic tail pathology if pain radiates to the back 4.

However, the clear temporal relationship with iron supplementation and fatty food intolerance makes iron-induced gastritis the primary diagnosis 5, 1, 2.