In an adult patient with burning epigastric pain possibly due to bile reflux, is the refluxate alkaline or acidic, and does it cause a burning sensation?

Bile Reflux into the Stomach: Alkaline Nature and Burning Pain

Bile that refluxes into the stomach is alkaline (not acidic), and it does cause burning epigastric pain, nausea, and bilious vomiting—symptoms that are clinically indistinguishable from acid reflux despite the different pH. 1, 2, 3

Chemical Composition and pH of Bile Reflux

• Duodenogastric reflux consists of alkaline duodenal contents, including bile acids, pancreatic enzymes, and bicarbonate, that flow retrograde from the duodenum into the stomach 1, 4.
• The refluxed material has an alkaline pH (above 7.0), in contrast to gastric acid which has a pH below 4.0 1.
• Bile acids—particularly cholic acid, deoxycholic acid, and chenodeoxycholic acid—are the primary irritants in the refluxed duodenal contents 3, 4.

Clinical Presentation: Burning Pain Despite Alkaline pH

• Patients with bile reflux gastritis experience the same triad of symptoms as acid reflux: epigastric burning pain, nausea, and bilious vomiting 1, 2, 3.
• The burning sensation occurs because bile acids directly damage the gastric mucosa, causing inflammation, erythema, friability, and erosions—not because of acidity 5, 3.
• Endoscopic findings include erythematous and friable gastric mucosa, visible bile staining, thickened gastric folds, and erosions in 64–72% of cases 5.
• Histologic examination reveals chronic inflammation (84%), foveolar hyperplasia (40%), intestinal metaplasia (35%), and chronic atrophic gastritis (13%) 5.

Pathophysiology: Why Alkaline Bile Causes Burning

• Bile acids disrupt the gastric mucosal barrier, allowing back-diffusion of hydrogen ions and direct cellular injury independent of pH 1, 4.
• The irritating effect is mediated by the detergent properties of bile salts, which solubilize lipid membranes and cause mucosal inflammation 3, 4.
• Mixed reflux (both acid and bile) can occur when bile refluxes into the stomach and then refluxes further into the esophagus, creating combined alkaline and acid esophagitis 1.

Risk Factors and Clinical Context

• Bile reflux gastritis occurs most commonly after gastric surgery (gastric resection, pyloroplasty, gastroenterostomy) in 73% of cases, with an average latency of 15 years post-operatively 5.
• Cholecystectomy and biliary surgery account for 7% of cases, also with a 15-year average latency 5.
• Primary bile reflux can occur without prior surgery, often associated with pyloric dysfunction or previous cholecystectomy 2, 4.
• The male-to-female ratio is 1.5:1, with peak incidence between ages 51–80 years 5.

Diagnostic Approach

• Upper endoscopy reveals bile-stained, erythematous, friable gastric mucosa in the majority of symptomatic patients 5, 3.
• 24-hour intraluminal bile monitoring is the gold standard for quantifying duodenogastric reflux, though not routinely available 1.
• The presence of visible bile in the stomach during endoscopy was documented in 58% of cases 5.

Treatment Implications

• Proton pump inhibitors decrease the volume of gastric secretions but do not directly address the alkaline bile component; they work by reducing the "upstream effects" of bile on the esophagus when mixed reflux is present 1.
• Ursodeoxycholic acid (1000 mg/day) profoundly reduces pain intensity and frequency by changing the bile acid composition to a less toxic profile, increasing ursodeoxycholic acid to 50% of total bile acids while decreasing cholic and deoxycholic acids 3.
• Prokinetic agents improve gastric emptying and reduce gastric exposure to duodenal secretions, though their efficacy is limited 1, 4.
• Surgical diversion procedures (Roux-en-Y choledochojejunostomy, duodenal switch) achieve 87% complete symptom relief in severe, medically refractory cases 2.

Critical Clinical Pitfall

• Do not assume that "alkaline" reflux cannot cause burning pain—the clinical presentation of bile reflux gastritis is identical to acid reflux, with epigastric burning as the cardinal symptom despite the alkaline pH of the refluxate 1, 2, 3.
• The burning sensation is caused by direct mucosal injury from bile acids, not by acidity 3, 4.