Overview

• Clinical entity associated with chronic intermittent vomiting of bile thought to be the result of reflux of intestinal contents (bile) into the stomach. The normal aboral gastric and intestinal motility along with a functional pylorus prevents the reflux of bile and other intestinal contents back into the stomach. When bile is refluxed into the stomach, it is normally rapidly removed by subsequent peristaltic contractions. Bile remaining in the gastric lumen along with the presence of gastric acid and pepsin can subsequently cause gastric mucosal damage. Bilious vomiting syndrome (BVS) is suspected to be secondary to alterations in normal gastrointestinal motility.
• Clinical signs often occur early in the morning, suggesting that prolonged fasting or gastric inactivity may modify normal motility patterns, resulting in bile reflux.

Signalment

• Commonly observed in dogs, rarely in cats
• Most animals are middle-aged or older
• No breed or sex predisposition

Signs

• Chronic intermittent vomiting of only bile associated with an empty stomach. Signs generally occur late at night or early in the morning. Signs may occur daily but are usually more intermittent. Between episodes, the animal appears normal in all other respects, and most dogs appear healthy immediately after vomiting episodes.
• Results of physical examination are usually unremarkable.

Causes & Risk Factors

• Cause is unknown (idiopathic).
• Primary gastric hypomotility or abnormal (oral-directed) intestinal peristaltic motility are suspected as the probable underlying causes.
• Conditions causing gastritis, duodenitis or intestinal obstructive disease may be responsible for altered proximal gastrointestinal motility and can cause bile reflux. Investigate Giardia, inflammatory bowel disease, intestinal neoplasia, or obstructions as possible etiologies.
• Previous pyloric opening or resection surgery will also increase the risk of enterogastric reflux.

Differential Diagnosis

• Any number of gastrointestinal and non-gastrointestinal disorders can cause chronic vomiting. Giardia should be excluded since the signs of this disease may mimic those of idiopathic bilious vomiting.
• Inflammatory bowel disease can result in bile reflux.
• Intestinal obstruction or partial obstructions should be ruled out.

CBC/Biochemistry/Urinalysis

Results usually unremarkable

Other Laboratory Tests

Fecal examination to detect Giardia or other parasites

Imaging

• A barium contrast study may reveal delayed gastric emptying, although must be interpreted with caution in the hospital setting.
• Barium given with meals, radiopaque markers, or using special motility capsules (Smartpill) may also demonstrate delayed gastric motility.

Diagnostic Procedures

• Endoscopic findings are frequently unremarkable and helps rule out underlying gastrointestinal disease.
• There may be evidence of bile in the stomach or gastritis in the antral region of the stomach.
• Endoscopy is useful to rule out structural or inflammatory disease of the stomach or duodenum.

Drug(s)

• Choices include agents for gastric mucosal protection against the refluxed bile or the use of gastric prokinetic agents to improve motility.
• Often a single evening dose of a medication may be all that is required to prevent clinical signs if the signs occur at night.
• Drugs for gastric mucosal protection include various antacids or sucralfate (1 g/25 kg).
• Drugs that block gastric acid production including famotidine (0.5–1.0 mg/kg q12h), ranitidine (1–2 mg/kg q8–12h), nizatidine (1–5 mg/kg q24h) and omeprazole (0.7–1.5 mg/kg q24h) may be beneficial. Ranitidine and nizatidine also have mild gastric prokinetic effects in vitro and may be beneficial.
• Specific gastric prokinetic agents include metoclopramide (0.2–0.4 mg/kg PO q6–8h) and cisapride (0.5 mg/kg PO q8–12h). Cisapride is only available through compounding pharmacies.
• Erythromycin (0.5–1 mg/kg q8h) given at physiologic doses stimulates gastric motility by activation of motilin receptors and may also resolve signs.

Contraindications/Possible Interactions

• Gastric prokinetic agents should not be administered in patients with gastrointestinal obstruction.
• Metoclopramide is contraindicated with concurrent phenothiazine and narcotic administration and in animals with epilepsy. Metoclopramide can cause nervousness, anxiety, or depression.
• Cisapride at higher doses can cause vomiting, diarrhea, or abdominal cramping.
• Erythromycin can cause vomiting.

Associated Conditions

Gastroesophageal reflux

See Also

• Chapters on gastric or gastrointestinal motility disorders
• Gastroesophageal Reflux