School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
The esophageal mucosa can be damaged by gastric juices and bile in gastroesophageal reflux disease (GERD). This disease is a common complication of lower esophageal sphincter relaxation during general anesthesia, but often remains subclinical. Esophagitis may also occur in dogs with frequent and severe vomiting. In addition, esophageal foreign bodies and swallowing of caustic substances may also cause esophagitis. In endemic areas, Spirocerca lupi infections may be at the origin of esophageal diseases. The adult worms generally inhabit the esophageal submucosa and adventitia, and lead to the formation of granulomatous nodules in the caudal esophageal wall.
Strictures share the same etiology as severe esophagitis (foreign bodies, gastroesophageal reflux, ingestion of caustic substances). They occur when the submucosa and muscularis layers of the esophageal wall are affected, and lead to excessive scarring causing partial or near total obstruction of the esophageal lumen.
Regurgitation, dysphagia, swallowing attempts “on empty,” halitosis, odynophagia (pain on swallowing as demonstrated by hesitation in swallowing, tension of neck muscles), excessive salivation, anorexia/inappetence, tachypnea, dyspnea, cough, exercise intolerance, fever (in case of aspiration pneumonia).
History often reveals previous esophageal disease (for instance esophageal foreign body) or general anesthesia prior to the development of signs. Same clinical signs as for esophagitis. Regurgitation may only occur with a specific food consistency (e.g., dry food but not a pureed diet).
A tentative clinical diagnosis of esophagitis is made on the basis of clinical signs and history. Survey radiography is usually unremarkable. The esophagus may be dilated with gas or fluid but this is a nonspecific finding. Confirmation of diagnosis and assessment of the extent and severity of lesions requires endoscopic examination. For Spirocerca lupi infections, diagnosis relies on positive fecal floatation and ultimately endoscopic confirmation of esophageal wall nodules (early) or masses (late) in dogs with compatible signs.
A diagnosis of esophageal stricture in a patient with compatible clinical signs is confirmed either by the use of endoscopy or barium contrast radiography. It is essential to differentiate stricture of the esophageal lumen from external compression.
Symptomatic treatment of esophagitis is focused on the protection of the mucosa against further damage, and facilitation of mucosal healing. Fasting for 24 h is recommended, if feasible without compromising the dog’s condition. A diet low in fat is recommended because high fat diets may be associated with increased episodes of gastroesophageal reflux. Sucralfate suspension is used to promote mucosal healing (1 g every 8 h for large dogs, 0.5 g at the same frequency for smaller dogs. Inhibitors of gastric acid secretion such as omeprazole (1–2 mg/kg PO every 12 h) and a prokinetic agent that accelerates gastric emptying (metoclopramide 0.5 mg/kg PO, SC q 8 h, or constant rate infusion of 1–2 mg/kg over 24 h) or promotes gastric emptying and increases the distal esophageal sphincter tone (cisapride 0.5–1 mg/kg PO q 8 h) should be administered preferably 30–60 min before meals.
Treatment of spirocercosis consists in administering high doses of the avermectin drug doramectin (off label). One author recommends a daily dose for 6 weeks followed by a recheck endoscopy.
For strictures, treatment consists of dilating the stricture(s) using balloons of different diameters under endoscopic control, or “bougies” of different sizes under fluoroscopic or endoscopic control. Multiple sessions at intervals of 1–2 weeks are often necessary. Injection of triamcinolone in the esophageal submucosa at the level of the stricture can help reduce the risk of relapse. After stricture dilation, treatment as described for esophagitis is recommended.
In severe cases of esophagitis, placement of a gastrostomy tube via endoscopy or surgery is beneficial to provide enteral nutrition and prevent complications associated with malnutrition while resting the esophageal mucosa.
Esophagitis of mild and moderate severity generally has a good prognosis. Severe inflammatory mucosal lesions may lead to esophageal stricture development. The prognosis for strictures is guarded. In the best-case scenario, 2–3 procedures for stricture dilation will be required, and the clinical signs will be under control, at least with soft food. In the worst-case scenario, repeated attempts at dilating the stricture will remain unsuccessful.