Medical management of pneumoperitoneum, gastric pneumatosis, and hepatic venous gas secondary to 3% hydrogen peroxide toxicity in a dog

Objective To describe the medical management and outcome of a dog suffering severe hydrogen peroxide toxicity. Case Summary A 3‐year‐old neutered female Bichon Frise was presented to an emergency and referral practice after ingestion of 10–20 mL/kg 3% hydrogen peroxide. On presentation, the dog was obtunded, was tachypneic, and had severe gastric tympany. Abdominal radiographs revealed pneumoperitoneum, gastric pneumatosis, and hepatic venous gas. The dog was managed conservatively with supportive care and oxygen therapy. Repeat radiographs 6 hours later showed complete resolution of all gas inclusions. While hospitalized, the dog developed severe hematemesis, and abdominal ultrasound revealed severe gastric wall thickening. Subsequent endoscopy confirmed severe gastric mucosal necrosis without evidence of deeper ulceration and relatively mild petechiation of the esophagus. The dog was ultimately discharged after 5 days of hospitalization and continued to do well at home. Recheck ultrasound 5 weeks postdischarge showed normal gastric wall appearance. New or Unique Information Provided To the authors’ knowledge, this is the first reported case of pneumoperitoneum secondary to hydrogen peroxide toxicity and the first description of the clinical course of severe toxicity in dogs.