NSAID Induced Gastric Ulcers in Dogs

Fig 1: Perforating gastric ulcer of the pyloric antrum (arrow)

Non-steroidal antinflammatory drugs (NSAIDs) that are labeled for dogs have markedly improved management of chronic pain. However NSAIDs make the stomach more prone to ulceration by several mechanisms including mucosal irritation, reduction in prostaglandin production, decreasing gastric blood flow, and interfering with repair of superficial injury to the mucosa. This is a well-established phenomenon in humans and animals. A clinical study in dogs many years ago found that the most common causes of non-neoplastic ulcers in dogs were NSAIDS and hepatic disease.¹  In the past few years, most likely due to widespread and chronic use of NSAIDS in dogs, we have seen an alarming number of dogs with perforating gastric ulcers. Ulcers have been associated with multiple drugs and in some cases due to more than one type of NSAID being used concurrently or a NSAID used with a corticosteroid drug.

Fig 2: The forceps is demonstrating the full thickness ulcer

Diagnosis

The dogs with perforating gastric ulcers present with variable signs that include vomiting, anorexia, lethargy, and abdominal pain. Abdominal radiographs frequently show pneumo-peritoneum and loss of serosal detail. (Fig. 3) Emergency abdominal exploratory is indicated.

Fig 3:Right lateral abdominal radiograph of a dog with
pneumoperitoneum. Note the intraabdominal air visible under the
crura of the diaphragm. (arrows) Radiograph courtesy of Dr. David Biller
Kansas State University College of Veterinary Medicine

Surgery

The perforating ulcers tend to be located at the lesser curvature of the pyloric antrum very close to the pylorus. (Fig. 1-2) Inflammation and omental and serosal adhesions are commonly found on the affected area.  Generalized peritonitis is usually present with serosal inflammation and peritoneal effusion.

After performing a complete surgical exploratory attention is focused on the ulcer. Adhesions are removed and the edges of the ulcer are debrided. The edges of the ulcer tend to be very thickened and friable. This resected tissue is saved and submitted for histopathology to rule out malignancy. Samples of peritoneal fluid are submitted for culture and sensitivity.

Fig 4: Closure of gastric ulcer using a local full thickness flap.

To close the ulcer I have found it helpful to develop a full thickness local advancement flap of pyloric antrum and move it to the site of the defect. (Fig. 4) Closure is with 3-0 or 4-0 PDS in a simple interrupted pattern.  A Jackson-Pratt (closed suction) drain is placed in the abdomen to remove fluid and is left in place for several days.  Postoperative intensive care is required for management of the peritonitis including fluid therapy, nutritional therapy, antibiotics, and gastric antacids and protectants.

Prevention

Prevention of this potentially life threatening complication of NSAID administration should be considered for all dogs and cats receiving these drugs.

Recommendations to prevent gastric ulcers secondary to NSAIDS:

• Allow a “wash-out” period of 3-5 days when changing from 1 NSAID to another;
• Never prescribe more than 1 NSAID at a time;
• Never administer a NSAID and a corticosteroid at the same time ²;
• Avoid using NSAIDs in dogs with gastrointestinal disease or after gastrointestinal surgery of any kind;
• Avoid using NSAIDs in dogs with mast cell tumors (histamine release by the tumor can cause gastrointestinal irritation);
• Avoid administering NSAIDs to animals that are anorexic.

 References

Stanton ME, Bright RM. Gastroduodenal ulceration in dogs. Retrospective study of 43 cases and literature review. J Vet Intern Med. 1989 Oct-Dec;3(4):238-44.

Boston SE, Moens NM, Kruth SA, Southorn EP. Endoscopic evaluation of the gastroduodenal mucosa to determine the safety of short-term concurrent administration of meloxicam and dexamethasone in healthy dogs. Am J Vet Res. 2003 Nov;64(11):1369-75.