Pyloric stenosis

From Dog

Pyloric stenosis (antral pyloric hypertrophy syndrome) is a rare genetic disease of dogs characterized by narrowing or hypertrophy of the stomach opening[1].

The etiology of this condition in dogs is unknown and congenital pyloric stenosis appears commonly in brachycephalic breeds such as the Boxer, Boston Terrier and Bulldog. An acquired version has been observed in the Lhasa Apso, Shih Tzu, Pekingese, Poodle and Rottweiler[2]. Males appear to be more predisposed to this disease than females[3].

Clinically affected dogs are often young at first diagnosis and the disease frequently presents in young dogs with chronic, intermittent projectile vomiting or regurgitation after eating[4]. Weight loss, polydipsia and anorexia may also be observed[5].

Pyloric stenosis produces gastric hypersecretion and is thought to stimulate the growth of the gastric mucosa as well as result in the projectile vomiting which is so characteristic of this condition[6].

Endoscopic visualization is usually confirmatory[7], but ultrasonography may show narrowing and hypertrophy of the pyloric opening into the duodenum. Occasional mucosal polyposis may be observed.

Contrast radiography may also be used to assist a diagnosis and often reveals delayed stomach emptying.

Histological analysis of biopsied pyloric tissue is characterized by gross hypertrophy and disorganised whorls of muscle, with an apparent reduction in the amount of neural tissue present[8].

A differential diagnosis would include gastric mucosal polyps[9], paraesophageal hiatal hernia[10], gastritis, gastrinoma, gastric carcinoma and Helicobacter spp-associated infections.

Treatment may be implemented conservatively with antiemetic medication but surgical intervention is required in many cases due to the refractory nature of this condition. Pyloric balloon dilation, pyloromyotomy or gastroduodenostomy are usually curative in most cases[11][12].


  1. Abel RM et al (2002) A quantitative study of the neural changes underlying pyloric stenosis in dogs. Anat Histol Embryol 31(3):139-143
  2. Spellman DG et al (1989) Acquired pyloric stenosis in a rottweiler. Vet Rec 125(13):356-357
  3. Prole JH (1989) Acquired pyloric stenosis. Vet Rec 125(25):630
  4. Walter MC & Matthiesen DT (1993) Acquired antral pyloric hypertrophy in the dog. Vet Clin North Am Small Anim Pract 23(3):547-554
  5. Bellenger CR et al (1990) Chronic hypertrophic pyloric gastropathy in 14 dogs. Aust Vet J 67(9):317-320
  6. Chen D et al (1995) Trophic effects in the acid-producing part of the rat stomach after pyloric stenosis. Scand J Gastroenterol 30(12):1147-1152
  7. Leib MS et al (1993) Endoscopic diagnosis of chronic hypertrophic pyloric gastropathy in dogs. J Vet Intern Med 7(6):335-341
  8. Abel RM (2000) The ontogeny of the peptide innervation of the human pylorus with special reference to understanding the aetiology and pathogenesis of infantile hypertrophic pyloric stenosis. Ann R Coll Surg Engl 82(6):371-377
  9. Kuan S et al (2009) Ultrasonographic and surgical findings of a gastric hyperplastic polyp resulting in pyloric obstruction in an 11-week-old French Bulldog. Aust Vet J 87(6):253-255
  10. Miles KG et al (1988) Paraesophageal hiatal hernia and pyloric obstruction in a dog. J Am Vet Med Assoc 193(11):1437-1439
  11. Walter MC & Matthiesen DT (1989) Gastric outflow surgical problems. Probl Vet Med 1(2):196-214
  12. Peeters ME (1991) Pyloric stenosis in the dog: developments in its surgical treatment and retrospective study in 47 patients. Tijdschr Diergeneeskd 116(3):137-141