Pyloric Stenosis

Pyloric stenosis is a common abnormality involving the stomach. The condition results from thickening of the muscles of the pyloric sphincter (the "exit" of the stomach) and is thought to be inherited. The thickening of this opening slows or blocks the flow of the digested food from the stomach to the small intestine. Affected breeds include toy breeds (Lhasa Apso, Maltese, Pekingese and Shih Tzu) and those with flattened, shortened heads, especially <Boxers and Boston Terriers. Male dogs are more often affected than females.

Signs of Pyloric Stenosis

Clinical signs include vomiting which may occur soon after eating, but in many cases can be delayed for up to 24 hours after a meal. Normally, the stomach should be completely empty within 7 to 8 hours after the ingestion of food. Thus the vomiting of food eaten 24 hours previous is essentially indicative of pyloric stenosis (gastric retention). Bloating is often observed after consuming a meal. In most cases, the appetite remains normal, although most dogs are underweight.

Treatment of Pyloric Stenosis

Treatment is through dietary modification and medication which involves placing the pyloric muscle at rest with gastric decompression and anticholinergics. In more severe cases, surgery may be required, but the prognosis is generally good.

Secondary pyloric stenosis (cicatricial) can occur following remission of the main clinical effects after accidental ingestion (dogs) of packaging materials used to contain household cleaning products (powders, etc.), or of products used to unblock sinks, drains and wastepipes, and in industrial detergents. Dermal and ocular discharges may occur following contact. The cicatricial pyloric stenosis (cicatricial) is slow in onset and generally fatal.

References:
1. Textbook of Small Animal Medicine By John K. Dunn
2. UC Davis Book of Dogs By Mordecai Siegal