Congenital Pyloric Stenosis
Introduction
This is an uncommon condition where there is thickening or hypertrophy of the pyloric circular smooth-muscle layer that results in delayed gastric emptying of solid foods.
It is primarily reported in young male dogs and brachycephalic breeds such as the Boxer and Boston terrier. It is rare in cats, but occurs almost excusively in young Siamese cats.
Concurrent megaoesophagus is often present in cats, suggesting an underlying autonomic disorder.
One proposed aetiology for the disease is that it is caused by the excessive secretion of gastrin, which has a potent trophic effect on pyloric smooth muscle and on the mucosa.
Clinical Signs
Clinical signs are seen in kittens and puppies which have just been weaned, since outflow of solid foods is affected.
The main sign is vomiting partially digested food without bile, usually several hours after eating.
The animal may appear stunted and aspiration pneumonia may be present.
Diagnosis
Diagnosis is firstly based on history and clinical signs.
Delayed gastric emptying should be diagnosed on radiographic studies.
Radiographic signs may include gastric distention or delayed emptying of contrast material (swallowed barium or barium-impregnant polyethylene spheres, BIPS)
Ultrasonography may demonstrate thickening of the pyloric area.
Diagnosis can be confirmed by exploratory laparotomy.
Treatment
In cats, treatment is difficult and often unsuccessful.
Medical therapy includes: prokinetic drugs such as metoclopramide, cisapride and erythromycin
Dietary manipulation such as feeding a low-fat diet or liquid food to encourage gastric emptying.
Surgical techniques can also be used:
Fredet-Ramstedt pyloromyotomy: longitudinal incision through the serosa, muscularis and submucosa to permit bulging of the mucosa, relieving constriction of the pylorus. The incision is left open.
Heineke-Mikulicz pyloroplasty: similar incision but this one penetrates the mucosa and enters the pyloric lumen. The incision is closed transversely in a simple interrupted pattern penetrating all tissue layers.
Post-operative care includes: providing fluids to maintain fluid balance, providing bland food within 24 hours.
The response to surgery varies considerably between individuals, but approximately 50% of cases respond favourably.
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References
Hoskins, J. (2001) Veterinary pediatrics Elsevier Health Sciences
Hosgood, G. (1998) Small animal paediatric medicine and surgery Elsevier Health Sciences
Dunn, J. (1999) Textbook of small animal medicine Elsevier Health Sciences