VSR 421: Regional Veterinary Surgery (2+1)

PYLORIC  STENOSIS IN DOGS

Definitions

• Pyloric stenosis – It refers to benign muscular hypertrophy of the pylorus.
• Chronic antral mucosal hypertrophy – Refers to benign hypertrophy of the pyloric mucosa causing outflow obstruction.
• Chronic hypertrophic pyloric gastropathy ( CHPG ) Denotes pyloric hypertrophy without specifying whether the mucosa or the muscularis is involved.

Synonyms

• Pyloric stenosis also known as – – Benign antral muscular hypertrophy. – Congenital hypertrophic stenosis – Congenital pyloric muscle hypertrophy
• The cause of pyloric stenosis is unknown, but it may be due to
  • Hypergastrinemia – major regulator of gastric acid secretion and is trophic for gastric smooth muscle and mucosa.
  • Gastrin administration to pregnant bitches
  • Neurogenic dysfunction – spinal cord disorders.
  • Acute stress
  • Inflamatory disease
  • Trauma
  • Prolonged gastric distention
  • Foreign body
  • Neoplasm

Diagnosis

Clinical presentation

• Signalment
  • Most commonly seen in brachycephalic breeds ( Boxers, Bulldogs, & Boston terriers )
  • Siamese cats are also affected– Males may be more commonly affected.
  • More common in young animals although all age groups of animals are susceptible.
• History – the clinical signs are caused by obstruction of gastric outflow.
  • Vomiting – most common sign either intermittent or delayed hours after feeding or both.
  • Regurgitation
  • Aspiration pneumonia
  • Severe dehydration is uncommon but may occur
  • Later chronic vomiting
  • Electrolyte imbalance
  • Metabolic alkalosis

Physical examination findings

• Generally nonspecific findings   – Weight loss , Anorexia , Depression – Dehydration and / or  – Abdominal pain .
• Aspiration pneumonia or reflux esophagitis ( or both ) may occur secondary to chronic vomiting

Radiography

• Survey Radiographic findings – – Survey radiograph of abdomen may reveal gastric distention ( usually filled with fluid ) –
• Contrast Radiographic findings – – It reveals delayed emptying – Pyloric wall thickening – And / or filling defect in the pylorus.

Note: Normal elimination of liquid barium does not rule out gastric outflow obstruction

Diffrential diagnosis

• Any condition that causes vomiting is a differential diagnosis
  • Gastrointestinal foreign body
  • Gastritis
  • Neoplasia
  • Ulceration
  • Uremia
  • Hypoadrenocorticism
  • Diabetic ketoacidosis
  • Hepatic insufficiency
  • Peritonitis, pancreatitis
  • Inflammatory bowl disease