Contributors: Ed Hall, Cheryl Hedlund
Species: Feline | Classification: Diseases
- Bowel obstruction is a frequent occurrence and is the most common indication for surgical intervention involving the gastrointestinal tract.
- Classified as simple (mechanical or functional), or strangulated Intestine: strangulated obstruction / hernia .
- Simple obstructions can be high (proximal), and involve the pylorus, duodenum and the proximal jejunum. A low (distal), small bowel obstruction involves the lower one-half of the jejunum and ileum.
- Signs: variable but may include dehydration, hypovolemic shock Shock , endotoxic shock Shock: septic , and death.
- Diagnosis: radiography.
- Treatment: usually surgical intervention.
- Prognosis: higher mortality rates are associated with strangulation and high obstructions.
- Weight loss.
- Intermittent vomiting.
- Death, (chronic cases).
- Severe clinical signs.
- Fever or hypothermia.
- Abdominal pain or tenderness.
- Palpable abdominal mass.
- Incarcerated bowel in hernia.
- Endotoxic shock Shock: septic .
- Young: more likely to play with novel objects.
- Cost of surgery.
- Distension of the bowel begins proximal to the obstruction, thus causing fluid and gas accumulation.
- The content of the fluid will depend upon the location of the obstruction.
- Large foreign body → ulceration and pressure necrosis.
- High intramural pressure → compromized blood supply → possible shunting away from intestinal capillaries to arteriovenous anastomoses → hypoxia to the bowel, loss of viability and increased permeability to toxins, including endotoxins.
- Duodenum is more sensitive to circulatory changes associated with distension.
Obstruction proximal to the pylorus
- Hydrogen ion loss → metabolic alkalosis often with hypokalemia.
Obstruction below the pancreatic and biliary ducts
- Vomiting and loss of absorption of fluid collecting proximal to the obstruction → rapid and severe losses with significant amount of bicarbonate ion → dehydration and/or hypovolemic shock → metabolic acidosis due to lactic acidosis.
- Fluid and electrolyte losses less severe but significant in chronic cases.
- Less severe distension of intestinal wall → circulation of affected intestine unimpeded.
- Partial or total obstruction of venous drainage and an intact arterial supply → intramural sequestration of blood and eventually bowel wall edema.
- Distended bowel proximal to the strangulation filled with gas and fluid containing a significant amount of blood → non-viable and necrotic bowel wall → transmural migration of toxins and bacteria → hypovolemia, endotoxic shock and death.
- Acute: proximal and strangulated obstruction.
- Chronic: low obstruction.
- Weight loss.
- Hypovolemic shock.
- Endotoxic shock.
- Abdominal pain.
- Abdominal mass.
- See abdominal radiography Radiography: abdomen , for technique.
- Radiopaque foreign body.
- Gas and fluid accumulation proximal to obstruction.
- Linear foreign bodies; pleated pattern and eccentric gas bubbles Intestine: foreign body - linear , , .
- Intussusception; soft tissue mass Intussusception , .
- Strangulated obstruction (+hernia); loops of intestine outside peritoneal cavity Intestine: strangulated obstruction / hernia Small intestine: neoplasia .
- Typically neutrophilia may be leukopenia in endotoxic shock Hematology: complete blood count (CBC) .
- Electrolyte abnormalities common due to vomiting and fluid pooling in intestine Blood biochemistry: overview .
- Monitor sodium Blood biochemistry: sodium , potassium Blood biochemistry: potassium , chloride Blood biochemistry: chloride , acid base balance.
- See gastrography Radiography: gastrography .
- To visualize radiolucent foreign body (FB) or obstruction .
- See GI ultrasonography Ultrasonography: GI system .
- May be able to visualize multilayered sections of intestine indicative of intussusception .
- Laparotomy/celiotomy to visualize obstruction Laparotomy: midline .
- Other causes of acute vomiting:
- Obstruction due to other cause:
Initial Symptomatic Treatment
- Fluid therapy to stabilize animal prior to surgery Fluid therapy: overview .
- Post-operative peritonitis Peritonitis , and enterotomy.
- For development of stricture at site of repair.
- Excellent in acute cases with rapid surgical correction.
- Guarded if chronic obstruction, particularly if intestine perforated.
- Cessation of vomiting.
- Breakdown of surgical repair.
- Pre-existing peritonitis.
- Bacteria breach intestine wall → endotoxic shock.