Introduction

• Ileus is defined as a failure of gut motility.
• It can be a cause of colic, and can also be a post-operative complication of colic surgery.
• Cause: possibilities include grass sickness, electrolyte disturbances and other agents which interfere with motility.
• Signs: abdominal pain, anorexia, lack of defecation and nasogastric reflux.
• Diagnosis: clinical signs and history.
• Treatment: some cases are refractory to treatment, but the treatment of choice is generally cisapride.
• Prognosis: guarded.

Pathogenesis

Etiology

• Grass sickness   Grass sickness  causes degenerative changes in the sympathetic ganglia   →   increase in sympathetic tone   →   in loss of intrinsic progressive motility of bowel.
• Gastrointestinal surgery, anterior enteritis   Intestine: enteritis  and peritonitis   Abdomen: peritonitis  can all predispose to the development of ileus.

Predisposing factors

• Endotoxemia   Endotoxemia: overview  .
• Pre-existing gastrointestinal disease.
• Repeated use of detomidine   Detomidine hydrochloride  and butorphanol   Butorphanol  in combination for analgesia may predispose to the development of ileus.

Pathophysiology

• Loss of intrinsic gut motility that causes peristalsis.
• Gut stasis results, and behaves like functional obstruction.
• Severe symptoms of abdominal pain, dehydration and circulatory collapse can develop.
• In cases that do not respond to treatment euthanasia   Euthanasia  may be the only option.
• Ileus can result from changes in sympathetic tone in the bowel (in grass sickness) but can also result from the actions of other biochemical compounds on bowel wall receptors.
• Presence of endotoxins   Endotoxemia: overview  , hypocalcemia   Hypocalcemia  and hypokalemia   Blood: biochemistry - potassium  all have recognized involvement in the development of ileus.
• Ileus involves the paralysis of the bowel (particularly small intestine) wall. This results in a failure of movement of bowel wall contents. The resulting stretching of the bowel wall, which would normally initiate a peristaltic wave, because excessive and further impairs motility. In addition, dehydration and bowel stasis predispose to the development of further endotoxemia, hypocalcemia and hypokalemia, which can predispose to the development of more serious ileus.
• Fluid build up or tympany can result, and can   →   gut rupture   Stomach: rupture  .

Timecourse

• Disease generally becomes life threatening within 2-3 days of inciting cause.

Diagnosis

Treatment

Prevention

Outcomes