View source for 10. Bowel obstruction (ileus)

Ileus is defined as a complete cessation of bowel passage. There is no passing of stool or gas. The partial form of ileus is called subileus.

Miserere, the vomiting of faecal matter, may occur. X-ray shows distended segments of the gut filled with fluid and gas. A splashing sound can be heard after pushing on the side of the abdomen.

The pathophysiology is complex and not fully understood. The lack of passage itself isn’t dangerous in itself, however it does induce significant stretch of the bowel wall. Bacterial degeneration of gut content leads to gas formation and even more wall stretch. This stretch evokes pathological reflexes that further inhibit gut motility. The stretch also impairs the circulation of the intestines, causing localized ischaemia with increased gut permeability. Necrosis, perforation and translocation of bacteria and toxins into the circulation may occur. Peritonitis is a possibility.

Another danger comes from salt, water, bicarbonate and potassium loss, causing exsiccosis, metabolic acidosis and hypokalaemia.

Three types of ileus exist:

* Obstructive – where something mechanically obstructs the intestine
* Dynamic – where there is no obstruction but also no motility
** Paralytic – where there is no muscle activity
** Spastic – where the muscle activity is uncoordinated and therefore inefficient

The obstructive and paralytic types are the most important.