why bilious emesis with intestinal volvulus?

Answer 1

Here is a diagram of volvulus:
http://digestive.niddk.nih.gov/ddiseases/pubs/anatomiccolon/images/Volvulus.gif

As you can see, anything that goes into the stomach isn't going to go much farther. One of the things that will end up in the stomach is bile, from the liver. It has to go somewhere, and that somewhere is up and out. And there's your bilious vomiting!

Answer 2

The simple answer is that whenever there is obstruction beyond the ampulla (the opening of the bile duct into the duodenum) there will be bilious vomiting. Our cut and paste artist who provided the first answer has not said anything relevant to the question.

Answer 3

Volvulus of the midgut may result in several manifestations. Venous and lymphatic obstructions occur first because of lower intravascular pressures. Vascular congestion leads to bowel edema and possible oozing of blood, causing melena. Lymphatic congestion causes the formation of a mesenteric cyst and chylous ascites. If volvulus is intermittent, children may have chronic malabsorption from congestion and edema or intermittent bouts of symptoms, usually vomiting and alternating diarrhea and constipation. Arterial compromise requires higher obstructive pressures but is more acutely dangerous. Sequelae include ischemia, mucosal necrosis, intramural air formation, gram-negative sepsis, perforation, peritonitis, and death.

Answer 4

Bile empties into the intestines proximal to this type of bowel obstruction, so the bile has no place to go except "up".