Gall stone causes intestinal obstruction when it gets impacted in which part of the intestine commonly
a. Passage of a stone through a spontaneous biliary-enteric fistula leading to a mechanical bowel obstruction is known as gallstone ileus.
b. Most (75%) of these fistulas develop between the gallbladder and duodenum, occur in elderly people, and account for 1% of all small bowel obstructions.
c. Gallstone ileus may account for as many as 25% of cases of intestinal obstruction in patients older than 70 years who have no previous surgery or hernias on physical exam.
d. Biliary-enteric fistulas usually follow an episode of acute cholecystitis with gangrene and perforation of the gallbladder wall into the adjacent viscus or from pressure necrosis from an impacted gallstone.
e. Nausea, vomiting, and abdominal pain, signs and symptoms of intestinal obstruction, are the common presentation of patients with gallstone ileus.
f. A history of gallbladder-related symptoms is present in only half of the patients.
g. The pain may be episodic and recurrent as the impacted stone temporarily obstructs the bowel lumen and then dislodges and moves distally, known as tumbling obstruction.
h. Abdominal films will demonstrate evidence of an intestinal obstruction with pneumobilia or a calcified stone distant from the gallbladder.
i. The most common site of obstruction is the terminal ileum because of its narrow lumen.
j. Relieving the obstruction by removing the gallstone through a proximal enterotomy is the initial management of gallstone ileus; the stone is “milked” proximally, and then removed from a healthy portion of bowel.