An 81-year-old woman is brought to the emergency department by a neighbor due to abdominal pain. The pain comes in waves and is associated with nausea and vomiting. The patient is confused and unable to provide additional information. Past medical history is unknown, but she comes with a bag containing medications used in type 2 diabetes mellitus, hypercholesterolemia, hypertension, and dementia. On examination, the patient has a low-grade fever and mild tachycardia. She appears in distress due to pain. Mucous membranes are dry, and there is decreased skin turgor. Abdominal examination shows diffuse tenderness with high-pitched bowel sounds. Imaging of the abdomen reveals a complete small bowel obstruction. The patient undergoes laparotomy with extraction of a hard mass obstructing the ileocecal valve. The cholesterol content of the mass is 85%. Which of the following radiographic findings is most consistent with this patient's clinical presentation?
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This patient, an older woman with intermittent abdominal pain and a cholesterol-containing mass lodged at the ileocecal valve, has a gallstone ileus. Gallstone ileus is not a true ileus (nonmechanical disruption of intestinal motility) but rather a mechanical obstruction that occurs when a large gallstone (usually >2.5 cm in diameter) erodes into the intestinal lumen through a cholecystoenteric fistula. As the gallstone travels down the intestine, it intermittently obstructs the lumen, causing episodic symptoms. Eventually, the gallstone may come to rest in the ileum, which has the smallest lumen of the intestinal tract.
Typical symptoms of gallstone ileus include crampy pain, vomiting, and bloating. Examination will show signs of small bowel obstruction, such as abdominal distension, tenderness, and high-pitched (tinkling) bowel sounds. Abdominal radiographs may reveal dilated bowel loops with air-fluid levels. Careful inspection may also reveal air in the biliary tree (pneumobilia) due to retrograde passage of intestinal gas through the fistula.
(Choice B) Bladder distension due to urinary retention is most often associated with underlying prostatic hyperplasia, anticholinergic medication use, and underlying neurologic impairment.
(Choice C) Air in the peritoneal cavity is suggestive of bowel perforation. Although the bowel wall is disrupted in gallstone ileus, the cholecystoenteric fistula is usually associated with fibrotic adhesions between the biliary tree and the bowel, and there is no free communication with the peritoneal cavity.
(Choice D) Heavily calcified vessels are a sign of chronic atherosclerotic arterial disease. Common intra-abdominal complications in such patients would include intestinal ischemia and abdominal aortic aneurysm.
(Choice E) Pancreatic calcifications are suggestive of chronic pancreatitis, which is most commonly seen in alcohol abuse, cystic fibrosis, or outlet obstruction due to tumor, pseudocysts, or recurrent passage of gallstones.
(Choice F) Pleural effusion may be seen in a broad range of intra-abdominal conditions, such as pancreatitis, esophageal rupture, or chronic hepatic or renal disease.
Educational objective:
Gallstone ileus is a mechanical bowel obstruction caused when a large gallstone erodes into the intestinal lumen. Pneumobilia (air in the biliary tract) is a common finding.