Hepatobiliary and pancreatic: Cystic duct obstruction after metallic stents

Abstract

A 58-year-old man was admitted to hospital with jaundice and abdominal pain. The diagnosis of pancreatic cancer was confirmed on a fine-needle aspirate at the time of endoscopic ultrasonography and he was treated with an uncovered metallic biliary stent. Subsequently, his liver function tests returned to normal. After 5 months, he was readmitted to hospital with fever and abdominal pain. At endoscopic retrograde cholangiography, the stent appeared to be occluded and a second uncovered metallic stent was placed within the first stent. Six days later, he developed abdominal discomfort and abdominal distension. On physical examination, there was distension and tenderness in the right abdomen (Figure 1). A computed tomography scan showed that distension was caused by an enlarged gallbladder with a thickened gallbladder wall (Figure 2). After treatment with antibiotics, the gallbladder remained enlarged but was asymptomatic. An enlarged gallbladder in the presence of malignant obstruction of the bile duct is often called Courvoisier's sign. The sign develops because increases in intrabiliary pressure associated with obstruction of the lower bile duct are transmitted through the cystic duct to the gallbladder. However, the frequency of Courvoisier's sign in contemporary patients with malignant obstruction is only approximately 30%. A second mechanism for an enlarged gallbladder is obstruction of the cystic duct, often with the development of acute cholecystitis but sometimes with the development of a mucocele. One cause of cystic duct obstruction is plastic or metallic biliary stents. In relation to the latter, uncovered stents have a low frequency of migration but a higher frequency of stent obstruction by tumor ingrowth. In contrast, covered stents have a lower frequency of tumor ingrowth but a higher frequency of stent migration and perhaps cystic duct obstruction. In the patient described above, we assume that placement of a second uncovered stent resulted in obstruction of the cystic duct and the development of acute cholecystitis. When acute cholecystitis occurs in the setting of biliary stents, options for treatment include conservative measures with antibiotics, removal of the stent (and perhaps the use of a shorter stent) and cholecystectomy. As many of these patients are unwell, a trial of medical therapy is likely to be adopted in the first instance.