Clinical History
An elderly male with multiple comorbidities is hospitalised to undergo endoscopic retrograde cholangiopancreatography (ERCP) to treat choledocholithiasis. After an initial unsuccessful procedure, repeat ERCP is performed including pre-cut sphincterotomy of the Vaterian papilla and stone retrieval using a basket device. A few hours after the procedure, the patient develops acute abdomen.
Imaging Findings
During ERCP, fluoroscopy (Fig.1) showed opacification of dilated intrahepatic and common bile ducts, and of a sizeable extraluminal collection of contrast medium (CM), consistent with periampullary perforation (Type II according to Stapfer’s classification system).
Hours later, urgent multidetector CT (Fig.2) showed diffuse gaseous bowel distension from insufflation during endoscopy, and presence of posterior pneumomediastinum, perihepatic and right parietocolic pneumoperitoneum, and of extensive retroperitoneal emphysema. The intrahepatic and common bile ducts appeared persistently distended and opacified with CM, with a few residual choledocholithiasis fragments.
Considering the worsening clinical conditions with development of peritonitis, and the imaging findings including periampullary perforation and pneumoperitoneum, the attending surgeon chose to perform urgent laparotomy. After confirmation of intra-abdominal free air, surgery included opening and toilet of common bile duct, and positioning of Kehr T-tube. Ten days later, the patient finally recovered and was discharged from hospital.
Discussion
Currently endoscopic retrograde cholangiopancreatography (ERCP) is extensively used to treat several disorders of the biliopancreatic system, including choledocholithiasis, benign and malignant biliary strictures, postoperative and traumatic ductal injuries, Oddi sphincter dysfunction, acute and chronic pancreatitis. However, ERCP is invasive and associated with non-negligible procedure-related morbidity (4-16%) and mortality (0.5-1.4% of patients), particularly in elderly patients with comorbidities. Complications include acute pancreatitis (AP), cardiovascular events, bleeding, cholangitis, and duodenal perforation (DP) in descending order of frequency. Whereas the risk of bleeding and perforation is similar to younger patients, the elderly are less likely to experience AP [1, 2].
Representing the rarest yet most feared occurrence, DP complicates 0.1-0.6% of ERCP procedures, Stapfer et al. categorized DPs according to mechanism and anatomical location, into type-I duodenal wall perforations distant form the ampulla caused by endoscope before sphincter cannulation, which invariably require surgery. Conversely, type-II periampullary injuries of variable severity caused by standard or pre-cut sphincterotomy, and type-III (limited bile duct injuries from guidewire or basket instrumentation for stone extraction) are usually amenable to conservative management [1-4].
As in this patient, DP is sometimes fluoroscopically diagnosed during ERCP. Alternatively, clinical presentation may occur hours or days later, and physical findings are often unreliable because of the retroperitoneal site of most injuries. Manifestations closely resemble those of iatrogenic AP, including abdominal pain, tenderness and distension, variable fever, leukocytosis, elevated serum lipase, amylase and acute phase reactants [1-4].
Although the therapeutic approach is increasingly conservative, delayed diagnosis of type-I DP and failure of nonsurgical treatment are often (roughly 50% of patients) fatal. Therefore, the use of CT is paramount as the gold standard technique to investigate patients with suspected ERCP-related complications, particularly to differentiate AP from DP and to closely monitor nonsurgically treated patients. Findings suggesting DP include extraluminal air behind the duodenum, in the right perirenal and anterior pararenal spaces, often tracking along perivascular planes and across the midline, sometimes pneumoperitoneum, pneumomediastinum, or pneumothorax. The amount of air poorly correlates with the injury severity, and rather reflects continuous insufflation during ERCP. In asymptomatic patients isolated retroperitoneal air (type-IV injury) is not indicative of perforation and does not require treatment. The most worrisome imaging features include extensive contrast extravasation during ERCP, intra- or retroperitoneal fluid collections, free pneumoperitoneum, massive subcutaneous emphysema, retained stones or instruments, which suggest the need for surgical treatment along with worsening laboratory and clinical parameters, particularly with peritonitis and fever [5-7].
Differential Diagnosis List
Iatrogenic duodenal perforation after endoscopic retrograde cholangiopancreatography (ERCP)
Post-procedural acute pancreatitis
Iatrogenic cholangitis
Iatrogenic haemobilia
Pneumoperitoneum
Final Diagnosis
Iatrogenic duodenal perforation after endoscopic retrograde cholangiopancreatography (ERCP)