Accuracy of abdominal ultrasonography and the role of a second investigation in surgical obstructive jaundice

Summary

The diagnostic accuracy of ultrasonography (US) was evaluated in delineating the site and cause of biliary obtruction in 59 patients of surgical obstructive jaundice (SOJ). A final analysis of the ultrasonographic data was carried out in 42 patients on whom laparotomy or endoscopic papillotomy with removal of common bile duct stones, confirmed the diagnosis. Evaluation of the role of second investigation following ultrasound in 28 patients (side-viewing endoscopy in 13, ERCP in 12 and PTC in 3) was also done to determine whether they provide any additional information over ultrasonography in delineating the exact level and etiology of biliary obsruction. US was done by the clinician who interpreted the findings in conjunction with the clinical profile of the patient. US correctly diagnosed SOJ in all 42 patients. In 26 of the 28 patients with distal CBD block (specificity 87.5%; sensitivity 100%) and in 14 out of 16 patients with proximal CBD block (specificity 100%; sensitivity 87.5%) US provided and accurate diagnosis of the site of obstruction. US was correct in diagnosing a malignant etiology in 26 out of 27 malignant cases whereas it accurately indentified the benign nature of biliary obstruction in 14 of the 15 patients of SOJ due to benign obstruction (specificity and senstivity range 93.3% to 96.3%). A second investigation could crrectly change the etiology and site of biliary obstruction in only 5 patients (17.9%) whereas in the remaining 23 patients (82.1 %) it did not add any additional information over the US findings. Six out of fifteen patients (40%) who underwent cholangiography had cholangitis and in one severe septicemia led to death. When the US data was interpreted along with the findings of sideviewing endoscopy (SVE) a correct pre-operative diagnosis could be reached in 85% cases of distal common bile duct (CBD) obstruction. The present study reveals that US should be the investigation of choice in the delineation of the site and cause of obstruction in the vast majority of SOJ cases. A second investigation such as cholangiography should be sparingly advised. Side viewing endoscopy should be routinely performed in patients with US diagnosis of distal CBD block.