Non-invasive techniques in the diagnosis of jaundice--ultrasound and computer

Computer-aided decision support in hepatology

The aim of this study was to describe and to evaluate the publications of the last 30 years devoted to computer-aided decision support in clinical hepatology. The search used Medlars and references of articles. Computer-aided decision support (CADS) was classified in two categories: statistical systems and knowledge-based systems. Two specific questionnaires were used for methodologic evaluation, one for statistical systems and one for knowledge-based systems. They were filled out independently by two observers. A total of 31 papers were selected among 55 identified between 1960 and 1991. The maximum possible for the two scores was 24. The methodologic quality ranged from 4 to 22 (median, 12) for statistical systems and from 8 to 12 (median, 9) for knowledge-based systems. The poor level of methodology could explain in part the lack of utilization of computer-aided decision support in the daily clinical practice of hepatologists.

Hepatobiliary complications of oral contraceptives

Complications secondary to the use of oral contraceptive agents are rare. Hepatobiliary complications, while often dramatic in presentation, occur infrequently. In a patient without predisposing conditions to complications, the benefits achieved with estrogen/progesterone products outweigh the risks. Those conditions that would absolutely and relatively contraindicate the use of oral contraceptives are listed in Table 4. Patients with a past history of liver disease in whom liver function tests have returned to normal may tolerate the introduction of oral contraceptives. They need to be monitored closely for adverse reactions. Patients who have experienced cholestatic jaundice of pregnancy should avoid all contraceptives because of a high risk of disease recurrence. Women whose first-degree relatives have experienced cholestasis of pregnancy or oral contraceptive-induced cholestasis may be at increased risk and should be closely monitored while taking birth-control pills. Women with current or previous benign or malignant hepatic tumors should not take oral contraceptives. Active hepatitis is an absolute contraindication to using birth control pills, although patients with a past history of hepatitis and no evidence of active disease can have a trial of these drugs with close follow-up. A final group of women who should avoid oral contraceptives is those with familial defects of biliary excretion, including the Dubin-Johnson syndrome, Rotor's syndrome, and benign intrahepatic recurrent cholestasis. Dubin-Johnson syndrome is often asymptomatic and may manifest only during pregnancy or during the use of oral contraceptives. The reduction in hepatic excretory function induced by the sex steroids can transform the mild hyperbilirubinemia into frank jaundice. Oral contraceptive agents are the most widely used reversible means of birth control currently available. Fortunately, the complications associated with these drugs are infrequent and may be decreasing due to lower-dose products. Complications still occur, however, and need to be recognized by the general internist as medication-induced problems so the offending drugs can be discontinued and appropriate treatment and follow-up initiated. In addition, patients at risk for the development of complications need to be recognized and advised prior to the introduction of oral contraceptives.

Ultrasound examination in jaundiced patients. Is computer-assisted preclassification helpful?

In this study we attempted to determine the diagnostic accuracy and reproducibility of ultrasonography (US) for jaundice and to see how US can best be combined with preliminary clinical-biochemical diagnoses to plan the invasive work-up. US proved reproducible in two diagnostic departments (127 agreements in 135 cases). But, since obstruction was underdiagnosed (15 double-false negatives), the predictive value of a negative result was only 0.83. By adding a term which represents the US conclusion, obstruction or not, to the Copenhagen pocket diagnostic chart score (based on the logistic model) we found that an obstructive conclusion increases the odds of obstruction by a factor of 25, and a non-obstructive conclusion decreases the odds by a factor of only 1.9. We conclude that the preliminary diagnosis is frequently sufficiently certain to be unalterable by US. This leaves only 40% of the jaundice cases in which US is necessary to plan invasive work-up. The US workload can even, it appears, be reduced to about 22% without appreciable penalty in terms of unrewarding invasive procedures. Using these strict indications, four US examinations seem to suffice to avoid one such error. Relying on either US or clinical-biochemical data alone is inferior to the combined strategy.

Computer diagnosis in jaundice. Bayes' rule founded on 1002 consecutive cases

Extensive clinical and clinical chemical information was collected from 1002 consecutive jaundiced patients. Initial selection of variables based on Chi 2-tests or Mann-Whitney U-test allowed the removal of 64 of the 107 variables originally collected. A further selection of variables was carried out using a modified version of Bayes' rule thus reducing the number of variables from 43 to 22. Of the 982 patients with a final diagnosis 743 patients (76%) could be classified correctly into one of 13 diagnostic categories. The Bayes' rule was also applied to a test group of a further 110 jaundiced patients and found to perform equally well: of 108 patients with a final diagnosis 81 (75%) were correctly classified. A comparison between the clinician's diagnosis and the computer-aided diagnosis according to Bayes' rule demonstrated agreement with regard to one of the 13 diagnostic alternatives in 734 patients (75%), of whom 81 patients were wrongly diagnosed. In the test group agreement upon diagnosis was found in 80 patients (74%). By plausibly combining the computer-aided and the clinician's preliminary diagnoses, more correct classifications were obtained than with either method alone. Many diagnostic modalities such as ultrasound examination, CT-scan, and direct cholangiography are at hand today for the differential diagnosis of jaundice. Computer-aided diagnosis using Bayes' rule has proved a reliable tool for the clinician and can be used in the planning of a diagnostic strategy for the individual jaundiced patient.

Differential diagnosis of jaundice: a pocket diagnostic chart

Based on extensive clinical and clinical chemical information (107 different items) from 1002 jaundiced patients, we developed a diagnostic algorithm which was evaluated on a test sample of another 110 jaundiced patients. A primary classification into categories of obstructive jaundice (probability of obstruction greater than or equal to 0.80), non-obstructive jaundice (probability of obstruction less than or equal to 0.20), and of doubtful causes of jaundice (probability of obstruction: 0.20-0.80) was attempted. Among 234 patients in the data base who were classified as obstructive, 220 (94%) proved to be so, as did 36 (97%) of 37 in the test sample. The corresponding figures for non-obstructive jaundice were 463 (96%) of 483 patients correctly classified in the data base and 47 (92%) of 51 patients in the test sample. Altogether 69% of the patients in the data base and 75% of those in the test sample were correctly classified, in 27% and 20% the cause of jaundice was doubtful, and only 4% and 5%, respectively, were misclassified. A slight majority of the patients in whom the algorithmic diagnoses were doubtful proved obstructive. A close correlation was found between the preliminary diagnoses made by the algorithm and by the clinicians. A secondary classification of the patients by the algorithm into benign versus malignant causes of obstructive jaundice performed equally well in the data base and the test sample.

The value of clinical, biochemical, ultrasound and liver biopsy data in assessing patients with liver disease

To determine the value of clinical, biochemical, ultrasound and liver biopsy data in the management of patients with liver disease, eight doctors each assessed 75 case histories. With clinical and biochemical data alone, the predictive accuracy was significantly higher when identifying patients as 'medical' rather than 'surgical' (97 compared with 79%, p less than 0.001). However, when making a specific diagnosis as opposed to classifying into medical and surgical categories, clinical and biochemical information resulted in a much lower predictive accuracy for both medical (67%) and surgical (56%) patients. With ultrasound data the predictive accuracy increased to 91% when identifying patients as 'surgical'; with liver biopsy it increased to 99% when identifying patients as 'medical'. The value of the different data assessed involves more than an evaluation of diagnostic accuracy, and in this study the relative worth of each test was therefore assessed on a five point scale based on the effect of the information on the doctors. This included a willingness to give specific treatment and make a specific diagnosis, as well as classifying patients into medical and surgical categories and the confidence they felt in their diagnoses. After clinical, biochemical and ultrasound information the doctors were only prepared to give specific treatment to 11.9% of the medical and 9.3% of the surgical patients. After liver biopsy data, however, they were willing to give specific treatment to an additional 66.6% of the medical patients and 25% of the surgical patients. Further evidence of the value of liver biopsy information came from an analysis of the changes in the doctors' confidence in a diagnosis. Thus, 96 patients were assigned a correct specific diagnosis with clinical and biochemical data alone but none were considered as 'definitive' by the doctors; when liver biopsy information was provided 59 (61%) were placed in this category.

Current concepts in diagnosis. Approach to the patient with cholestatic jaundice

On the basis of clinical evaluation, the physician should decide whether extrahepatic biliary obstruction is highly unlikely, possible, or very likely. If it is highly unlikely, no further workup for obstruction is indicated unless the clinical picture is altered on follow-up examination. Further evaluation of the biliary tree is warranted in other patients. Ultrasonography is currently the noninvasive imaging technique of first choice. Computed tomography is indicated if ultrasonography has yielded technically inadequate results or in special circumstances when it is anticipated that decisions regarding further diagnostic evaluation or treatment will be importantly influenced by the results. Negative findings obtained in a technically adequate examination may represent a logical stopping point in the workup of patients in whom obstruction is considered merely a possibility to be excluded, but they should not dissuade the clinician from further diagnostic evaluation if obstruction is considered very likely. Indeed, in selected circumstances, such as cases in which choledocholithiasis is suspected after cholecystectomy, direct cholangiography is appropriate as an initial test. If evidence of obstruction is obtained by noninvasive imaging, direct cholangiography will be required in many patients before treatment, and the choice between percutaneous or retrograde cholangiography should be made on an individual basis. The challenge to the clinician is to minimize the risk, expense, and time involved in obtaining sufficient information for a definitive diagnosis and treatment.

The reliability and clinical limitations of sonographic scanning of the biliary ducts

Sonographic scanning of the biliary ducts has been successfully used as a screening test to distinguish between patients with surgical and medical jaundice, with an accuracy of 90%. However, there is no consensus in the literature on what numerically defines a dilated biliary duct. To clarify this problem a prospective study of 102 consecutive patients was initiated to determine the sonographic size range of bile ducts in patients with and without extrahepatic ductal obstruction. The ultrasonic measurements were compared with direct measurements of the common bile duct, at surgery. The extrahepatic ductal system was visualized sonographically in 62% of the patients, while the intrahepatic ducts were found in 81% of the population. Direct measurements at operation agreed with the ultrasonic measurements in 84% of the patients. Analysis of the size range of the biliary ducts in patients with and without extrahepatic obstruction, by chi square analysis and the Student's t-test, allowed the following guidelines to be established. Extrahepatic bile duct obstruction was present if the extrahepatic bile ducts was 1 cm or wider (p less than 0.001) or if the intrahepatic bile duct was in excess of 0.5 cm (p less than 0.001). Similarly if the extrahepatic bile duct measured less than 0.8 cm sonographically, and the intrahepatic bile duct was 0.4 cm or less than bile duct, obstruction was not present (p less than 0.001).

Endoscopic retrograde cholangiography and pancreatography in investigation of post-cholecystectomy patients

102 severly symptomatic post-cholecystectomy patients were studied by endoscopic retrograde cholangiography (ERCP), and successful ampullary cannulation was achieved in 101. All 29 patients with jaundice were correctly classified into intrahepatic and extrahepatic causes. 8% (73) patients with abdominal pain but no history of jaundice had retained biliary calculi, and 25% had an abnormal pancreatogram suggesting pancreatitis. The measurement of bileduct calibre alone did not reliably distinguish between the presence or absence of retained stones. It is suggested that ERCP is the investigation of choice in the symptomatic post-cholecystectomy patient.