Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (193 page)

   Conjugated serum bilirubin is increased; unconjugated serum bilirubin is normal or slightly increased. Urine bilirubin is increased; urine urobilinogen decreased. There is decreased stool bilirubin and urobilinogen (clay-colored stools).

   
Lipids
: Serum phospholipids are increased. Serum cholesterol is increased (acute, 300–400 mg/dL; chronic, ≤1,000 mg/dL).

   
Hematology
: PT is prolonged, with response to parenteral vitamin K more frequent than in hepatic parenchymal cell disease.

Considerations

   Laboratory findings due to underlying causative disease are noted (e.g., stone, carcinoma of duct, metastatic carcinoma to periductal lymph nodes).

   Bile duct obstruction (one): Characteristic pattern is serum bilirubin that remains normal in the presence of markedly increased serum ALP.

CANCER OF THE GALLBLADDER AND BILE DUCTS

   Laboratory Findings

   Laboratory findings of duct obstruction are of progressively increasing severity in contrast to the intermittent or fluctuating changes due to duct obstruction caused by stones. A papillary intraluminal duct carcinoma may undergo periods of sloughing, producing the findings of intermittent duct obstruction. These reflect varying location and extent of tumor infiltration that may cause partial intrahepatic duct obstruction or obstruction of the hepatic or common bile duct, metastases in the liver, or associated cholangitis; 50% of patients have jaundice at the time of hospitalization.

   
Hematology
: Anemia is present.

   
Cytology
: Examination of aspirated duodenal fluid may demonstrate malignant cells.

   
Stool findings
: Silver-colored stool due to jaundice combined with GI bleeding may be seen in carcinoma of the duct or ampulla of Vater.

CHOLANGITIS, ACUTE

   Laboratory Findings

   
Culture
: Blood culture positive in approximately 30% of cases; 25% of these are polymicrobial. Infection of bile ducts usually due to gram-negative (e.g.,
E. coli, Klebsiella
sp., gram-positive, and anaerobic [
Streptococcus faecalis
, enterococcus,
Bacteroides fragilis
]) organisms usually associated with obstruction