Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (171 page)

   A diagnosis of intrahepatic cholestasis made by clinical assessment and supported by negative findings from ultrasound or CT scan offers 95% specificity. In a patient in whom extrahepatic obstruction is not strongly suspected, no further investigation of the extrahepatic biliary tree is indicated.

TABLE 5–6. Differential Diagnosis of Jaundice

HYPERBILIRUBINEMIA

UNCONJUGATED HYPERBILIRUBINEMIA

   Causes

   Increased destruction of RBCs

   Isoimmunization (e.g., incompatibility of Rh, ABO, other blood groups)

   Biochemical defects of RBCs (e.g., G6PD deficiency, pyruvate deficiency, hexokinase deficiency, congenital erythropoietic porphyria, and α- and γ-thalassemias)

   Structural defects of RBCs (e.g., hereditary spherocytosis, hereditary elliptocytosis, infantile pyknocytosis, hereditary xerocytosis)

   Physiologic hemolysis of the newborn

   Infection (viral, bacterial, and protozoal)

   Congenital causes

   Extravascular blood (e.g., subdural hematoma, ecchymoses, hemangiomas)

   Erythrocytosis (e.g., maternal-to-fetal or twin-to-twin transfusion, delayed clamping of the umbilical cord)

   Recommended Laboratory Evaluation