Differential diagnosis of jaundice

1. Big picture

Jaundice is yellow discoloration of the sclera, skin, and mucosa due to increased serum bilirubin. In the exam, the key is not to list random causes, but to classify jaundice by bilirubin type and liver enzyme pattern:

Jaundice → fractionate bilirubin → check liver enzymes → ultrasound first → decide hemolytic vs hepatocellular vs cholestatic/obstructive.

The most important exam question: “A patient presents with jaundice. What is the first imaging test?” → abdominal ultrasound. It is noninvasive and can detect gallstones, common bile duct dilatation, pancreatic head/liver masses, and guides further testing.