The sources of these cases are as follows:

1. The majority are derived from my own clinical experience. Because this experience covers a period of 30 years, many of these are reconstructed from memory, and therefore some of the details, especially the child's age and sex, may not be accurate.

2. Three cases are based on reports in the Morbidity and Mortality Weekly Reviews (MMWR). This is indicated by “(MMWR)” with the number of the case and in the reference.

3. Several cases are composites of different cases from my experience. These are indicated by (“COMP”).

4. The remainder of the cases are hypothetical, based on current knowledge of the clinical manifestations of a particular illness. These include cases in which I have constructed a clinical scenario to match a photograph. These are indicated by (“HYP”).

Where names of the cases have been used, they are not the patients' real names, but they contain clinically important information.

CASE 1. A previously well 13-year-old girl presents with a history of nausea, anorexia, abdominal pain, and dark urine for 3 days. On examination she has mild right upper quadrant discomfort. Jaundice cannot be detected. The rest of the examination is normal.

1. What is your differential diagnosis?

2. What quick (2-minute) test can you do to help you?

3. further studies might you do?

The differential diagnosis in this patient includes the following:

1. acute hepatitis

2. cholecystitis, cholangitis, cholelithiasis

3. gastritis and peptic ulcer disease

4. pancreatitis

5. pyelonephritis

6. hepatic sludging/sequestration if she has sickle cell disease

7. liver abscess