Abdominal pain in children and the diagnosis of appendicitis

A 5-year-old girl presents to the emergency department (ED) because of vomiting, abdominal pain, and fever for the past 36 hours. The pain is periumbilical and cramping in nature, and its location has not changed since onset. The child does not have diarrhea, rash, dysuria, sore throat, or upper respiratory tract symptoms. Her temperature is 38.7degreesC (101.7degreesF), and abdominal examination reveals diffuse tenderness to deep palpation with notable rebound tenderness. There is guarding, and the pain does not decrease when the patient is distracted. The findings of the examination are otherwise normal. Plain abdominal radiographs show no abnormalities. The white blood cell (WBC) count is 16.9 x 10(9)/L (16,900/muL) with 0.88 (88%) neutrophils. The patient is unable to provide a urine specimen. You are concerned that this child might have acute appendicitis and question the value of the history, examination, and preliminary investigations in confirming this diagnosis.