Some abdominal pain can be evaluated in a measured way, but the acute surgical abdomen may require immediate surgical intervention. Three major diagnoses must be considered that are the most common and the most likely to cause complications if treatment is delayed. These diagnoses are (1) malrotation and midgut volvulus, which usually presents in the newborn period, (2) intussusception, which occurs most often in children between the ages of 2 months and 2 years, and (3) appendicitis, which is most common in children older than 5 years. Other causes of abdominal pain, some requiring immediate surgical intervention, are highlighted in BOX 336-1.