Pediatric emergency medicine trisk 3749 3749

FIGURE 116.3 Perforated appendicitis with abscess and fecalith Ultrasonography of the pelvis shows a complex mass (A ) with a fecalith (arrow ) producing characteristic acoustic shadowing to the right of the bladder (B ) Initially, the findings may be confused with those of pneumonia because the extreme abdominal pain may cause rapid shallow respirations, grunting, and decreased air entry to the lower lung fields In young children, the findings may also be confused with meningitis because of paradoxical irritability—any motion of the child, even trying to comfort the child, may cause pain and irritability The laboratory findings in the child with perforated appendicitis often suggest this diagnosis The WBC count is significantly elevated, usually higher than 15,000/mm3, with a marked shift to left; leukopenia may be seen with perforation when associated with overwhelming sepsis The radiologic evaluation of suspected perforated appendicitis should include plain abdominal radiographs and either US, CT, or MRI The plain film of the abdomen may show free air or evidence of peritonitis The US of the pelvis may show a complex mass with or without a calcified fecalith or free fluid within the abdominal cavity ( Fig 116.3 ) CT is generally performed with IV and enteral contrast to define the size and location of an associated abscess ( Fig 116.4 )