ESSENTIAL DIAGNOSIS OF ABDOMINAL EMERGENCIES
1019
range from loose diarrhea with mild abdominal distention and no systemic manifestations to explosive diarrhea with mucosal ulceration, marked abdominal distension, and sepsis [67]. Toxic megacolon is a life-threatening complication of enterocolitis. It is associated with fever, abdominal distention, bilious vomiting, explosive diarrhea, volume depletion, and shock [63,64]. Radiographs typically will show air fluid levels and the absence of air in the distal rectosigmoid colon [68]. Pneumatosis intestinalis also may be seen on radiograph [64,68]. Spontaneous perforation is estimated to occur in about 3% of patients [66]. Differential diagnosis For those patients who present with enterocolitis, necrotizing enterocolitis, omphalitis, appendicitis, and malrotation with volvulus should be considered. Medical conditions such as infectious colitis, congenital hypothyroidism, and meconium ileus from cystic fibrosis also should be considered for those newborns who present with abdominal distention, vomiting, and constipation. Laboratory and imaging diagnostics A high index of suspicion is required to diagnose Hirschsprung’s disease. Abdominal radiographs may be suggestive of a toxic megacolon and may show dilated loops of bowel with mucosal changes or pneumatosis intestinalis. Free peritoneal air also can be detected. A radiograph additionally may demonstrate pathologic air–fluid levels without rectal air, which is suggestive of Hirschsprung’s disease (Fig. 6). A contrast enema may show the
Fig. 6. Plain radiographs demonstrating air–fluid levels in the intestine and no gas in the rectum. This is suggestive for Hirschsprung’s disease. (Courtesy of Loren G. Yamamoto, MD, Honolulu, Hawaii.)