sometimes takes a high position, and this could give a false impression of malrotation If an US is obtained, as with possible pyloric stenosis or intussusception, an abnormal relationship between the superior mesenteric artery and vein should lead to an upper GI series As in the case of a child with an unreduced intussusception, a child with a possible volvulus should be prepared for immediate surgery The operating room and operating team should be notified IV fluid and electrolyte replacement should begin immediately Laboratory studies should be obtained, but they not add to the diagnostic evaluation A nasogastric tube should be inserted and blood cross-matched Because this entity can present even in adulthood, every physician should understand the pathogenesis and the need for emergency surgical treatment of volvulus If immediate transfer to a pediatric hospital cannot be accomplished within an hour, a laparotomy should be performed without delay FIGURE 116.11 Malrotation Upper gastrointestinal study showing absence of the ligament of Treitz and coiled spring appearance of jejunum FIGURE 116.12 Sigmoid volvulus Abdominal radiograph shows a markedly distended sigmoid colon (arrows ) (Reprinted with permission from Lee E Pediatric Radiology: Practical Imaging Evaluation of Infants and Children Philadelphia, PA: Wolters Kluwer; 2017.) Sigmoid Volvulus Children with a history of severe chronic constipation or colonic dysmotility are at risk of developing sigmoid volvulus due to dilatation of the sigmoid colon Symptoms may be insidious in onset but often progress to signs and symptoms of complete bowel obstruction Children with a history of colonic dysmotility who present with acute severe abdominal pain, especially if vomiting or distension are present, should have abdominal radiographs obtained in order to evaluate for possible sigmoid volvulus ( Fig 116.12 ) Pyloric Stenosis Goals of Treatment Pyloric stenosis is not a surgical emergency, but proper diagnosis and correction of electrolyte abnormalities are important for rapid recovery of the infant CLINICAL PEARLS AND PITFALLS Pyloric stenosis leads to nonbilious emesis only Pyloric stenosis may present with hematemesis Severe metabolic alkalosis can lead to apnea Very early in the course of pyloric stenosis, ultrasound diagnosis based on measurements may be falsely reassuring; repeat US should be performed if symptoms persist Current Evidence Pyloric stenosis refers to an idiopathic hypertrophy of the pyloric muscle and occurs in in 250 births There is a male:female ratio of 4:1, and first born males are at higher risk A familial incidence has been shown, particularly if the mother had hypertrophic pyloric stenosis as an infant The age of onset is usually to weeks Rarely, the onset may be late in the second month of life The cause of the muscle hypertrophy is unknown, but the symptoms, diagnosis, and therapy are well defined Clinical Considerations Initial Assessment Characteristically, the infant does well, without vomiting, for the first few weeks of life and then starts vomiting, either at the end of feedings or within 30 minutes The infant is hungry and will eat immediately after vomiting The vomiting becomes more prominent and eventually becomes forceful, projectile emesis The vomitus is always nonbilious With protracted emesis, hematemesis can occur Infants with pyloric stenosis may also become jaundiced with the onset of the other symptoms The hyperbilirubinemia usually improves or abates postoperatively for reasons that are unknown Early in the course, infants may appear perfectly active and well hydrated In infants with protracted symptoms, moderate to severe dehydration may exist The abdomen is soft and nondistended and if the infant is relaxed, an “olive” mass may be palpable in the midepigastrium Sugar water can be used to help relax the ... radiograph shows a markedly distended sigmoid colon (arrows ) (Reprinted with permission from Lee E Pediatric Radiology: Practical Imaging Evaluation of Infants and Children Philadelphia, PA: Wolters... volvulus ( Fig 116.12 ) Pyloric Stenosis Goals of Treatment Pyloric stenosis is not a surgical emergency, but proper diagnosis and correction of electrolyte abnormalities are important for rapid