Pediatric emergency medicine trisk 637

Clinical Recognition The incidence of clinically evident malrotation occurs in approximately in 6,000 live births Over half will present in the neonatal period, and the remainder typically within the first year of life Consultation with pediatric general surgery is warranted early in evaluation for any neonate presenting with bile-stained emesis to help facilitate timely treatment Early signs can be falsely reassuring because signs of peritonitis or shock may not be evident until well after the onset of volvulus and bowel ischemia Triage Considerations Neonates with bilious emesis should be triaged urgently as volvulus can progress rapidly Ill-appearing neonates with suspected volvulus should undergo emergent surgical intervention and exploratory laparotomy FIGURE 96.38 Abdominal radiograph showing massively dilated stomach with no distal air, consistent with proximal intestinal obstruction in a patient with malrotation (Reprinted with permission from Fleisher GR, Ludwig S, Baskin MN Atlas of Pediatric Emergency Medicine Philadelphia, PA: Lippincott Williams & Wilkins; 2004.) Clinical Assessment The most common presenting sign in the neonate is bilious emesis The examination may reveal a distended abdomen; however, signs of peritonitis or shock are late findings and may not be present Abdominal radiograph may reveal obstruction of the stomach with little or no distal air in the bowel ( Fig 96.38 ) However, plain radiographs can be nonspecific or even normal appearing, particularly with intermittent volvulus, or may show a complete lack of bowel gas US with Doppler interrogation of the superior mesenteric vessels may reveal abnormal configuration of the superior mesenteric vein in relation to the mesenteric artery (normal configuration is where the superior mesenteric vein lies to the right of the superior mesenteric artery), however this is inconsistent and normal Doppler evaluation does not exclude malrotation Contrast enema may reveal abnormal position of the cecum, but again, a normal study does not exclude malrotation Therefore, the diagnostic test of choice is the upper GI series using fluoroscopy to determine the position of the ligament of Trietz, its relation to the ileocecal junction, and the position of the duodenojejunal junction to the left of midline and fixed posteriorly In volvulus, the site of the obstruction tapers, similar in appearance to a bird’s beak In a partial or intermittent obstruction, the upper GI may reveal a spiral or corkscrew appearance Laboratory findings including CBC, BMP, and inflammatory markers may be normal, particularly early in diagnoses In more advanced presentations, these labs may reveal signs of hypovolemia, dehydration, infection, or shock, particularly in the setting of volvulus or bowel necrosis Management The definitive treatment of malrotation in a symptomatic infant is emergent surgical repair In the otherwise healthy infant with an incidental diagnosis of malrotation, elective surgical repair is still recommended given the high risk of future volvulus For infants with congenital diaphragmatic hernia or abdominal wall defects and known malrotation, the low risk of volvulus allows for expectant management, as long as the family is well counseled to seek care should symptoms of obstruction develop For infants with heterotaxy, there remains significant debate whether routine surgery should be performed to prevent complications, or if watchful waiting is sufficient Current studies are ongoing to better understand the natural progression of malrotation in this population Certainly, if the infant with heterotaxy presents with clinical signs of obstruction and bilious emesis, immediate consultation with pediatric surgery is warranted In preparation for surgery, the infant should be NPO and started on parenteral hydration and nutrition If the infant is dehydrated, initial resuscitation should include intravenous fluid bolus The stomach should be decompressed with a nasoenteric tube Blood should be drawn for type and cross-match prior to surgical procedure, an evaluation of the CBC and serum chemistry should be evaluated and any abnormalities addressed Serum glucose should be checked as neonates have fewer glucose stores and can develop hypoglycemia rapidly Blood cultures should be sent and the infant started on intravenous antibiotics, as bowel ischemia can interrupt the gastrointestinal barrier and allow for bacterial translocation into the blood stream Other Causes of Intestinal Obstruction CLINICAL PEARLS AND PITFALLS Distal bowel obstructions may present without vomiting Intestinal obstruction can lead to bacterial translocation and lifethreatening sepsis in a neonate Decompression of obstructed bowel with a nasogastric tube will reduce hydrostatic pressure and lower the risk of ischemia of the gut Abdominal distention can compromise respiratory function in a neonate by diminishing pulmonary reserve and mechanical impedance from pressure on the diaphragm Small Bowel Atresia and Stenosis Complete small bowel atresia will often present with emesis and feeding intolerance immediately after birth, and many are now being diagnosed prenatally However, type atresias, with luminal webs or stenosis of the bowel, may not present until several days later, depending on the degree of obstruction Duodenal obstructions are often associated with other congenital anomalies, most commonly trisomy 21 and CHD Duodenal stenosis can occur as a result of extrinsic compression from the hepatobiliary tree or pancreas, as in annular pancreas malformations If the obstruction is distal to the ampulla of Vater, the infant will present with bilious emesis and therefore may be difficult to distinguish from midgut malrotation A plain film radiograph may reveal the classic “double bubble” ( Fig 96.39 ) with air in the stomach and proximal portion of the duodenum, and no air in the bowel distal to the obstruction Jejunoileal atresias and stenosis can be associated with malrotation, meconium peritonitis, or ileus, but are not commonly associated with known genetic syndromes Infants typically present with bilious emesis, and plain film radiograph often reveals dilated bowel loops The more distal the obstruction, the more bowel loops that are evident If the level of obstruction is unclear, malrotation must be urgently ruled out, and can be done with a limited upper GI series to assess the position of the ligament of Treitz Small bowel stenosis or stricture can also result from an acquired condition, particularly in the infant with a history of necrotizing enterocolitis (NEC) In this population, stricture formation may not occur until several months after recovery from NEC FIGURE 96.39 Abdominal radiograph revealing “double bubble” sign in a patient with duodenal atresia Note the air fluid levels in the stomach (open arrow ) and proximal dudoenum (black arrow ) (Reprinted with permission from Eisenberg RL An Atlas of Differential Diagnosis 4th ed Philadelphia, PA: Lippincott Williams & Wilkins; 2003.) Gastrointestinal Duplications Gastrointestinal duplications can occur along any level of the GI tract As with small bowel obstruction, more and more are being diagnosed prenatally Proximal obstructions of the stomach or duodenum often present in the neonatal period with bilious or nonbilious emesis Upper GI may suggest external compression of the stomach or small bowel, but US and CT can reveal the duplication mass more clearly More distal duplications of the small or large intestine may also present with obstruction, but can also lead to volvulus or hemorrhage Treatment requires surgical resection of the duplication Hypertrophic Pyloric Stenosis Hypertrophic pyloric stenosis is an acquired disease where the muscle of the pyloric sphincter becomes enlarged and obstructs gastric emptying It most often presents between and weeks of age, but can present in neonates as young as ... heterotaxy presents with clinical signs of obstruction and bilious emesis, immediate consultation with pediatric surgery is warranted In preparation for surgery, the infant should be NPO and started