Pediatric emergency medicine trisk 638

weeks Infants will present with progressive, projectile nonbilious emesis, and in advanced cases, severe dehydration, electrolyte imbalances, and hypoglycemia Some infants may tolerate clear fluids, such as Pedialyte, but will vomit with milk Early exposure to macrolides has been associated with the development of hypertrophic pyloric stenosis Diagnosis can be confirmed by clinical examination of a palpable mass in the epigastrium that is roughly the size and shape of an olive In the absence of a palpable mass, diagnosis can be made by US, which would reveal increased diameter, thickness and length of the pylorus Definitive treatment remains surgical pyloromyotomy As hypertrophic pyloric stenosis is not a surgical emergency, the infant should be fully stabilized and resuscitated with adequate fluids and any electrolyte disturbances corrected prior to surgical repair (see Chapter 12 Abdominal Distention ) Preterm infants with hypertrophic pyloric stenosis are not affected by corrected gestational age at presentation, however are more likely to have a higher complication rate and longer length of stay compared to term infants Meconium Syndromes Meconium syndromes can result in intestinal obstruction due to thick, inspissated meconium Meconium ileus occurs in up to 20% of infants with cystic fibrosis and is often the first manifestation of the disease Abnormal mucosal cell secretion in this population results in thickened meconium throughout the small intestines and into the colon It often presents with failure to pass meconium within 48 hours, progressive abdominal distention, eventual feeding intolerance, and clinical signs of bowel obstruction, including bilious vomiting Abdominal radiography may reveal distended bowel loops typical of obstruction, as well as a granular appearance of the retained meconium within the bowel Complications of meconium ileus include volvulus, necrosis, or perforation—which can also occur prenatally Contrast enema will often demonstrate microcolon, but can also be therapeutic if the contrast can reflux into the ileum and the retained meconium is washed out The infant must be well hydrated to compensate for fluid shifts associated with the hyperosmolar enema, and care must be taken to avoid perforation or enterocolitis If the enema is incomplete or the patient has complicated meconium ileus, management typically requires surgical intervention to irrigate the bowel and evacuate the meconium, as well as address any associated atresia, necrosis, perforation, or volvulus Meconium peritonitis can occur from in utero bowel necrosis and perforation with subsequent leak of meconium into the peritoneal cavity Meconium in the peritoneum is often accompanied by inflammatory changes that may result in peritoneal calcifications and abdominal scarring Infants with meconium peritonitis and signs of intestinal obstruction often require exploratory laparotomy Meconium plug syndrome is thought to occur because of colonic hypomotility, and is commonly seen in preterm infants and infants of diabetic mothers Similar to meconium ileus, neonates typically present with failure to pass meconium within the first few days of life and progressive abdominal distention Contrast enema is often diagnostic and therapeutic, with much higher success rate of fully evacuating the meconium than with meconium ileus The need for surgical evacuation of the meconium is uncommon; however, meconium plug syndrome may be associated with Hirschsprung disease and cystic fibrosis, so patients should be evaluated for both Hirschsprung Disease Hirschsprung disease results from an aganglionic segment of the colon that results in a distal intestinal obstruction Up to 90% of infants present in the neonatal period with abdominal distention, emesis, and failure to pass meconium The abdomen is often soft, and a digital rectal examination may result in explosive stool Contrast enema can be diagnostic in up to 80% of cases when a transition zone is identified Definitive diagnosis is achieved by identification of complete aganglionosis on a biopsied specimen Eight percent of cases will have total colonic Hirschsprung Hirschsprung-associated enterocolitis occurs in up to 10% of cases but can be life threatening if unrecognized Treatment for enterocolitis requires emergent decompression of the rectum and broad-spectrum antibiotics Definitive treatment of Hirschsprung disease requires surgical resection of the aganglionic segment Anorectal Malformations Anorectal malformations leading to intestinal obstructions include the imperforate anus Most patients have associated fistulas that result in some meconium passage that can delay diagnosis In males, the fistulas can occur between the rectum and urinary tract, and in females between the rectum and perineum, vestibule, or bladder Clinicians should examine the perineum closely and look for associated malformations of the sacrum, spine, spinal cord, and genitourinary tract Treatment requires surgical correction of the malformation, which may include primary repair or colostomy, depending on the presence of associated anomalies Adhesions Infants with a history of bowel surgery can develop adhesions that present with intestinal obstruction This could include patients with a history of congenital diaphragmatic hernia, omphalocele, gastroschisis, intestinal atresia, or meconium syndrome, as well as patients with a history of NEC Necrotizing Enterocolitis CLINICAL PEARLS AND PITFALLS Although necrotizing enterocolitis (NEC) is most common in the premature infant, up to 10% of cases occur in the term infant Term infants with NEC often have specific risk factors that increase the risk of intestinal asphyxia or altered gut perfusion Infants with a history of NEC can present with small bowel obstruction months after resolution of NEC Current Evidence NEC is a gastrointestinal emergency where progressive mucosal injury and inflammation result in bowel necrosis While the incidence of NEC is inversely proportional to gestational age, up to 10% of cases occur in the term neonate Up to a third of cases of NEC result in death, and postsurgical survivors have an increased risk of developing short-bowel syndrome While the exact etiology remains unknown, elements of ischemic injury, intestinal hypoxia, coagulation necrosis, acute or chronic inflammation, and bacterial overgrowth of the GI tract are all likely contributors Term infants with a history of intrauterine growth restriction or SGA, congenital heart disease, meningomyelocele, and gastroschisis have increased risk of developing NEC Similarly, term and preterm infants with a history of polycythemia, exchange transfusion, umbilical catheterization or asphyxia, are also at increased risk of developing NEC Goals of Treatment The primary goal of treatment is early recognition of NEC so that supportive therapy can ameliorate bowel necrosis Treatment includes fluid resuscitation and blood pressure support, bowel rest, and broad-spectrum antibiotics that cover enteric bacteria Acidosis, anemia, and thrombocytopenia should be corrected Evidence of intestinal perforation (up to 50% of cases) requires surgical intervention with either a drain procedure or laparotomy Patients with necrotic bowel may present without perforation but worsening abdominal discoloration and distention and persistent thrombocytopenia and acidosis Exploratory laparotomy is often indicated in this group to identify and remove the necrotic segment Clinical Considerations Clinical Recognition The signs associated with NEC are often nonspecific and can include hematochezia, emesis or feeding intolerance, abdominal distention, lethargy, and apnea and bradycardia In advanced disease, there is also tachycardia, abdominal tenderness with discoloration, respiratory failure, and shock Laboratory analysis may reveal neutropenia, thrombocytopenia, metabolic acidosis, and/or hyponatremia Triage Considerations Neonates with suspected NEC should be triaged urgently as the disease can progress rapidly to respiratory failure and shock Clinical Assessment The most common presenting sign in the neonate is emesis The examination may reveal a distended abdomen; however signs of peritonitis or shock are often late findings and may not be present The diagnosis is made by the identification of pneumatosis intestinalis, portal venous gas, or pneumoperitoneum on abdominal radiograph ( Fig 96.40 ) In mild cases, plain radiographs may reveal signs of ileus but no evidence of pneumatosis; in these cases, portal venous gas may be appreciated by US Management There is no specific treatment for NEC other than supportive therapy Bowel rest is indicated, with gastric decompression Fluid resuscitation is often required, and in advanced disease, may also require blood pressure support Due to the mucosal injury and bacterial translocation of intestinal flora, broad-spectrum antibiotics are indicated Blood cultures should be drawn prior to the initiation of antibiotics, and will be positive in approximately one-third of cases Two-view radiographs of the abdomen are indicated to detect pneumatosis and/or pneumoperitoneum Laboratory evaluation should include blood cultures, complete blood count, basic metabolic profile, blood gas, and, in severe cases accompanied by disseminated intravascular coagulation, coagulation studies Surgical intervention is warranted if there is evidence of intestinal perforation or if there is worsening of clinical symptoms that suggest a necrotic segment Bowel necrosis is often accompanied by persistent thrombocytopenia and acidosis, with systemic signs of respiratory failure and shock  ... small bowel obstruction months after resolution of NEC Current Evidence NEC is a gastrointestinal emergency where progressive mucosal injury and inflammation result in bowel necrosis While the incidence