TABLE 81.3 COMMON CAUSES OF VOMITING Newborn (birth to wks) Normal variations (“spitting up”) Gastroesophageal reflux Gastrointestinal (GI) obstruction—congenital anomalies Necrotizing enterocolitis (premature birth) Infectious—meningitis, sepsis Older infant (2 wks to 12 mo) Normal variations Gastroesophageal reflux Gastrointestinal (GI) obstruction—especially pyloric stenosis, intussusception, incarcerated hernia Gastroenteritis Infectious—sepsis, meningitis, urinary tract infection Posttussive—reactive airways disease, respiratory infections, foreign body Drug overdose Older child (older than 12 mo) GI obstruction—incarcerated hernia, intussusception Other GI causes—gastroenteritis, gastroesophageal reflux, appendicitis Infectious—meningitis, urinary tract infection Posttussive—asthma, respiratory infections, foreign body Metabolic—diabetic ketoacidosis Concussion Toxins/drugs Pregnancy APPROACH TO CHILDREN BY AGE GROUPS With these introductory concepts in mind, we can approach the differential diagnosis of the principal causes of vomiting on an age-related basis An algorithm for such an approach that uses the key clinical features previously outlined is illustrated in Figure 81.1 TABLE 81.4 SIGNS AND SYMPTOMS ASSOCIATED WITH SIGNIFICANT UNDERLYING CAUSES OF VOMITING Bilious emesis —concerning for obstruction distal to the ampulla of Vater Headache, especially early morning —concerning for increased intracranial pressure Hematemesis —concerning for esophagitis, gastritis, or peptic ulcer disease Hematochezia/melena —may suggest mucosal GI disease such as inflammatory bowel disease (IBD) Weight loss or poor weight gain —consider chronic illness such as celiac disease, IBD, metabolic disorders Severe dehydration —concerning for electrolyte imbalance, warrants exclusion of underlying conditions such as obstruction FIGURE 81.1 Differential diagnosis of vomiting GI, gastrointestinal; NEC, necrotizing enterocolitis; GE, gastroesophageal; CNS, central nervous system Neonates A careful history should focus on the perinatal history, onset and duration of vomiting, nature of the vomitus, associated GI symptoms, and the presence of symptoms referable to other organ systems Onset of vomiting in the first days of life should always prompt evaluation for one of the common congenital GI anomalies that cause obstruction, such as esophageal or intestinal atresia or web, malrotation, meconium ileus, or Hirschsprung disease If the vomiting is bilious, bright yellow, or green, an urgent surgical consultation is required In most cases, a serious and possibly life-threatening mechanical obstruction may be the cause of bilious vomiting All neonates in whom the possibility of GI obstruction is entertained must have immediate flat and upright abdominal films and an upper GI series Other clinical features, such as toxicity, dehydration, and lethargy, attest to the length of time of the obstruction and its severity Except for some cases of malrotation, most neonates with a congenital basis for their bowel obstruction will present during their initial nursery stay; only rarely will the first presentation be in the ED In those rare cases where an intestinal atresia presents to the ED in the first few days of life, infants will have been vomiting since birth, evidence of obstruction with abdominal distention and bilious emesis, and plain abdominal films may show findings such as the “double bubble” of duodenal atresia Correction of dehydration and metabolic abnormalities, nasogastric decompression, and surgical consultation are the most immediate ED interventions Neonates or infants with malrotation and volvulus may present with abdominal pain (crying, drawing up their knees, poor feeding), with evidence of obstruction (bilious emesis), or an acute abdomen (abdominal distention or rigidity) Malrotation is confirmed by the abnormal radiographic location of the duodenal–jejunal junction (upper GI series) and/or the cecum (contrast enema) Immediate fluid resuscitation, GI decompression, and surgical consultation are indicated Infants with Hirschsprung disease most commonly present with delayed passage of meconium in the nursery, but may also present later with a distended abdomen and bilious vomiting Children with delayed diagnosis may also present with Hirschsprung-associated enterocolitis, with foul-smelling diarrhea, fever, and abdominal distention, or progress to life-threatening toxic megacolon Prompt recognition and treatment of electrolyte imbalance, antibiotics, and surgical consultation are essential Other serious causes of neonatal vomiting that may present to the ED include infection, such as meningitis, sepsis, pyelonephritis, omphalitis, or necrotizing enterocolitis (it should be noted that such serious infections may not be accompanied by fever in the neonate); increased intracranial pressure (ICP) related to cerebral edema, subdural hematoma, or hydrocephalus; metabolic acidosis or hyperammonemia caused by the inborn errors of amino acid and organic acid metabolism; and renal insufficiency or obstruction Such infants usually appear ill, with associated lethargy and irritability In some cases, findings such as a fever or hypothermia, a full fontanel, a diminished urinary stream, an abdominal mass, or respiratory signs will suggest the underlying cause Neonates and young infants with congenital adrenal hyperplasia may present with vomiting, growth failure, and lethargy They may appear critically ill with a similar appearance to those with sepsis, and may have electrolyte abnormalities including hyponatremia and hyperkalemia Any ill-appearing neonate with vomiting, with or without evidence of intestinal obstruction, requires hospitalization and prompt, broad evaluation for sepsis and neurologic, renal, and metabolic disease Commonly, however, a young infant in the first to weeks of life who appears entirely well is brought to the ED with the complaint of persistent vomiting The birth history and perinatal course are unremarkable The baby is vigorous, has gained weight appropriately (5 to oz per week after the first week of life), and has a normal physical examination Usually, a close description of the “vomiting” (or a trial feeding in the ED) reveals the problem to be physiologic regurgitation or reflux This is a common and usually insignificant problem, representing normal variation in the developmental maturation of the lower esophageal sphincter (LES) GER in infants is discussed further below Older Infants Older infants presenting with vomiting must also be evaluated for signs of obstruction, however the causes of obstruction in this age group differ from those in the neonate Although malrotation with volvulus must continue to be considered, other causes of obstruction in this age group include hypertrophic pyloric stenosis (HPS), intussusception, enteric duplication cysts, incarcerated hernia, and complications of Meckel diverticulum Causes of intestinal obstruction most often diagnosed in the neonatal period, such as Hirschsprung disease, may also present at this age, though less commonly The various causes of intestinal obstruction must be considered in the vomiting infant before nonobstructive causes are considered in order to make a timely diagnosis and initiate treatment HPS most commonly presents between and weeks of age It is caused when thickening of the pyloric muscle leads to gastric outlet obstruction Infants present with nonbilious emesis, during or shortly after feeds, which is often described as