Pediatric emergency medicine trisk 399

TABLE 81.3
COMMON CAUSES OF VOMITING
Newborn (birth to 2 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 2 to 4 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 7 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 3 and 6 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