What Is Vomiting?

Vomiting is a highly coordinated reflex process that results in forceful expulsion of gastric contents through the mouth. Vomiting is a common problem in children and can be a symptom of many disorders affecting different organ systems. The many causes of vomiting in children can usually be distinguished with a thorough history and a complete physical examination. Vomiting must be distinguished from gastroesophageal reflux.

What Is Gastroesophageal Reflux?

Most parents of young infants us the term “spitting up” to describe gastroesophageal reflux, which is the effortless regurgitation of stomach contents, usually after feeding. Reflux occurs when the lower esophageal sphincter relaxes transiently and allows stomach contents to enter the esophagus. This process differs from vomiting because it is not forceful. In most cases, reflux causes no problems for infants, although parents are often alarmed. In older children, reflux can present as vomiting or heartburn. Persistent reflux can lead to esophagitis, a condition known as gastroesophageal reflux disease (GERD) that can result in irritability, poor weight gain, and sometimes cough or concerning behaviors.

How Do I Categorize Causes of Vomiting?

It is useful to classify causes of vomiting depending on the age of children. Table 41-1 lists some common and uncommon causes of vomiting in three different age groups. Remember that regurgitation or spitting up is common in infants and indicates physiologic gastroesophageal reflux, not true vomiting. Viral gastroenteritis and gastroesophageal reflux are common causes at all ages, although they tend to occur predominantly in infants and younger children. Infections outside the gastrointestinal tract (extraintestinal infections), such as otitis media, pneumonia, and urinary tract infection, are more likely to cause vomiting in younger children than in adolescents. Persistent vomiting in neonates or infants should raise suspicion about anatomic obstructions in the gastrointestinal tract such as intestinal atresia, malrotation, or pyloric stenosis. Peptic disorders such as Helicobacter gastritis or duodenal ulcer are seen most often in adolescents. Raised intracranial pressure is an important condition that can cause vomiting at any age. The likely causes of raised intracranial pressure are meningitis and hydrocephalus in infants and brain tumors in older children. Motion sickness can cause vomiting in children and adolescents. Cyclic vomiting syndrome is an uncommon disorder characterized by recurrent episodes of vomiting separated by symptom-free intervals, without any obvious organic cause.

Table 41-1 Causes of Vomiting According to Age

What Is Pyloric Stenosis?

Pyloric stenosis is a condition unique to the young infant in the first 2 to 6 months of life. Hypertrophy of the pyloric muscle at the stomach outlet prevents stomach emptying and causes persistent vomiting that can eventually result in severe dehydration with hypochloremic metabolic alkalosis. The cause is unknown, but it is not congenital. Unlike intestinal atresia or malrotation that present with vomiting in the first days to weeks of life, pyloric stenosis takes time to manifest symptoms because the hypertrophic pylorus develops after birth.

How Does the Nature of Vomiting Help with Diagnosis?

Details about the nature of vomiting can provide important diagnostic clues that help you focus your history and examination. Start with an open-ended question, such as “Tell me more about the vomiting.” Then, ask specific questions to identify duration, temporal pattern, relation with meals, color, and intensity of vomiting. Table 41-2 provides some diagnostic clues for the nature of vomiting. It is important to remember that bilious vomiting indicates intestinal obstruction unless proven otherwise.

Table 41-2 Diagnostic Clues to Vomiting

What Symptoms Are Associated with Vomiting?

Location and quality of abdominal pain may lead you to specific intraabdominal organ pathology. Painless “vomiting” in a happy, growing infant is usually gastroesophageal reflux. Epigastric pain is suggestive of peptic disorders such as duodenal ulcer, gastritis, or reflux esophagitis. Pain of acute pancreatitis is also in the epigastrium, often radiating to the back. Pain of acute appendicitis is initially periumbilical, then moves into the right lower quadrant. Diffuse severe acute abdominal pain may indicate peritonitis, perforated viscus, or intestinal obstruction. Nausea is a common symptom in gastrointestinal causes of vomiting, although it is absent in patients with raised intracranial pressure. Headache with vomiting should raise suspicion of neurologic causes, such as brain tumor or central nervous system (CNS) infection with elevated intracranial pressure, but is also seen in sinusitis. Weight loss may indicate chronic vomiting, as in pyloric stenosis. Other symptoms associated with vomiting may include fever, which signifies an infection that could be gastrointestinal or outside the gastrointestinal tract. Diarrhea along with vomiting is suggestive of gastroenteritis.

What Else Helps Identify the Cause of Vomiting?

Consider the possibility of a toxic ingestion or a side effect of a medication. Nausea and vomiting are adverse effects of many prescribed medications, including cancer chemotherapy. Over-the-counter medications such as nonsteroidal antiinflammatory drugs can cause gastric irritation, vomiting, and even hematemesis. Ask about herbal and “alternative” treatments. If a child has both vomiting and diarrhea, you should ask about travel, daycare, exposure to contaminated water, or similar illness in family or friends. Pregnancy should be considered in sexually active adolescent girls. Psychogenic vomiting may be seen in adolescents with anxiety or bulimia.

What Should I Look for on Physical Examination?

First evaluate vital signs and general appearance to identify the acutely ill child who is likely to require urgent therapeutic intervention. Vomiting can lead to dehydration that manifests as tachycardia, dry mucous membranes, and low urinary output. Surgical conditions such as peritonitis or a perforated viscus can lead to septic shock with poor capillary refill and hypotension. In the abdominal examination, you should assess for tenderness, bowel sounds, organomegaly, and masses. Guarding and rebound tenderness indicate acute abdomen or significant intraabdominal pathology, such as peritonitis. Epigastric tenderness suggests pancreatitis or peptic disorders. A child with acute vomiting plus localized right lower quadrant tenderness and guarding has acute appendicitis until proven otherwise. Bowel sounds are sluggish in paralytic ileus and may be hyperdynamic in mechanical intestinal obstruction. Children with gastroesophageal reflux and gastroenteritis may not have any abnormal findings on physical examination. If increased intracranial pressure is suspected, you should look for bulging fontanelle in infants and papilledema by funduscopy in older children.

When Are Diagnostic Tests Indicated?

After a thorough history and physical examination, laboratory workup should be ordered with a specific focus on possible causative disorders.

Ill-appearing child: A child who has vomiting and acute abdominal pain and who also appears to be sick should be admitted to the hospital for surgical evaluation. Tests including complete blood count (CBC) with differential, electrolytes, amylase, lipase, and studies of liver and renal function are useful. Imaging studies can identify intraabdominal pathology: Plain x-ray of the abdomen should be ordered if bowel obstruction is suspected. Contrast study of the gastrointestinal tract is useful to diagnose intussusception, partial bowel obstruction, and anatomic abnormalities. Ultrasound is especially useful to diagnose pyloric stenosis and, along with computed tomography (CT) scan, is used to diagnose other intraabdominal pathology, such as appendicitis or pancreatitis.

Well-appearing child: Infants with uncomplicated physiologic gastroesophageal reflux rarely require any investigations. Rotavirus antigen test and stool cultures may be obtained in a child with vomiting that is followed by diarrhea. For children with possible peptic disorders, endoscopy with biopsy and 24-hour pH study are useful tests. A well-appearing child with chronic vomiting can be evaluated as an outpatient, but consider brain imaging by CT or magnetic resonance imaging (MRI) scan for a child with chronic headache and vomiting. Children with cyclic vomiting syndrome require extensive metabolic, neurologic, and gastrointestinal workup.

How Do I Treat a Vomiting Child?

Treatment of vomiting is directed at the underlying disorder. Hospitalization and intravenous fluid resuscitation may be necessary for dehydration. Surgical intervention is necessary for conditions of acute abdomen, such as acute appendicitis, intussusception, and intestinal obstruction. An infant with pyloric stenosis must first have fluid and electrolyte abnormalities corrected before undergoing the surgical procedure to relieve the pyloric hypertrophy. Gastroenteritis is usually a self-limiting illness, and most children do not require any specific treatment except for oral rehydration. For growing infants with physiologic gastroesophageal reflux, no treatment is usually required, except for reassurance; older children with significant gastroesophageal reflux may benefit from acid suppression treatment, such as proton pump inhibitors. Adolescents with Helicobacter gastritis and duodenal ulcer require antibiotics specific for Helicobacter, plus treatment with proton pump inhibitors. Raised intracranial pressure and extraintestinal infections require specific treatment depending on the cause.

What Is the Role of Antiemetic Medications?

Avoid use of antiemetic agents unless you have a clear understanding of the underlying cause of vomiting. The antiemetic agents include medications such as antihistamines, phenothiazines, and selective serotonin inhibitors (e.g., ondansetron). These medications are useful in patients who have chemotherapy-induced vomiting, motion sickness, or cyclic vomiting syndrome. However, they are contraindicated in surgical emergencies and in situations in which specific treatment for the underlying cause is available.

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