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