Nausea is the sensation of impending emesis and is frequently accompanied by autonomic changes, such as increased heart rate and salivation. Nausea and vomiting typically occur in sequence; however, they can occur separately (eg, vomiting can occur without preceding nausea as a result of increased intracranial pressure).
Vomiting is uncomfortable and can cause dehydration because fluid is lost and because the ability to rehydrate by drinking is limited.
Vomiting is the final part of a sequence of events coordinated by the emetic center located in the medulla. The emetic center can be activated by afferent neural pathways from digestive (eg, pharynx, stomach, small bowel) and nondigestive (eg, heart, testes) organs, the chemoreceptor trigger zone located in the area postrema on the floor of the 4th ventricle (containing dopamine and serotonin receptors), and other central nervous system centers (eg, brain stem, vestibular system).
The causes of vomiting vary with age and range from relatively benign to potentially life threatening (see Table: Some Causes of Vomiting in Infants, Children, and Adolescents). Vomiting is a protective mechanism that provides a means to expel potential toxins; however, it can also indicate serious disease (eg, intestinal obstruction). Bilious vomiting indicates a high intestinal obstruction and, especially in an infant, requires immediate evaluation.
Infants normally spit up small amounts (usually < 5 to 10 mL) during or soon after feedings, often when being burped. Rapid feeding, air swallowing, and overfeeding may be causes, although spitting up occurs even without these factors. Occasional vomiting may also be normal, but repeated vomiting is abnormal.
The most common causes of vomiting in infants and neonates include the following:
Other important causes in infants and neonates include the following:
Less common causes of recurrent vomiting include sepsis and food intolerance. Metabolic disorders (eg, urea cycle disorders, organic acidemias) are uncommon but can manifest with vomiting.
The most common cause is
Nongastrointestinal infections may cause a few episodes of vomiting. Other causes to consider include serious infection (eg, meningitis, pyelonephritis), acute abdomen (eg, appendicitis), increased intracranial pressure secondary to a space-occupying lesion (eg, caused by trauma or tumor), and cyclic vomiting.
In adolescents, causes of vomiting also include pregnancy, eating disorders, and toxic ingestions (eg, acetaminophen, iron, ethanol).TABLESome Causes of Vomiting in Infants, Children, and Adolescents
Evaluation includes assessment of severity (eg, presence of dehydration, surgical or other life-threatening disorder) and diagnosis of cause.
History of present illness should determine when vomiting episodes started, frequency, and character of episodes (particularly whether vomiting is projectile, bilious, or small in amount and more consistent with spitting up). Any pattern to the vomiting (eg, after feeding, only with certain foods, primarily in the morning or in recurrent cyclic episodes) should be established. Important associated symptoms include diarrhea (with or without blood), fever, anorexia, and abdominal pain, distention, or both. Stool frequency and consistency and urinary output should be noted.
Review of systems should seek symptoms of causative disorders, including weakness, poor suck, and failure to thrive (metabolic disorders); delay in passage of meconium, abdominal distention, and lethargy (intestinal obstruction); headache, nuchal rigidity, and vision changes (intracranial disorders); food bingeing or signs of distorted body image (eating disorders); missed periods and breast swelling (pregnancy); rashes (eczema or urticaria in food allergies, petechiae in sepsis or meningitis); ear pain or sore throat (focal nongastrointestinal infection); and fever with headache, neck or back pain, or abdominal pain (meningitis, pyelonephritis, or appendicitis).
Past medical history should note history of travel (possible infectious gastroenteritis), any recent head trauma, and unprotected sex (pregnancy).
Vital signs are reviewed for indicators of infection (eg, fever) and volume depletion (eg, tachycardia, hypotension).
During the general examination, signs of distress (eg, lethargy, irritability, inconsolable crying) and signs of weight loss (cachexia) or gain are noted.
Because the abdominal examination may cause discomfort, the physical examination should begin with the head. The head and neck examination should focus on signs of infection (eg, red, bulging tympanic membrane; bulging anterior fontanelle; erythematous tonsils) and dehydration (eg, dry mucous membranes, lack of tears). The neck should be passively flexed to detect resistance or discomfort, suggesting meningeal irritation.
Cardiac examination should note presence of tachycardia (eg, dehydration, fever, distress). Abdominal examination should note distention; presence and quality of bowel sounds (eg, high-pitched, normal, absent); tenderness and any associated guarding, rigidity, or rebound (peritoneal signs); and presence of organomegaly or mass.
The skin and extremities are examined for petechiae or purpura (severe infection) or other rashes (possible viral infection or signs of atopy), jaundice (possible metabolic disorder), and signs of dehydration (eg, poor skin turgor, delayed capillary refill).
Growth parameters and signs of developmental progress should be noted.
The following findings are of particular concern:
Initial findings help determine severity of diagnosis and need for immediate intervention.
Other findings can be interpreted primarily depending on age (see Table: Some Causes of Vomiting in Infants, Children, and Adolescents).
In infants, irritability, choking, and respiratory signs (eg, stridor) may be manifestations of gastroesophageal reflux. A history of poor development or neurologic manifestations suggests a central nervous system or metabolic disorder. Delayed passage of meconium, later onset of vomiting, or both may indicate Hirschsprung disease or intestinal stenosis.
In children and adolescents, fever suggests infection; the combination of vomiting and diarrhea suggests acute gastroenteritis. Lesions on fingers and erosion of tooth enamel or an adolescent unconcerned about weight loss or with distorted body image suggests an eating disorder. Morning nausea and vomiting, amenorrhea, and possibly weight gain suggest pregnancy. Vomiting that has occurred in the past and is episodic, short-lived, and has no other accompanying symptoms suggests cyclic vomiting.
Testing should be directed by suspected causative disorders (see Table: Some Causes of Vomiting in Infants, Children, and Adolescents). Imaging studies are typically done to evaluate abdominal or central nervous system pathology. Various specific blood tests or cultures are done to diagnose inherited metabolic disorders or serious infection.
If dehydration is suspected, serum electrolytes should be measured.
Treatment of nausea and vomiting is targeted at the causative disorder. Rehydration is important.
Drugs frequently used in adults to decrease nausea and vomiting are used less often in children because the usefulness of treatment has not been proved and because these drugs have potential risks of adverse effects and of masking an underlying condition. However, if nausea or vomiting is severe or unremitting, antiemetic drugs can be used cautiously in children > 2 years. Useful drugs include
Promethazine is an H1 receptor blocker (antihistamine) that inhibits the emetic center response to peripheral stimulants. The most common adverse effects are respiratory depression, sedation, dizziness, anxiety, blurred vision, dry mouth, impotence, and constipation; the drug is contraindicated in children < 2 years. Therapeutic doses of promethazine can cause extrapyramidal adverse effects, including torticollis.
Prochlorperazine is a weak dopamine receptor blocker that depresses the chemoreceptor trigger zone. Drowsiness, dizziness, anxiety, strange dreams, insomnia, galactorrhea, akathisia, and dystonia are the most common adverse effects.
Metoclopramide is a dopamine receptor antagonist that acts both centrally and peripherally by increasing gastric motility and decreasing afferent impulses to the chemoreceptor trigger zone. Drowsiness, dizziness, agitation, headache, diarrhea, akathisia, and dystonia are the most common adverse effects.
Ondansetron is a selective serotonin (5-HT3) receptor blocker that inhibits the initiation of the vomiting reflex in the periphery. A single dose of ondansetron is safe and effective in children who have acute gastroenteritis and do not respond to oral rehydration therapy (ORT). By facilitating ORT, this drug may prevent the need for IV fluids or, in children given IV fluids, may help prevent hospitalization. Typically, only a single dose is used because repeated doses can cause persistent diarrhea. Other common adverse effects include headache, dizziness, drowsiness, blurred vision, constipation, muscle stiffness, tachycardia, and hallucinations.
