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Nausea and Vomiting in Infants and Children


Deborah M. Consolini

, MD, Sidney Kimmel Medical College of Thomas Jefferson University

Last full review/revision Jun 2020
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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).



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:

Older children

The most common cause is



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).

Physical examination

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.

Red flags

The following findings are of particular concern:

  • Bilious emesis

  • Lethargy or listlessness

  • Inconsolability and bulging fontanelle in infant

  • Nuchal rigidity, photophobia, and fever in older child

  • Peritoneal signs or abdominal distention (surgical abdomen)

  • Persistent vomiting with poor growth or development

Interpretation of findings

Initial findings help determine severity of diagnosis and need for immediate intervention.


Testing should be directed by suspected causative disorders (see Table: Some Causes of Vomiting in Infants, Children, and Adolescents Some Causes of Vomiting in Infants, Children, and Adolescents 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;... read more ). 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.


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: For children > 2 years, 0.25 to 1 mg/kg (maximum 25 mg) orally, IM, IV, or rectally every 4 to 6 hours

  • Prochlorperazine: For children > 2 years and weighing 9 to 13 kg, 2.5 mg orally every 12 to 24 hours; for those 13 to 18 kg, 2.5 mg orally every 8 to 12 hours; for those 18 to 39 kg, 2.5 mg orally every 8 hours; for those > 39 kg, 5 to 10 mg orally every 6 to 8 hours

  • Metoclopramide: 0.1 mg/kg orally or IV every 6 hours (maximum 10 mg/dose)

  • Ondansetron: 0.15 mg/kg (maximum 8 mg) IV every 8 hours or, if the oral form is used, for children 2 to 4 years, 2 mg every 8 hours; for those 4 to 11 years, 4 mg every 8 hours; for those ≥ 12 years, 8 mg every 8 hours

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 Oral Rehydration Oral fluid therapy is effective, safe, convenient, and inexpensive compared with IV therapy. Oral fluid therapy is recommended by the American Academy of Pediatrics and the WHO and should be... read more (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.

Key Points

  • In general, the most common cause of vomiting is acute viral gastroenteritis.

  • Associated diarrhea suggests an infectious gastrointestinal cause.

  • Bilious emesis, bloody stools, or lack of bowel movements suggests an obstructive cause.

  • Persistent vomiting (especially in an infant) requires immediate evaluation.

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