Paediatrics chapters
Approach to vomiting in children
How to tell vomiting from reflux, the common causes at each age, the red flags that point to surgery or serious illness, the tests worth doing, and how to manage dehydration and the cause.
- Vomiting is forceful, preceded by nausea and retching; regurgitation (reflux, "spitting up") is effortless; the cause depends strongly on age.
- Red flags: bilious (green) vomiting, blood or coffee-ground vomit, severe pain or distension, early-morning vomiting with headache, bulging fontanelle, lethargy, poor growth or severe dehydration.
- Treat dehydration and electrolytes first, then the cause; avoid antiemetics until the cause is known and never in surgical emergencies; ondansetron may help viral gastroenteritis.
On this page
Overview
Vomiting is one of the commonest symptoms in children. Most episodes are due to viral gastroenteritis or a minor infection and settle with fluids. The skill is to spot the few children with a surgical, neurological or metabolic cause, using the age, the nature of the vomit and the red flags, and to treat dehydration and electrolyte loss early.
Definitions
| Term | Features |
|---|---|
| Vomiting | A coordinated, forceful emptying of stomach contents through the mouth, usually preceded by nausea and accompanied by retching |
| Regurgitation (reflux, "spitting up") | Effortless, not preceded by nausea; the baby looks well |
| Bilious vomiting | Green vomit; bile means the obstruction is below the ampulla of Vater |
| Haematemesis | Vomiting blood or coffee-ground material |
Common causes by age
| Age | Gastrointestinal | Outside the gut |
|---|---|---|
| Newborn | Intestinal atresia, malrotation with volvulus, meconium ileus, Hirschsprung disease, NEC, swallowed maternal blood | Sepsis, meningitis, inborn errors of metabolism (galactosaemia, urea cycle defects, organic acidaemias), congenital adrenal hyperplasia, hydrocephalus |
| Infant | GER, pyloric stenosis (first weeks to 4 months), cow's milk protein allergy, intussusception, gastroenteritis, incarcerated hernia | UTI, otitis media, pneumonia, meningitis, raised ICP |
| Child | Viral gastroenteritis, food poisoning, appendicitis, hepatitis, intussusception, peptic disease | Streptococcal pharyngitis, UTI, otitis media, DKA, migraine, cyclic vomiting, brain tumour, motion sickness, drugs and poisons |
| Adolescent | Gastroenteritis, peptic ulcer, pancreatitis, cholecystitis, IBD | Pregnancy, migraine, drugs, eating disorders, DKA, raised ICP |
Vomiting is often a sign of illness outside the gut (UTI, otitis media, pneumonia, meningitis). Always examine the whole child.
Clues from history and examination
| Clue | Points to |
|---|---|
| Fever, diarrhoea, sudden onset, no pain | Viral gastroenteritis |
| Effortless, chronic, after feeds, thriving baby | GER |
| Projectile, non-bilious, after feeds, hungry baby, weight loss, under 4 months | Pyloric stenosis |
| Bilious, neonate, polyhydramnios | Atresia, malrotation |
| Colicky pain, drawing up legs, lethargy, redcurrant-jelly stool, mass | Intussusception |
| Pain moving to right lower quadrant, fever | Appendicitis |
| Severe epigastric pain radiating to back | Pancreatitis |
| Jaundice, contact history | Hepatitis |
| Early-morning vomiting, headache, diplopia, getting worse | Raised ICP / brain tumour |
| Fever, neck stiffness, bulging fontanelle | Meningitis |
| Stereotyped attacks with well periods between | Cyclic vomiting syndrome, migraine |
| Worse with fasting or certain feeds, early in life | Metabolic disease |
| Blood or coffee-ground material, epigastric pain | Peptic ulcer, gastritis, varices |
Red flags
- Bilious (green) vomiting, especially in a newborn
- Blood or coffee-ground vomit
- Abdominal distension, severe pain, tenderness or guarding
- Projectile vomiting in a young infant
- Early-morning vomiting with headache, bulging fontanelle, altered consciousness, focal signs
- Lethargy, signs of sepsis or shock, severe dehydration
- Poor weight gain or weight loss
- Associated jaundice, hepatosplenomegaly, or vomiting worse with fasting (metabolic)
Bilious vomiting in a neonate is malrotation with volvulus until proved otherwise. It needs urgent imaging and a surgeon, not an antiemetic.
Gastroenteritis can cause ileus with bile-stained vomit (Akbar), but bilious vomiting must never be assumed to be "just gastroenteritis" without examining for obstruction.
Examination
- Hydration: capillary refill, mucous membranes, skin turgor, fontanelle, pulse, BP, weight
- Abdomen: distension, visible peristalsis, olive-shaped pyloric mass, organomegaly, tenderness, guarding, bowel sounds, hernial orifices
- Chest, ears, throat, urine for infection
- Neurology: fontanelle, head size, fundi, neck stiffness
- Rectal examination and stool for occult blood when indicated
Investigations
| Test | Why |
|---|---|
| Serum electrolytes, urea, creatinine, glucose | Dehydration; hypochloraemic, hypokalaemic metabolic alkalosis in pyloric stenosis and protracted vomiting |
| CBC | Infection, anaemia, blood loss (haematocrit) |
| Amylase, lipase, liver tests | Pancreatitis, hepatitis |
| Urinalysis and culture | UTI; ketones; pregnancy test in teenage girls |
| Abdominal X-ray | Obstruction (dilated loops, fluid levels), large gastric bubble in pyloric stenosis |
| Ultrasound | Pyloric stenosis (thick, long pylorus), intussusception (target sign), gallstones, renal stones, malrotation |
| Upper GI contrast study | Malrotation, anatomical obstruction; "string sign" in pyloric stenosis |
| Contrast or air enema | Diagnoses and reduces intussusception |
| Endoscopy | Bloody vomit, oesophagitis, peptic disease |
| CT/MRI brain | Suspected raised ICP |
| Metabolic tests (ammonia, blood gases, urine organic acids) | Suspected inborn error |
Key conditions
Gastro-oesophageal reflux (GER) versus GERD
- GER is the passage of gastric contents into the oesophagus. Nearly half of infants reflux at 2 months; it is physiological and usually stops by 8 to 12 months as the baby sits up and takes solids.
- Contributing factors: liquid diet, lying flat, short oesophagus, small stomach, large frequent feeds, and transient relaxation of the lower oesophageal sphincter (main mechanism).
- GERD is reflux causing problems:
| GER (physiological) | GERD (disease) |
|---|---|
| Thriving, no weight loss | Poor weight gain or weight loss |
| No breathing symptoms | Apnoea, cyanosis, aspiration, wheeze, recurrent pneumonia |
| No oesophagitis | Irritability, arching, haematemesis, dysphagia, anaemia, stricture |
| No neurobehavioural signs | Sandifer syndrome (neck tilting, arching) |
- Risk of GERD is higher with neurological impairment, asthma, cystic fibrosis, hiatus hernia and repaired oesophageal atresia.
- Diagnosis: usually clinical; 24-hour oesophageal pH monitoring (pH below 4) is a sensitive test; impedance monitoring; endoscopy for oesophagitis; contrast study to exclude anatomical causes.
- Management: reassurance for physiological reflux; thickened, smaller, more frequent feeds, upright position after feeds, avoid smoke exposure. GERD: acid suppression (PPI or H2 blocker); fundoplication (Nissen) for failure to thrive, stricture or apnoea not responding to medical treatment.
Pyloric stenosis
- Hypertrophy of the pyloric muscle causing gastric outlet obstruction; about 6 to 8 per 1000 births, boys 5:1, commoner in first-born (Nelson).
- Starts in the first weeks of life: increasingly forceful, projectile, non-bilious vomiting just after feeds; the baby stays hungry, then becomes dehydrated and thin.
- Visible gastric peristalsis in the left upper abdomen and a palpable "olive".
- Blood: hypochloraemic, hypokalaemic metabolic alkalosis, raised urea; sometimes unconjugated jaundice.
- Ultrasound confirms a long, thick pylorus.
- Correct fluids and electrolytes first, then pyloromyotomy.
The alkalosis comes from repeated loss of hydrochloric acid in purely gastric vomit; the vomit has no bile because the block is above the duodenum.
Cyclic vomiting syndrome
Two or more episodes of intense nausea and unremitting vomiting lasting hours to days, with return to normal health between attacks; related to migraine and often a family history of migraine.
Complications of vomiting
- Dehydration, shock
- Metabolic alkalosis, hypochloraemia, hypokalaemia, hyponatraemia
- Mallory-Weiss tear (haematemesis after forceful retching), oesophagitis
- Aspiration pneumonia (especially with neurological problems)
- Malnutrition and failure to thrive with chronic vomiting
- Dental erosion (chronic reflux)
Management
- Resuscitate: airway, breathing, circulation; 20 mL/kg isotonic bolus for shock.
- Rehydrate: ORS in small, frequent amounts for mild to moderate dehydration; IV fluids for severe dehydration, persistent vomiting, distension or shock.
- Correct electrolytes with the right fluid (for example normal saline with potassium in pyloric stenosis once urine is passed).
- Nil by mouth and nasogastric decompression for suspected obstruction; urgent surgical review for bilious vomiting, peritonism or intussusception.
- Treat the cause: antibiotics for UTI or meningitis, enema reduction for intussusception, surgery for pyloric stenosis or malrotation.
Antiemetics
| Drug | Use |
|---|---|
| Ondansetron (5-HT3 blocker) | Viral gastroenteritis (improves ORS tolerance), chemotherapy vomiting (with dexamethasone) |
| Phenothiazines (prochlorperazine) | Food poisoning, motion sickness; side effects limit use |
| Antihistamines, hyoscine | Motion sickness |
- Do not prescribe antiemetics until the cause is known, and only for severe symptoms.
- Never in surgical emergencies, or when specific treatment of the cause is available.
- Correcting dehydration, ketosis and acidosis often stops the vomiting in gastroenteritis by itself.
Persistent vomiting in a child with diarrhoea is not a reason to stop ORS. Give it in small sips after a 10-minute pause; ondansetron can help if vomiting persists.
Monitoring and follow-up
- Repeated hydration checks, weight, urine output, electrolytes during IV therapy
- Watch for bilious vomiting, distension or worsening pain that changes the diagnosis
- Growth monitoring for chronic vomiting and GERD
- Safety-net advice: return if green or bloody vomit, drowsiness, no urine, persistent pain
Expect: vomiting versus regurgitation; age-based causes (atresia and malrotation in neonates, pyloric stenosis and GER in infants, gastroenteritis and extra-intestinal infections in children); bilious vomiting as a surgical red flag; projectile non-bilious vomiting with an olive and hypochloraemic hypokalaemic alkalosis in pyloric stenosis; physiological reflux resolving by 8 to 12 months and GERD features (poor growth, apnoea, Sandifer syndrome); early-morning vomiting with raised ICP; complications such as Mallory-Weiss tear and alkalosis; and the rule against antiemetics in surgical emergencies.
Quick revision
- Vomiting is forceful with nausea; regurgitation is effortless.
- Neonate: bilious = obstruction (malrotation, atresia) until proved otherwise.
- Pyloric stenosis: projectile, non-bilious, hungry, olive, hypochloraemic hypokalaemic alkalosis.
- GER normal in infants, resolves by 8 to 12 months; GERD = poor growth, apnoea, oesophagitis, Sandifer.
- Look outside the gut: UTI, otitis, pneumonia, meningitis, DKA, raised ICP.
- Early-morning vomiting with headache = raised ICP.
- Fluids and electrolytes first; antiemetic only when cause known, never in surgical cases.
Written by The House Job from standard references (Basis of Paediatrics by Pervez Akbar; Nelson Essentials of Paediatrics).
FAQ
Why is bilious vomiting so worrying in a newborn?
Green vomit means the blockage is beyond the duodenal ampulla; malrotation with volvulus can strangle the gut within hours, so urgent imaging and surgery are needed.
Does a baby who spits up after every feed need treatment?
Not if the baby is thriving and comfortable. Physiological reflux settles by about 8 to 12 months; treatment is for poor growth, breathing problems or oesophagitis.
What blood picture is typical of pyloric stenosis?
Low chloride, low potassium and metabolic alkalosis, with a raised urea from dehydration.
Is ondansetron safe in gastroenteritis?
It can be used to reduce persistent vomiting and help oral rehydration, but only after surgical causes have been excluded.