Regurgitating a small amount of milk, known as posseting, is normal in babies. Vomiting refers to more complete emptying of the stomach. Vomiting is one of the commonest symptoms in childhood, and is often due to gastroenteritis. It may be associated with more serious infections such as pyelonephritis, or may be the presenting symptom of life-threatening conditions such as meningitis or pyloric stenosis. In newborn infants bile-stained vomiting suggests a congenital intestinal obstruction, such as duodenal or ileal atresia or volvulus of a malrotated intestine. These need urgent investigation with an upper gastrointestinal (GI) contrast study.

Gastro-Oesophageal Reflux

Gastro-oesophageal reflux (GOR) is a common symptom in babies and in some older children with cerebral palsy or Down’s syndrome. It is especially common in the preterm. It is due to weakness of the functional gastro-oesophageal sphincter which normally prevents stomach contents refluxing into the oesophagus. GOR may present with trivial posseting or significant oesophagitis, apnoea or even aspiration. Vomiting is worse after feeds and on lying down, and may occasionally cause failure to thrive. Abnormal posturing may occur with severe acid reflux—this is known as Sandifer’s syndrome and can be mistaken for seizures.

GOR is usually diagnosed clinically on the basis of a typical history. Investigations should only be performed if the reflux is significant. These include a barium swallow and monitoring the oesophageal pH for 24 hours using a pH probe. The presence of acid in the oesophagus usually reflects reflux of stomach acid and the percentage of time that this occurs can be calculated over 24 hours. Endoscopy is used to confirm oesophagitis. Simple reflux can be managed by nursing the infant in a more upright position and by thickening the feeds with thickening agents (carob flour, or rice-flour thickeners). Formula milk is now available which thickens on contact with stomach acid, which can be helpful. Breast-fed infants may be helped by taking Gaviscon before a feed. Winding the baby well after feeds is important. In very severe reflux, drugs that affect gastric emptying and gut motility can be used and a small number of children with recurrent aspiration require surgical fundoplication. Most gastro-oesophogeal reflux resolves over time as the infant sits upright more and is weaned on to a more solid diet.

Pyloric Stenosis

Pyloric stenosis is caused by hypertrophy of the pylorus muscle. It usually develops in the first 2–8 weeks of life and is said to be most common in first-born male infants. It occurs in 1 in 300 to 1 in 500 newborn infants, and is the commonest indication for surgery in infancy. The vomiting increases in intensity and is characteristically projectile, occurring immediately after a feed. The vomitus is not bile-stained and the infant is usually hungry. There may be a history of constipation. Examination shows weight loss and dehydration and the infant is irritable due to hunger. Careful palpation after a test feed with the left hand, from the left side of the body reveals a hard mobile mass to the right of the epigastric area. Prominent peristaltic waves may be visible over the stomach. If there is doubt ultrasound examination shows a thickened and elongated pyloric muscle. Blood tests typically show a low plasma chloride, potassium and sodium, and a metabolic alkalosis secondary to protracted vomiting of stomach acid. The infant should be fully rehydrated with careful correction of the electrolyte imbalance before definitive surgery is performed. Rehydration may take at least 24 hours. Surgery involves splitting the pylorus muscle without cutting through the mucosa (Ramstedt’s pyloromyotomy). Laparoscopic pyloromyotomy is sometimes performed. Oral feeds can usually be commenced soon after surgery.

Vomiting Due to Gastroenteritis

Gastroenteritis (discussed in Chapter 30) is by far the commonest cause of vomiting in childhood, and is usually part of a gastrointestinal illness with diarrhoea. Viral gastroenteritis may sometimes cause vomiting without associated diarrhoea. This is typical of norovirus infection, which causes fever, myalgia, abdominal cramps and vomiting for 24–48 hours. Acute food poisoning or food allergy may also cause sudden vomiting.

Bowel Obstruction

Bile-stained vomiting in the first days of life should always be investigated urgently. It may be due to congenital duodenal or ileal atresia or malrotation of the small bowel. Duodenal atresia is more common in Down’s syndrome. Other causes of bowel obstruction include Hirshprung’s disease (colonic aganglionosis) and meconium ileus (in cystic fibrosis). In older infants intussusception should be suspected (see Chapter 28). All newborn infants with bile-stained vomiting should have a nasogastric tube passed to aspirate the stomach and feeds should be stopped pending investigation with an upper GI contrast study. In congenital malrotation the small bowel is rotated on its mesentery and a Doppler ultrasound scan may show malalignment of the mesenteric vessels. Once the cause of the obstruction has been identified and the child has been rehydrated, definitive surgery can take place. In older children bowel obstruction may be secondary to adhesions from previous abdominal surgery (e.g. appendicectomy).

Sepsis Presenting with Vomiting

In young infants the signs of sepsis may be very non-specific. In an unwell infant with vomiting, urinary tract infection or early meningitis should always be considered.

Vomiting Due to Raised Intracranial Pressure

If an older child has a history of regular vomiting for more than a few days then raised intracranial pressure (e.g. due to a brain tumour) must be excluded by careful neurological examination including examination of the optic discs. Early morning vomiting is said to be typical of raised intracranial pressure.