Both vomiting and gastro-oesophageal reflux result in the ejection of gastric contents through the mouth, but the pathophysiology and treatment of the two disorders is entirely different.
The history needs to distinguish between acute, chronic and cyclical patterns of vomiting.
Hirschsprung’s disease: the colon becomes enlarged
Viruses are the most common cause of gastroenteritis in childhood. Rotavirus has a peak of infection between six and 24 months of age. Vomiting with low grade fever will usually precede diarrhoea and generally lasts less than 24 hours. Treatment is supportive.
UTI is an important cause that should not be missed, especially in infants where underlying renal disease may be a contributory factor. Children with CNS infections will commonly vomit, although typically other features predominate.
There are many possible causes of early onset, often bile-stained vomiting, including intestinal atresias, malrotation with volvulus, and motility disorders including Hirschsprung's disease, meconium ileus and intestinal pseudo- obstruction.
Surgical referral is mandatory for infantile bile-stained vomiting, as abdominal signs can on occasion be minimal until the situation has become grave.
In older infants, typically over six months, intussusception should be considered. In addition to mechanical causes of intestinal obstruction, vomiting can be a symptom of surgical emergencies such as appendicitis.
Food allergy includes both IgE-mediated and non-IgE mediated reactions. In some patients this is manifest as acute onset watery diarrhoea and in others in rapid induction of emesis.
This can be a source of confusion in infants as milk coming up from the stomach following a feed is most often due to gastro-oesophageal reflux.
Pain is also a common part of these acute onset reactions. A trial of feeding with an oligoantigenic (hypoallergenic) feed will usually have immediate benefit.
Non-IgE mediated food allergy is commonly associated with delayed hypersensitivity reactions within the intestine in which eosinophilic infiltration of the GI mucosa can be prominent. On occasion vomiting can be a feature. Diagnosis is made by GI endoscopy and mucosal biopsy.
Other types of foregut GI inflammation can result in dysmotility, which can present with symptoms in which nausea, early satiety and vomiting are prominent.
Coeliac disease should always be considered as it is common, affecting approximately one in 100 European children.
Recurrent episodes of acute vomiting are seen in association with acute metabolic crises in a number of inborn errors of metabolism.
Most of the time these patients will have encephalopathy, although foregut dysmotility is a prominent feature in some patients with methylmalonic acidaemia even when they are well.
In early childhood, posterior fossa tumours predominate among intracranial space-occupying lesions and intermittent vomiting might be the only symptom until relatively late in the disease process.
Because of this paucity of clinical signs, cranial CT scanning is an integral part of the diagnostic algorithm where no other causes are apparent.
Cyclical vomiting is defined as episodes of vomiting between which the child is entirely healthy. Almost invariably the disease improves with age, although small numbers of affected teenagers continue to have symptoms in adulthood.
Some children with cyclical vomiting suffer migraine, often diagnosed due to the strong family history, a definite prodrome (often with a defined precipitant and associated unilateral headache) and intense nausea with or without vomiting. The response to first-line antimigraine treatments is often excellent.
Most gastroenterologists will consider idiopathic cyclical vomiting syndrome a diagnosis of exclusion when the above conditions have been excluded. Distinguishing it from migraine can be difficult.
Three phases are recognised: a prodrome of variable length, a vomiting phase during which the affected child can appear exhausted, withdrawn and frequently adopting a flexed or fetal position, and a recovery phase of variable length.
In some families there is an increased incidence of hypothyroidism, IBS and migraine without aura in females on the maternal side of the family, supporting the possibility of mitochondrial genetic influences. Hypertension and hyponatraemia due to vasopressin overproduction can occur.
Precipitants of a vomiting episode include travel, stress, infection and menstruation.
Cyclical vomiting syndrome can be mimicked by intermittent pelviureteric junction obstruction and it may be necessary to obtain an acute renal ultrasound during an attack.
- Dr Lindley is consultant paediatric gastroenterologist at UCL Institute of Child Health and Great Ormond Street Hospital for Children.