What is gastroesophageal reflux?

GASTRO-OESOPHAGEAL REFLUX AND APPARENT LIFE-THREATENING EVENTS IN INFANCY

GASTRO-OESOPHAGEAL reflux is the commonest cause of recurrent vomiting or regurgitation in well babies, and usually resolves in the first year of life. Investigation is only thought necessary if there are associated problems, such as failure to thrive and recurrent respiratory symptoms, or if hiatus hernia, oesophagitis, or stricture is suspected. If not, but vomiting is troublesome, parents are advised to sit the child upright as much as possible or to thicken the feeds.

These treatments have been thoroughly investigated by use of continuous oesophageal pH monitoring and, more recently, radiolabelled milk. Two well-controlled studies in babies less than 6 months old with symptoms show that, compared with the prone position, sitting upright 60° from horizontal increases reflux;  similar observations have been made in older children. Studies in newborn and 4-12-week-old babies suggest that less reflux occurs in the prone than in the supine position.  Keeping babies prone in a harness with face head elevated at 30° may be more effective in preventing reflux than in the horizontal prone position. Feeds given to infants and children with symptoms have been thickened with alginate/antacid ('Gavisoon'), carob seed powder (eg, 'Nestargel'), and rice cereal. Except in one study, all these therapies appeared to reduce vomiting in the short term, but reductions in reflux varied with the position adopted. The   best combination of feed thickening and posture has not been established.

Another unresolved issue concerning gastro-oesophageal reflux is whether this usually harmless condition predisposes to apparent life-threatening events in infancy (ALTEs, or near-miss sudden infant deaths) and if so, how often. Reflux of even small quantities of gastric contents could produce sudden asphyxia by various mechanisms including simulation of laryngeal chemoreceptors or airways obstruction. Gastro-oesophageal reflux has been described as a cause of respiratory arrest in many infants. Moreover, reflux (usually symptomless), was found to in 50-80% of unselected babies investigated after ALTEs in the first 9 months; this figure is considerably more than in normal babies of similar age and clearly merits further attention. Even if reflux is causally associated with ALTE, it occurs too commonly to be the only factor. Babies at increased risk of ALTE may have another disorder, such as a defective arousal response to laryngeal-induced apnoea or to airways obstruction.

Almost 2% of infants with ALTE subsequently die, a few sustain brain damage, and up to 40% have a recurrent episode. Whilst those with symptoms   of gastro-oesophageal reflux are investigated and treated, either medically or by fundoplication, those   without symptoms may not be.  In babies with ALTE and no symptoms should doctors look for and treat gastro-oesophageal reflux? Is it a cause or a result of ALTE? Clearly, more studies are required into silent reflux in Infants after ALTE. If a high incidence is confirmed, the next step would be establishing the best medical therapy for reflux. Subsequently, a trial would be needed to show whether antireflux therapy reduced the rate of subsequent adverse events compared with conservative management. Such a study would require hundreds of infants to show a conclusive fall in the rate of recurrence of ALTE, thousands to document a reduction in subsequent mortality, and an intermediate number if both outcomes were combined. Mortality is a more objective yardstick, but recurrent ALTE is a valid outcome measure—and no less objective than febrile convulsions, which have been the focus of several randomized trials. Without such trials unproven and potentially harmful treatments creep into use— eg, xanthines, which are often prescribed for infants after ALTE as respiratory stimulants .These drugs Increase gastric acid secretion and can relax gastro-oesophageal sphincter, causing reflux. If the association between gastro-oesophageal reflux and ALTE were confirmed, the case for an adequate trial of xanthines or, still better, a simultaneous test of antireflux vs. conservative management and xanthenes vs. placebo, would be hard to resist.