Definition

Gastro-oesophageal reflux is the non-forceful regurgitation of milk and other gastric contents into the oesophagus. It should be distinguished from vomiting which is an active process, requiring the forceful contraction of diaphragm and abdominal muscles. It occurs where there is incompetence of sphincter of the gastro-oesophageal junction or where raised intragastric or intra-abdominal pressures exist sufficient to overcome this mechanism.

Physiological, asymptomatic reflux occurs in all adults and children but is infrequent (<5% of any 24-hour period, mostly occurring postprandially). Gastro-oesophageal reflux disease (GORD) occurs when reflux is persistent, more frequent and gives rise to troublesome symptoms or complications.

Epidemiology

• Approximately 85% of infants have reflux and vomiting during the first week of life and another 10% have symptoms by six weeks of age.
• Reflux is most common between the ages of 1 and 4 months; however, sometimes it persists in teenagers.
• Uncomplicated gastro-oesophageal reflux is common in infancy, with regurgitation of at least one episode a day found in half of all infants aged 0-3 months. This is due to the functional immaturity of the lower oesophageal sphincter.
• By 12-18 months, most symptomatic reflux will spontaneously resolve as the sphincter matures, the infant adopts an upright posture and begins having a more solid diet.
• The prevalence of pathological GORD in infants is between 2-10%.

Risk factors for GORD

• Low birth weight.
• Obesity.
• Cow's milk allergy.
• Immaturity of the lower oesophageal sphincter.
• Chronic relaxation of the lower oesophageal sphincter.
• Increased abdominal pressure.
• Gastric distension.
• Hiatus hernia.
• Oesophageal dysmotility.
• Prematurity.
• Cerebral palsy or other severe neurodevelopmental problems.
• Congenital oesophageal anomalies.

Presentation

Presenting symptoms include:

• Recurrent regurgitation or vomiting
• Epigastric and abdominal pain (often presenting as distress after feeds, behavioural problems, feeding difficulties and failure to thrive).
• Witnessed episode of choking or apparent life-threatening event can sometimes occur.

Complications of GORD include:

• Oesophagitis (with haematemesis, anaemia or stricture formation).
• Respiratory problems (eg, cough, apnoea, recurrent wheeze and, less commonly, aspiration pneumonia).
• Feeding and behavioural problems.
• Failure to thrive.

Sandifer's syndrome is where reflux episodes are associated with dystonic neck movements (torticollis or opisthotonus).^[1]

Diagnosis

In the majority of cases, this is made clinically, based on the history of effortless vomiting occurring after meals.
Where the history is less clear or where symptoms are more severe, investigation may be required.

Differential diagnosis

Consider congenital hiatus hernia, gastroenteritis, pyloric stenosis, urinary tract infection.

Investigations

Investigations are not always necessary in mild cases. However, the following may be performed in more severe cases:^[2]

• FBC.
• 24-hour ambulatory oesophageal pH study - usually will show frequent dips in pH <4.
• Barium meal - to exclude underlying anatomical abnormalities in the oesophagus, stomach and duodenum that may cause symptoms similar to GORD.^[3] This is now less commonly performed.
• Endoscopy - where oesophagitis is suspected.
• Manometry - to assess oesophageal motility and lower oesophageal sphincter function.

Management^[4] 

The main aims of treatment are to alleviate symptoms, promote normal growth, and prevent complications^[5] .

General measures

Mild reflux in an otherwise well baby who is growing adequately and free of complications:

• Reassurance (benign condition, likely to resolve spontaneously).
• Simple feeding advice (avoid overfeeding, try increasing frequency and decreasing volume of feeds).
• Positioning - left lateral after feeding appears to improve oesophageal pH variables, although they should not be left in this position and should be supine for sleeping.
• Elevating the head of the baby's cot can be beneficial.

If cow's milk allergy is suspected then it is recommended that there should be complete elimination of cow's milk from the diet (or the mother's diet if breast-feeding) for two to three weeks and observing if symptoms resolve. This is will usually confirm suspected cases.^[6]

Pharmacological

When simple measures fail to reduce reflux:

• Feed thickening (with agents such as Carobel® or Nestrogel®) may be helpful. Breast-fed infants can be given the thickener mixed to a paste prior to their feed.
• Switching to an anti-regurgitation formula - for example, Enfamil AR® and SMA Staydown® may be beneficial for some infants. These are available on prescription and should not be given for more than six months. They should not be given with any other feed thickener or antacids. These cannot be given for more than six months.
• Infant Gaviscon® is mixed with water for babies who are breast-fed prior to the feed or with formula. Gaviscon® cannot be given with a thickener.
• Older children should be advised about lifestyle changes (avoiding provoking foods, weight reduction) and may be helped by an alginate-containing antacid.
• For more significant reflux or reflux-associated complications, advice from a paediatrician is usually required.
• H2-receptor antagonists (H2RAs) relieve symptoms of GORD and promote mucosal healing.
• However, H2RAs can exhibit tachyphylaxis or tolerance which limits their long-term use^[3] .
• Proton pump inhibitors (PPIs) are sometimes used in infants and children with moderate, non-erosive oesophagitis.
• Although omeprazole is effective at reducing gastric acidity and oesophageal acid exposure in infants, there is significant evidence that it is not effective in treating symptoms attributed to infant reflux or GORD.^[7]
• Administration of long-term acid suppression without a diagnosis is inadvisable. When acid suppression is required, the smallest effective dose of a PPI should be used^[3] . 
• Omeprazole is currently not recommended for treating irritability, reflux or uncomplicated GORD. It should only be considered in cases of severe infantile reflux oesophagitis or if GORD is causing complications such as failure to thrive. The decision to prescribe is usually made in consultation with a paediatrician or gastroenterologist.
• Domperidone is sometimes given to speed gastric emptying.

Surgical

When medical therapy fails, anti-reflux surgery (for example, fundoplication) may be considered in selected patients but it carries a significant risk of morbidity, including high failure rates.^[8]

Prognosis

Most cases are benign with 55% resolved by 10 months and the vast majority resolved by 18 months. Not all infants require medications to control the symptoms. Surgery is required in a minority of patients.

• In patients whose reflux persists into later childhood, chronic cough, wheeze, clubbing, and recurrent pneumonias are a continuing theme.
• Growth and weight gain are adversely affected in two thirds of patients. Cerebral palsy, Down's syndrome, developmental delay, and Sandifer's syndrome are all associated with reflux. Two thirds of patients have delayed gastric emptying, and one third aspiration pneumonia.