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CHAPTER 49

Gastro-oesophageal Reflux Disease

Merrill McHoney

Introduction The importance of the presence of intraabdominal oesophagus is
Gastro-oesophageal reflux (GOR) is defined as involuntary (passive) demonstrated by the fact that in patients who have a length of less than
reflux of gastric contents into the oesophagus not caused by noxious 1 cm, the incidence of reflux is high (85%). This is a common situation
stimuli. Gastro-oesophageal reflux disease (GORD) is defined as symp- in the newborn period. This compares to the situation at 3 months of
toms and complications arising from gastro-oesophageal reflux. GOR is age, when the length of intraabdominal oesophagus reaches 3 cm and
present in many newborns, in whom it does not necessarily represent a the incidence of reflux decreases. With an intraabdominal oesophagus
clinical disease, but rather a somewhat delayed physiological development length of 3–4.5 cm, reflux is mostly abolished. This development
which occurs with time; some GOR can be considered “physiological” up partially underlies the relatively common finding of reflux in young
to 3 months of age, and the reflux (without the disease) may also occur infants that abates with age.
in many individuals during certain physiological processes and normal Another important oesophageal factor is the presence of a high
activities during the day. GORD, however, differs from this variant of pressure zone (HPZ) in the lower oesophagus, also known as the
normal physiological development, with complications and symptoms physiological lower oesophageal sphincter (LOS). This mechanism is
that lead to presentation and the need for medical or surgical intervention. thought to contribute between 10 and 30 mm Hg pressure resistance
to GOR. This HPZ is identifiable on manometry studies, but not
Demographics anatomically. This HPZ relaxes in advance of a food bolus to allow
As discussed further in the next section, GOR is common, but not swallowing to occur. One major contribution to GORD in children is
necessarily pathological, in many newborns. GORD is not common in thought to be inappropriate or excessive relaxation of this HPZ, called
otherwise healthy children. There is no sex predilection. GORD itself transient lower oesophageal sphincter relaxation (TLOSR).
has no age preponderance. The incidence in African countries and These oesophageal mechanisms are reinforced by an important
1-3
blacks is less than that seen in Westernised countries. In one study, contribution from the crura of the diaphragm. The right crus of the
the prevalence was 4–7% of the population. 1 diaphragm slings around the oesophagus, as the latter enters the
GORD is more common in neurologically impaired children abdomen. This provides a pinch-cock effect that contributes to the
and those with neuromuscular disease. Congenital gastrointestinal HPZ, and, more importantly, increases lower oesophageal pressure
anomalies associated with a high incidence are: oesophageal atresia, during inspiration, when thoracic pressure is most negative and would
congenital diaphragmatic hernia, and abdominal wall defects. favour reflux.
Populations in which the incidence or survival of premature neonates A physiological mechanism contributed by the stomach is timely
with neurological impairment is high may also have a higher incidence and efficient stomach emptying. Some studies have linked the presence
of GORD. of delayed gastric emptying (DGE) to reflux by demonstrating a higher
Aetiology/Pathophysiology incidence and recurrence rate of reflux in children who have DGE. Some
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Several anatomical or physiological factors prevent GOR; they can be pharmacological treatments target DGE in an attempt to treat GORD.
further broken down into oesophageal factors, diaphragmatic contribu- Another anatomical contribution to reducing reflux is the presence
tion, and stomach contribution. of the acute angle of His between the oesophagus and the stomach. This
Oesophageal clearance is thought to act as an antireflux mechanism. acute angle allows a valve-like mechanism to occur. This arrangement
The presence of an oesophageal food bolus promotes lower (distal) is further supplemented by mucosal folds (rosettes) in the stomach. The
oesophageal relaxation as a normal enteric reflex to allow swallowing. contribution of this mucosal fold mechanism is minimal, and is thought
Therefore, a lack of oesophageal clearance can promote reflux by this by some not to contribute at all.
effect. Also, if reflux does occur (which is an occasional event in most Some pathological causes and consequences of GORD with
people; even those without GORD), oesophageal clearance rids the reference to these mechanisms are outlined in Table 49.1.
oesophagus of irritant acid (or alkali). Poor oesophageal clearance will In addition to these pathophysiological changes, any process that
increase contact time and promote oesophagitis and GORD. leads to a significant increase in intraabdominal pressure sufficient
One of the most important oesophageal contributions is the enough to overcome these mechanisms may induce reflux and GORD.
occurrence of a length of intraabdominal oesophagus. Intraabdominal This may underlie the causation of GORD after tight abdominal closure
pressure can reach 10 mm Hg. During times of increased intraabdominal (e.g., in gastroschisis and congenital diaphragmatic hernia).
pressure, and with changes during inspiration, there is a positive Clinical Presentation
pressure gradient that can encourage reflux of stomach contents into History
the lower oesophagus. However, this positive pressure in the abdomen
is transmitted to the entire length of intraabdominal oesophagus, which Infant
partially closes under this positive pressure and prevents reflux. If Vomiting is the most common symptom of GOR in an infant, and is
the length of oesophagus to which this pressure can be transmitted is usually nonbilious and effortless. The presence of bilious vomiting
decreased, the incidence of reflux is higher. should prompt the search for another diagnosis. GOR should not be