Læknablaðið : fylgirit - 01.06.1996, Blaðsíða 10

10
LÆKNABLAÐIÐ 1996; 82/FYLGIRIT 31
Gastro-oesophageal reflux disease:
major concepts of
pathogenesis and treatment
John Dent
Gastrointesinal Medicine, Royal Adelalde Hospital,
North Terrace, Adelalde, South Australia.
The term gastro-oesophageal reflux disease is
used inconsistently: it seems most appropriate that it
is taken to cover all of the clinically significant con-
sequences of gastro-oesophageal reflux. Reflux oe-
sophagitis is correctly considered to be a very re-
liable indicator of the presence of reflux disease, and
current concepts of pathogenesis and treatment are
derived largely from patients with definite oeso-
phagitis. This is defined as the presence of breaks in
the oesophageal mucosa that can be readily identi-
fied at endoscopy.
Excessive exposure of the oesophageal mucosa to
refluxed gastric contents is the overwhelmingly
dominant cause of reflux oesophagitis. This results
primarily from excessively frequent occurrence of
episodes of gastro-oesophageal reflux. Abnormally
slow normalisation of the oesophageal luminal pH
after its acidification by reflux, a process known as
oesophageal clearance, frequently compounds the
problem of frequent reflux. Current evidence sug-
gests that impaired oesophageal mucosal resistance
may play a role, but that this is minor. It now ap-
pears unlikely that acid hypersecretion is a factor of
any significance.
The mechanisms that cause abnormally frequent
reflux are complex and varied, but transient lower
oesophageal relaxation appears most important.
This is a specific pattern of abrupt lower oesoph-
ageal sphincter relaxation that lasts from about 5 to
35 seconds which is unrelated to swallowing.
Reflux disease usually has a distinctive symptom
pattern, so that a confident clinical diagnosis is fre-
quently possible. Heartburn is the hallmark symp-
tom, and the major source of morbidity. Episodes of
heartburn are clearly related to episodes of acid
reflux in both patients with and without oesophag-
itis. There is now increasing recognition that around
two thirds of people with troublesome heartburn
have no endoscopic oesophagitis. Oesophageal pH
monitoring studies confirm that this heartburn is
reflux-induced, so that this problem fits within the
definition of gastro- oesophageal reflux disease. At-
tention is now turning to identification of the best
options for treatment of these patients.