Gastro-oesophageal reflux disease
The innovations of recent years, chiefly more powerful antisecretory drugs and minimally invasive surgery, have produced major changes in the treatment of upper gastrointestinal disease, in particular of acid-related disorders. Gastro-oesophageal reflux disease, the most common cause of dyspepsia, varies from a mildly symptomatic entity to a complicated aggressive disorder that can lead to stricture formation, pulmonary complications and possibly Barrett's oesophagus. Approximately 10 per cent of the American population have heartburn daily and more than one-third have intermittent symptoms. Furthermore, there may be an association with reflux disease in up to 50 per cent of patients with non-cardiac chest pain, 78 per cent of those with chronic hoarseness and 82 per cent of those with asthma'-4.
The causes of failure of the antireflux mechanism may lie in inadequacies of the oesophageal pump, the lower oesophageal sphincter, or abnormalities in the gastric reservoir. The lower oesophageal sphincter may fail for reasons of lack of strength, duration of contraction and relaxation, length and position. Subtle changes in vagal function may allow variation in these features and may be the leading factor in the pathogenesis of the condition in the absence of hiatal hernia. It is now recognized that transient relaxation of the lower oesophageal sphincter, not resting pressure level, is the most important determinant of refluxs. Episodes of transient relaxation are more common after a meal and are stimulated by fat in the duodenum, which also slows gastric emptying. Although pathological reflux may occur in the absence of hiatal hernia, herniation leads to loss of the positive pressure effect on the intraabdominal oesophagus, loss of the oesophagogastric angle, impairment of the 'mucosal rosette' phenomenon and, sometimes, impaired gastric emptying. Duration of contact of acid/pepsin on the mucosa is affected by frequency of reflux and oesophageal peristalsis.
The history is important in evaluating the patient and the therapeutic effect of empiric antacids may contribute to the diagnosis. Thereafter, endoscopy is the first line and most cost-effective investigation; it is valuable for grading and stratifying the extent of reflux disease. Several biopsy specimens of the diseased area should be taken to rule out Barrett's oesophagus or a potential malignancy; in immunecompromised patients these biopsy specimens should be cultured. A barium swallow examination may be a useful adjunct to endoscopy, particularly when a stricture is suspected, under which circumstances it should precede endoscopy. The Bernstein test of mucosal sensitivity to acid is fairly reliable for confirming that symptoms are acid related, although there is likely to be a lack of positivity in patients with Barrett's oesophagus.
Unfortunately, the data obtained by 24-h ambulatory lower oesophageal pH estimation and manometry, although specific and sensitive, do not always correlate well with symptom severity score or severity of oesophagitis as graded endoscopically. Accepted limits of normality also vary and herein lies a dilemma6. The clinician is, after all, treating symptoms of gastro-oesophageal disease, although other considerations are also pertinent, such as the development of Barrett's oesophagus with its underlying potential for malignancy. The major role of ambulatory pH and manometry in this situation is to evaluate those patients with atypical reflux symptoms, non-cardiac chest pain, unexplained pulmonary symptoms or hoarseness. Manometry is helpful in positioning the oesophageal probe and a high percentage of abnormal oesophageal contractions or the presence of a hypotensive lower oesophageal sphincter supports the diagnosis of a severe type of gastro-oesophageal reflux disease.
Lifestyle modifications should be recommended, such as elevation of the head of the bed, avoidance of fat, reduction of alcohol intake, cessation of smoking and avoidance of eating before sleeping. Weight reduction is often the key to achieving improvement of symptoms and relatively subtle weight reduction may alleviate even severe symptoms. Conventional over-the-counter antacids and alginates are more beneficial than placebo. Variable and often unimpressive results have been associated with the use of H2-receptor antagonist therapy, in conventional dosage, in this disorder. Standard doses produce symptomatic relief in 32-82 per cent of Layden TJ. Limitations of 24-hour intraesophageal pH monitoring in the hospital setting. Gastroenterology 1985; 89: