“Functional” should not be shorthand for “I don't know” in dyspepsia

Editor—With reference to the article by Talley et al on dyspepsia, it is saddening to see the perpetuation of the term “functional” as shorthand for “I don't know the nature of the problem.”¹ Dyspepsia is the commonest presenting gastrointestinal symptom. Dyspepsia of recent onset, sometimes accompanied by weight loss, rings alarm bells over the possibility of malignancy and dictates the need for endoscopy, but most patients do not fit this paradigm.

The commonest cause of non-malignant dyspepsia is gastro-oesophageal reflux. This is a true functional disorder; acid that should reside in the stomach is retropelled into the oesophagus. A proportion of patients with this disorder will have overt inflammatory damage to the oesophageal mucosa identifiable at endoscopy, but the macroscopic damage is not always easily identified. Many years ago, Baron et al showed that sigmoidoscopic evaluation of possible rectal inflammation was no better than a random decision This is likely to be true for the gullet.

The accepted causes of dyspepsia are acid related. If endoscopy does not show any acid-related mucosal damage, then the clinician should move to the next step. The simplest step is a therapeutic trial of treatment with proton pump inhibitors. Alternatively, or if the therapeutic trial is positive, the next step is 24 hour measurement of oesophageal pH.

Most patients will be shown to have acid reflux. Aerophagy usually occurs concomitantly with reflux; patients who have retrosternal discomfort because of acid tend to swallow air in the hope of relieving the discomfort, and this leads to belching. I can recall few, if any, patients with aerophagy who did not have reflux, but I can recall a number of reflux patients in whom the only symptom was belching. The difficult patients with dyspepsia are not those who have functional dyspepsia but the minority who have no evidence of any disturbance of function. These patients have normal endoscopy results and normal pH values, and they do not respond to treatment with proton pump inhibitors. To label the problems of these patients as functional is an abuse of terminology, as there is no evidence of any disturbance of function. Ready access to a pH measuring service is mandatory in achieving a diagnosis of the cause of non-malignant dyspepsia. Given the fact that acid reflux is a much more probable cause of dyspepsia than duodenal ulcer, it can be argued that, if there is no reason to suspect malignancy, pH measurement is a more cost effective first line investigation than endoscopy. It should be available to all clinics dealing with referrals for dyspepsia.