Indigestion: When is it functional?

Patients often complain of indigestion, but what do they mean? Indigestion is an old English word that means lack of adequate digestion, but patients and doctors interpret this in different ways. Many patients mean heartburn or acid regurgitation, the classic symptoms of gastro-oesophageal reflux disease. Some describe belching, abdominal rumblings, or even bad breath as indigestion. Others mean pain localised to the epigastrium or a non-painful discomfort in the upper abdomen which may be described as fullness, bloating, or an inability to finish a normal meal (early satiety). Dyspepsia is best restricted to mean pain or discomfort centred in the upper abdomen. #### Major structural causes of dyspepsia Overlap of subgroups of dyspepsia based on symptoms in patients with documented functional dyspepsia There are many causes of dyspepsia, but at least two thirds of patients have no structural or biochemical explanation for their symptoms. It has been suggested that dyspepsia can be subdivided based on groups (or clusters) of symptoms. However, subgroups have not proved to be of value in identifying the underlying cause of dyspepsia and overlap considerably. Some patients report having troublesome burping associated with abdominal bloating or discomfort that is transiently relieved by bringing up the wind. These patients have aerophagy, and repeated swallowing of air may be obvious during the consultation. History taking is key to identifying the likely cause of dyspepsia. ### Gastro-oesophageal reflux disease It is important and practical to distinguish gastro-oesophageal reflux disease (GORD) from dyspepsia. Frequent heartburn is a cardinal symptom of GORD; acid reflux causes a retrosternal or epigastric burning feeling that characteristically radiates up towards the throat, is relieved transiently by antacids, and is precipitated by a meal or by lying down. #### Uncommon causes of upper abdominal pain or discomfort that may be confused with dyspepsia