A Tour around Indigestion
(Date of publication 09 January 2004)

With the over-indulgence of the festive season still fresh in our memories, many of us are probably familiar with the unpleasant symptoms of indigestion, or dyspepsia: abdominal discomfort, a feeling of fullness or bloating, and nausea. Fortunately it is rarely a serious health problem; the US National Library of Medicine states that it often results simply from consuming certain foods, drinking carbonated beverages, eating too quickly or too much, and that the condition is exacerbated by anxiety or depression.

Interestingly, most sites concerned with indigestion cite too much caffeine as a cause, but there appears to be little concrete evidence for this view. The only relevant study turned up by a search concluded that the apparent association with caffeine disappeared once adiposity was taken into account. The Coffee Science Information Centre cites a number of conflicting references to support its view that research into any association between coffee and indigestion has been far from conclusive.

Approximately 20% of US citizens suffer indigestion, but only about 10% of these seek medical attention, according to MedicineNet.com. It makes the point that most cases of dyspepsia are functional in origin: i.e. either the muscles of the gastrointestinal organs or the nerves controlling them are not functioning normally, but no causative abnormality can be detected. Much of the rest of this site is devoted to diagnosis, including the exclusion of non-gastrointestinal and psychiatric disease.

Turning to non-functional causes of indigestion, between 10% and 20% of adults (in the USA) have gallstones, so it is surprising that cholecystitis, or inflammation of the gall bladder, is not found to be the source of the problem more frequently. Only some 1% to 3% of people with gallstones develop symptoms in any given year, the stereotypical patient being 'fair, female, fat and fertile'. Continue with this site if you want to learn in detail about differential diagnosis and treatment - particularly of acute cholecystitis. However, indigestion is more likely to be caused by chronic cholecystitis, a simple overview of which can be found here. There is a clear photograph of an excised gall bladder with acute cholecystitis here, and a series of pictures showing the surgical removal of a gall bladder using minimally invasive surgery at Laparoscopy.com. Simply click here, select cholecystectomy from the drop-down list under the 'ABDOMEN' heading, and click on 'Go'.

Indigestion symptoms are often produced by gastritis , or inflammation of the gastric mucosa (stomach lining), which has a number of causes. One of the most frequent is infection with the Helicobacter pylori bacterium, which is also implicated in the development of peptic ulcers. Others are the regular use of non-steroidal anti-inflammatory drugs (NSAIDs) and excessive alcohol consumption. This information from the Mayo Clinic has good sections on treatment and prevention, but to see what the condition actually looks like, here is a photograph of an apparently mild case. If your interests veer towards complementary medicine, a great deal of information about alternative threrapies for gastritis - such as nutritional supplements, herbs, homoeopathy and acupuncture - is produced by IntegrativeMedicine.

Long-standing alcohol abuse is a major contributory factor to chronic pancreatitis, another condition which produces abdominal pain and nausea. The loss of functioning glandular tissue leads to a lack of pancreatic enzymes and an inability to digest fats properly. Insulin production is also affected and diabetes mellitus may develop. The explanation on this page is fairly brief, but it includes many links to other pages on the site with further detail. Areas of calcification often develop within the pancreas as result of the persistent inflammation, and can be seen on this CT scan.

We have already seen that Helicobacter pylori infection is important in the development of gastritis, and this organism is now also thought to be responsible for the majority of peptic ulcers. These are breaks in the mucous membrane lining the stomach (gastric ulcer) or duodenum (duodenal ulcer) and constitute another frequent cause of indigestion. Photographs of both types can be seen here. Infection with H. pylori is very common - these bacteria are present in approximately 50% of US citizens aged over 60 - but most of these people do not develop ulcers. It is not known why. Potential complications of peptic ulcers include bleeding, perforation and gastrointestinal obstruction, and in the USA about 6,000 people die from these complications each year. The most effective current treatment is a two-week course of triple therapy, which involves taking two antibiotics plus a drug either to suppress the secretion of gastric acid or to protect the gastric mucosa.

The three types of medication that may be used to counteract the discomfort of indigestion - antacids, H₂ antagonists and proton pump inhibitors - have been mentioned by some of the sites already visited, but perhaps we ought to look at them in a little more detail.

Antacids have a beneficial effect by reducing the impact of gastric acid, either by chemical neutralisation (e.g. sodium bicarbonate) or by absorbing it (e.g. calcium and magnesium salts). Chemical antacids have the most rapid onset of action, but may produce 'acid rebound', while calcium and magnesium salts are particularly prone to drug interactions. However, provided antacids are taken as directed, side effects are rare and minor in nature.

The release of gastric acid is stimulated by the action of histamine on the parietal cells of the stomach lining. H2 antagonists work by binding to the H₂ (or histamine) receptors on the parietal cells without triggering acid production. Low dosage products are available over-the-counter in the UK for the short term relief of indigestion, but otherwise they are prescription-only. Again, these drugs have relatively few side effects.

Unlike the previous two categories, proton pump inhibitors completely block the production of stomach acid, by shutting down the proton pump, or 'hydrogen-potassium adenosine triphosphate enzyme system'. They are primarily used to heal gastric and duodenal ulcers. One problem that can occur with their long term use is the development of stomach infections, because the absence of gastric acid raises the pH in the stomach, creating a more hospitable environment for micro-organisms.

As the memories of office parties, Christmas dinners and New Year celebrations disappear into the mists of time, it may be tempting to forget most of this useful information. Not necessarily wise, because there's always next year.

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