Indigestion and functional dyspepsia

What dyspepsia means

Dyspepsia is the medical word for indigestion. It describes symptoms coming from the stomach and the first part of the small bowel, and it covers four in particular: pain in the upper abdomen, burning in the same place, feeling uncomfortably full after a normal meal, and being unable to finish a meal that would once have been easy.

It is a description of symptoms, not a diagnosis. The job of the assessment is to work out which of several quite different things is producing them.

When investigation finds nothing structural to account for the symptoms, the diagnosis is functional dyspepsia. About 80 per cent of people investigated for dyspepsia fall into this group, so it is the usual answer rather than the leftover one.

The two patterns

The international criteria divide functional dyspepsia into two patterns, because they behave differently and respond to different treatment. Many people have features of both.

• Postprandial distress syndrome. Symptoms are tied to eating. Fullness that lasts long after a meal, or filling up within the first few mouthfuls. This is the more common pattern
• Epigastric pain syndrome. Pain or burning in the upper abdomen that is not confined to mealtimes, and may come on when the stomach is empty

For the formal diagnosis, symptoms need to have been present for the last three months and to have started at least six months earlier. Those timeframes exist to separate a persistent problem from a passing one, not to delay assessment of someone who has just become unwell.

How common it is

Functional dyspepsia affects roughly 7 per cent of people when the strict symptom criteria are applied, and considerably more when a broader definition is used. It is one of the most common reasons for a referral to a gastroenterologist, and most people with it are managed by their GP without ever needing one.

Several things make it more likely: a previous bout of gastroenteritis, which can be followed by symptoms that persist long after the infection has cleared; smoking; regular use of anti-inflammatory painkillers; Helicobacter pylori infection; and periods of significant stress, anxiety or low mood. It is somewhat more common in women.

Being common does not make it minor. It is a relapsing condition that fluctuates over years, and for some people it interferes substantially with work, eating and social life.

What else it can be

Before settling on functional dyspepsia, the conditions that produce the same symptoms need to be considered. The important ones are:

• Peptic ulcer. The one finding consistently more common in people with dyspepsia than in people without it.
• Helicobacter pylori infection, with or without an ulcer.
• Reflux disease. Reflux and functional dyspepsia overlap heavily and frequently coexist, which is why treating one sometimes only partly helps.
• Medications. A long list, headed by anti-inflammatory painkillers such as ibuprofen (commonly known as Nurofen) and aspirin, and including iron supplements, some antibiotics, potassium supplements and the newer weight and diabetes injections. Paracetamol (commonly known as Panadol) does not cause ulcers and is generally the safer choice for pain.
• Gallstones. Typically a different pattern of pain, but worth distinguishing properly, because removing a gall bladder does not reliably relieve indigestion.
• Coeliac disease, which can present as upper abdominal symptoms rather than the classic ones.
• Delayed stomach emptying, which overlaps with functional dyspepsia so considerably that the two are hard to separate and are sometimes the same thing described two ways.
• Cancer of the stomach or oesophagus. Uncommon, and the reason for careful assessment rather than for alarm.

What warrants assessment

Some features change the urgency, and they are worth stating plainly because they deserve attention at any age:

• Difficulty swallowing, or food sticking.
• Persistent vomiting.
• Weight loss that was not intended.
• Vomiting blood, or black tarry stools.
• Iron deficiency or anaemia.
• A lump felt in the upper abdomen.
• A first-degree relative with stomach or oesophageal cancer.

Whether a gastroscopy is needed is decided on the symptoms, the examination and the background, not on a birthday. The usual first step for persistent indigestion is a test for Helicobacter pylori and a trial of treatment, and a gastroscopy follows where any of the features above are present, where symptoms are new, persistent or changing, where treatment has not worked, or where the background raises the risk. Growing up in a country where stomach cancer is common, and a family history of stomach or oesophageal cancer, both lower the threshold considerably.

What a gastroscopy does and does not find

A gastroscopy is a short procedure, usually under sedation, in which a thin flexible camera is passed through the mouth to look directly at the oesophagus, the stomach and the first part of the small bowel, and to take biopsies.

It is the definitive way to answer the structural question. It is worth being clear about what it usually shows. Across studies of people investigated for dyspepsia, inflammation of the oesophagus was the commonest finding, at around 13 per cent, and peptic ulcer was found in about 8 per cent. Cancer was found in well under 1 per cent.

So for most people the result is a normal or near-normal examination. That is a useful result, not a wasted one. It rules out the things that would change management, it allows biopsies that confirm or exclude Helicobacter pylori and coeliac disease, and it permits the diagnosis of functional dyspepsia to be made positively rather than by assumption. For many people, knowing definitively that there is no ulcer and no cancer is itself part of the treatment.

More about the procedure itself is on the gastroscopy page.

The Helicobacter pylori step

Everyone with persistent indigestion should be tested for Helicobacter pylori, and treated if it is present. The test is a breath test or a stool test, and it needs no procedure.

Clearing the infection helps a minority of people with functional dyspepsia, and it is difficult to predict which. It is still worth doing, both for the chance of symptom relief and for the separate long-term benefit of reducing the risk of ulcers and of stomach cancer.

Two things follow. First, a repeat test afterwards to confirm it has actually gone, since symptoms are not a guide. Second, if symptoms persist once the infection is confirmed cleared, that is not a failure but a useful piece of information: the diagnosis is functional dyspepsia and treatment moves on. The Helicobacter pylori page covers the testing and treatment in detail.

Why it happens when the tests are normal

A normal gastroscopy is often delivered as though it were the end of the matter, which leaves people with symptoms and no explanation. There is an explanation, and it has improved considerably over the past decade.

Functional dyspepsia is now understood as a disorder of gut-brain interaction. The structure of the stomach is normal; the way it senses, moves and signals is not. Several mechanisms have been identified, and different people have different combinations of them.

• Heightened sensitivity. The nerves supplying the stomach and duodenum register normal volumes and normal acid as uncomfortable. This is the best established mechanism.
• The stomach not relaxing properly to accommodate a meal. Normally the upper stomach expands as food arrives. When it does not, a modest meal produces the sensation of a very large one, which is what early fullness actually is.
• Altered emptying. Slow in some people, and faster than normal in others.
• Low-grade inflammation in the duodenum. Pooled analysis of 22 studies found more eosinophils and mast cells, immune cells associated with allergy and irritation, in the lining of the duodenum in people with functional dyspepsia than in people without it, and the excess was greatest in those whose symptoms began after a gut infection. This has shifted thinking towards a subtle immune and barrier problem. The authors are careful to say that the studies vary considerably and that cause has not been proven, so this is a promising line of explanation rather than a settled one. Australian researchers have led much of this work.
• Changes in the gut microbiota, and in the signalling between the gut and the brain in both directions.

The practical importance of this is that symptoms are generated by a real and identifiable mechanism. Functional does not mean psychological, and it does not mean nothing was found because nothing is there.

What helps

There is no single treatment that works for everyone, and finding the right approach usually takes more than one attempt. The options with evidence behind them are:

Reducing stomach acid

Acid-lowering medication helps a proportion of people, and works better for the pain and burning pattern than for the fullness pattern. It is usually the first thing tried. Where it works it is worth reviewing the dose periodically rather than continuing indefinitely without review.

Medicines that change gut sensitivity

Low doses of medicines originally developed as antidepressants are among the most effective treatments for functional dyspepsia, and the dose used is well below the dose used to treat depression. They work by damping down the nerve signalling between the gut and the brain, not by altering mood. This is worth saying clearly, because being offered one of these is frequently misread as being told the problem is imagined.

Medicines that help the stomach empty and relax

Useful particularly where fullness after meals is the dominant symptom.

Diet and eating pattern

Smaller and more frequent meals, reducing fat content and eating more slowly all help some people, especially with the fullness pattern. Spicy food, alcohol, coffee and fizzy drinks are common individual triggers. Stopping smoking helps. Where a specific dietary approach is worth trialling, it is better done with a dietitian than by progressive self-restriction, which tends to narrow the diet without improving symptoms.

Reviewing medications

Often the most valuable single step. Anti-inflammatory painkillers are the common culprit, and many people do not consider them medications at all.

Gut-directed psychological therapies

Gut-directed hypnotherapy and cognitive behavioural therapy have evidence in disorders of gut-brain interaction, and are aimed at the nerve signalling rather than at any assumption about the person's mental state. They are most useful where symptoms are persistent and have not responded to medication.

The overlap with irritable bowel syndrome

Functional dyspepsia and irritable bowel syndrome overlap a great deal. A substantial number of people have both, and the overlap group tends to have more severe symptoms and a harder time finding effective treatment than either condition alone.

This is not a coincidence. Both are disorders of gut-brain interaction, both involve heightened sensitivity to normal gut activity, both are more likely after an episode of gastroenteritis, and both respond to several of the same treatments, including the gut-directed therapies and the low-dose medicines that alter gut nerve signalling.

It matters practically. Someone whose upper abdominal symptoms have been treated in isolation, while the bowel symptoms are managed separately or not at all, is often being treated for half the problem. It is worth asking about both. The irritable bowel syndrome page covers the lower half.

Reflux overlaps in the same way, which is why some people improve only partly on acid-lowering treatment: it is addressing one of two mechanisms that are both contributing.

What to expect over time

Functional dyspepsia is a long-term condition that fluctuates. Periods of good control are interrupted by flares, often around stress, illness, a change in medication or a period of poorer eating and sleep. This pattern is the norm rather than a sign of deterioration.

It does not turn into cancer and it does not damage the stomach. Once the assessment has been done properly, repeated investigation of unchanged symptoms adds little. What does change the picture is a genuine change in the symptoms themselves, or the appearance of any of the features listed above, and those are worth reporting rather than absorbing into an established diagnosis.

Most people improve substantially with treatment aimed at the right mechanism. Getting there usually means trying more than one approach, giving each a fair trial, and being willing to combine them.

Where indigestion and dyspepsia are assessed in Sydney

A/Prof Viraj Kariyawasam is a consultant gastroenterologist and hepatologist. Persistent indigestion and upper abdominal discomfort are assessed at consultation in Norwest, Rouse Hill, Pennant Hills and Macquarie Park.

Where a gastroscopy is needed, it is performed at Norwest Private Hospital, Macquarie University Hospital and Pennant Hills Day Surgery. A referral from your GP is needed for a consultation.