How is functional dyspepsia diagnosed?

The doctor will ask about the type of symptoms you have and how severe they are, when they occur, and how long they last for. They will also ask about your eating habits, any food intolerances and changes in your weight, as well as any medication you take and if you drink alcohol or smoke. Other things that they might be interested in include stress factors at work or in your private life, and whether you have anxiety or depression.

To be able to rule out a serious disease – or detect and treat it as soon as possible – the doctor will probably ask you about the following warning signs, too:

• Losing quite a lot of weight for no known reason
• Vomiting
• Fever
• Blood in your stool (poop) or vomit
• Problems and pain when swallowing
• Stomach and bowel disease in the family
• Functional dyspepsia symptoms that only started at age 60 and above

Your doctor will feel your abdomen (belly), listen to your heart and lungs, and measure your pulse and blood pressure. Blood tests and stool tests are also common. An ultrasound scan of the upper abdomen may also be done to spot other causes, like gallstones.

A gastroscopy is usually done to check that the symptoms aren't being caused by a physical medical condition like an inflammation or ulcer. This procedure allows doctors to look at the food pipe, stomach and the first part of the small intestine (duodenum) on a screen. They insert a thin tube with a tiny camera through your mouth and into the entrance to your duodenum. A small instrument can also be inserted through the tube to take tissue samples (biopsies). Injuries from the procedure are very rare.

If people with stomach problems don't have any signs of physical medical conditions and there are no other warning signs, a gastroscopy isn’t needed at first. If there is no improvement after several weeks of treatment, a gastroscopy may be done.

Digestion problems can be caused by certain bacteria that live in the mucous membrane lining the stomach. Called Helicobacter pylori, these bacteria can be found in tissue samples taken during gastroscopy. But they can also be detected with a breath test or in a stool sample. Certain medications shouldn’t be taken before the tests. For instance, proton pump inhibitors can interfere with the results up to two weeks after they were last taken, and antibiotics up to four weeks. That is also true of certain foods like corn and corn products, broccoli, pineapple, and sugar cane. These foods shouldn’t be eaten for two days before the test, either. Still water, black coffee and unsweetened tea are allowed until the evening before.

The breath test involves blowing into a bag or glass tube a total of two times. After blowing once, you will be given urea with tagged carbon molecules (called 13C) in it – for example, in a capsule or syrup. Then you will be asked to blow again after about 30 minutes. If the bacteria is in your stomach, it will break down the urea. The breakdown products will then be detected in the second breath sample. The samples are tested in a laboratory, and the results are usually ready after two or three days.

Stool tests involve taking a stool (poop) sample to your family doctor’s office. Parts of the bacteria can be found directly in the stool. These lab results are also ready within two to three days.

If a Helicobacter infection is found, it can be treated with antibiotics for one to two weeks. After that time, another test is done to check whether the treatment was successful.

Other examinations are sometimes offered if the symptoms don't go away on their own, or if they don't go away despite treatment. The aim is to see if there are any other medical conditions that might explain the symptoms. They include examinations to find out how long it takes for your stomach to empty, and whether you have any food intolerances or signs of inflammation. But these tests aren't enough to determine exactly what is causing the functional dyspepsia.

If children and teenagers have digestive problems or belly ache for a number of weeks, the doctor will ask about the type of pain and how long they have had it. The doctor will also ask children and their parents about possible signs of a treatable cause. These include:

• Unexpected weight loss
• Fever for no known reason
• Difficulties or pain when swallowing
• Vomiting
• Diarrhea that is watery, lasts for a long time, or also happens at night
• Blood in stool
• Urinary tract problems like pain when peeing
• Back pain
• Irritable bowel syndrome, a gluten intolerance (celiac disease), or stomach ulcers in the family
• Skin changes, such as rashes or pimples

The doctor will also ask about any stress factors in the child’s life. Children often experience stress differently to adults and in different ways, depending on their age. They get stressed if they are worried or anxious – for instance, if they feel out of their depth or have experienced drastic events such as accidents or separations.

Like with adults, the first physical examination involves feeling the belly from the outside. A stool test can then be done to find out whether there is blood in the stool. Depending on how much the child is affected by the symptoms, the doctor may do a blood test, or tests for food intolerances and infections. Other diagnostic examinations like imaging scans are often not needed.

Causes for the symptoms are found in about 5 out of 100 children, and can then be treated. This is a lot more often than in adults: A physical cause is found in about half of all adults who have stomach problems.