In the oral cavity, pharynx, esophagus and gastrointestinal tract, food is mixed and broken down, the food pulp is transported further, the nutrients are broken down and absorbed into the blood, and the waste products are excreted. On the way from the mouth to the anus, many disorders can affect these functions of the digestive tract. To detect them, there are various diagnostic options. We present to you which examinations are available
Digestion: what happens in the gastrointestinal tract?
There’s a lot going on in the digestive tract:
- Humans swallow about 25 times per hour, and the crushed food enters the esophagus after about 30 seconds of chewing and continues to the stomach in a few seconds.
- There they are mixed, digested and transported further – liquids after a few minutes, oil sardines, for example, only after more than 8 hours.
- They enter the intestine, which folded apart gives a total length of about five meters. Through large and small protrusions, the surface of the small intestine increases by 300 times and can thus absorb the digestible food components particularly well.
- In the large intestine, about a trillion bacteria of 400 different species convert the no longer usable food residues in feces and form 15 ml of gas per hour (after bean consumption also times ten times).
This small excerpt already illustrates the variety of functions and flexibility of the digestive tract, but also shows that the process can be disturbed in many places.
Symptoms of gastrointestinal disease
Complaints that are particularly indicative of disorders of the gastrointestinal tract are:
- Swallowing problems
- Heartburn
- Bad breath
- Abdominal pain
- Diarrhea
- Constipation and flatulence
- Nausea and vomiting
- Stool changes
- Weight changes
Jaundice and abdominal dropsy indicate, among other things, disorders of the liver, bile ducts or pancreas, whose secretions are needed for the digestive process.
Anamnesis as the first step in the examination
As with all diseases, the most important tool is to ask for the patient’s medical history, known in technical language as anamnesis. In this way, the physician can already presort the complaints and set priorities in the diagnosis. Particularly helpful are the current symptoms – where, when and how often they occur, what makes them better or worse, what other complaints accompany them, and so on. In addition, questions are asked about dietary habits, alcohol consumption, bowel movements and weight, among other things. Other illnesses, operations and accidents, risk factors and medications, family illnesses, and social and occupational environment are also important.
Basic diagnostics
The physical examination is usually performed on the undressed, supine patient. Basic diagnostics include several components.
Inspection
Externally visible signs of disease (inspection) include water retention, signs of emaciation, or skin changes such as liver asterisks or congested veins. Scars, asymmetries, and protrusions (for example, in a hernia) also give the physician clues.
Palpation
For palpation, the patient must have as relaxed an abdominal wall as possible. A pillow under each head and knees is helpful for this. The physician palpates the organs, especially the liver, and also pays attention to whether certain pressure points trigger pain.
Auscultation and percussion
Listening (auscultation) and tapping (percussion) the abdomen can be used to assess bowel sounds and determine the size of some organs and free fluid in the abdomen.
Rectal examination
Rectal examination, that is, palpation of the anal area and rectum, is also important. In men, the prostate is palpated at the same time. This examination is part of the cancer screening also paid by health insurance.
Laboratory examinations
Depending on the question, various laboratory values in the blood are often determined during the initial examination, for example blood count, coagulation, sugar, fats, liver and kidney values, minerals and proteins. The stool is also examined, for example for blood components to rule out a tumor, for pathogens in the case of chronic diarrhea or for the fat content if digestive disorders are suspected.
Imaging techniques
After basic diagnostics, various imaging techniques are available to examine the stomach and intestines:
- Ultrasonography (sonography) is an important procedure for the examination of the abdomen. It has the advantage that, on the one hand, it is quite easy to perform, is not stressful for the patient, and is inexpensive; on the other hand, it can be used to visualize many structures and changes. However, the assessment requires some experience.
- With an additional device can be made by means of Doppler and duplex sonography, the blood flow colored visible and audible, with the help of special transducers and cannulas, the doctor can target suspicious areas under ultrasound control and take tissue samples there.
- An x-ray of the abdomen (abdominal overview image) has almost no meaning except to show free air under the dome of the diaphragm; otherwise, it offers no advantage over sonography. However, if it is coupled with the administration of contrast medium (swallowed as a porridge or given as an enema) and possibly air (double contrast image), it is possible to assess intestinal movement and gross structure.
- The areas of application of computed tomography (CT) are comparable to those of ultrasound; however, the resolution and thus distinguishability is better. Against this are the radiation exposure for the patient and the higher costs.
- Magnetic resonance imaging can be used primarily to show changes in the liver, bile ducts and pancreas.
- If vascular disease or bleeding is suspected, angiography may also be indicated. This involves inserting a small tube into the vessels, introducing contrast medium above it and displaying its distribution in the X-ray image.
Endoscopy: endoscopy of the esophagus, stomach and intestines.
An endoscopy of the esophagus, stomach and intestines has the advantage that the doctor can look directly at the diseased organ section and take tissue samples. It also allows for therapeutic procedures such as hemostasis, widening of strictures, sclerotherapy of varicose veins, or insertion of a plastic tube to keep a section open. For this reason, endoscopy is of great importance in disorders of the gastrointestinal tract. The esophagus, stomach and upper small intestine (gastroscopy), as well as the rectum and colon (colonoscopy) can be viewed quite easily. The intervening section of the small intestine can be accessed with the aid of video capsule endoscopy. In this procedure, the patient swallows a capsule containing a miniature camera, a transmitter and a battery. As the capsule passes through the intestine, it shoots an image at regular intervals, which is then compiled into a film on a computer. The capsule is finally excreted with the stool.
Functional tests of the digestive tract.
Scintigraphy can be used to assess gastric emptying with a test meal and liver function and bile flow with a substance injected into the vein. These substances are radioactively labeled and their distribution in the digestive tract or in the blood vessels of the liver can be observed with a special camera. In addition, a number of other tests are available, although they are of little importance today – due to the diagnostic options mentioned above. These include manometry, i.e. measuring the pressure conditions in the esophagus and stomach, and ph-metry, which uses a catheter to record how acidic the environment in the esophagus or stomach is. If dysfunction is suspected, particularly in the small intestine, respiratory tests are used. Since the function of the digestive tract is closely coupled with that of the liver, gallbladder and pancreas, these are also examined more closely – depending on the suspected diagnosis.