VERIFIED CONTENTAuthor: lek. Patryk Jasielski
The examination of the digestive system allows to assess the functioning of a given organ (e.g. secretion of hydrochloric acid by the stomach) or its appearance (e.g. in colonoscopy). Each organ can be tested by different methods depending on the diagnosed disease. Some of them are simple publicly available tests, while others are performed only in specialized centers. Find out what types of digestive examinations are and how each organ should be tested.
The digestive system consists of several parts: the esophagus, stomach, duodenum, small and large intestines, liver, bile ducts and pancreas. For each of these organs, differenttestscan be performed. They are divided into:
- laboratory tests where the concentration of various substances in the blood is measured
- functional tests, assessing organ functioning
- and pictorial to highlight different structures.
The endoscopy is also performed, i.e. the observation of the lumen of the digestive tract from the inside, using specialized equipment.
Urea breath test
This is one of the tests used in the diagnosis of H. pylori infection in the stomach. It is a microorganism responsible for the chronic inflammation of the stomach and the formation of peptic ulcer disease.
The test detects an infection without the need for gastroscopy. The test consists in ingesting urea labeled with special carbon, radioactive or not. Then, after 10 or 30 minutes, the patient blows air into the test tubes through the tube.
In test tubes, the content of labeled carbon in the form of carbon dioxide is calculated using a special counter. If infection with H. pylori is present then this bacterium will break down the labeled urea into water and carbon dioxide which can be measured.
In the absence of bacteria, the exhaled gas will not contain labeled carbon. It is a very reliable study. Just remember not to take antibiotics 4 weeks before the test and drugs from the group of proton pump inhibitors (PPIs) for 2 weeks.
oesophageal pH and manometry
This is currently the best way to diagnose gastro-oesophageal reflux disease. In this condition, the acid content regressesup into the esophagus. It irritates its walls and causes symptoms such as heartburn, a burning sensation and pain behind the breastbone, and the reflux of food into the mouth.
This test allows you to evaluate the frequency and duration of gastric reflux by measuring the pH (or acidity) in the lower esophagus. It involves inserting a special probe with an electrode through the nose, which measures the concentration of hydrogen ions (i.e. pH).
This examination is completed with manometry. It is used to assess the contractility of the esophageal muscles and diagnose gastroesophageal reflux disease. It measures changes in pressure in the lumen of the esophagus.
Amylaza and lipase
Amylase is an enzyme that breaks down complex sugars into simple ones. Lipase, in turn, is responsible for the breakdown of fats. Both substances are secreted by the pancreas.
Their measurement is used in the diagnosis of diseases of this organ, mainly acute pancreatitis, less often chronic. Increasing the levels of these enzymes in the blood above three times the normal result is characteristic of acute pancreatitis.
The concentration of amylase also increases in other diseases, incl. in cholecystitis, in diseases of the salivary glands or in chronic renal failure. This enzyme also passes into the urine and can be measured there.
Lipase is specific for pancreatic diseases, i.e. its level is elevated only in diseases of this organ. Therefore, it is better at diagnosing acute pancreatitis.
Alanine and Aspartate Aminotransferase (ALT and AST)
Both enzymes are responsible for protein metabolism. They are found in large amounts in liver cells and are used in the diagnosis of liver diseases. Their elevated level above the norm indicates damage to liver cells, i.e. hepatocytes.
Moderate increase in concentration (less than 5 times above normal) or large (5-15 times) occurs in diseases such as:
- fatty liver,
- alcoholic liver disease,
- chronic hepatitis B and C (hepatitis B / hepatitis C),
- in drug and toxin damage and in other medical conditions.
Very large increases (more than 15-fold) are seen in acute viral hepatitis, drug damage (mainly paracetamol poisoning) and toxins (especially after eating toadstool), and acute liver ischemia.
Bilirubin
Is a product of heme decomposition from hemoglobin, which is a transport of oxygen and contained in red blood cells. It is metabolized in the liver and excreted into the bile and then into the intestines. It is the increase in bilirubin that is responsiblefor the occurrence of jaundice, which is the yellow discoloration of the skin and eyes. It is divided into unconjugated, which has not been transformed in the liver, and into conjugated, already secreted by the liver. Together they are called integer bilirubin.
Depending on the cause, the concentration of one type of bilirubin may increase. Unconjugated, it indicates an increased breakdown of red blood cells, i.e. hemolysis.
Conjugate is elevated in the event of obstruction of the bile ducts, i.e. in diseases such as stones in the bladder and bile ducts, tumors of the liver, pancreas, bladder and bile ducts.
The increase in both types of bilirubin (i.e. conjugated and unconjugated) may occur in the case of acute and chronic hepatitis (viral, alcoholic and other), poisoning or metabolic diseases.
Gamma-glutamyltransferase (GGT) and alkaline phosphatase
Both of these enzymes are used in the diagnosis of diseases of the liver and bile ducts. Alkaline phosphatase is elevated in inflammation and cirrhosis (i.e. fibrosis) of the liver. It is also a sensitive indicator of the presence of gallstones in the bladder and bile ducts and cholecystitis.
GGT is also elevated in bile duct stones. In this disease, it is a better indicator than alkaline phosphatase because its concentration increases faster and lasts longer.
Measurement of GGT is useful in the diagnosis of alcoholic liver disease - its level is elevated in the early stages of the disease. Increase in GGT concentration may also be caused by liver cancer.
Endoscopic retrograde cholangiopancreatography (ERCP)
It is a test to visualize the bile ducts. The initial stage looks like gastroscopy. An endoscope is inserted through the esophagus and stomach into the duodenum. Next, a contrast to the common bile duct is given, which can be seen on X-rays. It is also possible to insert the endoscope into the bile ducts.
This test is used to diagnose neoplasms within the bile ducts by taking samples for analysis. It is also used to remove stones from the biliary tract or to put on a prosthesis in case of narrowing.
Abdominal X-ray
It is one of the basic imaging tests used in diseases of the digestive system. They are usually performed standing and / or supine. In the era of the availability of modern and more accurate equipment, X-ray of the abdominal cavity is performed in rare cases.
It is indicated in suspected intestinal obstruction and in gastrointestinal perforation. Sometimes there isused in the diagnosis of acute ulcerative colitis and its complications in the form of colonic distension.
Abdominal ultrasound
It is the basic method of imaging diagnostics in diseases of the digestive system. It allows you to visualize various diseases of the organs in the abdominal cavity, especially the liver, bile ducts, pancreas, and to a lesser extent the stomach and intestines.
It can be used to visualize the size and structure of the liver, ascites (i.e. the accumulation of water in the abdominal cavity) and focal lesions of this organ.
The ultrasound of the abdominal cavity is very helpful in diagnosing cholecystitis because it allows the visualization of gallstones within the gallbladder.
In pancreatic diseases, it is useful in the diagnosis of acute inflammation and neoplasms. The ultrasound allows the gastric filling to be assessed. It is also helpful in the diagnosis of appendicitis.
Gastroscopy and colonoscopy
These are the two basic and most frequently performed endoscopic examinations of the gastrointestinal tract. Gastroscopy is used to assess the esophagus, stomach and duodenum. It is the basic test in the diagnosis of neoplasms in these organs.
It is useful in the diagnosis of gastric and duodenal ulcer disease and H. pylori infection. It allows you to take samples for microscopic examination. Gastroscopy is used to stop bleeding from esophageal varices or gastric ulcer.
Colonoscopy is an endoscopic examination of the large intestine. Similarly to gastroscopy, it is used in cancer diagnostics.
It is also useful in the diagnosis of other intestinal diseases, including ulcerative colitis or diverticular disease. During colonoscopy, samples of the intestinal mucosa can be taken, as well as polyps can be removed and examined. It is the best test in the prevention of colorectal cancer.