A stomach ulcer (peptic ulcer) is an open sore that forms on the protective lining of the stomach (gastric ulcer) or the first part of the small intestine (duodenal ulcer). This erosion occurs when corrosive digestive acids overcome the defensive mucus layer. The majority of ulcers are caused by two factors: infection with the bacterium Helicobacter pylori or the long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or aspirin. Determining the presence and cause of a peptic ulcer requires a systematic diagnostic approach to guide effective treatment.
Initial Patient Evaluation
The diagnostic process begins with a detailed conversation about the patient’s medical history and current symptoms. A doctor will inquire about the nature of the pain, often described as a burning or gnawing sensation in the upper abdomen (epigastrium). The timing of this pain is a significant clue; pain from a duodenal ulcer often occurs two to five hours after eating or may wake a patient at night, while gastric ulcer pain may be worsened by food intake.
The physician will ask about the regular use of NSAIDs, as these medications disrupt the stomach lining’s protective mechanisms. Other symptoms that raise suspicion include unexplained weight loss, nausea, vomiting, a feeling of early fullness, and signs of gastrointestinal bleeding such as black, tarry stools, or vomiting blood.
Testing for H Pylori Infection
Since the majority of peptic ulcers are caused by Helicobacter pylori, non-invasive tests to detect this bacterium are a common first step. The Urea Breath Test (UBT) is a highly accurate method that relies on the bacteria’s unique metabolism. The patient drinks a solution containing urea labeled with a special carbon isotope, which the H. pylori bacterium breaks down using its urease enzyme. This breakdown produces labeled carbon dioxide, which is then exhaled in the breath, confirming an active infection.
Another highly effective non-invasive option is the Stool Antigen Test (SAT), which detects specific H. pylori proteins, or antigens, shed by the bacteria in the feces. This test is also valued for its high accuracy in diagnosing an active infection and is often used to confirm successful eradication after a course of antibiotics. Both the breath test and the stool test are preferred because they confirm the presence of a live, active bacterial colony.
A third method involves a blood antibody test, or serology, which measures the presence of immunoglobulin G (IgG) antibodies against H. pylori. The major limitation of this test is that it can only confirm exposure to the bacterium at some point in the past. Antibodies can remain in the bloodstream for months or even years after the infection has been successfully treated. For this reason, serology is rarely used to diagnose an active ulcer or to check for successful treatment, as a positive result does not distinguish between a current and a resolved infection.
Direct Visualization of the Ulcer
When symptoms are severe, or if non-invasive tests are inconclusive, physicians rely on methods that allow for direct visualization and assessment of the physical sore. Upper endoscopy, also known as esophagogastroduodenoscopy (EGD), is considered the definitive diagnostic procedure. This involves the use of an endoscope, a thin, flexible tube equipped with a light and a camera that is passed through the mouth, down the esophagus, and into the stomach and duodenum. The EGD allows the specialist to directly view the lining of the upper gastrointestinal tract, precisely locating the ulcer, assessing its size, and checking for signs of active bleeding.
A crucial feature of endoscopy is the ability to perform a biopsy, where a tiny tissue sample is collected from the ulcer site. This sample can be analyzed under a microscope to check for malignancy, which is a concern with all gastric ulcers, and to confirm the presence of H. pylori directly in the tissue.
A less common imaging technique, the Upper GI Series, or barium swallow, can also visualize the ulcer but is far less sensitive than endoscopy. For this procedure, the patient swallows a chalky liquid containing barium, a radiopaque contrast material that coats the lining of the esophagus, stomach, and duodenum. The coating allows the ulcer to appear as an indentation or crater when X-rays are taken. While non-invasive and quick, this method cannot detect small ulcers, and unlike endoscopy, it does not allow for tissue sampling to rule out cancer or test for active infection.