Endoscopy and mucosal biopsy
The primary tool for visual study of the mucous membrane is endoscopy. Unlike X-ray examination, this method can detect even minimal superficial changes. In addition, the method has a therapeutic function: in case of ongoing bleeding, the physician can perform local hemostasis.
Of particular importance in gastroenterology is the rule of oncological alertness. If a gastric ulcer is detected radiologically, endoscopy is strictly mandatory. The physician must visually examine the defect and take tissue fragments for analysis to rule out an ulcerated tumor. A direct indication for the procedure is any suspicion of an oncological process, particularly in the presence of symptoms such as unexplained weight loss or anemia.
Despite its high informativeness, endoscopy has its limitations. If a tumor grows infiltratively (penetrating the thickness of the wall without damaging the superficial layers), the mucous membrane remains intact, and the endoscopic picture may be uninformative.
Histological evaluation Tissue sampling is performed from several points, which allows for differential diagnosis (confirming or ruling out cancer). The accuracy of the morphological diagnosis reaches 80–90%, though both false-positive and false-negative results are possible. Additionally, biopsy is used to detect Helicobacter pylori and evaluate tissue morphology (presence of inflammation, atrophy, metaplasia).
Study of gastric secretion
Assessment of the functional state of gastric glands is carried out by sounding using a thin tube. The procedure involves collecting gastric contents on an empty stomach, and then in portions every 15 minutes after administering a stimulant.
- Basal secretion (BAO). Represents the sum of hydrochloric acid production over four 15-minute intervals without stimulation. Normally, this indicator is 0–12 mmol/h (on average 2–3 mmol/h).
- Stimulated secretion (MAO). To assess the reserve secretory capacities, histamine or pentagastrin is used. Pentagastrin is considered a more preferable drug as it causes fewer side effects.
The results of the secretory study have a clear clinical interpretation:
- In duodenal ulcer, high figures of both basal and maximum (stimulated) secretion are usually recorded.
- In gastric ulcer, acid production is usually reduced compared to healthy individuals.
- If achlorhydria (complete absence of acid) is detected in a gastric ulcer defect, this is extremely atypical. Such a situation requires an immediate review of the diagnosis and a targeted search for cancer.
Laboratory markers and H. pylori detection
In laboratory practice, an important place is occupied by determining the level of gastrin in blood serum using radioimmunoassay. On an empty stomach, its reference values are within 100–200 ng/L. If this indicator exceeds 600 ng/L, it indicates Zollinger–Ellison syndrome (presence of a gastrinoma). Hypergastrinemia is also often observed in pernicious anemia.
Diagnostic methods for Helicobacter pylori Detection of this bacterium is necessary for the correct management of patients with gastric diseases.
The "gold standard" is invasive methods based on the study of biopsy material of the mucosa obtained during EGD. The rapid urease test is particularly popular. The obtained piece of tissue is placed in a special gel with urea. Since H. pylori produces the enzyme urease, the gel changes its color in a matter of minutes.
Other techniques have significant limitations:
- The culture method (bacterial plating) is technically complex and extremely labor-intensive.
- The serological method (determining antibodies in the blood) is unsuitable for assessing dynamics and monitoring cure, as specific antibodies persist in the bloodstream for a long time.
Briefly: answers to topical questions
What non-invasive diagnostic methods are used to monitor Helicobacter pylori eradication?
The cited sources do not contain an exact list of non-invasive methods specifically for monitoring Helicobacter pylori eradication.
Only the following limitation is explicitly stated:
- The serological method is unsuitable for assessing treatment dynamics because antibodies persist for a long time.
To determine the indications for eradication therapy, the sources indicate:
- 13C-urea breath test;
- determination of H. pylori antigen in stool.
To remember the connection between acidity and ulcer location: in duodenal ulcer, secretion (BAO/MAO) is usually increased, while in gastric ulcer it is decreased (achlorhydria requires ruling out cancer).
Class and exam questions
Can gastric cancer be ruled out based solely on X-ray examination results?
No. According to the rule of oncological alertness, if an ulcer is found on an X-ray, it is mandatory to perform an endoscopy with biopsy to rule out an ulcerated tumor.
Which drug is better to use to stimulate gastric secretion during sounding?
It is preferable to use pentagastrin. Unlike histamine, it causes significantly fewer side effects.
Is a blood antibody test suitable for checking cure from Helicobacter pylori?
No, the serological method is unsuitable for this. Antibodies to the bacterium can persist in the blood for a long time after its complete eradication.
What else to study on this topic
- Morphological signs of atrophy and metaplasia of the gastric epithelium
- Features of infiltrative growth of gastric tumors
- Pathogenesis of Zollinger–Ellison syndrome (gastrinoma)
- Causes of false-positive and false-negative biopsy results
- The connection between pernicious anemia and serum gastrin levels
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