The human digestive tract is divided into the esophagus, stomach, duodenum, small intestine, colon, and rectum. Small bowel diseases have not been fully recognized for many years, mainly because there are not many means to examine the human small bowel. Small intestinal diseases mainly include unexplained gastrointestinal bleeding; vascular diseases; small intestinal tumors; unexplained abdominal pain and diarrhea; malabsorption syndrome; inflammatory bowel disease; and NSAID-related small intestinal mucosal damage.
In the past, due to the lack of detection means, it was empirically believed that the incidence of small intestinal diseases was low, and once detected it was nearly late. With the development of science and technology and the continuous improvement of clinical detection methods, such as the application of capsule endoscopy and double-balloon endoscopy in recent years, the diagnosis rate of small intestinal diseases has been increasing.
Characteristics and detection methods of small intestine diseases
Small intestinal diseases have insidious onset, poor symptom specificity and deep and irregular lesion sites
The small intestine is the longest organ in the human digestive tract, and the average length of the small intestine is about 5-7 meters in adults, which is the main place for food digestion and absorption, and also has endocrine and immune defense functions. The small intestine is curved, and the intestinal tubes overlap each other, so small intestine diseases are insidious in origin, and the specificity of symptoms is not strong and the lesions are deep and not fixed, so the diagnosis of small intestine diseases is still a difficult point in clinical practice.
Second, the small intestine has a variety of effective examination means, complement each other
Small intestine examination methods include: small intestine barium imaging, radionuclide imaging, angiography, capsule endoscopy, double balloon small intestine microscopy, CT simulation endoscopy (CT VirtualEndoscopy).
1.Small intestine barium angiography
Small intestine barium imaging can show the location and scope of small intestine disease, but the positive rate is low. The gas-barium double imaging method, especially the intubation method of small intestine gas-barium double imaging, can increase the diagnosis rate of small intestine hemorrhagic lesions by 10%-25%. Small intestine barium imaging has almost no diagnostic value for vascular lesions.
2.Radionuclide imaging
Radionuclide imaging is a non-invasive technique, mainly used for the localization of small intestinal bleeding, and its sensitivity is stronger than that of angiography. Technetium 99-labeled red blood cells can be scanned, and the bleeding volume of 0.5ml-1ml can be detected.
In recent years, the scan of target-labeled red blood cells has significantly prolonged the semi-absence period in plasma, and the delayed scan can be performed within 24-48 hours after injection, which has a positive diagnostic rate of 40%-50% for active bleeding in the small intestine, but sometimes there are false positives.
3.Angiography
This method is an effective diagnostic method when chosen for small bowel disease, especially gastrointestinal bleeding. As long as we see the extravasation of contrast agent, we can make a clear diagnosis and embolization treatment can be carried out at the same time.
4.Capsule endoscopy
The introduction of capsule endoscopy has brought a revolution in the diagnosis of small bowel diseases. The capsule endoscope is about 2 cm in size, only the size of a crankpin, and the patient does not need to be hospitalized for this examination. During the examination, the patient simply swallows the capsule endoscope like a drug capsule and wears a data logger undershirt. After swallowing the capsule, the physician tests the capsule to confirm that it has entered the small intestine and then leaves the hospital. The whole examination process takes 8-10 hours.
5.Double-balloon endoscopy
Double-balloon endoscopy was introduced to China in 2003, making it an important tool for the diagnosis of small bowel diseases. Double-balloon endoscopy can make up for the shortcomings of capsule endoscopy which cannot be used for pathological examination and endoscopic treatment, further improving the diagnosis rate of small intestinal diseases. The diagnosis rates of small bowel bleeding, small bowel obstruction and unexplained abdominal pain are 96%, 95%, and 88%, respectively. It is now the gold standard for the diagnosis of small bowel diseases. The disadvantage is that the examination takes longer and is more painful for the patient. In view of the time-consuming operation of double-balloon endoscopy and the high technical requirements of the operator, it has certain operational risks and has not been fully popularized in China.
6.CT simulation endoscopy
The method is the use of spiral CT thin layer without interval scanning, the use of computer software for three-dimensional reconstruction, you can get similar to the dynamic reconstruction of endoscopic images. Its limitations are: it cannot observe mucosal color changes, it cannot distinguish superficial fine structure changes, and it cannot perform biopsy and microscopic treatment.
Even so, small bowel diseases are still a difficult area for clinical diagnosis and treatment, and there is still a lack of effective means to examine functional diseases of the small intestine, and it is believed that better science and technology will emerge in the near future to relieve the suffering of more patients.