Endoscopy allows a visual examination of internal organs and body parts without invasive exploratory surgery.
Endoscopy is performed with either a rigid or flexible fibre-optic instrument. Flexible endoscopes such as those used in the examination of the stomach consist of a long, flexible insertion tube with a bending tip at the end that enters the body, an eyepiece, and a control section. The tip of the endoscope is manipulated using a control knob in the hand piece. In addition to the fibre bundles which provide the light source, two channels are present within the endoscope. One channel permits various endoscopic tools to be passed and fluids to be suctioned or samples taken. The other allows air or water to be passed into the stomach/intestine to insufflate (inject air into the area), or wash away mucus from the viewing port. Special video cameras can be attached to the endoscopes which allow viewing of the exam on a television screen, as well as recording the exam on video. The rigid endoscope cannot be used in some areas, such as the stomach because it does not have the bending tip, so it cannot be flexed to allow examination of all parts of the stomach.
Types of endoscopy include:
- Bronchoscopy: an exam of the lower airways.
- Colonoscopy: an exam of the colon, large bowel, and rectum.
- Endoscopy: an exam of the oesophagus, stomach, and upper intestines.
- Arthroscopy: an exam of soft tissue structures and joint cartilage, which is not visible on radiographs.
- Cystoscopy: an examination of the vagina, urethral opening, urethra, bladder, and ureteral openings.
- Laparoscopy: an exam of the abdominal cavity performed through a small incision in the wall of the abdomen or through the navel. It is done in veterinary medicine to obtain hepatic (liver) and renal (kidney) biopsy samples.
- Proctoscopy: an exam of the large bowel and rectum.
- Rhinoscopy: an exam of the nasal cavity and nasopharynx (junction between the nasal area and the back of the throat).
- Thoracoscopy: an examination of the chest cavity. This is currently not performed frequently in veterinary medicine.
Candidates for endoscopy of the upper gastrointestinal tract include those with a stricture (abnormal narrowing) or foreign body in the oesophagus. Symptoms, such as vomiting with or without blood and/or melena (blood in the stool) may indicate a stomach ulcer or cancer are present and are indications for an endoscopic exam. If a duodenal aspirate (sample of fluid in the intestine) is required for culture or isolation of Giardia, pancreatic response testing, or biopsies are necessary, endoscopy would be indicated.
The advantage of endoscopy over other methods of evaluating the digestive system is that it is nonsurgical. The technique allows for visualisation of the lining of the digestive system and for taking samples of the lining of these organs, including biopsies. Many foreign bodies in the oesophagus and stomach may be removed via endoscopy.