Gastrointestinal Endoscopy

'Endoscopy' means 'looking inside' and typically refers to looking inside the body for medical reasons using an endoscope, an instrument used to examine the interior of a hollow organ or cavity of the body. Unlike most other medical imaging devices, endoscopes are inserted directly into the organ.

History

The first endoscope was developed in 1806 by Philipp Bozzini in Mainz with his introduction of a "Lichtleiter" (light conductor) "for the examinations of the canals and cavities of the human body". However, the Vienna Medical Society disapproved of such curiosity. The use of electric light was a major step in the improvement of endoscopy.

Basil Hirschowitz and Larry Curtiss invented the first fiber optic endoscope in 1957. Earlier in the 1950s Harold Hopkins had designed a "fibroscope" consisting of a bundle of flexible glass fibres able to coherently transmit an image. This proved useful both medically and industrially, and subsequent research led to further improvements in image quality. Further innovations included using additional fibres to channel light to the objective end from a powerful external source, thereby achieving the high level of full spectrum illumination that was needed for detailed viewing, and colour photography. The previous practice of a small filament lamp on the tip of the endoscope had left the choice of either viewing in a dim red light or increasing the light output - which carried the risk of burning the inside of the patient. Alongside the advances to the optics, the ability to 'steer' the tip was developed, as well as innovations in remotely operated surgical instruments contained within the body of the endoscope itself. This was the beginning of "key-hole surgery" as we know it today.

GI Tract The gastrointestinal tract (GI tract): Beginning from the oral cavity extending up to the rectum, the gastrointestinal tract is one of the longest organ, working in extreme precision with liver, gall bladder, pancreas to achieve absorption of nutrients.

Examination of the digestive system involves imaging, either radiologic or endoscopic. Endoscopy however has the advantage of real time intervention to aid diagnosis in the form of ability to biopsy suspicious lesions, or offer therapeutics in the form of securing bleed, placement of stents or resecting mucosal / submucosal tumors.

Endoscopic examination of the gastrointestinal tract involves, direct visualization of mucosa, with a gastroscope, one can reach up to the duodenum and with a colonoscope up to the terminal part of the small intestine i.e. the ileum.

Endoscopy of the gastrointestinal tract involves the following:

  1. Gastroscopy
  2. Colonoscopy
  3. ERCP
  4. Enteroscopy
  5. Endoscopic Ultrasound
  6. Capsule Endoscopy

Although endoscopic examination can be done quickly under topical anesthesia, in the west it is always done under conscious sedation (Midazolam/Propofol). However in India, due to cost concerns among others issues, usually diagnostic procedures are done under topical anesthesia.

Gastroscopy

This procedure is done for examination of the upper gastrointestinal tract. It involves visualization of the oesophagus, stomach and duodenum. For this examination the patient needs to be fasting ideally for 6-8 hours, however in case or emergency examination for GI bleed or foreign body extraction, empty stomach may not be possible.

Indications

Dyspepsia - not responding to medical treatment
Dysphagia - difficulty in swallowing
Hematemesis - vomiting of blood
Anorexia with weight loss
Surveillance in post operative cases of Ca Stomach, Ca Oesophagus

Therapeutic interventions

Stricture dilations (benign / malignant)
Foreign body removal
Mucosal tumor resections
Hemostasis (injections / clips / glue / bands / APC)
Stent placement for strictures (malignant)
Percutaneous endoscopic gastrostomy tube placement

Colonoscopy

This procedure endoscopic examination of the entire large intestine, and part of the terminal ileum. Preparation is necessary for complete colonoscopy examination. In most cases, laxative tablets are given on the previous night and colonoscopy preparation solution given 3-4 hours prior to colonoscopy examination.

Indications

Recent change in bowel habits
Anorexia with weight loss
PR bleeds with or without pain
Chronic blood and mucus diarrhea

Therapeutic interventions

Stricture dilations (benign / malignant)
Mucosal tumor resections
Hemostasis (injections / clips / APC)
Stent placement for strictures (malignant)

ERCP

Endoscopic reterograde cholangiopancreatography

C Arm Endoscopic examination of the common bile duct and pancreatic duct. This procedure requires endoscopy and radiology (C-arm) interface for completion of the procedure, done under propofol anesthesia in prone position. In certain situations (post op, obese) ERCP can also be done in supine position.
The role of diagnostic ERCP is more or less taken over by MRCP and EUS examination, hence only therapeutic ERCP’s are done.

Indications

Obstructive jaundice (stone, stricture, tumor,worms)
Bile leaks (post op, anastamotic)
Palliation of Malignancy causing obstructive jaundice by metallic stenting
Pancreatic duct stenting for ductal leaks, pancreatic ascites

ERCP has its share of complications in the form of bleeding, perforation of duodenum, pancreatitis to name a few, hence it is very important to carefully choose cases for optimum benefit with minimum or no risk to the patient.
Gastrointestinal endoscopy has made it possible to accurately diagnose and treat various diseases more effectively.
Documentation of gastric / duodenal ulcers, their treatment with anti h.pylori medications has made a huge impact, by almost eliminating the need for surgery.
It is very important to use this diagnostic modality judiciously for effective medical care. In India, less than a third of GI malignancies are diagnosed early, so that curative resection could be offered.
Meticulous history, careful and detailed clinical examination and early thought with regards to endoscopic examination would help us diagnose lesions early and make an impact towards saving lives.

Enteroscopy

Involves examination of the small bowel from jejunum to ileum, basically used for rare lesions in the small bowel. It has the option of diagnostic and therapeutic intervention which score over capsule endoscopy.

It is most useful in the evaluation of obscure GI bleed, where in, complete endoscopic examination of the small bowel can be done, lesions (AV malformations, ulcers, stromal tumors etc) can be identified, biopsied and treatment (injections, clips, APC, thermo coagulation) offered in the same setting. In case of a large lesion (eg. large leiomyoma) precise surgical margins for resection (india ink tattooing) can be marked.

Endoscopic Ultrasound

It’s the most advanced endoscope, which uses dual technology, the conventional endoscope along with a sonography probe which sees from within outside. Useful specifically in the imaging of pancreas.

Indications

Suspected CBD stones, prior to cholecystectomy
Assessment and FNAC/FNAB of pancreatic mass
Drainage of pancreatic pseudocyst
Suspected Gall bladder microlithiasis

Capsule Endoscopy

C Arm A small capsule, which has a camera, which captures and transmits, images of the mucosa. However its limited indicated use, incomplete test by it self, lack of tissue diagnosis and high costs make it less useful in patient care.