Upper Gastrointestinal Stenoses Coagulation and Botulinum Toxin

■ Argon Plasma Coagulation

Principle and Key Characteristics

► Principle: high-frequency energy is transmitted to the lesion through argon gas, coagulating the tissue without direct contact.

► The effect is relatively superficial, so there is less risk of perforation than with a laser.

Indications

► Malignant strictures

Technique

► Advance the endoscope to the stricture.

► Insert the probe to within a few millimeters of the stricture.

► Coagulate the tumor tissue, then stop due to the low penetration depth.

► Repeat the treatment at intervals of several days.

■ Injection of Botulinum Toxin

Principle and Key Characteristics

► Principle: botulinum toxin very selectively inhibits acetyl-choline release at cholinergic nerve endings, diminishing excitatory nerve impulses in the gastrointestinal tract.

► Injection into the lower esophageal sphincter induces temporary, reversible relaxation of the sphincter muscles.

► Disadvantage

- Effect lasts for approximately two to six months, rarely for 12 months.

Indications

► Achalasia (experimental)

Contraindications

► Myasthenia gravis

► Motor neuron disorders

► Pregnancy and nursing

► Concurrent use of other medications (aminoglycosides, calcium antagonists)

Materials

► Botulinum toxin

Technique

► Advance the endoscope to the lower esophageal sphincter.

► Inject a total of 100 I.U. of botulinum toxin into the four quadrants of the esophageal sphincter.

Complications

► Reflux following treatment

Most gastrointestinal tumors are diagnosed at a fairly advanced stage and consequently have a poor prognosis. Since early carcinomas have a very favorable prognosis, early diagnosis is of key importance in reducing the mortality from gastrointestinal tumors. It has been shown that the early diagnosis of epithelial gastrointestinal tumors can be improved by the use of chro-moendoscopy and magnification endoscopy.

■ Definition and Stains

Chromoendoscopy refers to the intravital staining of epithelial structures during the endoscopic examination. Several types of stain are used in chromoendoscopy: absorptive, contrast, and reactive (Table 4.16). Absorptive stains are taken up by special epithelial cells and can differentiate cells according to whether they are stained or unstained. Contrast stains cause relatively marked enhancement of intestinal mucosa and are often used in magnification endoscopy. Reactive stains are used to identify certain secretions in which the stain induces a color reaction.

At present, the chromoendoscopy of Barrett esophagus is of greatest importance in the upper gastrointestinal tract (Table 4.17).

Table 4.16 Stains used in chromoendoscopy

► Absorptive stains

- Lugol solution

- Methylene blue

- Toluidine blue

► Contrast stains

- Indigo carmine

► Reactive stains

- Congo red

- Phenol red

Table 4.17 Early carcinomas that are accessible to chromoendoscopy

- Squamous cell carcinoma

- Adenocarcinoma in the distal esophagus (Barrett carcinoma)

- Early carcinoma in high-risk groups (pernicious anemia, operated stomach)

Lugol Solution

Principle and Key Characteristics

Principle: Lugol solution is a solution of iodine and potassium iodide. It reacts with the glycogen in the normal squamous epithelium of the esophagus to produce a dark brownish-green stain.

Lugol solution stains healthy squamous epithelial cells in the esophagus.

It does not stain inflammatory, dysplastic, or carcinomatous areas.

Thus, staining with Lugol solution (Fig. 4.59) is useful for identifying:

- Intact squamous epithelium (stained)

- Abnormal areas within healthy squamous epithelium (unstained)

Inflammatory, dysplastic, and carcinomatous changes cannot be differentiated by their staining properties alone.

Technique

► Irrigate the esophageal mucosa with water.

► Inspect the area endoscopically and take selective biopsies.

Indications

► Patients at high risk for developing squamous cell carcinoma of the esophagus (preexisting squamous cell carcinoma of the head or neck, achalasia)

Contraindications

► Iodine allergy

► Hyperthyroidism

Side Effects

► Pharyngeal irritation

Table 4.17 Early carcinomas that are accessible to chromoendoscopy

- Squamous cell carcinoma

- Adenocarcinoma in the distal esophagus (Barrett carcinoma)

- Early carcinoma in high-risk groups (pernicious anemia, operated stomach)

Fig. 4.59 Staining with Lugol solution a Adenomas in the esophagus b The squamous epithelium of the esophagus is deeply stained by Lugol solution, while the adenoma is weakly stained

Fig. 4.59 Staining with Lugol solution a Adenomas in the esophagus b The squamous epithelium of the esophagus is deeply stained by Lugol solution, while the adenoma is weakly stained

■ Methylene Blue and Barrett Epithelium

Principle and Key Characteristics

► Principle: blue-staining absorptive stain

► Methylene blue stains:

- Actively absorbing epithelial cells in the small intestine and colon

- Areas of complete and incomplete intestinal metaplasia in the esophagus and stomach

- Columnar epithelial metaplasia of the fundus and cardia type

- Squamous epithelium

► Tissues showing weak, nonhomogeneous, or no uptake of methylene blue:

- Dysplasias and carcinomas within actively absorbing epithelium

► Barrett epithelium

- Usually shows a mosaic of columnar epithelial metaplasia of the fundus and cardia type and of the intestinal type. Barrett carcinoma arises predominantly from columnar epithelial metaplasia of the intestinal type.

► Thus, methylene blue staining (Figs. 4.60, 4.61) permits the identification of:

- Specialized intestinal-type columnar epithelium (positive stain)

- Dysplasias and early carcinomas for selective biopsy (weak, nonhomogeneous, or no uptake in areas of columnar epithelial metaplasia)

Technique

► Apply acetylcysteine solution to remove superficial mucus.

► Spray with 0.5 % methylene blue solution.

► Wait for three minutes.

► Rinse with saline solution or water.

► Inspect the area endoscopically and take selective biopsies.

Indications

► Barrett esophagus

Side Effects

► The only side effect is greenish discoloration of the urine.

Fig. 4.60 Methylene blue staining of a short Barrett esophagus a Short Barrett esophagus, unstained

Magnified view after methylene blue application shows deep blue staining at the right edge of the tonguelike epithelial extension c At higher magnification, the intensely blue-stained area at the right edge of the epithelial extension represents a site of complete intestinal metaplasia b

Fig. 4.60 Methylene blue staining of a short Barrett esophagus a Short Barrett esophagus, unstained

Magnified view after methylene blue application shows deep blue staining at the right edge of the tonguelike epithelial extension c At higher magnification, the intensely blue-stained area at the right edge of the epithelial extension represents a site of complete intestinal metaplasia b

Fig. 4.61 Barrett esophagus. The reddish area on the left represents columnar epithelial metaplasia of the fundus and cardia type. The blue-stained area on the right is intestinal metaplasia. Between them is a pale blue area of dysplasia

Was this article helpful?

0 0

Post a comment