Colonoscopy

In the thirty years since 1971 when total colonoscopy was first described, significant technical advancements have been made in terms of instrument handling and imaging capability. Nevertheless. colonoscopy remains a procedure requiring manual dexterity and concentration. The experienced examiner can now successfully reach the cecum in 98% of patients and in most cases can also reach the terminal ileum. Proper training and experience are necessary for correct diagnosis. The diagnostic spectrum of colonoscopy encompasses not only macroscopic assessment of the condition of the mucosa but also the possibility of collecting a targeted biopsy sample and, more recently, the use of dye spraying techniques and magnification.

 


Indications for colonoscopy:
- Constipation
- Diarrhea 
- Abdominal pain
- Bleeding per rectum, unexplained anemia, weight loss
- Postpolypectomy surveillance 
- Prevention/aftercare colorectal carcinoma
- Pathological thickening of the colon wall detected by other imaging procedures 
-  Primary tumor search with metastasizing malignancy, if resulting therapeutic measures

 

Preparing for the Colonoscopy Examination
Oral preparation. Thorough bowel cleansing is essential for a sufficient endoscopic examination of the colon. The development in 1990 of a nonabsorbable electrolyte solution (polyethylene glycol. PEG) by Fordtran was a significant improvement over earlier laxatives using sodium sulfate and modified forms are still in use today. But, due to the large quantity of liquid that must be consumed (up to 4L) and the salty taste, these solutions are not tolerated by all patients. Their effectiveness has, however, been verified by numerous studies: data on sodium
phosphate solutions (e.g., Fleet) and whether these are an improvement in terms of cleanliness and patient acceptability are less conclusive (8). Though they may appear to be a viable alternative for some patients, caution should be exercised if the patient has kidney insufficiency given the high phosphate content.

 
Colonoscopy Complications and Risks
Perforation, bleeding, and Infection. Endoscopy of the colon entails risk of perforation. injury to blood vessels causing bleeding. and infection. The rate of complications can be minimized if the examiner takes precautions such as advancing the instrument only under conditions of high visibility. Sigmoidoscopy involves an average perforation rate of 1.8 per 100000 examinations: bleeding severe enough to require a blood transfusion and perforations requiring surgical repair occur at the same rate so that the number of patients who experience a serious complication is 6.4 per 100000 (10). Comparing diagnostic and therapeutic colonoscopy (1. 4) statistics indicate that, with a total morbidity of 0.4%. more complications arise from therapeutic measures, such as
polypectomies (1.2% vs. 0.2%) (Tab. 1.4) treatment. Not all complications require surgical intervention.
Bleeding can be stopped in 92% of patients endoscopically and infections can be controlled with antibiotics. Injury to the serosa related to perforation of the intestine is painful for the patient and in most cases is surgically repaired before peritoniticurs. In some patients, gaping wound edges can be closed with endoscopically applicable clips and further healed with liquid diet and antibiotics for Cardiopulmonary complications. The use of analgesics for colonoscopic examination increases the risk of cardiopulmonary complications, even when the utmost caution is exercised in selecting medication and dosage. Older and comorbid patients are especially at risk for medicamentosus hypotension, cachycardia, and respiratory failure.