12.10: Endoscopic Procedures II: Colonoscopy

The colon, or large intestine, is the final segment of the digestive system. Its primary functions include absorbing water and vitamins produced by gut bacteria and transforming waste from liquid to solid to form stool. In adults, the large intestine is approximately 5 feet long and consists of four main sections:

1. Ascending Colon: Rises upward on the right side of the abdomen.
2. Transverse Colon: Stretches from the ascending colon across the body to the left side.
3. Descending Colon: Travels downward from the transverse colon on the left side.
4. Sigmoid Colon: Connects the descending colon with the rectum.

The rectum leads to the anus, the exit point for stool from the body.

Colonoscopy: This procedure is both diagnostic and therapeutic, allowing for a detailed examination of the entire colon and the terminal ileum. It is utilized for cancer screening in individuals with gastrointestinal symptoms, a strong family history of colorectal cancer, and post-treatment colon evaluation.

Applications of Colonoscopy: A colonoscopy helps detect and treat colon polyps, tumors, ulcerations, inflammation, diverticula (pouches in the colon wall), and strictures (narrowed areas). It also assists in the investigation of chronic diarrhea or gastrointestinal bleeding.

Procedure Overview:

1. Preparation: During a colonoscopy, the patient wears a gown for comfort. Sedation or anesthesia is usually recommended for a painless experience. The sedative, often combined with intravenous pain relief, helps minimize discomfort.
2. Beginning the Procedure: The procedure begins with the patient lying on their left side on the examination table, with knees drawn towards the chest. The healthcare provider then inserts a colonoscope into the rectum. This flexible tube, long enough to navigate the entire colon, contains a light and a channel for air, carbon dioxide, or water to offer a clear view of the colon lining.
3. During the Procedure: Movement of the scope or the introduction of air may cause stomach cramps or the urge to pass stool. The colonoscope, equipped with a tiny camera at the end, transmits images to a monitor for the healthcare provider's assessment. Through the channel, tissue samples can be collected, polyps removed, or any irregular areas addressed.
4. After the Procedure: A colonoscopy usually takes 30 to 60 minutes, and the initial sedation usually wears off in about an hour. As the sedating effects can linger for up to a day, patients should arrange a ride home and avoid driving, making important decisions, or working for the rest of the day.
5. Post-Procedure Care: After the examination, some bloating and gas may occur as the colon clears. Walking can help ease any discomfort. A small amount of blood during the first post-procedure bowel movement is expected but not usually concerning. However, persistent blood passage, blood clots, abdominal pain, or fever should prompt consultation with the healthcare provider. While rare, these symptoms may appear immediately or within one to two weeks following the procedure.