A diagnostic colonoscopy is a medical procedure used to examine the inner lining of the large intestine, including the colon, rectum, and anus. This examination helps healthcare providers investigate the cause of various gastrointestinal symptoms or abnormal test results. It provides a detailed view of the inner lining of the bowel, allowing for the identification of potential issues.
Defining Diagnostic Colonoscopy
A diagnostic colonoscopy involves the insertion of a long, flexible tube called a colonoscope into the rectum and advancing it through the colon. This tube is equipped with a small camera and a light source, transmitting images to a monitor for the doctor to review the intestinal lining. Its primary purpose is to investigate specific symptoms or abnormal findings, distinguishing it from a screening colonoscopy performed on individuals without symptoms to detect early signs of disease.
Patients typically undergo this procedure for unexplained symptoms like rectal bleeding, changes in bowel habits like persistent diarrhea or constipation, chronic abdominal pain, or unexplained weight loss. It is also recommended for abnormal results from other tests, such as a positive fecal occult blood test or radiology scans. This procedure helps identify conditions like inflammatory bowel disease (Crohn’s disease or ulcerative colitis), diverticulosis, colonic strictures, or the source of gastrointestinal bleeding.
Preparing for the Procedure
Thorough preparation of the bowel is essential for a successful diagnostic colonoscopy. Patients must adhere to specific dietary restrictions, typically starting a few days before the procedure. This involves shifting to a low-residue diet, followed by a clear liquid diet the day before the colonoscopy.
The clear liquid diet includes transparent, easily digestible items like water, clear broths, clear juices without pulp, clear sodas, sports drinks, plain gelatin, and popsicles without fruit or red/purple dyes. Alcoholic beverages, milk, smoothies, and juices with pulp are typically prohibited. Additionally, a bowel preparation solution, usually a laxative, is consumed to completely empty and cleanse the colon. Following these instructions ensures the colon lining is clear, allowing the physician an unobstructed view during the examination.
The Procedure Itself
Upon arrival, an intravenous (IV) line is typically inserted to administer fluids and sedation. Most patients receive sedation, ranging from moderate (conscious) to deep sedation or general anesthesia. Moderate sedation allows patients to be relaxed and sleepy, often with little memory of the procedure, while deep sedation or general anesthesia typically leads to a complete lack of awareness. The choice is discussed with the healthcare provider, considering the patient’s health and preferences.
During the colonoscopy, the patient lies on their side. The lubricated colonoscope is gently inserted through the anus and advanced. Air or carbon dioxide is introduced to inflate the colon, helping the physician gain a clearer view of the intestinal walls. The doctor examines the lining on a monitor, looking for abnormalities like polyps, inflammation, ulcers, or bleeding. If suspicious areas are identified, specialized instruments passed through the scope allow for polyp removal (polypectomy) or tissue sample collection (biopsies) for laboratory analysis. The procedure usually takes about 30 to 60 minutes.
Post-Procedure and Interpreting Results
After the colonoscopy, patients are moved to a recovery area where they are monitored as sedation wears off, typically taking 30 minutes to two hours. It is normal to experience some bloating, gas, or mild abdominal cramping due to introduced air; walking can help alleviate this discomfort. A responsible adult must drive the patient home, as sedation effects can impair judgment and coordination for up to 24 hours. Patients can usually resume their normal diet and activities the day after the procedure, though strenuous activities may need to be avoided for a few days, especially if polyps were removed.
Preliminary findings are often discussed immediately after waking from sedation. If biopsies were taken or polyps removed, full laboratory results may take several days to a few weeks. These results indicate the nature of any abnormalities found, such as whether polyps are benign, precancerous, or cancerous, or if inflammation or other conditions are present. Based on the findings, the healthcare provider will discuss appropriate next steps, including follow-up appointments, medication, or further treatment if significant issues are identified.