An endoscopy is a medical procedure that uses a thin, flexible tube with a tiny camera and light on its tip to look inside your body. The camera sends real-time images to a monitor, giving your doctor a direct view of your organs and tissues without making large incisions. Endoscopy can be used to diagnose problems, take tissue samples, and even treat certain conditions on the spot.
How Endoscopy Works
The instrument itself is called an endoscope. It’s a long, narrow tube, usually flexible, that enters your body through a natural opening like your mouth, nose, or rectum. In some cases, the scope enters through a small surgical incision. Once inside, the camera at the tip transmits a magnified image to a screen, allowing your doctor to examine the lining of your organs in detail. Many endoscopes also have a small channel that lets your doctor pass tools through the tube to take biopsies, remove growths, or stop bleeding.
Types of Endoscopy
The word “endoscopy” is an umbrella term. The specific name of the procedure depends on which part of the body is being examined.
- Upper endoscopy (EGD): The scope goes through your mouth to examine your esophagus, stomach, and the upper part of your small intestine. This is what most people mean when they say “endoscopy.”
- Colonoscopy: The scope enters through the rectum to view your entire large intestine.
- Sigmoidoscopy: Similar to a colonoscopy but only examines the lower portion of the colon.
- Bronchoscopy: The scope goes through your mouth or nose to look at your windpipe and lungs.
- Cystoscopy: The scope enters through the urethra to examine the bladder.
- Hysteroscopy: The scope goes through the vagina to examine the uterus.
- Laparoscopy: The scope enters through a small incision in the abdomen to view abdominal and reproductive organs.
- Arthroscopy: The scope enters through an incision near a joint to look for damage or conditions like arthritis.
Less common types include enteroscopy (small intestine), laryngoscopy (voice box), ureteroscopy (the tubes connecting your kidneys to your bladder), and even neuroendoscopy, where a scope enters through a small opening in the skull to examine the brain.
Why Doctors Order an Endoscopy
Endoscopy serves two broad purposes: finding problems and fixing them. On the diagnostic side, your doctor can visually inspect organ surfaces, spot ulcers or inflammation, and take small tissue samples (biopsies) to check for infection, precancerous changes, or other abnormalities. Upper endoscopy detects about 90% of stomach and intestinal lesions in experienced hands.
On the treatment side, the same procedure can often address what it finds. Polyps in the stomach or colon can be removed during the exam and sent for testing. Bleeding ulcers or blood vessels can be sealed with heat or clips. Narrowed passages in the esophagus can be stretched open using balloon dilation. Bile duct stones can be extracted with a success rate above 90%. Stents can be placed in blocked ducts to restore flow. The ability to diagnose and treat in a single session is one of the biggest advantages of endoscopy over imaging tests like CT scans or X-rays.
Capsule Endoscopy
For areas that are hard to reach with a traditional scope, particularly the small intestine, there’s a swallowable capsule roughly the size of a large vitamin pill. It contains a tiny camera that takes thousands of pictures as it travels through your digestive tract, transmitting them wirelessly to a recorder you wear on a belt. The capsule passes naturally and is not retrieved.
Capsule endoscopy is purely diagnostic. It can’t take biopsies or treat anything. Its most common use is tracking down a source of gastrointestinal bleeding after upper endoscopy and colonoscopy have come back normal. In that scenario, the capsule detects the bleeding source 35% to 77% of the time. It’s also used to monitor Crohn’s disease when other tests are inconclusive and for colon cancer screening in patients who can’t tolerate a standard colonoscopy. It works best as a complement to other tests, not a replacement for them.
How to Prepare
Preparation depends on the type of endoscopy, but for the most common procedures involving the digestive tract, fasting is required. For an upper endoscopy, you’ll typically need to stop eating solid food eight hours beforehand and stop drinking liquids four hours before. A colonoscopy requires more extensive bowel preparation, usually involving a liquid diet and a strong laxative solution the day before.
If you take blood-thinning medications, your doctor will likely ask you to stop them several days in advance, since some endoscopic procedures carry a small risk of bleeding. People with diabetes, heart disease, or high blood pressure may need adjusted medication schedules. The key step is to give your doctor a complete list of everything you take, including supplements, well ahead of the procedure.
What the Procedure Feels Like
Most endoscopic procedures involve some form of sedation. For an upper endoscopy, you’ll usually receive sedation through an IV that puts you in a drowsy, relaxed state. Many people don’t remember the procedure afterward. A colonoscopy typically uses a similar level of sedation. Some shorter or less invasive procedures, like a sigmoidoscopy or cystoscopy, may use only local numbing.
The procedure itself is generally quick. An upper endoscopy usually takes 15 to 30 minutes. A colonoscopy runs about 30 to 60 minutes. You’re lying on your side or back, and while you may feel mild pressure or fullness, significant pain is uncommon with proper sedation. If your doctor needs to take a biopsy or remove a polyp during the exam, you typically won’t feel it.
Recovery After the Procedure
You’ll spend time in a recovery area while the sedation wears off. Most people are alert enough to be discharged within about 50 minutes to two hours after the procedure. Staff will check that you can answer questions clearly and walk steadily before releasing you. Because sedation impairs your judgment and reflexes for the rest of the day, you’ll need someone to drive you home.
After an upper endoscopy, you may have a mild sore throat for a day or two. After a colonoscopy, bloating and gas are common as the air used to inflate the colon works its way out. For routine diagnostic procedures, you can typically resume eating within a few hours. If a simple finding like a clean-based ulcer is identified, you can return to a normal diet right away. Your care team will give you written instructions covering diet, activity, medications, and any follow-up appointments before you leave.
Most people return to normal activities by the next day. If a biopsy was taken, results usually come back within a few days to two weeks.
Risks and Complications
Endoscopy is considered very safe. Serious complications are rare. In a large study of over 3,000 patients undergoing one of the more invasive endoscopic procedures (fine needle aspiration of pancreatic masses), severe bleeding occurred in only 0.23% of cases, no perforations were observed, and there were zero deaths within 30 days. For standard upper endoscopy and colonoscopy, complication rates are even lower.
The most commonly discussed risks include a small tear (perforation) in the organ wall, bleeding at a biopsy or polyp removal site, infection, and reactions to sedation. Bleeding that does occur can often be treated during the endoscopy itself with clips or heat. One notable finding from research: complication rates are lower at facilities that perform a high volume of procedures. The severe bleeding rate at low-volume hospitals was roughly five times higher (0.48%) than at medium- and high-volume centers (0.10%). If you have a choice of where to have your procedure, a facility that does them regularly is a reasonable preference.