Colonoscopy

Colonoscopy is the minimally invasive endoscopic examination of the large colon. A flexible tube called a colonoscope is passed through the Anus to the Cecum (to the appendicle orifice) It may provide a visual diagnosis (e.g. ulceration, polyps) and grants the opportunity for biopsy or removal of suspected lesions. Colonoscopy can remove polyps (fleshy small tumor) smaller than one millimeter. Once polyps are removed, they can be studied with the aid of a microscope to determine if they are precancerous or not. Colonoscopy is similar but not the same as sigmoidoscopy. The difference between colonoscopy and sigmoidoscopy is related to which parts of the colon each can examine. Sigmoidoscopy allows doctors to view only the final two feet of the colon, while colonoscopy allows an examination of the entire colon, which measures four to five feet in length.

Polyp

Uses

Indications for colonoscopy include gastrointestinal hemorrhage, unexplained changes in bowel habit or suspicion of malignancy. Colonoscopies are often used to diagnose colon cancer, but are also frequently used to diagnose inflammatory bowel disease. In older patients (sometimes even younger ones) an unexplained drop in hematocrit (one sign of anemia) is an indication to do a colonoscopy, usually along with an EGD (oesophagoastroduodenoscopy), even if no obvious blood has been seen in the stool (feces).

Fecal occult blood is a quick test which can be done to test for microscopic traces of blood in the stool. A positive test is almost always an indication to do a colonoscopy. In most cases the positive result is just due to hemorrhoids; however, it can also be due to polyps (which are easily removed during the colonoscopy procedure), diverticulosis, inflammatory bowel disease (Crohn's disease, ulcerative colitis), or colon cancer.

Due to the high mortality associated with colon cancer and the high effectivity and low risks associated with colonoscopy, it is now also becoming a routine screening test for people 50 years of age or older. Medicare approves screening colonoscopies.

Procedure

Preparation
There are various preparations in the market for cleaning your colon. Your Doctor will discuss these during initial consultation at his office. It is very important for your colon to be free of solid matter (stool) for the test to be performed properly. Make sure you follow the instructions of the Physician and his staff carefully.

The investigation
During the procedure the patient is often given sedation intravenously by Board Certified Anesthesiologists at the Center of Surgical Excellence. An intravenous line will be inserted in you forearm by certified Nurses to give you fluids and conscious sedation.

The first step is usually a digital rectal examination, to examine the tone of the sphincter and to determine if preparation has been adequate. The endoscope is then passed though the anus up the rectum, the colon (sigmoid, descending, transverse and ascending colon, the cecum), and ultimately the terminal ileum. The endoscope has a movable tip and multiple channels for instrumentation, air, suction and light. The bowel is occasionally insufflated with air to maximize visibility. Biopsies are frequently taken for histology.

In most experienced hands, the endoscope is advanced to the junction of where the colon and small bowel join up (cecum) in under 10 minutes in 95% of cases. Due to tight turns and redundancy in areas of the colon that are not "fixed", loops may form in which advancement of the endoscope creates a "bowing" effect that causes the tip to actually retract. These loops often result in discomfort due to stretching of the colon and its associated mesentery. Maneuvers to "reduce" or remove the loop include pulling the endoscope backwards while torquing the instrument. Alternatively, body position changes and abdominal support from external hand pressure can often "straighten" the endoscope to allow the scope to move forward. In a minority of patients, looping is often cited as a cause for an incomplete examination.

For screening purposes, a closer visual inspection is then often performed upon withdrawal of the endoscope over the course several minutes.

Suspicious lesions may be cauterized, treated with laser light or cut with an electric wire for purposes of biopsy or complete removal polypectomy. Medication can be injected, e.g. to control bleeding lesions. On average, the procedure takes 20-30 minutes, depending on the indication and findings. With multiple polypectomies or biopsies, procedure times may be longer. As mentioned above, anatomic considerations may also affect procedure times.

After the procedure, some recovery time is usually allowed to let the sedative wear off. Most facilities require that patients have a person with them to help them home afterwards (again, depending on the sedation method used).

One very common after effect from the procedure is a bout of flatulence and minor wind pain caused by air insufflation into the colon during the procedure.

An advantage of colonoscopy over x-ray imaging or other, less invasive tests, is the ability to perform therapeutic interventions during the test. If a polyp is found, for example, it can be removed by one of several techniques. A snare can be placed around a polyp for removal with electrical cauterization.

Risks
This procedure has a low (0.2%) risk of serious complications.

The most serious complication is a tear or hole in the lining of the colon called a gastrointestinal perforation, which is life-threatening and requires immediate major surgery for repair; however, the rate of perforation is less than 1 in 2000 colonoscopies.

Bleeding complications may be treated immediately during the procedure by cauterization via the instrument. Delayed bleeding may also occur at the site of polyp removal up to a week after the procedure and a repeat procedure can then be performed to treat the bleeding site

As with any procedure involving anesthesia, other complications would include cardiopulmonary complications such as temporary drop in blood pressure and oxygen saturation, usually the result of overmedication and easily reversed. In rare cases, more serious cardiopulmonary events such as a heart attack, stroke, or even death may occur; these are extremely rare except in critically ill patients with multiple risk factors.

Getting Ready for the Test

1 Week before the test

Do not take Vitamin E, Aspirin, Ibuprofen, Motrin, Aleve or Advil.

Tylenol is acceptable and can be taken

No fiber supplements, flaxseed or iron.

Stop Aspirin, Plavix, Coumidin (3-5 days) before the test except if advised by you Physician.

The Day before the Test

Start your prep to cleanout your bowels at the suggested times.

Diabetics are to take ½ dose of insulin the day before procedure and no insulin the morning of the exam.

Wear easy-to-remove shorts or pants (like sweat pants). You may feel an urgent need to get to the bathroom.

You may have hard candy or gum. AVOID the colors red, purple, orange and green.

Diarrhea from the bowel prep medicine may make the skin around your anus (rectum) burn, especially if you have hemorrhoids. Use diaper rash ointment as needed (can buy at supermarket or drugstore)

Until midnight, you may drink clear liquids after taking all of your bowel prep medicine. After midnight, do NOT eat or drink ANYTHING – INCLUDING WATER.

Please do not smoke after midnight and the morning before your test.

The Day of the Test

Do not eat or drink anything on the morning of the test.

Wear loose fitting, comfortable clothing.
Avoid wearing girdles, pantyhose, or tight fitting clothes. You will be asked to put on a hospital gown.

No medications are to be taken on the day of the procedure.
Exceptions: blood pressure, heart, epilepsy, anti-anxiety, respiratory, or Parkinson medication. Take these medications with a SIP of water. Please bring all respiratory inhalers to the center on the day of your procedure.
*****Diabetics who take oral diabetic medication are to hold it the morning of the exam.