| Colonoscopy |
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| Colonoscopy is the endoscopic examination of the large colon and the distal part of the small bowel with a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected lesions. Colonoscopy can remove polyps 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. |
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| Due to the high mortality associated with colon cancer and the high effectively and low risks associated with colonoscopy, it is now also becoming a routine screening test for people 50 years of age or older. Subsequent rescreenings are then scheduled based on the initial results found. |
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| The patient may be asked to skip aspirin and aspirin products such as Motrin, Ibuprofen or Aleve, for up to ten days before the procedure to avoid the risk of bleeding if a polypectomy is performed during the procedure |
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| The colon must be free of solid matter for the test to be performed properly. Prior to the examination patients required to follow a clear-fluid only diet. Examples of clear fluids are apple juice, bouillon, colorless soda or sports drink, and of course water. Before the colonoscopy, the patient is given a laxative preparation and large quantities of fluid to help in the evacuation process and hydration during this process. |
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During the procedure the patient is often given sedation intravenously.
The endoscope is passed though the anus up the rectum, the colon 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. |
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| 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. Bbody 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. |
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| Suspicious lesions may be cauterized or cut with an electric wire for purposes of biopsy or complete removal polypectomy. 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. |
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| After the procedure, some recovery time is usually allowed to let the sedative wear off. |
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| One very common aftereffect from the procedure is a bout of flatulence and minor wind pain caused by air insufflation into the colon during the procedure. |
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| 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. Even if the polyp is flat on the surface it can often be removed. |
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Esophagogastroduodenoscopy |
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| Esophagogastroduodenoscopy (EGD) is a diagnostic endoscopic procedure that visualizes the upper part of the gastrointestinal tract up to the first and second portion of the duodenum. It is considered a minimally invasive procedure since it does not require an incision into one of the major body cavities and does not require any significant recovery after the procedure. |
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| The patient is told not to eat before the procedure. During the procedure the patient is often given sedation intravenously, Informed consent is obtained before the procedure. The main risks are bleeding and perforation. The risk is increased when a biopsy or other intervention is performed. |
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| The patient lies on his/her left side with the head resting comfortably on a pillow. A mouth-guard is placed between the teeth, partly to protect the patient's teeth but more importantly to prevent the patient from biting on the very expensive endoscope. The endoscope is then passed over the tongue and into the orpharynx. This is the most uncomfortable stage for the patient. Quick and gentle manipulation under vision guides the endoscope into the esophagus. The endoscope is gradually advanced down the esophagus. The endoscope is quickly passed through the stomach and through the pylorus to examine the first and second parts of the duodenum. Once this has been completed, the endoscope is withdrawn into the stomach and a more thorough examination is performed. The air in the stomach is aspirated before removing the endoscope. |
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| In its most basic use, the endoscope is used to inspect the lining of the digestive tract. Often inspection alone is sufficient, but biopsy is a very valuable adjunct to endoscopy. Small biopsies can be made with a biopsy forceps which is passed through the scope and allows sampling of 1 to 3 mm pieces of tissue under direct vision. The intestinal mucosa heals quickly from such biopsies. |
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Problems of gastrointestinal function are usually not well diagnosed by endoscopy since motion or secretions of the gastrointestinal tract are not easily inspected by EGD. Nonetheless, findings such as excess fluid or poor motion of gut during endoscopy can be suggestive of disorders of function. |