I’ve had a colonoscopy (without pain relief) where they took biopsies. The doctors said the biopsies wouldn’t hurt because the colon couldn’t feel pain, and they were indeed painless. The amount of air they pumped in was horrifically painful however.
Trapped gas sounds trivial, but can also be extremely painful. Ulcerative colitis also hurts. So does diarrhoea.
So how do these pain mechanisms work? What causes the pain, if the interior of the colon is unfeeling?
In: Biology
Gastroenterologist here.
Since when does the colon not have pain receptors? Your entire GI tract is innervated heavily, both with nerves inside (the enteric nervous system), and nerves that project onto your skin (somatic nerves). Distension and gas absolutely cause pain, and your body is very finely tuned to detect when a portion of your bowel is distended. One of the most common causes of chronic pain is [irritable bowel syndrome](https://en.wikipedia.org/wiki/Irritable_bowel_syndrome), which causes intense pain with contraction of the colon and distension with gas. In short, there are about as many nerves in your GI tract as there are in your spinal cord. Many of these nerves are pain fibers.
Furthermore, there is something called the brain-gut axis that connects all this machinery to your brain, which is constantly being informed of the status of your GI tract. Hence the reason that your stomach hurts when you have anxiety.
The reason the doctor said that is because the part we biopsy, called the mucosa, is above the shallowest nerve layer, called the submucosa. Deeper biopsies can certainly hurt, but the biopsy forceps are very tiny, and we just get a little pinch of tissue.
Latest Answers