What is colon pain?
Colon pain is any soreness within the colon of the large intestine. It is a symptom of some underlying disease and may occur along with other symptoms like diarrhea, constipation, flatulence and abdominal distention. In most instances it is difficult to attribute pain within the abdomen as arising from any specific organ especially if there are no other symptoms. Colon pain is one such instance and should therefore be investigated as abdominal pain as a whole, preferably localizing the pain to a specific abdominal quadrant or region.
The colon is the longest portion of the large intestine which is located towards the end of the human gut. The large intestine is shorter but wider than the small intestine that precedes it. Most activities that occur within the large intestine like the reabsorption of excess water and storage of waste (feces) happens in the colon. The fluid contents of the small intestine pass into the cecum of the large intestine. From here it begins its transit through the different parts of the colon where it is transformed from a liquid mush into the solid yet soft feces that is eventually expelled into the environment. When the colon is diseased, passage of waste obstructed or cannot be emptied from the colon then pain may occur.
Colon Pain Location
The colon is located within the abdominal cavity. The abdomen can be broadly divided into four quadrants – (from top clockwise) right upper quadrant (RUQ), left upper quadrant (LUQ), left lower lower quadrant (LLQ) and right lower quadrant (RLQ). Different parts of the colon run through each of these quadrants. The course of the colon is as follows :
- Ascending colon – where contents from the cecum enter the colon and travel upwards (RLQ and RUQ).
- Transverse colon – where the colonic contents moves sideways from right to left (RUQ and LUQ).
- Descending colon – where the colonic content moves downwards (LUQ and LLQ).
- Sigmoid colon – where the colonic contents moves from left to right in a slightly downward orientation to empty into the rectum (LLQ).
The ascending colon starts in the right lower quadrant and runs up to the right upper quadrant. It bends at the hepatic flexure to follow through to the transverse colon. Therefore the right side of the abdomen is occupied by the entire ascending colon and first part of the transverse colon.
The left half of the transverse colon continues from the right upper quadrant to the left upper quadrant. It bends at the splenic flexure to become the descending colon and runs downwards to the left lower quadrant. Here it continues as the sigmoid colon and connects with the rectum.
Pain in the ascending colon occurs on the right side of the abdomen. There are various other causes of right side abdominal pain.
Pain in the transverse colon is felt across the upper abdomen. There are various other causes of upper abdominal pain.
Pain in the descending colon occurs on the left side of the abdomen. There are various other causes of left side abdominal pain.
Pain in the sigmoid colon is felt on the lower left quadrant (LLQ) of the abdomen or left side of the pelvis. There are various other causes of lower left abdominal pain.
Colon pain is a symptom that may accompany :
- Constipation or diarrhea
- Excessive flatulence
- Difficulty with or pain during defecation (dyschezia)
- Rectal bleeding
- Blood or mucus in the stool
- Abnormal bowel sounds
- Abdominal distention
- Nausea and sometimes vomiting
Causes of Colon Pain
There are a number of disorders that affect the colon which can lead to pain. These conditions may affect the entire length of the colon and even other parts of the gut or be isolated to specific segments of the colon. These causes can be further categorized according to the nature of the diseases – infectious, inflammatory, trauma, vascular and growths.
- Infectious colitis is inflammation of the colon due to an infection usually caused with bacteria like E.coli (Escherichia coli), Salmonella, Shigella and Campylobacter species or parasites like Entamoeba histolytica (amoebiasis).
- Pseudomembranous colitis is not actually an infection but arises with an overgrowth of a type of bacteria known as Clostridium difficile usually after the use of antibiotics. It is also commonly known as antibiotic-associated diarrhea (AAD). These bacteria secrete toxins that irritate the colon.
- Diverticulitis is inflammation of the outpouchings (diverticula) that develop in the colon, particularly the lower parts of the colon. It may arise with an infection but can also occur for other non-infectious factors like ischemia (reduced blood supply to the outpouchings).
- Inflammatory bowel disease is among the most common, non-infectious inflammatory conditions of the colon. Ulcerative colitis only affects the colon and rectum but Crohn’s disease may affect any part of the gut including the colon. It is believed to be due to an autoimmune mechanism.
- Microscopic colitis is an inflammation of the colon wall associated with thickening of the connective tissue (collagenous colitis) or a higher concentration of white blood cells in the colon (lymphocytic colitis). It may be a result of an infection or autoimmune disorder but the exact cause is unclear.
- Injury to the colon may arise with abdominal trauma either due to blunt-force or sharp-force trauma.
- Surgery to the colon or neighboring structures may lead to colon pain. This should be short term until the area heals.
- Colonoscopy or biopsy are diagnostic procedures that may cause pain after the procedure although this is short lived lasting a few days at most.
- Radiation exposure to the abdomen in the treatment of cancer of the colon or other abdominal structures may injure the colon.
- Colon polyps are small growths that form in the wall of the colon. Most are benign tumors and harmless but some have the potential to become cancerous. Polyps are usually asymptomatic till the later stages where it obstructs the colon.
- Colon cancer is a malignant tumor in the colon. It may arise from tissue in the colon wall (primary) or spread to the colon from cancer at a distant site (metastasis).
- Ischemic colitis is inflammation of the colon caused by an interruption of the blood supply to the colon. The low oxygen supply to the colon leads to ischemia which can occur over long periods of time.
- Bowel infarction is death of a portion of the colon wall usually following interruption of its blood supply (ischemic colitis) or sometimes with a bacterial infection. The tissue decomposes and is known as gangrene.
- Volvulus is a twisting of the intestines causing an obstruction of the bowel and may also interrupt the blood supply to the bowel wall. In the large intestine, it is more likely to occur in the cecum or sigmoid colon.
- Adhesions are bands of scar tissue that may constriction of the colon. It tends to follow inflammation or may arise after abdominal surgery particularly with repeat procedures.
- Fecal impaction is an accumulation of stool in the sigmoid colon or rectum which turns into a hard, dry mass. It is a complication of severe constipation.
- Other causes of obstruction of the colon includes colon polyps, colon cancer and diverticulitis which have been discussed above.