Detecting and Treating Diseases of the Colon and Rectum
Many Americans have difficulty moving their bowels. Many things contribute to this problem. Some causes include diet and activity level and others are unknown.
This article will describe some of the more common bowel problems.
Anatomy and physiology
The large bowel consists of the colon (5 feet long) and the rectum (8 inches long). Many times the rectum is referred to as the opening where stool emerges, but that is actually the anus. The rectum is 4 inches long and just upstream from the anus. Just upstream from the large bowel is the small bowel.
The colon's main function is to process the 3 pints of liquid stool it receives each day into a manageable amount of solid stool, ready for evacuation. The rectum coordinates the process of evacuation. Normally, a person can pass up to 200 grams of solid stool daily. However, there is a lot of variation in the amount of stool a normal person passes. This can vary from 3 times daily to 3 times per week.
Functional disorders are disorders in which the bowel looks normal but doesn't work properly. These are the most common problems affecting the colon and rectum. The direct cause is frequently unknown.
Constipation is defined as small, hard, difficult, or infrequent stools. Constipation may be caused by:
- Inadequate "roughage" or fiber in the diet
- Not enough oral fluid
- Poor habits, especially delaying using the toilet
- Movement problems in the large bowel, including slow or uncoordinated movement
A person who is constipated may strain during a bowel movement or just pass very hard stool. Passage of hard stool may contribute to the development of anal problems such as fissures (painful cracks in the anal tissue lining) or hemorrhoids.
Irritable bowel syndrome (sensitive colon; spastic colon)
Irritable or sensitive bowel is a condition in which the colon muscle contracts in an abnormal fashion, which may lead to several problems. Some patients have predominantly diarrhea; others have constipation; and others alternate between constipation and diarrhea. The abnormal contraction can lead to high pressure that builds up in the colon causing abdominal cramps, gas, bloating, and sometimes extreme urgency.
Treatment includes avoiding foods that make the problems worse, tailoring diet to the particular symptoms, managing stress, and medications.
Structural disorders are those in which there is something visually abnormal that may need to be removed, altered, or repaired by an operation. These may include removing a portion of the colon for diverticulitis or for a cancer.
Internal hemorrhoids are normal blood vessels that line the inside of the anal opening. We are born with them. They are thought to be the fine-tuning mechanism that allows us to contain gas and avoid passing it until we feel it is socially acceptable. When they become enlarged as a result of straining or pregnancy, they may become irritated and start to bleed. Occasionally internal hemorrhoids can become enlarged enough to protrude outside the anal opening.
New treatments are being developed all the time. Traditional care has included improving bowel habits, using elastic bands to pull the internal hemorrhoids back into the rectum, or removing them surgically. There are new devices that use sound waves to discover exactly where the excessive blood flow is occurring into these vessels and allow the doctor to specifically tie off the area. Also there is the 'stapled' hemorrhoidectomy where a special device is used to pull the hemorrhoid tissue back into the body and staple it in place. Doctors can examine patients and pick the treatment that would best treat their problems.
External hemorrhoids are veins that lie just under the skin on the outside of the anus. Usually they do not cause any symptoms. Occasionally a blood clot can form and can be very painful. Many times this will get better on its own. Sometimes, removal of the clot is done under local anesthesia in the doctor's office. These are not dangerous blood clots that can travel to other organs. The biggest concern they raise is pain.
An anal fissure is a split or tear in the lining of the anus that occurs after trauma, which can be from a hard stool or even diarrhea. As a result, the person experiences bleeding and intense burning pain after bowel movements. The pain is caused by spasm of the sphincter muscle, which is exposed to air by this tear. The pain with bowel movements has been described as the feeling of passing razor blades.
Fissures are the anal problem misdiagnosed most commonly. They frequently are mistaken for hemorrhoids.
Fissures often get better by themselves. If they don't improve, your doctor can recommend an ointment or medication that will relieve the pain. In certain cases, surgery may be recommended if the tear does not heal due to excessive sphincter spasm.
Our anal region has tiny glands that open on the inside of the anus and probably aid in passage of stool. When one of these glands becomes blocked, an infection may develop. When pus forms, there is an abscess (a pocket of pus). Treatment includes draining the abscess, usually under local anesthesia in the doctor's office.
In about 50% of cases after drainage of a perianal abscess, a tunnel develops from the gland on the inside of the anus to the skin around the anus. This is termed a fistula-in-ano. Fistulas drain mucous fluid onto the skin and blood. They rarely heal by themselves and usually need surgery.
Other perianal infections
Between the anal area and the tailbone, hair in this region can burrow under the surface and causing infection. This is called pilonidal disease. It may present as abscess in this area just below the tailbone or small draining openings. Usually surgery is needed to treat this problem.
Sexually transmitted diseases that can affect the anus include herpes, AIDS, chlamydia, and gonorrhea. Anal warts that are small growths on the anal skin that look like tiny pink cauliflowers and are caused by a virus (HPV).
Colon and rectal disorders
Colonic diverticula are little out-pouchings or sacs in the bowel lining that occur when the lining gets pushed through weak spots in the muscle of the bowel wall. They usually occur in the sigmoid colon, where the large bowel exerts the highest pressure.
Diverticular disease is very common in Western societies and may be due to low-fiber Western diets. Diverticula rarely cause symptoms unless one of the sacs gets blocked and infected. This occurs in about 10% of people with diverticula and is termed diverticulitis. Occasionally, bleeding will occur in this area.
Surgery is needed in about half the patients who have complications of their diverticula.
Polyps and cancer
Cancer of the colon and rectum is a major health problem in America today. It occurs when there is a complete loss of control of the way lining cells of the large bowel grow and divide. Many things contribute to this loss of control. Some of these things are in our environment, some are contained in our diet, and some are in our genetics (what we inherit from our parents).
The first abnormality seen in this pathway when the control of the lining cells is first affected is a polyp. A polyp is a small growth that may look like a mushroom protruding from the lining tissue of the large bowel. There are many types of polyps and not all are the type that can turn into cancer. However, removing these polyps before they develop severe changes and grow can prevent the progression to cancer.
With prompt, expert treatment, most people can be cured of colorectal cancer. Many people are worried about the risk of having a colostomy or bag on the abdominal skin to collect stool. Hardly anyone needs a permanent colostomy.
Because colorectal cancer comes from polyps, colonoscopy can prevent colorectal cancer by finding and removing polyps. People at special risk for colorectal cancer include those who have had polyps or cancers in the past, or those who have a history of colorectal cancer in their family. Indeed, the decreased incidence of colorectal cancer in the U.S. in recent years can be attributed to the rising acceptance of cancer surveillance colonoscopy.
Colitis is a group of conditions that cause inflammation of the large bowel. There are several types of colitis, including:
- Infectious colitis (due to an infection that attacks the large bowel)
- Ischemic colitis (caused by not enough blood going to the colon)
- Radiation colitis (after radiotherapy usually for prostate, rectal, or gynecological cancer)
- Ulcerative colitis (cause not known)
- Crohn's disease (cause not known)
Colitis causes diarrhea, rectal bleeding, abdominal cramps, and urgency. Treatment depends on the diagnosis, which is made by colonoscopy and biopsy.
Many diseases of the colon and rectum can be prevented or treated by seeking prompt medical care.
Most importantly, colon cancer is a preventable disease. The most important risk factor is having a direct family member who had colon cancer. Discussion with your doctor can determine when you need an evaluation (usually a colonoscopy) to look for polyps. For people with no family history and no symptoms, the current recommendation is that everyone should have their first colonoscopy at age 50.
People who have symptoms of any of these conditions should consult their doctor without delay.