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Protect Your Colon From Diverticular Disease
Last reviewed by Faculty of Harvard Medical School on January 24, 2013
By Harvey B. Simon, M.D.
Harvard Medical School
Many health-conscious men can recite their cholesterol numbers, blood pressure readings and PSA levels without even glancing at their medical records. But few of these well-informed guys can tell you if they have diverticular disease of the colon, even though it's an extremely common condition.
That's understandable, because the most common form of the problem has few symptoms. But one type of diverticular disease can result in painful complications you don't want to ignore.
Find out what you can do to avoid this largely preventable disease.
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The colon is a 4½ foot-long tube that makes up the final part of the intestinal tract. The wall of the colon contains two groups of muscles:
- A circular muscle that rings the colon
- Three long muscles that run the entire length of the tube
Like all tissues, the colon requires a blood supply. Many small arteries that pass through the colon's muscular wall carry blood to its inner layer of cells.
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You may worry more about the polyps and cancers that can develop in the lining of the colon. But problems can also develop in other areas of the colon.
Diverticular disease of the colon accounts for 3,400 deaths in the United States each year while draining our economy of over $2.4 billion a year. That's quite a toll for a disease you may never have heard of.
Diverticular disease includes:
- Diverticular bleeding
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Sometimes small sac-like pouches, called diverticula, develop and protrude from the normally-smooth muscular layer of the colon. This condition is called diverticulosis. The pouches typically develop where the muscles are weakest: at the places where arteries cross through the muscles. In Western societies, most diverticula occur where the colon is narrowest in the sigmoid.
Diverticulosis is uncommon before age 40, but about one-third of all Americans will develop the condition by age 60; two-thirds will have it by age 80.
Diverticulosis was uncommon in the United States 100 years ago. It's still rare in the developing world. What accounts for all the difference? The principal factor is a diet that is low in fiber. Without enough fiber, the stools are small and hard, and the colon must contract with extra force to expel them. That puts extra pressure on the wall of the colon, increasing the risk of diverticulosis.
Other possible risk factors for diverticular disease include:
Dietary fiber is found in unrefined, unprocessed carbohydrates: whole grains, nuts, seeds, fruits, dried beans, legumes and vegetables. Animal foods don't contain fiber. Humans cannot digest these special carbs. They have little caloric value but has plenty of health value.
Among other things, the fiber found in wheat bran, whole-grain products, and most vegetables draws water into the feces making the stools bulkier, softer, and easier to pass. This type of dietary fiber is called insoluble fiber. It speeds the process of elimination, greatly reducing the likelihood of constipation.
The other type of fiber, soluble fiber, has less benefit for the colon but is still excellent for health: It helps lower cholesterol and blood sugar levels.
- A diet high in fat and red meat
- Cigarette smoking
- Nonsteroidal anti-inflammatory drugs
On the other hand, regular exercise reduces the risk.
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Diverticulosis is so common in Americans that it may hardly seem like a disease. Indeed, about 75% of men with the condition never develop serious problems.
But some 15% to 20% of men with the condition develop an inflammatory complication called diverticulitis. Five to ten percent of men with the condition develop bleeding, which can be life-threatening.
Inflammation puts the 'itis' into diverticulitis. The bacteria in feces are responsible for the inflammation. Doctors don't fully understand why some diverticula become infected and inflamed while many do not.
Symptoms: Pain is the major symptom. Because diverticulosis typically occurs in the sigmoid colon, the pain is usually most pronounced in the lower left part of the abdomen, but other areas may be involved. Fever is also very common, sometimes with chills. If the inflamed sigmoid is up against the bladder, a man may develop enough urinary urgency, frequency and discomfort to mimic prostatitis or a bladder infection. Other symptoms may include nausea, loss of appetite and fatigue. Some patients have constipation, while others have diarrhea.
Diagnosis: A doctor's exam may reveal tenderness in the lower left abdomen, where tissues are inflamed. As in other infections, the white blood cell count is usually elevated. But because these symptoms can occur with other conditions, further testing is needed to make the correct diagnosis.
The best test is a computed tomography (CT) scan of the abdomen. For best results, you may need to drink a liquid dye to make organs or blood vessels stand out more clearly on the CT scan. This is called a contrast medium. It may also be injected into your vein.
A month or two later, after treatment has quieted things down, the doctor will usually recommend a colonoscopy to check the diverticular disease and to be sure that no other abnormalities are present.
Therapy: Bacteria are responsible for the inflammation, so antibiotics are the primary treatment. Because the colon harbors so many types of bacteria, doctors must prescribe medications that target a broad range of "critters." Some examples include:
- Metronidazole (Flagyl) along with ciprofloxacin (Cipro, generic)
- Trimethroprim-sulfamethoxizole (Bactrim, generic)
- Amoxicillin-clavulanic acid (Augmentin)
In choosing the right drug, a doctor must always take their patients' allergies and general health into consideration.
Patients with mild-to-moderate diverticulitis can take their antibiotics in pill form at home. But patients with severe inflammation or complications (see below) should receive intravenous (IV) antibiotics in the hospital, and then finish up with pills at home. In most cases, 7 to 10 days of antibiotics will do the trick.
Bowel rest is also important for acute diverticulitis. At home that means sticking to a diet of clear liquids for a few days, then gradually adding soft solids and moving to a more normal diet over a week or two.
Because diverticulitis tends to recur, prevention is always part of the treatment plan. And that means a high-fiber diet.
Complications: Ordinary diverticulitis is bad enough, but its complications can be life-threatening. The most common complications include:
- Abscesses An abscess is a walled off collection of bacteria and white blood cells pus. Patients with abscesses are sicker than those with uncomplicated diverticulitis: They have higher temperatures, more pain and higher white blood cell counts. Treatment involves antibiotics and bowel rest, but it also requires drainage of the abscess. In many cases, specially-trained radiologists can accomplish that by using CT imagery to guide a thin plastic catheter through the skin into the abscess so the pus can drain out. Sometimes, though, open surgery is necessary.
- Peritonitis This major complication develops when infection spreads to the entire lining of the abdomen. Patients are critically ill with high fevers, severe abdominal pain and often low blood pressures. Prompt surgery and powerful antibiotics are required.
Less common complications include scarring and narrowing of the colon (strictures), and abnormal connections to other tissues (fistulas).
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Diverticulitis is one main complication of diverticulosis disease of the colon. The other is bleeding from the rectum. It is usually painless but results in bright red or maroon bowel movements. (In contrast, when bleeding occurs in the stomach, the blood is partially digested as it passes through the intestinal tract, so it appears as black, tar-like bowel movements).
In about two-thirds of patients, the bleeding is mild and it usually stops on its own, with bowel rest. But brisk bleeding is a life-threatening emergency. It requires expert hospital care with blood transfusions and IV fluids. It also requires aggressive attempts to locate the site of bleeding and to stop it. Surgery may be needed.
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How To Prevent Diverticular Disease
A high-fiber diet will sharply reduce the risk of developing diverticula and even after the pouches form, dietary fiber will reduce the risk of diverticulitis and bleeding.
The Institute of Medicine recommends 38 grams of fiber a day for men before age 50, and 30 grams a day for older men. (For women, the recommended amount is 30 grams a day before age 50 and 21 grams a day thereafter.) Most Americans get much, much less. You can check the fiber content of foods on the the U.S. Department of Agriculture website.
Fiber is important for bowel function and general health, but it can be hard to get used to. Many people feel bloated and gassy when they start a high-fiber diet. These side effects usually clear up within a month or so. Still, it's best to ease into a high-fiber diet. Increase your daily intake by about 5 grams per week until you reach your goal, and be sure to have plenty of fluids as well. For most people, a high-fiber cereal is the place to start, but if breakfast isn't your thing, you can have it any time during the day.
Until recently, doctors banned nuts, seeds, corn and popcorn from the diet of diverticulosis patients. Although they had no real evidence that these foods were harmful, doctors worried that these small particles might pass into the colon undigested and then lodge in the mouth of a diverticulum, blocking the pouch and making things worse. But a 2008 Harvard study put these fears to rest. During the 18-year study, the men who ate the most nuts and popcorn actually had a lower risk of acute diverticulitis than the men who ate the least; there was no change in the risk of bleeding.
Dietary fiber has many benefits. It:
- Prevents constipation
- Reduces the risk of hernias, hemorrhoids and even varicose veins by reducing straining, which puts pressure on the abdomen and the veins
- May reduce the risk of colon cancer, according to some studies
- Is filling and helps combat obesity
- Improves blood sugar metabolism, lowering the chances of developing diabetes
- Lowers blood pressure
- Reduces blood cholesterol levels and cuts the risk of heart attacks (soluble fiber)
From your heart to your colon, dietary fiber gives men plenty to chew on.
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Harvey B. Simon, M.D. is an Associate Professor of Medicine at Harvard Medical School and a member of the Health Sciences Technology Faculty at Massachusetts Institute of Technology. He is the founding editor of the Harvard Men's Health Watch newsletter and author of six consumer health books, including The Harvard Medical School Guide to Men's Health (Simon and Schuster, 2002) and The No Sweat Exercise Plan, Lose Weight, Get Healthy and Live Longer (McGraw-Hill, 2006). Dr. Simon practices at the Massachusetts General Hospital; he received the London Prize for Excellence in Teaching from Harvard and MIT.