Diverticulitis is a complication of a common, usually symptomless, condition called Diverticulosis of the colon (Large Intestine). Diverticulitis is a localized infection of the colon. The ending,“-osis”, means a medical condition. The ending, “-itis”, means infection or inflammation.
Diverticulitis means that a pocket has become infected. Worsening Diverticulitis will cause pain in the lower left abdomen, usually above the belt line. Fever and the other signs of infection (fatigue, sweating, chills, mental confusion) can occur. In the worst manifestations of Diverticulitis, several days of i.v. antibiotics in the hospital may be required. Milder episodes may be controlled with out-patient antibiotics. Rarely, surgery is required to drain the pocket of infection around a section of the colon.
Diverticulosis 150 years ago was a rare condition. Now, the frequent occurrence of Diverticulosis is considered a consequence of the modern Western diet: high in meat and refined sugar; and, especially, a diet low in plant and vegetable fiber. Over a lifetime, Diverticulitis occurs in at least 10 per cent of those with Diverticulosis. Diverticulitis results from a diet of meat and refined sugar that’s low in plant-based fiber. By age 40, about ten percent of consumers of a Westernized diet have Diverticulosis.
An episode of infection, Diverticulitis, requires antibiotics to treat the infection to minimize the risk of the infected area enlarging, forming an abscess (a pocket of pus) and, even worse, a perforation (hole) developing in the colon. This leads to infection spreading in the peritoneum (lining of the abdomen) and hospitalization. See about Complications and Treatment below.
The Anatomy of Diverticulitis
To understand how and why Diverticulitis occurs, first, a description of bowel function and why diverticuli (pockets or outpouchings) of the colon occur for many people.
The three known purposes of the Large Intestine are:
First, to store waste until a convenient time to evacuate (defecate or “poop”) accumulated leftovers from food and bacteria that form the contents of the colon, and, second, to reabsorb (save) water. The longer the waste stays in the body, the more water is reclaimed. The loss of water slows the bowel movement’s progress through the colon and the person may becomemore constipated.
Thirdly, and more recently understood, is the “discovery” of the microbiome, a mutually beneficial colony of hundreds of types of bacteria, numbering about 100 trillion (tera-) which inhabit the large intestine. These bacteria live on the left-overs of human digestion and the indigestible fiber that humans eat. The weight of colon contents for the adult human, eating a typical American lower fiber diet, consisting of water, bacteria, waste food and indigestible food residue, may range from 5-15 pounds.
The Gut Microbiome
The microbiome enables absorption of Vitamin K and also modulates the human immune system. These bacteria may contribute to digesting and releasing nutrients from food. Food and fibers for which we lack the ability (enzymes systems) may be partially digested by these good bacteria of the microbiome.
For example, cinnamon, the common spice, is the ground woody bark of the cinnamon tree. Cinnamon is indigestible by humans. But, human immune cells cross the wall of the small intestine, interact with the cinnamon particles and then cross back into the wall of the small intestine. So, although the particles of cinnamon do not enter into our cells, they may produce benefit through interactions with our cells during their passage from mouth to anus.
In addition to the fluid we drink, the stomach may produce up to a liter (1.1 quarts) of digestive fluid per hour in the process of digesting the food we eat. Up to 20 liters (22 quarts) of fluid traverse from stomach through small intestine, nutrients and some of the water are absorbed from this during the passage through the small intestine. Undigested material, many liters in volume, enters into the colon. Most of the remaining fluid is reabsorbed and the final volume of excreted stool averages 350 to 500 ml, about one pound.
How Diverticuli Form In The Colon
Normal bowel function including defecation, or passing stool, requires the automatic sequential contraction of the muscles in the walls of the colon.
What causes diverticuli to form is the repeated higher pressure squeezing of the muscles of the colon which are arranged as bands, not as a continuous sheet of muscle. Squeezed between adjacent bands of muscle is a section of colon made up of three layers: outer, middle and inner. As these muscle bands squeeze the content in between, the pressure causes the section of interposed colon to stretch and balloon out under the pressure.
Imagine the process of emptying a stuffed sausage casing. Starting at one end, one would begin squeezing the sausage casing and repeatedly squeeze out the contents, hand over hand. If one squeezes both end of the segment of sausage tubing at the same time, the contents of the casing will be pushed together and the pressure will increase inside the casing. This would also prevent the contents from being expelled.
Another component of normal bowel function is that the waste collects and is stored in the proximal (closer to the stomach) two-thirds to three-fourths of the colon which is about eight or nine feet long in the usual adult. The usual location of the colon in the abdomen is as follows: liquid from the small intestines spills into the colon at its beginning through the ileocecal valve. The beginning section of the colon, the cecum, in on the right side of the lower abdomen, at about the belt line.
The colon ascends on the right side, goes across the upper abdomen in front of the stomach (the transverse colon) and descends of the left side of the abdomen. As the waste liquid passes through these five or six feet of colon, water is progressively withdrawn from the liquid waste. The consistency of the forming stool now is between a thick paste to soft clay.
Waste awaiting expulsion is normally stored in the left colon. Normally the sigmoid colon and rectum are empty.
After a meal or after drinking a warm liquid, as part of one’s daily schedule, or automatically, the left colon will begin to contract pushing stool into the empty proximal sigmoid colon. As filling starts in the sigmoid colon, the sigmoid section is stretched and reacts with vigorous sequential contractions. This is accompanied by an awareness of the need to defecate.
If this sensation is mild it may be suppressed by conscious intention. Better (to lessen formation of diverticuli), however, is to respond with preparation for defecation by “assuming the position.” As stool is pushed into the distal sigmoid colon and rectum, a sensation of inevitable or urgent need to defecate occurs. If conscious repression of the urge is attempted now, it may become painful in the lower abdomen.
This urge to stool and rectal evacuation reflex may be overwhelming in intensity and intentional suppression may lead to more severe sigmoid contractions with even higher pressures inside the sigmoid colon leading to, over time, development of diverticuli and enlargement of existing diverticuli. A person may have only a few diverticuli. Rarely, hundreds of them form. Most diverticuli form in the sigmoid colon.
As noted, the last parts of the colon, the twisting sigmoid (which mean sigma or S-shaped) colon and rectum, are normally empty. For defecation to start, a person has to bear down and hold one’s breath to both push out stool and to stimulate the muscles at the very end of the colon (the rectum and anus) to relax and open enough for stool to extrude. These muscles are called the anal sphincter.
After the rectum and sigmoid colon are empty, if no further stool is pushed out of the left colon, the bowel movement will naturally end. If there is still stool in the rectum, there will be a sensation of further need to defecate. Sometimes, voluntary abdominal muscle (“abs”) contractions accompanied by repeatedly “bearing down” (the Valsalva maneuver) will be tried to voluntarily try to complete rectal evacuation. This will increase pressure and sometimes further contractions of the colon. If the rectum again has a series of automatic contractions, the rectum may finish emptying. These attempts to empty the rectum will be associated with repetitions of the Valsalva maneuver.
Diverticulitis and Constipation
The development of diverticuli (Diverticulosis) is associated with constipation, and also increasing age. When constipated, a person has to strain at stool longer and harder. This straining (holding one’s breath and bearing down or Valsalva maneuver) increases the pressure within the lumen (interior) of the colon. Because the structure of the colon includes nutrient arteries from the outside lining of the colon to the interior, the path of these arteries effectively poke “holes” in the wall of the colon, these “holes” are weakened areas.
With recurring and increasing pressure in the colon, the inner lining, called the mucosa, begin to pucker out through these holes in the middle colon wall and form vase shaped outpouchings pushing into the outermost layer of the colon. These “pockets” festooning the outside of the colon are called “diverticuli”. A single pocket is called a diverticulum. The medical condition of multiple outpouchings is called Diverticulosis. Infection of one of these pockets is Diverticulitis.
Because the vase shaped contour of the diverticulum includes a narrow neck, it can become inflamed or infected or obstructed at the neck. The swelling associated with infection or inflammation leads to the narrow neck swelling shut. This traps the infection inside the pocket. As the infection increases, trapped inside the diverticulum, the diverticulum becomes an abscess which, untreated, soon leads to a perforation (hole) in the diverticulum.
From the perforated diverticulum, the infection forms a local abscess in the abdomen or the infection can spread and cause a more severe infection in the abdomen, peritonitis.
Treatment for diverticulosis is preventative. Add dietary fiber. Drink lots of water to help the fiber bulk-up the stool contents and for the benefit of the intestinal helpful bacteria.
Diverticulosis has two known complications: bleeding manifest as red to dark reddish, almost black, stool (which can be life threatening bleeding) and infection (Diverticulitis).
What improves bowel function and reduces the severity of diverticulosis (pocket formation)?
First, add fiber (indigestible plant material) such as bran (the paper thin covering of grains) and unprocessed vegetables to your diet.
Second, add water. Drink enough water to void light colored (more diluted) urine at least four to five times a day. Compare the color to your first voided urine in the morning upon awakening. This morning urine is usually the most concentrated of the day. Cut back on extra water after 6 PM at night if the amount you are drinking during the day awakens you more than once at night to void.
Consume increased dietary fiber (eaten as high fiber foods – fruits, vegetables, whole grain pasta and whole grains or bran, vegetables, peas and beans) as tolerated to greater than 40 grams of fiber (one and one-third ounces) per day.
For some people, adding too much fiber too fast to the diet may make them feel gassy or bloated until their body and the bacterial content of the colon adjusts. This is natural and your body must microbiome must take some time to adjust to the increased fiber – trust me, this is a good thing, and much preferable to a serious complication like diverticulitis or peritonitis.
Dietary fiber works in several ways to benefit Diverticulosis. By absorbing water, the fiber bulks up, as if wetting a sponge, increasing water in the contents of the colon. This forms a softer bulkier stool. Increasing dietary fiber can help lower cholesterol (soluble fiber such as oat bran), decrease the risk of colon cancer and lessen the formation of hemorrhoids.
Why Eating Fiber Helps Diverticulitis
Good bacteria live on the indigestible fiber. These bacteria actually influence beneficial effects on the intestinal immune system (lymph nodes and immune cells) and enhance the whole immune system of our body.
The fiber and bulk “scour” the walls of the intestine, keeping bowel contents moving forward to excretion. Thus, toxic material stays in the body for a shorter time.
The preferred consistency of the stool is solid-looking, formed, and soft enough to form S-shaped curves in the toilet water. If stool is moving too slowly through the colon, it forms short, sausage shaped “links” with an appearance of small lumps of dry clay squeezed together. Too delayed and too dry stool, held inside longer than needed, forms lumpy “golf ball” shapes.
So, in summary, drink extra water, enough to urinate at least five times a day during the daylight hours. Add soluble and insoluble fiber to one’s diet. Fruit and fresh or minimally cooked vegetables are great sources of fiber. A pear has 14 grams of fiber. Try to achieve and maintain the initial goal of at least 40 grams of dietary fiber per day.
Thanks to George Knowles, M.D., an Emergency Room Physician with over 30 years experience for writing this article on Diverticulitis.