Diverticulosis and diverticulitis

Diverticulosis occurs when small defects in the muscle of the wall of the large intestine, or colon, allow small pockets or pouches (called diverticula) to form. Diverticulitis is infection or inflammation of these abnormal pouches. Together, these conditions are known as diverticular disease.

Although they share some symptoms with other bowel conditions, diverticulosis and diverticulitis are different problems. Diverticulitis, in particular, is often a medical emergency that requires immediate medical attention and frequently admission to hospital. Mild attacks can sometimes be managed at home, but they should always be assessed promptly.

How common it is#

Diverticulosis is extremely common. Age and diet appear to be the most important risk factors. More than half of all adults over the age of 70 have the condition, and most are unaware of it. Diverticulosis is much less common in people under 50.

It is more common in populations that typically eat a low-fiber, Western-style diet and less common in populations whose diets are higher in fiber. These patterns led to the theory that a low-fiber diet plays an important role.

Possible causes#

Diet and fiber#

Large epidemiological studies have found that people with a higher overall fiber intake have a lower incidence of diverticulitis, the main complication of diverticular disease. The type of fiber may matter, with grains, cereals and fruit appearing beneficial, while the benefit of vegetable intake is less clear. Exactly how a low-fiber diet contributes to diverticulosis is not fully understood.

Genetic factors#

The location of the pouches can differ between populations. In some people, diverticulosis tends to develop in the last third of the colon, while in others it tends to develop in the first section. Studies of people who move from one environment to another suggest that surroundings and diet influence the risk, but the typical location pattern for a person’s background often persists.

Analysis of families affected by diverticulitis has identified at least two genes linked with the condition, and one of these (TNFSF15) has been associated with diverticulitis in several studies.

How diverticulitis develops#

Diverticulitis seems to occur when a small puncture develops in the wall of a diverticulum. This allows a small infection to develop, which often forms an abscess.

Symptoms#

Diverticulosis usually causes no symptoms, so it is often discovered during tests for other conditions. When many pouches are present, the normal smooth working of the bowel can be affected, causing symptoms such as:

• abdominal pain and bloating
• constipation and diarrhea
• flatulence
• blood in the feces, which is usually minor but can occasionally be heavy, and may lead to anemia with repeated bleeding

Many of these symptoms are similar to those of bowel cancer. Because diverticulosis is more common, these symptoms are more often due to diverticulosis, but a doctor will usually arrange assessment, often referring you to a specialist, to rule out other causes.

Symptoms of diverticulitis can include:

• sharp pain, often at a specific point such as the lower left side of the abdomen
• fever
• nausea and vomiting
• distension (bloating) of the abdomen

Complications#

Possible complications of diverticular disease include:

• Abscess – if left untreated, diverticulitis may form a ball of pus.
• Perforation – a weakened pocket of bowel wall may rupture, allowing the contents of the bowel to seep into the abdominal cavity. This causes pain, high fever and chills, and is a medical emergency.
• Peritonitis – perforation can lead to infection of the membranes lining the abdominal cavity and organs. This is potentially life threatening.
• Hemorrhage – diverticula can be a source of bleeding. When bleeding occurs, it is important to exclude other causes.

Diagnosis#

Diverticulitis is usually diagnosed during an acute attack. Tests used to confirm diverticular disease may include:

• medical history, including dietary habits
• physical examination, including a rectal examination
• colonoscopy
• barium enema, where a contrasting dye is flushed into the bowel and x-rays are taken
• CT scan, to detect abscesses outside the bowel lining
• blood tests, to check for signs of infection
• stool tests

Treatment#

There is no proven way to prevent the formation of new diverticula. Treatment focuses on settling symptoms.

For diverticulosis#

A gradual switch to a diet with more soluble fiber, such as green vegetables, oat bran and fiber supplements like psyllium, usually improves bowel habit and mild symptoms. Short-term use of laxatives to treat or prevent constipation may be advised. Rarely, elective surgery is performed to remove seriously affected segments of bowel when symptoms are disabling.

The antibiotic rifaximin has been effective in randomized trials for people with more severe symptoms of diverticular disease, although it can be expensive.

For diverticulitis#

Diverticulitis is often a medical emergency. Mild attacks can be treated at home but should always be assessed promptly. Treatment may include:

• resting the bowel by avoiding food and drink, with fluids given intravenously
• antibiotics
• pain-relieving medication
• surgery, if weakened sections of bowel wall have ruptured or become obstructed, or if the infection fails to settle

If it is not possible to rejoin the healthy sections of bowel, a Hartmann’s procedure may be performed and a colostomy bag fitted. This is more common when surgery is carried out as an emergency. A colostomy is generally temporary, and the bowel can often be rejoined after 6 to 12 months if health permits. Some research has suggested better outcomes when the bowel is rejoined during emergency surgery rather than using a Hartmann’s procedure.

Self-care#

• Increase your daily intake of fiber, introducing it gradually to avoid unpleasant symptoms such as flatulence.
• Drink plenty of fluids to keep stools soft, moist and easy to pass.
• Stay physically active with regular exercise.

Key points#

• Diverticulosis is the formation of small pouches in the bowel wall and is very common with increasing age.
• Diverticulitis is infection or inflammation of these pouches and is often a medical emergency.
• A low-fiber diet is thought to be an important risk factor.
• Treatment centers on a higher-fiber diet for diverticulosis and prompt medical care, antibiotics and sometimes surgery for diverticulitis.

Where to get help#