[1] Risk factors may include obesity, lack of exercise, smoking, a family history of the disease, and use of nonsteroidal anti-inflammatory drugs (NSAIDs).

[2][6] Diagnosis is typically by CT scan, though blood tests, colonoscopy, or a lower gastrointestinal series may also be supportive.

[2] Avoiding nuts and seeds as a preventive measure is no longer recommended since there is no evidence these play a role in initiating inflammation in the diverticula.

[1] For severe cases, intravenous antibiotics, hospital admission, and complete bowel rest may be recommended.

[1] Patients commonly have elevated C-reactive protein and a high white blood cell count.

[11] In complicated diverticulitis, an inflamed diverticulum can rupture, allowing bacteria to subsequently infect externally from the colon.

[18][19] A 2022 study found that more frequent bowel movements appeared to be a risk factor for subsequent diverticulitis both in men and women.

[22] A 2012 study found that a high-fiber diet and increased frequency of bowel movements are associated with greater, rather than lower, prevalence of diverticulosis.

[26] There is no evidence to suggest that the avoidance of nuts and seeds prevents the progression of diverticulosis to an acute case of diverticulitis.

[7][27] In fact, it appears that a higher intake of nuts and corn could help to avoid diverticulitis in adult males.

[28][29][30] A 2017 analysis found a dietary pattern high in red meat, refined grains, and high-fat dairy was associated with an increased risk of incident diverticulitis whereas a dietary pattern high in fruits, vegetables, and whole grains was associated with decreased risk.

The associations between dietary patterns and diverticulitis were largely due to red meat and fiber intake.

[33] A 2011 long-term study found that a vegetarian diet and high fiber intake were both associated with lower risks of hospital admission or death from diverticulitis.

[35] A prospective cohort study found that a healthy lifestyle (defined as <51 g daily red meat, >23 g daily dietary fiber, 2 hours’ exercise weekly, normal BMI, and never a smoker) was associated with a substantially reduced risk of diverticulitis (relative risk 0.27, 0.15 to 0.48).

[2] Diverticulitis is postulated to develop because of changes inside the colon, including high pressures because of abnormally vigorous contractions.

[43] Amongst the complications that can be seen on CT scan are: abscesses, perforation, pylephlebitis, intestinal obstruction, bleeding, and fistula.

[46] Complicated diverticulitis additionally includes the presence of abscess, peritonitis, obstruction, stricture and/or fistula.

[63][66] Rifaximin was found in a meta-analysis to give symptom relief and reduce complications[67] but the scientific quality of the underlying studies has been questioned.

[68] In limited studies, patients with diverticulitis and symptomatic diverticular disease treated with mesalamine have shown improvement in both conditions.

The timing of the elective surgery is determined by evaluating factors such as the stage of the disease, the age of the person, their general medical condition, the severity and frequency of the attacks, and whether symptoms persist after the first acute episode.

The diseased section of the large intestine is removed, and then the two healthy ends are sewn or stapled back together.

[76] However, most surgeons prefer performing the bowel resection laparoscopically, mainly because postoperative pain is reduced with faster recovery.

Laparoscopic surgery is a minimally invasive procedure in which three to four smaller incisions are made in the abdomen or navel.

After incisions into the abdomen are done, placement of trocars occurs which allows a camera and other equipment entry into the peritoneal cavity.

[77] All colon surgery involves only three maneuvers that may vary in complexity depending on the region of the bowel and the nature of the disease.

After the mesenteric vessels are dissected, the colon is divided with special surgical staplers that close off the bowel while cutting between the staple lines.

The surgeon makes an opening in the abdominal wall (a colostomy) which helps clear the infection and inflammation.

[80] In most cases several months later, after the inflammation has healed, the person undergoes another major surgery, during which the surgeon rejoins the colon and rectum and reverses the colostomy.

In Western countries, diverticular disease most commonly involves the sigmoid colon (95 percent of people with diverticulitis).