Diverticulitis
Diverticulitis, also called colonic diverticulitis, is a gastrointestinal disease characterized by inflammation of abnormal pouches—diverticula—that can develop in the wall of the large intestine. Symptoms typically include lower abdominal pain of sudden onset, but the onset may also occur over a few days. There may also be nausea, diarrhea or constipation. Fever or blood in the stool suggests a complication. People may experience a single attack, repeated attacks, or ongoing "smoldering" diverticulitis.
The causes of diverticulitis are unclear. Risk factors may include obesity, lack of exercise, smoking, a family history of the disease, and use of nonsteroidal anti-inflammatory drugs. The role of a low fiber diet as a risk factor is unclear. Having pouches in the large intestine that are not inflamed is known as diverticulosis. Inflammation occurs in 10% and 25% at some point in time and is due to a bacterial infection. Diagnosis is typically by CT scan. However, blood tests, colonoscopy, or a lower gastrointestinal series may also be supportive. The differential diagnoses include irritable bowel syndrome.
Preventive measures include altering risk factors such as obesity, physical inactivity, and smoking. Mesalazine and rifaximin appear useful for preventing attacks in those with diverticulosis. Avoiding nuts and seeds as a preventive measure is no longer recommended since there is no evidence that these play a role in initiating inflammation in the diverticula. For mild diverticulitis, antibiotics by mouth and a liquid diet are recommended. For severe cases, intravenous antibiotics, hospital admission, and complete bowel rest may be recommended. Probiotics are of unclear value. Complications such as abscess formation, fistula formation, and perforation of the colon may require surgery.
The disease is common in the Western world and uncommon in Africa and Asia. In the Western world about 35% of people have diverticulosis while it affects less than 1% of those in rural Africa, and 4–15% of those may go on to develop diverticulitis. In North America and Europe the abdominal pain is usually on the left lower side, while in Asia it is usually on the right. The disease becomes more frequent with age, ranging from 5% for those under 40 years of age to 50% over the age of 60. It has also become more common in all parts of the world. In 2003 in Europe, it resulted in approximately 13,000 deaths. It is the most frequent anatomic disease of the colon. Costs associated with diverticular disease were around US$2.4 billion a year in the United States in 2013.
Signs and symptoms
Diverticulitis typically presents with lower quadrant abdominal pain of a sudden onset. Patients commonly have elevated C-reactive protein and a high white blood cell count. In Asia it is usually on the right, while in North America and Europe, the abdominal pain is usually on the left lower side. There may also be fever, nausea, diarrhea or constipation, and blood in the stool. Diverticulosis is associated with more frequent bowel movements, contrary to the widespread belief that patients with diverticulosis are constipated.Complications
In complicated diverticulitis, an inflamed diverticulum can rupture, allowing bacteria to subsequently infect externally from the colon. If the infection spreads to the lining of the abdominal cavity, peritonitis results. Sometimes, inflamed diverticula can cause narrowing of the bowel, leading to an obstruction. In some cases, the affected part of the colon adheres to the bladder or other organs in the pelvic cavity, causing a fistula, or creating an abnormal connection between an organ and adjacent structure or another organ.Related pathologies may include:
- Bowel obstruction
- Peritonitis
- Abscess
- Fistula
- Bleeding
- Strictures
Causes and prevention
Factors associated with increased diverticulitis risk
Genetics
A 2021 review estimated that 50% of the risk of diverticulitis was attributable to genetic factors. A 2012 study estimated that heritability made up 40% of cause and non-shared environmental effects 60%.Presence of other ill-health
Conditions that increase the risk of developing diverticulitis include arterial hypertension and immunosuppression. Low levels of vitamin D have been associated with an increased risk of diverticulitis.Frequency of bowel movement
A 2022 study found that more frequent bowel movements appeared to be a risk factor for subsequent diverticulitis both in men and women.Weight
has been regarded as a risk factor for diverticulitis. Some studies have found a correlation of higher prevalence of diverticulitis with overweight and obese bodyweight. There is some debate if this is causal.Diet
It is unclear what role dietary fiber plays in diverticulitis. It is often stated that a diet low in fiber is a risk factor; however, the evidence to support this is unclear. 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.There is no evidence to suggest that avoiding nuts and seeds prevents the progression of diverticulosis to an acute case of diverticulitis. In fact, it appears that a higher intake of nuts and corn could help to avoid diverticulitis in adult males.
Red meat consumption, particularly unprocessed red meat, has been linked to a higher risk of diverticulitis.
A 2017 analysis found that a dietary pattern high in red meat, refined grains, and high-fat dairy was associated with an increased risk of incident diverticulitis. In contrast, a dietary pattern high in fruits, vegetables, and whole grains was associated with decreased risk. Men in the highest quintile of Western dietary pattern score had a multivariate hazard ratio of 1.55 for diverticulitis compared to men in the lowest quintile. Recent dietary intake may be more strongly associated with diverticulitis than long-term intake. The associations between dietary patterns and diverticulitis were largely due to red meat and fiber intake. A systematic review published in 2012 found no high-quality studies, but found that some studies and guidelines favour a high-fiber diet for the treatment of symptomatic disease. A 2011 review found that a high-fiber diet may prevent diverticular disease, and found no evidence for the superiority of low-fiber diets in treating diverticular disease. 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.
While it has been suggested that probiotics may be useful for treatment, the evidence currently neither supports nor refutes this claim.
Pathology
Right-sided diverticula are micro-hernias of the colonic mucosa and submucosa through the colonic muscular layer, where blood vessels penetrate it. Left-sided diverticula are pseudodiverticula, since the herniation is not through all the layers of the colon. Diverticulitis is postulated to develop because of changes inside the colon, including high pressures because of abnormally vigorous contractions.Diagnosis
People with the above symptoms are commonly studied with computed tomography, or a CT scan. Ultrasound can provide preliminary investigation for diverticulitis. Amongst the findings that can be seen on ultrasound is a non-compressing outpouching of bowel wall, hypoechoic and thickened wall, or an obstructive fecalith at the bowel wall. Besides, bowel wall oedema with adjacent hyperechoic mesentery can also be seen on ultrasound. However, a CT scan is the mainstay of diagnosing diverticulitis and its complications. The diagnosis of acute diverticulitis is made confidently when the involved segment contains diverticula. CT images reveal localized colon wall thickening, with inflammation extending into the fat surrounding the colon. Amongst the complications that can be seen on CT scan are: abscesses, perforation, pylephlebitis, intestinal obstruction, bleeding, and fistula.Barium enema and colonoscopy are contraindicated in the acute phase of diverticulitis because of the risk of perforation.
Classification by severity
Uncomplicated vs complicated
Uncomplicated acute diverticulitis is defined as localized diverticular inflammation without any abscess or perforation. Complicated diverticulitis additionally includes the presence of abscess, peritonitis, obstruction, stricture and/or fistula. 12% of patients with diverticulitis present with complicated disease.Classification systems
At least four classifications by severity have been published in the literature. As of 2015, the 'German Classification' was widely accepted and is as follows:- Stage 0 – asymptomatic diverticulosis
- Stage 1a – uncomplicated diverticulitis
- Stage 1b – diverticulitis with phlegmonous peridiverticulitis
- Stage 2a – diverticulitis with concealed perforation, and abscess with a diameter of one centimeter or less
- Stage 2b – diverticulitis with abscess greater than one centimeter
- Stage 3a – diverticulitis with symptoms but without complications
- Stage 3b – relapsing diverticulitis without complications
- Stage 3c – relapsing diverticulitis with complications
The severity of diverticulitis can be radiographically graded by the Hinchey Classification.