Diverticulitis

Diverticulitis, specifically colonic diverticulitis, is a gastrointestinal disease characterized by inflammation of abnormal pouches—diverticula—which can develop in the wall of the large intestine. Symptoms typically include lower abdominal pain of sudden onset, but onset may also occur over a few days. In North America and Europe the abdominal pain is usually on the left lower side (sigmoid colon), while in Asia it is usually on the right (ascending colon). There may also be nausea; and diarrhea or constipation. Fever or blood in the stool suggests a complication. Repeated attacks may occur. Diverticulitis, specifically colonic diverticulitis, is a gastrointestinal disease characterized by inflammation of abnormal pouches—diverticula—which can develop in the wall of the large intestine. Symptoms typically include lower abdominal pain of sudden onset, but onset may also occur over a few days. In North America and Europe the abdominal pain is usually on the left lower side (sigmoid colon), while in Asia it is usually on the right (ascending colon). There may also be nausea; and diarrhea or constipation. Fever or blood in the stool suggests a complication. Repeated attacks may occur. The causes of diverticulitis are uncertain. Risk factors may include obesity, lack of exercise, smoking, a family history of the disease, and use of nonsteroidal anti-inflammatory drugs (NSAIDs). 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 between 10% and 25% at some point in time, and is due to a bacterial infection. Diagnosis is typically by CT scan, though blood tests, colonoscopy, or a lower gastrointestinal series may also be supportive. The differential diagnosis includes irritable bowel syndrome. Preventive measures include altering risk factors such as obesity, 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 these play a role in initiating inflammation in 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 use. 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 to 15% of those may go on to develop diverticulitis. The disease becomes more frequent with age, being particularly common in those over the age of 50. 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. Diverticulitis typically presents with left lower quadrant abdominal pain of sudden onset. There may also be fever, nausea, diarrhea or constipation, and blood in the stool. The causes of diverticulitis are poorly understood, with approximately 40 percent due to genes and 60 percent due to environmental factors. Conditions that increase the risk of developing diverticulitis include arterial hypertension and immunosuppression. Obesity is another risk factor. Low levels of vitamin D are associated with an increased risk of diverticulitis. It is unclear what role dietary fibre plays in diverticulitis. It is often stated that a diet low in fibre is a risk factor; however, the evidence to support this is unclear. There is no evidence to suggest that the avoidance of nuts and seeds prevents the progression of diverticulosis to an acute case of diverticulitis. It appears in fact that a higher intake of nuts and corn could help to avoid diverticulitis in adult males. 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. People with the above symptoms are commonly studied with computed tomography, or CT scan. The CT scan is very accurate (98%) in diagnosing diverticulitis. In order to extract the most information possible about the patient's condition, thin section (5 mm) transverse images are obtained through the entire abdomen and pelvis after oral and intravascular contrast have been administered. Images reveal localized colon wall thickening, with inflammation extending into the fat surrounding the colon. The diagnosis of acute diverticulitis is made confidently when the involved segment contains diverticula. CT may also identify patients with more complicated diverticulitis, such as those with an associated abscess. It may even allow for radiologically guided drainage of an associated abscess, sparing a patient from immediate surgical intervention.