Diverticulitis

Diverticulitis typically presents with lower quadrant abdominal pain of a sudden onset. In Asia it is usually on the right (ascending colon), while in North America and Europe, the abdominal pain is usually on the left lower side (sigmoid colon). 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 (the peritoneum), 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 (in the case of diverticulitis, the colon, and an adjacent organ). Related pathologies may include: • Bowel obstruction • Peritonitis • Abscess • Fistula • Bleeding • Strictures ==Causes and prevention==

The causes of diverticulitis are poorly understood. Formation of diverticula is regarded as likely due to interactions of age, diet, colonic microbiota, genetic factors, colonic motility, and changes in colonic structure. 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 Obesity 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. 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. 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 (HR) of 1.55 (95% CI, 1.20–1.99) 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. ==Pathology==

Right-sided diverticula are micro-hernias of the colonic mucosa and submucosa through the colonic muscular layer, where blood vessels penetrate it. ==Diagnosis==

(the abnormality is within the circled area) 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. 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 As of 2022, other classification systems are also used. Smoldering diverticulitis In "smoldering diverticulitis" (SmD), there are frequent relapsing symptoms Smoldering diverticulitis cases make up 4–10% of diverticulitis surgeries. Differential diagnoses The differential diagnoses include colon cancer, inflammatory bowel disease, ischemic colitis, and irritable bowel syndrome, as well as several urological and gynecological processes. In those with uncomplicated diverticulitis, cancer is present in less than 1% of people. ==Prognosis==

• Estimates for the proportion of people with diverticulosis who will develop diverticulitis range from 5% to 10% to 25%. • Most people with uncomplicated diverticulitis recover following medical treatment. The median time to recovery is 14 days. Approximately 5% of people experience smoldering diverticulitis. • Following surgical treatment, approximately 25% of people remain symptomatic. ==Treatment==

In uncomplicated diverticulitis, administration of fluids may be sufficient treatment if no other risk factors are present. Diet Diverticulitis patients may be placed on a low-fiber diet, or a liquid diet, although evidence for improved outcomes through diet has not been found. For mild, uncomplicated, and non-purulent cases of acute diverticulitis, symptomatic treatment, IV fluids, and bowel rest have no worse outcome than surgical intervention in the short and medium term, and appear to have the same outcomes at 24 months. With abscess confirmed by CT scan, some evidence and clinical guidelines tentatively support the use of oral or IV antibiotics for smaller abscesses (5 cm). Rifaximin was found in a meta-analysis to give symptom relief and reduce complications but the scientific quality of the underlying studies has been questioned. In limited studies, patients with diverticulitis and symptomatic diverticular disease treated with mesalamine have shown improvement in both conditions. Mesalazine may reduce recurrences in symptomatic uncomplicated diverticular disease. In 2022 Germany introduced guidance to use mesalamine to treat acute uncomplicated diverticulitis. Surgery Indications for surgery are abscess or fistula formation; and intestinal rupture with peritonitis. Surgery for an abscess or fistula is indicated either urgently or electively. 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. In most cases, elective surgery is indicated when the risks of the surgery are less than the risks of the complications of diverticulitis. Elective surgery is not indicated until at least six weeks after recovery from the acute event. Technique The first surgical approach consists of resection and primary anastomosis. This first stage of surgery is performed on people if they have a well-vascularized, nonedematous, and tension-free bowel. The proximal margin should be an area of the pliable colon without hypertrophy or inflammation. The distal margin should extend to the upper third of the rectum where the taenia coalesces. Not all of the diverticula-bearing colon must be removed, since diverticula proximal to the descending or sigmoid colon are unlikely to result in further symptoms. Approach Diverticulitis surgery consists of a bowel resection with or without colostomy. Either may be done by the traditional laparotomy or by laparoscopic surgery. The traditional bowel resection is made using an open surgical approach, called colectomy. During a colectomy, the person is placed under general anesthesia. A surgeon performing a colectomy will make a lower midline incision in the abdomen or a lateral lower transverse incision. The diseased section of the large intestine is removed, and then the two healthy ends are sewn or stapled back together. A colostomy may be performed when the bowel has to be relieved of its normal digestive work as it heals. A colostomy implies creating a temporary opening of the colon on the skin surface, and the end of the colon is passed through the abdominal wall with a removable bag attached to it. The waste is collected in the bag. Maneuvers All colon surgeries involve only three maneuvers that may vary in complexity depending on the region of the bowel and the nature of the disease. The maneuvers are the retraction of the colon, the division of the attachments to the colon, and the dissection of the mesentery. After the resection of the colon, the surgeon normally divides the attachments to the liver and the small intestine. 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. After resection of the affected bowel segment, an anvil and spike are used to anastomose the remaining segments of the bowel. Anastomosis is confirmed by filling the cavity with normal saline and checking for any air bubbles. Bowel resection with colostomy When excessive inflammation of the colon renders primary bowel resection too risky, bowel resection with colostomy remains an option. Also known as the Hartmann's operation, this is a more complicated surgery typically reserved for life-threatening cases. The bowel resection with colostomy implies a temporary colostomy, which is followed by a second operation to reverse the colostomy. The surgeon makes an opening in the abdominal wall (a colostomy), which helps clear the infection and inflammation. The colon is brought through the opening, and all waste is collected in an external bag. The colostomy is usually temporary, but it may be permanent, depending on the severity of the case. 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. Prophylactic endoscopic clipping Prophylactic endoscopic clipping is being researched for diverticulitis. ==Epidemiology==

Diverticulitis most often affects the elderly. In Western countries, diverticular disease most commonly involves the sigmoid colon (95 percent of people with diverticulitis). Diverticulosis affects 5–45% of individuals with the prevalence of diverticulosis increasing with age from under 20% of individuals affected at age 40 up to 60% of individuals affected by age 60. ==References==