Diverticulitis

Diverticulitis is a common digestive disease particularly found in the large intestine. Diverticulitis develops from diverticulosis, which involves the formation of pouches (diverticula) on the outside of the colon. Diverticulitis results if one of these diverticula becomes inflamed.

Causes

The development of colonic diverticulum is thought to be a result of raised intraluminal colonic pressures. The Sigmoid colon has the smallest diameter of any portion of the colon, and therefore the portion which would be expected to have the highest intraluminal pressure. The postulate that a lack of dietary fiber, particularly non-soluble fiber predisposes individuals to diverticular disease is supported within the medical literature.

It is thought that mechanical blockage of a diverticulum, possibly by a piece of feces or food particles, leads to infection of the diverticulum.

There is some evidence that a genetic component may be a causative factor.

Presentation

(Large bowel (sigmoid colon) showing multiple diverticula. Note how the diverticula appear on either side of the longitudinal muscle bundle (taenium).)

Patients often present with the classic triad of left lower quadrant pain, fever, and leukocytosis (an elevation of the white cell count in blood tests). Patients may also complain of nausea or diarrhea; others may be constipated.

Less commonly, an individual with diverticulitis may present with right-sided abdominal pain. This may be due to the less prevalent right-sided diverticula or a very redundant sigmoid colon.

Symptoms

Diverticulitis

The most common symptom of diverticulitis is abdominal pain. The most common sign is tenderness around the left side of the lower abdomen. If infection is the cause, then nausea, vomiting, feeling hot while having no fever, cramping, and constipation may occur as well. The severity of symptoms depends on the extent of the infection and complications. Diverticulitis worsens throughout the day, as it starts as small pains and slowly turns into vomiting and sharp pains.

Diverticulosis

Most people with diverticulosis do not have any discomfort or symptoms; however, symptoms may include mild cramps, bloating, and constipation. Other diseases such as irritable bowel syndrome (IBS) and stomach ulcers cause similar problems, so these symptoms do not always mean a person has diverticulosis.

Diagnosis

The differential diagnosis includes colon cancer, inflammatory bowel disease, ischemic colitis, and irritable bowel syndrome, as well as a number of urological and gynecological processes. Some patients report bleeding from the rectum.

Patients with the above symptoms are commonly studied with a computed tomography, or CT scan. The CT scan is very sensitive (98%) in diagnosing diverticulitis. In order to extract the most information possible about the patient's condition, thin section (5mm) transverse images are obtained through the entire abdomen and pelvis after the patient has been administered oral and intravascular contrast. Images reveal localized thickening and hyperemia (increased blood flow) involving a segment of the colon wall, with inflammatory changes extending into the fatty tissues surrounding the colon. The diagnosis of acute diverticulitis is made confidently when the involved segment contains diverticulae. 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. Other studies, such as barium enema and colonoscopy are contraindicated in the acute phase of diverticulitis due to the risk of perforation.

Treatment

An initial episode of acute diverticulitis is usually treated with conservative medical management, including bowel rest (ie, nothing by mouth), IV fluid resuscitation, and broad-spectrum antibiotics which cover anaerobic bacteria and gram-negative rods. However, recurring acute attacks or complications, such as peritonitis, abscess, or fistula may require surgery, either immediately or on an elective basis.

Upon discharge patients may be placed on a low residue diet. This low-fiber diet gives the colon adequate time to heal without needing to be overworked. Later, patients are placed on a high-fiber diet. There is some evidence this lowers the recurrence rate.

In some cases surgery may be required to remove the area of the colon with the diverticula. Patients suffering their first attack of diverticulitis are typically not encouraged to undergo the surgery, unless the case is severe. Patients suffering repeated episodes may benefit from the surgery. In such cases the risks of complications from the diverticulitis outweigh the risks of complications from surgery.

Most cases of simple, uncomplicated diverticulitis respond to conservative therapy with bowel rest and antibiotics.

Complications

In complicated diverticulitis, bacteria may subsequently infect the outside of the colon if an inflamed diverticulum bursts open. If the infection spreads to the lining of the abdominal cavity, (peritoneum), this can cause a potentially fatal peritonitis. Sometimes inflamed diverticula can cause narrowing of the bowel, leading to an obstruction. Also, the affected part of the colon could adhere to the bladder or other organ in the pelvic cavity, causing a fistula, or abnormal connection between an organ and adjacent structure or organ, in this case the colon and an adjacent organ.

• Bowel obstruction
  
• Peritonitis
• Abscess
• Fistula
• Bleeding
• Strictures

Epidemiology

Diverticulitis most often affects middle-aged and elderly persons, though it can strike younger patients as well. Central obesity may be associated with diverticulitis in younger patients, with some being as young as 20 years old.

Diverticular disease most commonly involves the sigmoid colon - section 4 - (95% of patients). The prevalence of diverticular disease has increased from an estimated 10% in the 1920s to between 35 and 50% by the late 1960s. 65% of those currently 85 years of age and older can be expected to have some form of diverticular disease of the colon. Less than 5% of those aged 40 years and younger may also be affected by diverticular disease.

Left-sided diverticular disease (involving the sigmoid colon) is most common in the West, while right-sided diverticular disease is more prevalent in Asia and Africa. Among patients with diverticulosis, 10-25% patients will go on to develop diverticulitis within their lifetimes.

Nut, corn and popcorn consumption has not been proven to increase the risk of diverticulosis or diverticular complications.

Controversy

There is no scientific evidence that suggests the avoidance of nuts and seeds prevents the progression of diverticulosis to an acute case of diverticulitis, and as such the widely held belief that small undigestable foods like seeds becoming lodged in the diverticula appears to be nothing more than an 'old wives' tale. Further, in a survey of fellows of The American Society of Colon and Rectal Surgeons at least half of the surgeons responding to the survey saw no value in avoiding such foods, however adherence to a low residue diet was still favored by the majority.