Diverticulitis overview

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Cafer Zorkun, M.D., Ph.D. [2]

Overview

Diverticulitis is a common digestive disease particularly found in the colon (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 or infected. The colon can become infected with craters of food stuck inside, which causes abdominal pain.

Pathophysiology

Diverticula is a protrusion of the intestinal layers consist of mucosa and serosa. It occurs mainly in the left side more than the right side. Diverticulitis is the inflammation of this protrusion. It is believed the first step in the pathogenesis of diverticulitis is the increase of the intraluminal pressure, change of the intestinal motility and the bacterial colonization. The inflammation is caused by histamine, tumor necrosis factor and metalloproteinases which were found in diverticulitis patients tissue biopsies. Obstruction of the diverticula leads to bacteria colonization which leads to inflammation by the end.

Causes

Common causes of diverticulitis include diverticulosis, a low-fiber diet, constipation, abdominal distension, and Meckel's diverticulum.

Risk Factors

Risk factors in the development of diverticulitis include advanced age, chronic constipation, connective tissue diseases (such as Marfan syndrome or Ehlers Danlos syndrome), low dietary fiber intake, high intake of fat and red meat, and obesity. There are risk factors for the disease recurrence as well. These factors include multiple diverticula, intraperitoneal abscess, family history of diverticulitis, and great portion of the colon involved in the disease.

Screening

There is insufficient evidence to recommend routine screening for diverticulitis.

Diagnosis

History and Symptoms

When taking a medical history, the doctor may ask about bowel habits, pain, other symptoms, diet, and medications. The physical exam usually involves a digital rectal exam. To perform this test, the doctor inserts a gloved, lubricated finger into the rectum to detect tenderness, blockage, or blood. The doctor may check stool for signs of bleeding and test blood for signs of infection.

Physical Examination

Diverticulitis diagnosis depends on taking a proper history and doing physical examination. The known diagnostic criteria for diverticulitis includes abdominal tenderness especially in the left lower quadrant, leukocytosis and CT scan findings helps in disease confirmation. Fever is common in diverticulitis patients. Abdominal examination will reveal tenderness, decreased bowel sounds and palpable mass may be felt. In some patients, genitourinary signs of cystitis would occur due to bladder irritation.

Laboratory Findings

Diverticulitis diagnosis starts by taking history precisely and perform physical examination. Lab tests are important in excluding other causes of abdominal pain and any other gastrointestinal disease. These lab tests include CBC, CRP, urinalysis and liver tests. Imaging procedures are important measures in diagnosing diverticulitis including the CT scan and colonoscopy.

CT scan

The CT scan is very sensitive (98%) in diagnosing diverticulitis. Using oral or intravenous contrast will have a good impact on the CT scan accuracy. It may also identify patients with more complicated diverticulitis, such as those with an associated abscess. CT also allows for radiologically guided drainage of associated abscesses, possibly sparing a patient from immediate surgical intervention. CT scan is not only important in the diagnosis of diverticulitis but also needed to exclude the cancer possibility in these patients.

MRI

MRI is a good imaging modality that can be used in diagnosis of diverticulitis since it has an advantage that there is no exposure to the radiation and it rules out other abdominal causes of acute abdomen. However, it is not the best diagnostic procedure to diagnose diverticulitis and CT scan is more preferred. MRI shows specific findings of diverticulitis which include thickening of the colon wall, presence of the diverticula, and exudates out of the colon. It may also shows presence of multiple abscesses.

Ultrasound

Meckel's diverticula are usually seen as tubular incompressible blind ending hypoechoic structure with irregular margins. Occasionally it may also be seen as a cyst, raising a different differential diagnosis of intestinal duplication which however is said to have regular margin.

X ray

X ray is a supportive diagnostic modality to diverticulitis although it is not the best modality. It can be used in case the CT scan is not available and in the uncomplicated cases. The radiographies used are the abdominal x ray, barium enema and the chest x-ray. The barium enema has disadvantages as if rupture happens, it will cause peritonitis. Abdominal x-ray shows multiple air and fluid levels in case of intestinal perforation. Chest x-ray is important to be done in patients with diverticulitis to investigate for the pneumoperitoneum which is a harbinger to a critical illness and will lead to change in the management plan in the case.

Other imaging findings

There are no other specific imaging findings for diverticulitis. Other studies, such as barium enema and colonoscopy are contraindicated in the acute phase of diverticulitis due to the risk of perforation.

Other diagnostic studies

There are no other specific diagnostic studies for diverticulitis. Other studies, such as barium enema and colonoscopy are contraindicated in the acute phase of diverticulitis due to the risk of perforation.

Treatment

Medical Therapy

An initial episode of acute diverticulitis is usually treated with conservative medical management, including bowel rest, IV fluid resuscitation, and broad-spectrum antimicrobial therapy which covers anaerobic bacteria and gram-negative rods. Patients who have recurring acute attacks or who develop diverticulitis-associated complications, such as peritonitis, abscess, or fistula, require surgery, either immediately or on an elective basis.

Surgery

If symptoms of diverticulitis are frequent, or the patient does not respond to antibiotics and resting the colon, the doctor may advise surgery. The surgeon removes the affected part of the colon and joins the remaining sections. This type of surgery—called colon resection—aims to prevent complications and future diverticulitis. The doctor may also recommend surgery for complications such as a fistula or partial intestinal obstruction.

Immediate surgery may be necessary when the patient has other complications, such as perforation, a large abscess, peritonitis, complete intestinal obstruction, or severe bleeding. In these cases, two surgeries may be needed because it is not safe to rejoin the colon right away. During the first surgery, the surgeon cleans the infected abdominal cavity, removes the portion of the affected colon, and performs a temporary colostomy, creating an opening, or stoma, in the abdomen. The end of the colon is connected to the opening to allow normal eating while healing occurs. Stool is collected in a pouch attached to the stoma. In the second surgery several months later, the surgeon rejoins the ends of the colon and closes the stoma.