Diverticular disease is one of the most prevalent gastrointestinal conditions in Western populations. Colonic diverticula are acquired herniations into the mucosal and submucosal layers of the colon wall and in the Western world, found more commonly in the left side of the colon. Approximately 20% of patients with diverticulosis will experience inflammation of their diverticula, called diverticulitis. These inflammatory complications may range from mild acute episodes to more severe episodes with complications or development of chronic symptoms.

Currently, the development of diverticula is felt to be secondary to altered gut motility and an increase in intraluminal pressure within the colon, the mechanism of which remains unclear. Previous links between low-fiber diet and diverticular disease have been put into question based on conflicting study data.

Less is known regarding the pathophysiology behind diverticular inflammation and development of diverticulitis. Classic teaching has been that diverticulitis results from obstruction of a diverticulum by a food particle or fecalith, giving rise to advice from providers to patients to avoid high-residue foods. However, a recent large prospective study of men with known diverticular disease, suggested that high-residue diets (nuts, popcorn, high fiber) are not associated with an increased risk of diverticulitis.

Diverticular disease can be divided into asymptomatic, symptomatic (single episode, recurrent episode, chronic symptoms), and complicated (abscess, perforation, bleeding) stages. Standard therapy for diverticular disease involves bowel rest, antibiotics, pain control, and surgical consideration for those with complicated disease. The role of antibiotics in uncomplicated disease is currently under debate, as are newer therapies under consideration for diverticular disease such as aminosalicylates and probiotics.

Diagnosis is based on presenting clinical symptoms, physical examination, and imaging studies to confirm and assess the severity of the disease.

Acute uncomplicated diverticulitis typically presents with fever, leukocytosis, and left lower quadrant abdominal pain. Patients can also present with altered bowel habits as well as nausea and/or vomiting. Complicated episodes can present with both immediate and long-term complications, including abscess formation, peritonitis, bowel obstruction, fistula formation, and hemorrhage. The clinical manifestations of chronic diverticular disease can be varied, ranging from asymptomatic disease to mild intermittent abdominal pain to chronic abdominal pain with hematochezia.

Diverticular disease is one of the most prevalent gastrointestinal conditions in the Western world, with an estimated prevalence rate of 60-70% in those over the age of 60 years. Approximately 20% of patients with diverticulosis will experience an inflammatory complication of the disease, ranging in severity from a single mild uncomplicated diverticulitis episode to more severe attacks including complicated diverticulitis.

There is pronounced geographic variation in the prevalence and manifestations of diverticular disease between Asian and Western countries. Diverticulosis is much less common in Eastern countries; when present, it is more likely to be localized to the proximal colon. This differs from Western populations, in that the sigmoid colon is the most commonly affected segment. Several factors have been proposed to account for both the decreased prevalence and proximal colon predilection in Asian patients, but observations that Asians who adopt a Western-style diet have increased rates of distal diverticulosis lend support to the role of environmental factors in the formation of diverticula.

Patients with chronic diverticular disease presenting with intermittent or constant abdominal pain can be mistakenly thought to have irritable bowel syndrome (IBS). Chronic diverticular disease can also present with abdominal pain and hematochezia, mimicking inflammatory bowel disease (IBD). Other differentials based on clinical presentation include ischemic colitis, appendicitis, infectious colitis, pelvic inflammatory disease, gynaecologic disorders, pyelonephritis, and colon cancer.

Patients with acute diverticulitis typically present with fever and abdominal tenderness localized to the left-lower quadrant. They may have signs of peritonitis with rebound and guarding on examination, as well as generalized abdominal tenderness.

As patients with acute diverticulitis typically present with leukocytosis +/- left shift, checking a complete blood cell count is helpful in establishing the diagnosis. Suspicion of complications, such as abscess formation, peritonitis, obstruction, and fistula, should prompt further labs tests including a lactate level, urinalysis, and renal function/electrolytes.

While the diagnosis of diverticular disease may be established by the clinical presentation, examination, and lab findings, a computed tomography (CT) scan is beneficial in confirming the diagnosis and helping establish the severity of the disease. CT abdomen with intravenous (IV) and oral (PO) contrast is the diagnostic test of choice. IV contrast is not usually required to make a diagnosis of diverticulitis, but can aid identifying complications and other diagnosis.

There are two radiologic classifications that attempt to assess the severity of acute diverticulitis based on CT findings: Buckley and Hinchey. The Buckley system ranges from mild (bowel wall thickening and fat stranding) to severe (bowel wall thickening greater than 5mm, abscess greater than 5cm, frank perforation). The Hinchey classification correlates with intraoperative findings of perforated diverticulitis. Both classification systems, however, need further validation against specific clinical outcomes as controversy persists regarding the optimal surgical approach in different stages.

Determination of the severity of the disease is important, as this will determine management and need for hospitalization. As CT scans can accurately diagnose disease and delineate its extent of involvement, it is often useful in aiding management of acute diverticulitis in ill patients or those who present atypically (right-sided diverticulitis). It can also be used as a therapeutic modality by permitting percutaneous drainage of localized abscesses.

Routine abdominal and chest radiographs are commonly performed in patients with acute abdominal pain, and are helpful in ruling out causes such as intestinal obstruction. However, these imaging studies do not aid in making the diagnosis of diverticulitis.

The mainstay of treatment remains antibiotics, bowel rest (if unable to tolerate oral intake), and pain control.

Conservative management is recommended for the treatment of uncomplicated diverticulitis. This usually includes antibiotics, bowel rest (if a patient can’t tolerate oral intake), and pain control. The goals of treatment are to control symptoms and minimize complications. Antibiotic regimens typically involve those which provide coverage of both aerobic and anaerobic gram-negative organisms. Examples of commonly used oral regimens include amoxicillin-clavulanic acid, fluoroquinolone plus metronidazole, and trimethoprim-sulfamethoxazole plus metronidazole. Average duration of treatment is 5 to10 days (or more) depending on clinical response. It is important to note, however, that clinical trials in comparing antibiotic regimens are lacking, so no specific recommendations can be made regarding specific agents or length of treatment. Additionally, a recent study has shown no benefit to giving antibiotics in acute uncomplicated diverticulitis and the AGA’s 2015 guidelines state that antibiotics should be used selectively. Decisions should therefore be based on specific clinical scenarios.

Outpatient management is appropriate when patients exhibit mild symptoms, are able to tolerate liquids, have preserved bowel function, and do not have evidence of complicated disease or significant comorbidities. Due to more severe illness, patients who are hospitalized are typically initiated on IV antibiotics, +/- total parenteral nutrition (TPN) depending on the severity of disease and nutritional status, and may require invasive management for complicated disease.

In complicated diverticulitis involving abscess formation, percutaneous drainage has been advocated for diverticular abscesses greater than 4cm in diameter; however, the timing and type of surgery for complicated diverticular disease remains controversial. A surgical consult should be considered to help guide management in complicated diverticulitis.

The 1969 landmark study by Parks demonstrated that recurrent diverticulitis is more virulent and more likely to require surgery than medical management. This study has formed the basis for recommendation to perform a sigmoid resection after the second episode of uncomplicated acute diverticulitis in patients older than the age of 50 years, and after the first episode in those younger than 50 years.

However, current data show that most patients who present with complicated disease did not have a prior attack and that patients with recurrent diverticulitis do not have higher morbidity and mortality when compared to patients with a single episode. Therefore, performing elective surgery after an uncomplicated episode of acute diverticulitis may not be justified. Due to the lack of randomized data, the optimal timing of surgery relies on various practice guidelines, expert opinion, and observational data. The American Society of Colon and Rectal Surgeons currently recommends that the decision to perform elective colectomy after recovery from an acute episode should be made on a case-by-case basis and no longer recommends routine resection in those less than 50 years of age.

There have been a few studies investigating the efficacy of mesalamine and rifaximin in prevention of recurrence and/or complications after acute uncomplicated diverticulitis. Currently, the guidelines do not recommend starting these medications due to the poor quality of evidence in these studies.

The patient’s general assessment and abdominal examination are important to follow throughout their course. Observing for fevers, dehydration, hypotension, signs of peritonitis, and blood in the stools is important, as any or all of these factors can signify worsening clinical status or development of complicated disease.

The patient’s white count should be assessed as clinically indicated while the patient is hospitalized, as worsening leukocytosis would be concerning for development of a complication or worsening clinic status. Once the white count normalizes and the patient’s clinical status stabilizes or improves, the white count likely does not need to be continuously monitored. Other helpful lab data may include a lactate (if there was concern for peritonitis on exam), hematocrit (if there was concern for hemorrhage), and electrolytes (to help assess volume status).

Patients should be counseled to consume a high-fiber diet once the acute phase has resolved; this recommendation, however, is based mostly upon uncontrolled studies and the low risk of harm in consuming a high-fiber diet. After recovery from an acute episode, direct evaluation of the colon should be considered to exclude other diagnoses, such as colon cancer. This is usually done by colonoscopy, although a flexible sigmoidoscopy plus a barium enema is reasonable.

With conservative management, the main side effects are secondary to the antibiotics being given. These side effects depend on the particular antibiotic being used.

Drug dosage reduction of some antibiotics may be necessary in renal insufficiency.

No change in standard management.

No change in standard management.

No change in standard management.

No change in standard management.

No change in standard management.

It is not clear whether immunocompromised patients have a higher incidence of diverticulitis; however, those that are immunosuppressed are more likely to have complicated diverticular disease, with an increase in risk for perforation, abscess formation, and postoperative infections. The clinical presentation of these patients also tends to be more indolent, with lack of the usual signs of the disease such as fever and leukocytosis. There is no change in standard management with this group of patients, however one must be more cautious and aware of potential complications in this population.

No change in standard management.

Patients unable to tolerate oral intake should have bowel rest with slow advancement of diet as pain and other symptoms improve. Patients should be generally advised to consume a high-fiber diet once the acute phase has resolved. There is no scientific evidence supporting the avoidance of foods containing seeds or nuts.

No change in standard management.

No change in standard management.

It is important that the patient’s clinical symptoms and abdominal examination be closely monitored. If there are worsening signs and symptoms, one needs to be concerned for possible complications. Re-imaging may be indicated based on the patient’s exam. Recheck of labs, such as a hematocrit, may be indicated if the patient has signs of a possible GI bleed. Depending on results of re-imaging, surgery and/or interventional radiology may need to be involved to address the complications.

Seventy to one hundred percent of patients with acute uncomplicated diverticulitis improve with conservative treatment. Length of stay is dependent on patients’ response to conservative management, their ability to take clears and keep themselves well hydrated, and their ability to tolerate oral antibiotics.

Duration of hospitalization for complicated diverticulitis is variable and dependent on the type of complication and the patient’s clinical response. For complications such as abscesses, fistulas, and peritonitis, hospitalization can be prolonged for weeks.

For acute uncomplicated diverticulitis, a patient is ready for discharge to home once clinical symptoms have improved, and he or she is able to tolerate clear liquids, and able to tolerate oral antibiotics.

For acute complicated diverticulitis, discharge can be considered once the patient’s clinical status has stabilized and has improved from that complication. Post-acute care facilities may need to be considered in lieu of discharge to home, if the patient requires prolonged courses of TPN, IV antibiotics, etc.

Primary care physician in 1-2 weeks to assess for resolution of symptoms once antibiotic course is completed.

Gastroenterologist in 2-6 weeks to arrange for follow-up colonoscopy once acute symptoms have resolved.

Surgery follow-up in 2-4 weeks for those with complicated diverticulitis.

Discharge set of labs, including a white count, hematocrit, and electrolytes, would be a helpful marker of the patient’s clinical status prior to discharge.


Patients with acute uncomplicated diverticulitis are typically discharged home once they are able to tolerate clears, oral antibiotics, and have improved clinically. For those patients that need prolonged courses of IV antibiotics or TPN, a peripherally inserted central catheter (PICC) line will need to be placed and discharge to home with Visiting Nurse Association (VNA) versus discharge to post-acute care facilities will need to be considered. Those with complicated disease requiring frequent and ongoing monitoring for resolution of the complication may need to be discharged directly to a post-acute care facility.

Following conservative management for a first episode of acute uncomplicated diverticulitis, approximately 13-23% will proceed to a second attack of diverticulitis. Twenty to thirty percent of patients may have some chronic symptoms such as pain after an episode of diverticulitis.

It was generally believed that prognosis is worse with a second attack of diverticulitis. However, current data show that most patients who present with complicated disease did not have a prior attack and that patients with recurrent diverticulitis do not have higher morbidity and mortality when compared to patients with a single episode. Therefore, performing elective surgery after an uncomplicated episode of acute diverticulitis may not be justified. Due to the lack of randomized data, the optimal timing of surgery is decided on a case-by-case basis.


DVT prophylaxis with unfractionated heparin (UFH) or low molecular weight heparin (LMWH) if no evidence of a GI bleed or diverticular hemorrhage.

Slow advancement of diet during the hospitalization and counseling of patients to follow a high-fiber diet once acute symptoms have resolved.

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