Diverticulitis FAQs

What is the difference between diverticulosis and diverticulitis?

DiverticulOSIS is when an abnormal sac or pouch forms in a weak section of the colon, usually in the sigmoid or descending colon.^1,3 Diverticulosis is often asymptomatic, but found during a colonoscopy. It affects about 5% of people younger than 40 years old, but up to 50% of people older than 60 years old.³

DiverticulITIS is when the sac or pouch becomes inflamed or infected and is associated with symptoms
(e.g., abdominal pain, nausea, tenderness, low fever). Diverticulitis can be uncomplicated. It becomes complicated if the following are present: abscess, fistula, stricture, bowel obstruction, or peritonitis with perforation.^3,7

What are risk factors for diverticulitis?

Though data are not robust, risk factors for diverticulitis may include:^1-3,5

• age (risk increases with age)
• use of alcohol or tobacco
• NSAIDs (Regular use [e.g., ≥2 times/week] is associated with about a 70% increased risk of diverticulitis.¹)
• physical inactivity, increased body mass index (BMI), and obesity

Long-term opioid or NSAID use may be associated with an increased risk of perforated diverticulitis. And NSAIDs may also increase risk of gastrointestinal (GI) bleeding.^1,17

There also may be an association between an increased risk of diverticulosis and/or diverticulitis with diets low in fiber, high in refined carbohydrates, and high in red meat.^3,5

The most common risk factors for RECURRENT diverticulitis are age younger than 50 years old AND a history of diverticulitis.²

What are symptoms of diverticulitis?

The most common symptom of diverticulitis is constant abdominal pain and tenderness, usually in the left-lower quadrant (may be in the right-lower quadrant in the Asian population). Pain often worsens with movement.¹

Other symptoms can include abdominal distention, diarrhea, nausea, vomiting, and constipation.¹

Constipation and abdominal distention may indicate an obstruction.¹ Obstructions are more common AFTER the first episode of diverticulitis.¹

How is diverticulitis diagnosed?

The most common diverticulitis presentation involves left-lower quadrant abdominal pain WITHOUT vomiting.²

Disease severity can be assessed with vital signs (e.g., temperature, heart rate, blood pressure), laboratory tests (e.g., CRP, WBC) and an abdominal exam. Hemodynamic instability (e.g., high fever, hypotension, tachycardia), abdominal rigidity and guarding, and significantly elevated CRP or WBCs are often associated with more severe disease, abscesses, perforation, and generalized peritonitis.^1,2

Imaging (abdominal CT scan) is recommended for patients with severe signs and symptoms (e.g., severe pain, hemodynamic compromise, diffuse tenderness, abdominal guarding or rigidity, significantly elevated WBC or
CRP [>50 mg/L]).^1,2

• CT scans may be appropriate for patients with mild diverticulitis who do not respond to initial medical management.¹
• Can consider CT scans for immunocompromised patients with mild symptoms, as they may not mount an inflammatory response.¹
• Imaging is more useful when diagnosing diverticulitis for the first time in a patient. Imaging may not be necessary for subsequent episodes, especially if presentation and severity are similar to prior episodes.^1,2

How is diverticulitis classified?

There are several available diverticulitis classification systems. The Modified Hinchey classification (based on CT findings) is commonly used in practice and in clinical trials to classify diverticulitis:^1,2

• Stage 0: clinically mild diverticulitis, or diverticula with colonic wall thickening
• Stage Ia: colonic wall thickening with phlegmon (pericolic fat)
• Stage Ib: diverticulitis with pericolic or mesenteric abscess
• Stage II: diverticulitis with intra-abdominal abscess distant from inflammation, pelvic or retroperitoneal abscess
• Stage III: diverticulitis with generalized purulent peritonitis
• Stage IV: diverticulitis with generalized fecal peritonitis

How should patients with diverticulitis be medically managed?

Most patients with uncomplicated diverticulitis (Hinchey stage 0 or Ia) can be managed as outpatients. Some patients with Hinchey stage Ib disease (small peridiverticular abscess) can also be managed as outpatients (e.g., those WITHOUT severe symptoms, unstable comorbid conditions, or immunosuppression).¹

Patients should be admitted if they have high fever (temperature >101.5°F [>38.6°C]), increased WBCs, complications (e.g., abscess, perforation), immunosuppression, serious coexisting conditions, a lack of home support, a need for pain control, or an inability to take things by mouth.³

There are little data for dietary management of acute diverticulitis. It is common for patients with diverticulitis to start with nothing by mouth (especially hospitalized patients with severe symptoms or with planned surgery) or a clear liquid diet and to gradually advance to a solid, low-fiber diet once symptoms begin to improve.¹

Which medications should be used to treat diverticulitis?

Use acetaminophen and antispasmodics (e.g., dicyclomine) first-line to manage diverticulitis-associated pain.¹

• If possible, avoid NSAID and opioids. There are no data using these in acute diverticulitis.¹ However, short-term opioids (e.g., morphine) are sometimes needed for severe pain uncontrolled with first-line options.¹

Antibiotics may not be necessary for otherwise healthy patients with uncomplicated diverticulitis. Current thinking is that diverticulitis involves inflammation, genetics, diet, lifestyle, meds, and gastrointestinal microorganisms.^1,17 Symptomatic management WITHOUT antibiotics leads to similar outcomes (e.g., complications, recovery time) compared to treatment with antibiotics in immunocompetent patients with uncomplicated diverticulitis, less severe pain and reliable follow-up [Evidence Level B-2].^2,6,7 However, antibiotics can be considered in patients who do not improve with medical management and “watchful waiting” for two or three days.¹

Antibiotics are considered first-line treatment for patients:^1,7

• with severe symptoms or complicated diverticulitis (e.g., abscess, peritonitis, bowel obstruction)
• with multiple or significant comorbidities (e.g., chronic kidney disease)
• who are immunocompromised
• who are pregnant

Which antibiotics are appropriate for diverticulitis?

Promote antimicrobial stewardship and select antibiotics to cover gram-negative and anaerobic bacteria (e.g., Escherichia coli, Klebsiella species, Bacteroides fragilis).²

Use the oral route (instead of IV) for stable, uncomplicated, immunocompetent patients. No particular antibiotic regimen has been shown to work better than any other.⁵ Usually use about seven days of one of the following:^3,4,8,9

• Amoxicillin/clavulanic acid 875 mg orally BID or 500 mg TID
• TMP/SMX DS orally BID plus metronidazole 500 mg orally TID
• Fluoroquinolone (e.g., ciprofloxacin 500 mg orally BID) plus metronidazole 500 mg orally TID
• Limit use of quinolones to patients unable to take or tolerate other antibiotic options due to principles of antibiotic stewardship and potential for adverse effects.

Save IV antibiotics for patients with perforations, large abscesses (i.e., >3 to 4 cm), unable to tolerate oral intake, or bowel obstruction.¹ Convert to oral antibiotics once clinically improving (e.g., resolution of fever, WBC trending down). Usually recommend four to five days of antibiotics if the infection source is controlled (e.g., surgical containment by draining abscess) [Evidence Level A-1].¹¹ For immunocompromised patients or if the source of the infection is difficult to control, longer durations of therapy may be needed based on clinical response.^3,4,8-13 Consider antibiotics with low resistance (e.g., <10%) on antibiograms. Common IV regimens include:^1,8,9,14

• Ceftriaxone 1 gram IV every 12 hours plus metronidazole 500 mg IV every eight to 12 hours
• Ciprofloxacin 400 mg IV every 12 hours plus metronidazole 500 mg IV every eight to 12 hours
• Limit use of quinolones to patients unable to take (e.g., severe penicillin allergies) or tolerate other antibiotic options due to principles of antibiotic stewardship and potential for adverse effects.

How can recurrent episodes of diverticulitis be prevented?

Though data are limited, dietary and lifestyle changes may be tried to reduce the risk of recurrent diverticulitis, including:¹

• maintaining a healthy weight
• getting regular exercise
• avoiding regular or long-term use of NSAIDs, opioids, and corticosteroids
• getting 25 to 30 grams of fiber in daily with high-fiber foods (e.g., bran, whole wheat, apples or pears [with the skin], beans, vegetables) or a fiber supplement^14-16
• limiting intake of red meat

There are not enough data to support the use of mesalamine, rifaximin, or probiotics to prevent recurrent diverticulitis.¹

Dispel the myth that all patients with diverticulitis need to avoid nuts, seeds, and popcorn. There are not data to confirm that nuts, seeds, and popcorn lead to or increase diverticulitis flares.^1,5

Use diverticulitis flares as an opportunity to review medication regimens for anything that might be problematic
(e.g., NSAID, opioids).¹