Provider Practice Essentials registered nurse continuing education

Diverticulitis Management: Outpatient or Inpatient

Melanie Jones, PA-C

Diverticulitis is an infection and/or inflammation in diverticula (small pouches) that occurs in the digestive tract, specifically the colon. In fact, there are more than 200,000 cases per year in the United States. Diverticulitis is the third leading cause of gastrointestinal complaints. Some patients may require inpatient treatment for severe pain or complications. Some patients can be treated out of the hospital.


Patients will usually present with lower abdominal pain in the left lower quadrant, abdominal tenderness in the left lower quadrant on physical exam and leukocytosis on lab testing. If a patient has not presented with diverticulitis before it is important to have imaging to diagnose the diverticulitis. Imaging should also look for colon cancer, irritable bowel syndrome or other gastrointestinal complaints. A CT of the abdomen and pelvis will rule out other potential causes and also distinguish uncomplicated diverticulitis from complicated diverticulitis.

Inpatient Management of Diverticulitis

While most patients may be treated as outpatients, there are some patients that require inpatient treatment. Patients also need to meet certain criteria for inpatient treatment. Generally speaking, patients with severe pain should have a CT of the abdomen and Pelvis. Complications found on CT meet inpatient criteria and can include frank perforation, abscess, obstruction or even fistula. CT scans that show diverticulitis without the above complications require the patient to have additional symptoms or findings. Admission criteria in these cases include:

  • High fever (102.5˚F or more)
  • Significant leukocytosis
  • Sepsis
  • Immunosuppression (use of immunosuppressive agents, HIV infection, B-cell or T-cell leukocyte deficiency, poorly controlled diabetes, chronic high-dose steroid use)
  • Micro-perforation or phlegmon
  • 70 years old or above
  • Diffuse peritonitis
  • Severe abdominal pain
  • Unable to tolerate oral intake
  • Failed outpatient treatment
  • Patient is unreliable or non-compliant
  • Lack of outpatient support system for the patient

The decision for inpatient treatment of diverticulitis is based on the degree of disease complication. Complicated diverticulitis with a perforation, abscess that fails IV antibiotics and percutaneous drainage, fistula or obstruction will likely require emergency surgery. Involve general surgery as soon as possible for these cases. This starts the surgery process early. Repeat imaging should be ordered if there is no symptomatic and/or objective improvement after 2 to 3 days of inpatient treatment.


These patients should receive IV fluids. Normal saline or lactated Ringer’s ensure adequate fluid volume. Most patients should be NPO status until they are able to tolerate clear liquids. Pain should be controlled by IV route if patients are NPO or orally if they are on a diet.

Inpatient diverticulitis patients should also receive IV antibiotics. Good choices should target gram negative rods and anaerobes. Empiric antibiotic therapy should also be started based on if the patient is low-risk or high-risk. Cultures are obtained from the infection either by surgery or percutaneous drainage. Likewise, these results should guide antibiotic therapy. IV antibiotics should be continued for 3 to 5 days, which is when abdominal tenderness and pain should have resolved. Afterwards patients should complete a 10 to 14 day antibiotic course.

Low-Risk Empiric Antibiotic Therapy

  • Single agent of Ertapenem 1g IV daily or
  • Piperacillin-tazobactam 3.375g IV every 6 hours.
  • Combination of one of the following with 500mg of IV or PO Metronidazole every 8 hours
    • Keflex 1g to 2g IV every 8 hours
    • Cefuroxime 1.5g IV every 8 hours
    • Ceftriaxone 2g IV daily
    • Cefotaxime 2g IV every 8 hours
    • Ciprofloxacin 400mg IV every 12 hours
    • Ciprofloxacin 500mg PO every 12 hours or
    • Levofloxacin 750mg IV or PO every 12 hours.

High-Risk Empiric Antibiotic Therapy

  • Single agent with Imipenem-cilastatin 500mg IV every 6 hours OR
  • Meropenem 1g IV every 8 hours OR
  • Doripenem 500mg IV every 8 hours OR
  • Piperacillin-tazobactam 4.5g IV every 6 hours
  • Combination of one of the following with 500mg of IV or PO Metronidazole every 8 hours
    • Cefepime 2g IV every 8 hours
    • Ceftazidime 2g IV every 8 hours

Discharge from Inpatient

Patients must also meet certain discharge criteria. These include resolution of abdominal pain, resolution of leukocytosis, ability to tolerate an oral diet, and normalized vital signs. The patient should be discharged with oral antibiotics. The length of treatment should be a total of 10 to 14 days that will include the time spent on IV antibiotics.

Outpatient Management of Diverticulitis

Outpatient treatment may be an option for a majority of patients that present with abdominal pain and then diagnosed with diverticulitis. Antibiotics are the mainstay of treatment and should be given for 7-10 days. Counsel your patients to take the full course of antibiotics prescribed. They should also understand the possible complications and risks of ending antibiotics early. You want to prescribe antibiotics that will cover gastrointestinal flora, specifically Escherichia coli and Bacteroides fragilis. There are several different antibiotics that may be given to cover gram-negative rods and anaerobes.

Antibiotics for Outpatient Diverticulitis Management

  • Ciprofloxacin 500mg 1 PO BID and metronidazole 500mg 1 PO q 8 hours (most commonly used)
  • Levofloxacin 750mg- 1 PO QD and metronidazole 500mg 1 PO q8 hours
  • Bactrim DS– 1 PO BID and metronidazole 500mg 1 PO q8 hours
  • Augmentin 1 PO q 8 hours or Augmentin XR 2 PO BID
  • Moxifloxacin 400mg 1 PO QD (use for patient with allergy or intolerance to metronidazole and beta-lactams)

Some clinicians may also choose to place the patient on a modified diet. Start with a clear liquid diet until re-evaluation in 2-3 days. Advance the diet when the patient improves.

Outpatient treatment of diverticulitis should have a close follow up to determine if antibiotics are working and if they will require escalation of treatment. Patients that are improving do not need repeat imaging but should continue antibiotics and follow up with a gastroenterologist for a colonoscopy if not done within the past 12 months. If there is no improvement after 2 to 3 days of oral antibiotics, a repeat CT abdomen and pelvis should be performed. This determines if there is a new complication.

Failure of outpatient treatment, such as persistent abdominal pain, fever and inability to keep down oral intake requires the patient to go from outpatient treatment and be admitted to the nearest emergency room for inpatient treatment.


Overall, diverticulitis is a common gastrointestinal complaint and should be recognized and able to be differentiated from other abdominal pain causes. These patients may present at your outpatient clinic, urgent care or local emergency room. Recognizing the signs and also getting a proper workup will lead to proper treatment. Patients without a previous diverticulitis diagnosis will likely need emergency room evaluation to rule out other causes.

Patients with chronic diverticulitis may sometimes be treated outpatient by a clinician without emergency room evaluation but should only be done if the clinician is comfortable with this. It is also important to refer a patient to a gastroenterologist for a colonoscopy or schedule a colonoscopy in 6-8 weeks after symptoms have resolved. Patient with chronic gastroenteritis should also be referred for possible surgical intervention. You will want to instruct patients on starting a new diet after they have had been diagnosed with diverticulitis. They should eat a high fiber diet and avoid seeds, nuts and corn. Diverticulitis is a treatable diagnosis and should be managed appropriately based on imaging and risk-factors. Patients generally have a good outcome if managed appropriately and in a timely fashion.

If you found this helpful you should also check out our clinical toolkit for more easy-to-reference clinical guidelines!

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