Most patients with diverticulosis are asymptomatic, and the presence of diverticula is commonly identified incidentally during colonoscopy or radiologic studies. Patients with acute diverticulitis may present with fever, left lower quadrant pain, and change in bowel habits. Left lower abdominal pain is the most common presenting feature in 70% of patients. The character of the pain is mostly described as crampy and may be associated with a change in bowel habits. Consequently, the presentation of diverticulitis may be confused with irritable bowel syndrome. Other symptoms of diverticulitis include nausea, vomiting, constipation, flatulence, and bloating. Acute presentation of diverticulitis may also be because of a complication, such as colonic abscess, intestinal perforation, and fistula formation.

Laboratory findings include leukocytosis and possibly elevated inflammatory markers.[15] Those patients with complicated diverticulitis may present with signs of sepsis and physical findings consistent with peritonitis. Physical findings may include abdominal tenderness, abdominal distension, a tender mass in the abdomen, absent bowel sounds, and findings related to fistula formation. The presence of fecaluria and pneumaturia must alert the clinician to the possibility of a colovesical fistula.

When the history, physical exam, and laboratory findings are consistent with the diagnosis of acute diverticulitis, confirmatory imaging studies are the next step. Different imaging modalities, including ultrasound and barium enema, may be used to diagnose diverticular disease. However, a CT scan of the abdomen and pelvis with intravenous and oral contrast is the preferred modality. Its diagnostic accuracy is high, with a sensitivity of 98%.[16] assessment of renal function prior to the administration of intravenous contrast is imperative. Findings of colonic wall thickening and fat stranding are typical for diverticulitis. Signs of complicated disease, including fistula formation, abscesses, and intra-abdominal free air, are easily identifiable with scans.[17] The Hinchey classification system is useful in determining the severity of disease as well as in the allocation of patients to different treatment algorithms.

Generally speaking, patients with Hinchey 1a and 1b diverticulitis are successfully manageable by non-surgical means. Patients with Hinchey 2 diverticulitis may require placement of a percutaneous drain followed by elective sigmoid colectomy. However, patients with Hinchey 3 and 4 require urgent surgical intervention.

If there is a suspicion of a colovesical fistula, the urinalysis may reveal red or white blood cells. In females of childbearing age who present with abdominal pain, a pregnancy test must be carried out to rule out an ectopic pregnancy.

The medical management of acute non-complicated diverticulitis includes oral or intravenous antibiotics, pain control, hydration, and restricted oral intake. Medical management of diverticulitis with antibiotics remains the standard of care. However, antibiotic choice, duration of treatment, and route of administration remain controversial.[18] Most cases of uncomplicated diverticulitis are successfully treatable in the outpatient setting. Oral antibiotics, such as ciprofloxacin and metronidazole or amoxicillin-clavulanate, are prescribed for 7 to 10 days with recommendations to minimize oral intake until the pain has resolved.[15]

Patients who are febrile, immunosuppressed, unable to stay hydrated or those with multiple medical comorbidities require admission to the hospital for treatment with parenteral antibiotics. As symptoms improve, the diet is advanced, and patients are started on oral antibiotics. Any patient failing to improve on parenteral antibiotics or deteriorates during therapy should undergo repeat evaluation with CT imaging to rule out evolving complications.[15]

After acute episode resolution of diverticulitis, a colonoscopy is recommended 6 to 8 weeks later, particularly if the patient has not had a colonoscopy in the past 2 to 3 years.[15]

Historically, elective sigmoid colectomy used to be performed after the second bout of uncomplicated diverticulitis. However, more recent evidence has disproved the benefit of this approach. Firstly, the recurrence rate of uncomplicated diverticulitis is lower than previously estimated, ranging from 13 to 23%. Secondly, the incidence of complicated recurrent episodes that may require a stoma is also low, approximately 6%. Therefore, current recommendations emphasize that selection criteria for elective surgery should be individualized according to the number, severity, and frequency of episodes of diverticulitis, persistent symptomatology after an episode of diverticulitis and the immunologic status of the patient. These criteria merit consideration in the context of the patient’s age, comorbidities, and social history. Finally, routine sigmoid colectomy in patients younger than 50 years of age is no longer the recommended therapeutic path.[10] Younger patients should receive the same treatment as their older counterparts.

Regardless of the indication and or technique used (open, laparoscopic, or robotic) when performing an elective sigmoid colectomy for diverticulitis, it requires the removal of the entire sigmoid colon, the proximal and distal anastomotic sites must appear healthy and well perfused, and the anastomosis performed without tension.

Approximately 1% of patients with an acute episode of diverticulitis will require surgical intervention during that episode.[19] Patients presenting with signs of peritonitis are candidates for emergent surgery. When intraoperative findings confirm perforated diverticulitis, the traditional operation is a Hartmann procedure, which includes resection of the sigmoid colon, preservation of the rectum in the form of a rectal pouch, and creation of an end colostomy. This procedure effectively eliminates the risk of an anastomotic leak, and patients are considered for colostomy reversal in 3 to 6 months. However, due to old age and associated comorbidities, nearly 30% of patients undergoing a Hartmann procedure never have colostomy reversal.[15] A second option for patients with Hinchey 3 and 4 diseases is a primary colorectal anastomosis with a proximal diverting ileostomy. Initial retrospective evaluation of this surgical modality shows a decreased overall mortality after performing a primary anastomosis. However, randomized controlled studies comparing a Hartmann procedure to the primary anastomosis with proximal diversion are not yet available.[20] An old approach, no longer considered in the surgical management of complicated diverticulitis, consisted of leaving the inflamed or perforated sigmoid colon in situ and placement of a proximal stoma with the plan of second and then third stage procedures.

Diverticulitis can occur anywhere in the colon; hence, the presentation may vary according to the site involved. For instance, diverticulitis in the right colon may present in a similar fashion to acute appendicitis. Similarly, diverticula in the transverse colon may appear as peptic ulcer disease, pancreatitis, or cholecystitis. Therefore the list of differential diagnoses is extensive as follows:

• Acute gastritis
• Acute pancreatitis
• Acute appendicitis
• Acute cholecystitis
• Acute pyelonephritis
• Cholangitis
• Mesenteric ischemia
• Constipation
• Irritable bowel disease
• Irritable bowel syndrome
• Pelvic inflammatory disease
• Ovarian cyst
• Ectopic pregnancy

Recent studies have demonstrated the resolution of uncomplicated diverticulitis without the use of antibiotics in very well-selected patients. Patients with peritonitis, perforation, signs of sepsis, and hemodynamic instability were excluded. Although some patients did develop perforations or abscesses, the risk was considered low, and there was no difference in primary outcomes between the group treated with antibiotics and the group without antibiotic therapy.[18] The evidence for this unique treatment approach is preliminary, and further study is needed.

Traditionally, patients with generalized peritonitis from perforated diverticulitis undergo a Hartman procedure or primary anastomosis with a proximal diverting stoma. Researchers have studied laparoscopic peritoneal lavage as an alternative to the standard surgical treatment of perforated diverticulitis.[21] Other studies have not duplicated the initial results, so this treatment remains controversial.

The prognosis of the patients depends on the severity of the illness and the presence of complications. Immunocompromised patients have higher morbidity and mortality as a result of sigmoid diverticulitis.[22]

After the first incident of acute diverticulitis, the five-year recurrence rate is approximately 20%.[23] Several studies have demonstrated the significant link between increased BMI and the risk of developing diverticulitis.[24]

There are many complications that can occur in a patient with diverticulitis which can be more severe in certain cases, such as in immunocompromised patients. For instance, those infected with HIV or those on immunosuppressants are more likely to develop perforation.[25] Following are the possible complications of diverticulitis:

• Abscess formation (commonest)
• Intestinal perforation
• Intestinal fistula
• Intestinal obstruction
• Generalized peritonitis
• Stricture disease
• Sepsis

The present management of diverticulitis must be delivered by interprofessional teams in the context of the most recent scientific evidence. These teams can include gastroenterologists, internists, general surgeons, colostomy care nurses, gastroenterology specialty-trained nurses, and pharmacists, working collaboratively to bring about optimal patient care and outcomes.

The incidence of diverticulitis continues to increase in all age groups, placing a substantial burden on the healthcare system. The primary care physician, nurse practitioner, gastroenterologist, and the dietitian must educate the public and patients that obesity, inactivity, and a poor diet contribute significantly to epidemiologic factors.

A positive paradigm change in the treatment of diverticulitis has resulted in the widespread use of outpatient management for non-complicated diverticulitis. However, many patients with a history of non-complicated diverticulitis are improperly managed empirically with antibiotics every time they call their doctor’s office with abdominal pain. This misuse of antibiotics must be corrected.  For patients undergoing surgery, a colostomy nurse should educate the patient on the care of the stoma.

Better and more sophisticated imaging modalities have allowed us to accurately classify the severity of disease and allocate different patients to more effective treatment algorithms.

The current emphasis on individualizing the need for elective sigmoid colectomy after resolving non-complicated diverticulitis will result in less unnecessary operations and better outcomes. [Level V]