A vast majority of patients presenting with diverticulitis will respond to conservative management. Patients who present with uncomplicated diverticulitis can be treated with a combination of bowel rest and antibiotics. This management can be accomplished in both the inpatient as well as outpatient settings, and for the most part will depend on symptoms and patient-physician comfort. Mild attacks can be managed with clear liquids and outpatient oral antibiotics. More severe attacks, especially in the presence of systemic symptoms (fever, tachycardia, etc.), can be managed with IV antibiotics and complete bowel rest in the hospital.
Appropriate antibiotic choice should include coverage for anaerobes (Bacteroides spp, Peptostreptococcus spp, Clostridium, and Fusobacterium spp) as well as facultative species such as Escherichia coli and Streptococcus.5 A combination of a fluoroquinolone and metronidazole or amoxicillin-sulbactam can be used for outpatient oral treatment. Intravenous formulations of the above or more extended coverage (piperacillin-tazobactam, imipenem, etc.) can be used for more severe cases requiring inpatient treatment.
In recent years, the benefit of antibiotics for acute uncomplicated diverticulitis has come into question. Some data suggest that bowel rest alone may be sufficient. However, data is limited at this point and should be interpreted with caution.6
For patients with abscess, percutaneous drainage should be added to the treatment plan if at all possible. Successful drainage of the abscess, in addition to antibiotic treatment, has been shown to significantly decrease rates of emergent surgical intervention and need for stoma. There is also an increasing body of literature suggesting that successful drainage of the abscess may eliminate the need for mandatory elective surgery, effectively moving complicated diverticulitis into the uncomplicated category.7,8
Chronic and Complicated Diverticulitis
Management of more complicated disease has changed significantly in the past 10 years. Having a number of episodes of diverticulitis or complicated disease increases a patient’s chance of developing further attacks. However, this does not seem to correlate with worsening severity or outcomes following these attacks. Most of these patients can be treated successfully with short courses of antibiotics without worsening their overall outcome. In addition, it seems to be the first attack that is most likely to need surgical intervention.9, 10, and 11 Cost-effectiveness data suggest that 3 to 4 episodes may warrant discussion of surgical options, but do not clearly mandate surgery. Patients with infrequent, uncomplicated attacks that are easily controlled with outpatient medical management can be treated medically, in some cases without the need for surgical intervention. A similar approach can be taken in patients with an abscess that was successfully drained on initial presentation. Most of these patients can be treated as uncomplicated diverticulitis patients without need for mandatory surgery.
Over the years, a number of strategies to prevent recurrences have been investigated, most with disappointing results. Fiber content of the diet is a major determinant of the development of diverticular disease, but once a patient has developed diverticulitis or diverticulosis, increasing fiber in the diet does not seem to lower the risk of further attacks.12 A number of medical therapies, including rifaximin and probiotics, have been investigated based on a theory that the change in bacterial flora can play a major role in development in this disease. Results have been inconsistent, with rifaxamin showing the biggest promise.13
It is very important to point out that the goal of treatment for both acute and chronic diverticulitis is being symptom-free. Patients whose symptoms never completely disappear, even if these patients return to their normal routine, are much more likely to need surgery.
Indications for surgery for acute diverticulitis include free perforation (Hinchey IV) and diverticulitis that does not respond to medical management. Free perforations are rare and should be treated as any acute colonic perforation. Contained but non-improving disease presents a bigger challenge. These patients typically present with milder symptoms and initially have a good response to medical management. However, after initial improvement, their progress plateaus, and some of them are not able to leave the hospital because of pain, or return to the hospital because their symptoms never completely resolve. For these patients, it is appropriate to set up parameters for when improvement can be expected and when surgery should be considered. These parameters are very individual and depend on a patient’s condition, medical comorbidities, and wishes. In this setting, repeat imaging is indicated. In some patients a failed response is caused by progression of the disease—from phlegmon to abscess, for example—and in such circumstances the treatment approach may change.
Clear indication for surgery in the chronic setting includes presence of complications. Stricture or fistula should be addressed surgically, and medical management is only useful in these cases to contain symptoms while a patient is being readied for surgery. Inability to rule out malignancy is rare, but requires a more aggressive approach.
As mentioned, multiple attacks of diverticulitis are an indication to discuss surgery. However, surgery is not required for most patients, and the decision to proceed with an operation based on a number of attacks should be individualized. For example, for patients with erratic schedules and infrequent but severe attacks requiring long hospital stays and time out of work, surgery may be a better early option. Patients with infrequent, minimal attacks, however, can be observed. Thorough discussion with the patient, including the potential natural history of diverticulitis, risks of surgery, and expected functional outcomes, is very important for patients who have an indication—but not a necessity—for surgery. In recent years, an observation has been made that younger patients tend to have more severe attacks, suggesting an indication for a more aggressive surgical approach. However, this phenomenon seems to be a function of age, with higher chances of developing attacks over a longer period of time. Thus, treatment options for younger patients remain the same.14
The approach to immunosuppressed patients is very different and requires a much more aggressive pursuit of surgery. These patients are more likely to present with perforation and to develop complications in the course of their disease. Although these patients oftentimes are not the best surgical candidates, and their surgical mortality can reach 23%, medical management is associated with 57% mortality.15 In these patients surgical options should be pursued early and aggressively.
Surgical treatment of diverticulitis underwent significant evolution as our medical management changed, with an emphasis on primary anastomosis and minimizing the need for diversion. Decision on the appropriate operation depends on the individual patient situation and the surgeon’s comfort. Surgical options include resection with primary anastomosis (done open or laparoscopically), primary anastomosis with proximal diversion, Hartmann’s procedure, diversion without resection, and laparoscopic lavage.
The underlying principles of surgery for diverticulitis include taking appropriate margins and dissecting an adequate length of the colon. Resection for diverticulitis has to include the entire sigmoid colon (even in cases when active disease is more proximal), with an anastomosis to the proximal rectum. Failure to accomplish this confers a significant increase of recurrent disease, but in cases when the appropriate segment is removed, the chance of recurrence is less than 5%. In most patients, this involves mobilization of the splenic flexure to achieve adequate length for a colorectal anastomosis. The ureters, especially on the left side, can be difficult to identify in cases of acute diverticulitis, and so liberal use of ureteral stents can be very helpful in these situations.
Functional implications should be discussed for elective cases. A number of patients will develop looser bowel movements, frequent urgency, and clustering. Most of these symptoms are minimal and will improve over time. However, in elderly patients with baseline continence problems, these can play a significant role in determining the appropriate surgical approach.
Ideally, patients with diverticulitis needing surgery would undergo single-stage, preferably laparoscopic resection with primary anastomosis. A number of studies indicate that for a vast majority of patients this is a safe and appropriate option. Laparoscopy in the setting of diverticular disease can be difficult and depends on a particular patient’s situation and the surgeon’s comfort. Even in cases when the case cannot be completed minimally invasively, laparoscopy can still be beneficial in the mobilization of splenic flexure, thus minimizing the incision. In patients with free perforation, or when significant phlegmon can be palpated, laparoscopy has minimal benefit.
Hartmann’s procedure with resection of the diseased segment and end colostomy has been the standard for many years and is still appropriate for patients with free perforation, sepsis, severe dilatation of the proximal colon due to stricture, the immunosuppressed, and elderly patients whose continence at baseline may be an issue. However, a number of studies have shown that the rate of complications following this surgery is significant (although partly due to selection bias), and Hartmann’s reversal is a difficult operation associated with significant morbidity. Thus, in cases of significant inflammation, borderline nutritional status, or notable comorbidities, performing a primary anastomosis with a proximal diverting-loop ileostomy is a useful operation that allows fewer complications. Diversion without resection should be avoided if at all possible, as it will not eliminate the infectious/inflammatory process, and effectively gives patients a stoma without treating their symptoms.
Laparoscopic lavage is an interesting new approach with rising popularity. Existing studies show impressive results in avoiding diversion, converting a colectomy from an emergent to an elective procedure, and even avoiding operation altogether.16,17 Patients with Hinchey III diverticulitis without clear perforation, with an indolent course, or with abscesses that cannot be drained percutaneously may benefit from the laparoscopic approach. However, there is a lot of variation in patient selection, and a general lack of randomization between laparoscopic lavage and current medical management. Further studies are needed to define the role of laparoscopic lavage in the treatment of diverticulitis.
In patients with diverticular stricture, especially if malignancy has not been completely ruled out, surgery should be performed utilizing general principles of oncologic resection, with good margins and adequate lymph node harvest.
Most of the fistulas encountered with diverticulitis are very small and oftentimes not identifiable once the colon is separated from the bladder or vagina. In cases of colovaginal fistula, repair of the vaginal cuff or additional postoperative precautions aside from colonic resection are not needed. In cases of colovesicular fistula, Foley catheters should be left in place for an extended period, depending on intraoperative bladder repair. Adequate time of urethral catheter decompression is not well defined.