Benign Colon: Diverticular Disease

18 Benign Colon: Diverticular Disease

Alan G. Thorson and Stanley M. Goldberg

The term “diverticular disease” of the colon represents a con- from around 5% near the turn of the century to 50% or more tinuum of anatomic and pathophysiologic change within the by 1975.2,3 colon related to the presence of diverticula. These changes It is now estimated that the risk of developing diverticular most often occur in the sigmoid colon. The continuum can disease in the United States approximates 5% by age 40 and range from the presence of a single diverticulum (a sac or may increase to more than 80% by age 80.5 pouch in the wall of an organ) to many diverticula (which may This increase in observed incidence was originally attrib- be too numerous to count). It can refer to an asymptomatic uted to new imaging techniques [the introduction of the bar- state (diverticulosis) or any one of a number of diverse com- ium enema (BE) in the early 20th century] and bias inherent binations of inflammatory symptoms, changes, and complica- to estimates based on a population presenting with symptoms tions (diverticulitis). requiring an investigation.6 It is now clear that not only diver- Symptoms may variably result from simple physiologic ticulosis but the incidence of related complications are changes in colonic motility related to altered neuromuscular increasing. This is exemplified by increasing costs in the activity in the sigmoid colon, varying degrees of localized treatment of diverticular disease which accounts for nearly inflammatory response, or complex inflammatory interac- 450,000 hospital admissions, 2 million office visits, 112,000 tions leading to diffuse peritonitis and septic shock. These disability cases, and 3000 fatalities each year in the United more complex symptoms and resulting complications arise States.7 It is estimated that costs will continue to increase as from breaches in the integrity of the wall of one or more the population continues to age in the next several decades. diverticula. Diverticula may be true, containing all layers of Proportionately few people become symptomatic from the the bowel wall (congenital), or false, lacking the muscular presence of diverticula. An estimated 10%Ð20% of people layer (acquired or pulsion diverticula). with diverticula develop symptoms of diverticulitis, and only This chapter will deal with inflammatory diverticular dis- 10%Ð20% of these will require hospitalization. Of those that ease and its associated complications. Bleeding from divertic- require hospitalization, 20%Ð50% will require operative ular disease is discussed in Chapter 20 (Lower Gastrointestinal intervention. The percentage of hospitalized patients requir- Hemorrhage). ing operation has been increasing as outpatient management becomes more common and those admitted as inpatients are more seriously ill.8 Overall, less than 1% of patients with Incidence diverticula will ultimately require surgical management.9 There is some evidence that males are more frequently Diverticulosis was first described in the mid-19th century as affected at a younger age and females at an older age; how- more of a curiosity than a significant disease entity. However, ever, significant bias may influence this impression. Young since the early 20th century, an increasing prevalence of the females may frequently be underdiagnosed because of confu- disease has been recognized in industrialized countries. The sion with gynecologic diseases in the young. Older females incidence increases with age and the adoption of a diet high may be overdiagnosed because of confusion with irritable in red meat, refined sugars, and milled flour but low in whole bowel syndrome (IBS). There also seems to be a dichotomy grain breads, cereals, and fruits and vegetables. Although the in age and sex with regard to complications of diverticular exact incidence is not well established, numerous autopsy, disease, particularly perforation. The incidence of perforation radiographic, and endoscopic series have shown that the inci- is higher in males younger than age 50 but in females older dence has increased dramatically over the past 75 years,1Ð4 than 50.10

269 270 A.G. Thorson and S.M. Goldberg

Pathophysiology the muscular changes already discussed, some patients fail to demonstrate this characteristic. These patients are more likely Diverticulosis is associated with high intraluminal pressures. to have diffuse diverticula throughout the colon, and are noted Pressures in patients with diverticular disease have been to have a higher incidence of bleeding. They may have an found as high as 90 mm Hg during peak contraction. This rep- underlying connective tissue abnormality. This would explain resents a value nearly 9 times higher than seen in patients with the development of diverticula in the absence of high intralu- normal colons.11 It is theorized that such pressures lead to minal pressures. The high incidence of bleeding in these segmentation. Segmentation refers to a process whereby the patients could be related to associated inadequate vascular colon effectively functions as a series of separate compart- support in the diverticular wall. ments rather than a continuous tube. Pain associated with diverticular disease may be related to The high pressures that each compartment is capable of muscle spasm as well as inflammation. Perforation can occur producing are directed toward the colonic wall rather than as in the absence of inflammation and may be secondary to the propulsive waves. These pressures predispose to herniation of extremely high intraluminal pressure.13 mucosa through the muscular defects that exist where blood vessels penetrate to reach the submucosa and mucosa (vasa recta brevia). Most of these penetrations occur between the Etiology mesenteric and anti-mesenteric tinea where, not coinciden- tally, most diverticula occur. As the mucosa herniates, it does The etiology of diverticulitis remains complex and relatively so without dragging the muscular layer along, leaving the poorly understood. Pathophysiologic studies reveal that com- diverticula denuded of muscle and consistent with the defini- plications do not occur until there is microperforation through tion of an acquired process. Thus, the most common divertic- the wall of a diverticulum into the pericolic tissue. A single ula are acquired or pulsion diverticula. diverticulum experiences a change in the permeability of its These high pressures are consistent with the sigmoid colon isolated mucosa from physical, biochemical, or physiologic being the most common site of involvement. This can be means. It is postulated that a free perforation then occurs lead- explained by the law of Laplace which states that the tension ing to a characteristic response and progressing to varying in the wall of a hollow cylinder is proportional to its radius degrees of inflammation. The perforation might be small and times the pressure within the cylinder. Because of segmenta- cause a microabscess, develop into a phlegmon, or form into tion, the sigmoid generates pressures so high that the effect of a large abscess. Free perforation occurs rarely, but fistuliza- a smaller radius is overcome resulting in total tension in the tion does frequently occur, most often to the bladder.14 wall of the sigmoid colon being higher than the rest of the The original communication with the lumen of the bowel is colon and thus the sigmoid has the highest risk of diverticu- usually rapidly obliterated by the inflammatory process. lum formation. It is hypothesized that at least a part of fiber’s Occasional failure of the diverticular neck to obliterate may protective effect is a result of stool bulking which maintains a lead to a free communication between the bowel and the peri- larger lumen, prevents segmenting contractions, and toneal cavity with resultant fecal peritonitis. Rupture of a decreases high pressures. noncommunicating abscess may lead to purulent peritonitis.15 Complementary to these theories of pathogenesis is the Low-grade inflammation of colonic mucosa, induced by consistent colonic wall muscle abnormality associated with changes in bacterial microflora, can affect the enteric nervous sigmoid diverticular disease. Both the circular and longitudi- system and alter gut function, leading to symptom develop- nal muscle wall is typically thickened resulting in a reduction ment. This explanation has been postulated as a source of in the size of the lumen and a shortening of the sigmoid. The symptoms in IBS. The same explanation can be easily extrap- reduced lumen size may be further enhanced by secondary olated to symptoms in diverticular disease because some pericolic fibrosis. patients with diverticular disease demonstrate bacterial over- The source of this muscular thickening is not clear. It has growth.16 This common source of symptoms reinforces the been observed that in the normal process of left colon peri- difficulty in sorting through the differential in patients with stalsis, smooth muscle in the rectosigmoid will relax in symptoms of bowel disease. response to a stimulus, causing contraction of the colon above Recent clinical investigations have shown that disturbances and the rectum below. A combination of poor diet, aging, and in cholinergic activity may contribute to diverticular disease. constipation could lead to malfunction of this relaxation Cholinergic stimulation in patients with diverticular disease response leading to a functional obstruction and the hypertro- leads to unsynchronized slow waves of relatively low fre- phy seen in the muscle.12 Cellular hypertrophy, cellular hyper- quency as opposed to bursts of action potentials normally plasia, and elastosis have all been described. Elastosis seems associated with peristalsis.17,18 This suggests a possible role to precede the development of diverticulosis. It is not found in for cholinergic denervation hypersensitivity in colonic any other inflammatory conditions of the colon. smooth muscle with upregulation of smooth muscle mus- Several alternative concepts have been advanced to explain carinic receptors.19 the differences in presentation of diverticular disease. The colon with diverticular disease has more cholinergic Although the most common finding in diverticular disease is innervation than normal colon. In addition, there is less 18. Benign Colon: Diverticular Disease 271 noncholinergic, nonadrenergic inhibitory nerve activity. This postulated mechanism is immunosuppressive and antiinflam- increased cholinergic activity and the relative paucity of matory effects hinder confinement of perforation in its early inhibitory activity may contribute to the high intraluminal stages. The use of other immunosuppressive drugs has also pressures and segmentation seen in the diverticular colon.20 been associated with such increased risks. The main risk seems to be more virulent complications once complications occur.33 Epidemiology Opiates Diet The use of opiate pain medications has been shown to Large cohort and case-control studies in the United States and increase intracolonic pressure and slow intestinal transit, both Greece have shown that diets high in red meat and low in fruit risks for complications of diverticular disease. Case series and vegetable fiber increase diverticular symptoms by as have shown high percentages of patients with perforation much as threefold.21,22 Vegetables and brown bread have been taking opiate analgesics.30,34 shown to be protective.22 Fiber may be protective by increasing stool weight and water content which decrease colonic Smoking segmentation pressures and transit times.23 Fiber, through the process of fermentation, also provides short-chain fatty acids A recent large case-control study showed that smokers had 3 to the colonic epithelial cells, an important source of fuel and times the risk of developing complications from diverticular mucosal health.24Ð26 Red meat has been associated with disease than did nonsmokers.35 However, a large cohort study heterocyclic amines, a factor in colon mucosal apoptosis.27 involving more than 46,000 men in the United States did not Dietary heme has been shown to be highly cytotoxic to find this same association.36 rat colons.28 Alcohol Age and Sex A Danish cohort study showed the risk of diverticulitis was 3 Population-based studies have reported differences in disease times higher in female alcoholics than the general population presentation according to age and sex. However, it is not clear and 2 times higher in male alcoholics. However, the data may that all of these associations would remain valid in the global be biased because of dietary and smoking habits associated population of diverticular disease. McConnell et al.29 reported with alcoholics.37 that female patients present with complications requiring surgery an average of 5 years later than males. Men have a higher incidence of bleeding and women a higher incidence of fis- Clinical Manifestations tula. Younger men present with fistula and older men bleeding. Young females present with perforation whereas older Clinical Patterns females with chronic disease and stricture. Overall, patients younger than age 50 present more often with chronic or recur- Diverticular disease may be classified into diverticulosis rent diverticulitis.29 Finally, more patients at younger and (asymptomatic) and diverticulitis (symptomatic) (Table 18-1). younger ages are being diagnosed with diverticular disease. Diverticulosis refers to the presence of diverticula with no related symptoms. This applies to the vast majority (80%Ð Nonsteroidal Inflammatory Drugs 90%) of patients with diverticular disease. Diverticulitis can be subclassified into noninflammatory, acute (simple or Nonsteroidal inflammatory drugs (NSAIDs) have been linked to increased rates of complications related to diverticular disease. The plausible mechanism of action is indirect through TABLE 18-1. The classification of diverticular disease known inhibition of cyclooxygenase and resultant decreased Diverticulosis Asymptomatic prostaglandin synthesis in the gut. Prostaglandins are impor- Diverticulitis tant in the maintenance of mucosal blood flow and an effec- Noninflammatory Symptoms without inflammation tive colonic mucosal barrier. A direct mechanism also exists Acute Symptoms with inflammation through mucosal damage caused by NSAIDs which leads to Simple Localized 30Ð32 Complicated With perforation increased translocation of toxins and bacteria. Chronic Persistent, low grade Atypical Symptoms without systemic signs Recurring, persistent Symptoms with systemic signs (may be Immunocompromise intermittent) The use of corticosteroids is associated with a higher risk of Complex With fistula, stricture, obstruction Malignant Severe, fibrosing perforation and more severe inflammatory complications. The 272 A.G. Thorson and S.M. Goldberg complicated), chronic (atypical or recurring/persistent), and complex disease. The term “malignant diverticulitis” has been used to describe a particularly severe form of fibrosing disease with phlegmonous inflammation extending below the peritoneal reflection, frequent fistula formation, obstruction, and high postoperative morbidity and mortality.38 Many consider this form to be misdiagnosed Crohn’s disease.

Noninflammatory Diverticular Disease Noninflammatory diverticular disease describes those patients with symptoms of diverticulitis but without associated inflammation.39 The diagnosis is made at the time of elective operation when no inflammatory changes are found in the specimen. This has been reported in 15%Ð35% of resections.39 Some would consider this a missed diagnosis (IBS). However, if that were always the case, then one would FIGURE 18-1. Diagrammatic representation of classification system expect a very low resolution of symptoms after resection. In for diverticular abscesses in which the cylinders represent the colon, fact, although a lack of inflammatory changes in the resected the circles an abscess, and the arrows perforation. A Hinchey stage specimen has been associated with lesser degrees of symptom I: localized pericolic or mesenteric abscess. B Hinchey stage II: relief, the success rate is not zero.40Ð42 One could conclude confined pelvic abscess. C Hinchey stage III: generalized purulent that resections are being performed for the right indication but peritonitis resulting from perforation of an abscess. D Hinchey the wrong pathology, delays in surgery may lead to complete stage IV: generalized fecal peritonitis secondary to free colonic perforation. resolution of previous inflammation, or noninflammatory diverticular disease is a real entity that sometimes requires surgical intervention. Careful follow-up on the long-term outcomes in these patients could go a long way in answering this Chronic Diverticulitis question. The term atypical has been applied to patients with chronic Patients with chronic diverticulitis remain symptomatic (left symptoms who never develop the necessary clinical and lab- lower quadrant pain) despite standard treatment. It is consid- oratory criteria to be judged as having acute diverticulitis. Up ered atypical if systemic signs never develop. With systemic to 24% of these patients are found to lack inflammatory signs, chronic disease may manifest as recurring, intermittent changes in the resected specimen thus fulfilling the criteria episodes of acute disease or as persistent, symptomatic low- for noninflammatory diverticular disease. The remaining grade disease. This is frequently associated with the presence members of this group could be considered as having had of a phlegmon. If resection is performed, there will be evi- acute diverticulitis based on histologic findings of inflamma- dence of inflammatory changes within the specimen. tion. A high percentage of atypical patients (88%) become 42 pain free at least on short-term (12 months) follow-up. Complex Diverticular Disease Acute Diverticulitis Complex diverticulitis refers to disease in those patients who manifest sequelae of chronic inflammation including fistula, Acute diverticulitis is heralded by signs and symptoms of stricture, and obstruction. Each of these complications will be acute inflammation and may be simple (limited to the colonic addressed later in this chapter. wall and adjacent tissues) or complicated (with perforation). Simple acute disease is usually accompanied by systemic signs of fever and leukocytosis whereas complicated acute dis- Natural History ease may have the added signs of tachycardia and hypotension. Complicated acute diverticulitis can be classified according The natural history of diverticular disease is one of increasing to the extent of spread of the inflammatory process. A com- risk with increasing age and a diet low in fiber and high in red mon classification for diverticulitis with perforation was first meat. The number and size of diverticula may increase with described by Hughes et al.43 in 1963 and slightly revised and age; however, progression from one segment of bowel to popularized by Hinchey et al.44 in 1978. Stage I diverticulitis another does not typically occur. The most common location is a localized pericolic or mesenteric abscess, stage II is a con- for complications is in the sigmoid colon. It is unusual for fined pelvic abscess, stage III is generalized purulent peritoni- complications to develop in the proximal colon after resection tis, and stage IV is generalized fecal peritonitis (Figure 18-1). of the diseased sigmoid colon. 18. Benign Colon: Diverticular Disease 273

Most patients who develop a first episode of symptomatic suggest possible bladder involvement because of an adjacent diverticulitis have been asymptomatic until 1 month before inflammatory mass or a colovesical fistula. Pneumaturia, presentation. Most will respond to bowel rest and antibiotics fecaluria, or passage of gas and stool through the vagina sug- as an outpatient. It is difficult to reliably estimate how many gest a colovesical or colovaginal fistula, respectively. Fever is outpatients will have recurrent episodes because outpatient common and proportional to the amount of inflammatory data are generally not reflective of a primary care population. response present. A high fever suggests a perforation with However, it has been reported that up to 10% of patients with abscess or peritonitis. a first episode who have responded to outpatient management Occasionally, diverticular disease will present in unusual will develop recurrent or persistent symptoms which will ways. These include lower extremity (hip) joint infections of require hospitalization.45 a chronic nature that culture positive for enteric bacteria. Data are more readily available on recurrence for patients Other unusual presentations include female adnexal masses who were initially treated as inpatients. But our understanding on the left; inflammation/necrosis of the perineum and geni- of the natural history continues to evolve as antibiotics become talia including complex anal fistula and Fournier’s gangrene; more effective and inpatient status means increasingly severe subcutaneous emphysema of the lower extremities, neck, and disease. These changes make historical data regarding these abdominal wall; isolated hepatic abscess caused by enteric issues of less value. In today’s world, inpatients might be organisms; brain abscess caused by enteric organisms and expected to be at a greater risk of recurrence. In fact, 10%Ð20% cutaneous lesions mimicking pyoderma gangrenosum.51 or more of these patients will develop a recurrence.45 Some, but not all of these patients, will require a second hospitalization. The interval between acute events may be prolonged (median 5 Physical Findings years).46 After a second hospital admission, up to 70% will continue with symptoms and more than half of those that require a Patients presenting with acute diverticulitis will be tender to third admission will do so within 1 year. The more complicated palpation in the left lower quadrant and left iliac region. There the attack, the higher the risk of recurrence.4,14,47Ð50 may be limited rigidity or localized guarding to deeper palpa- It has been estimated that up to 1% of all patients with tion. With resolution of the acute phase, palpation may reveal diverticulosis will eventually require operative intervention.9 a mass in the left lower quadrant A positive psoas sign and/or However, with an increasing overall number of individuals obturator sign may reflect retroperitoneal and/or pelvic affected with diverticulosis and better antibiotics for managing involvement of the inflammatory process. infections, this estimate may now be too high. In the event of a gross perforation with development of fecal or purulent peritonitis, the area of tenderness will spread throughout the abdomen. Guarding will become prominent Presenting Symptoms and the abdominal wall will become rigid. Patients with acute diverticulitis typically complain of left Complications lower quadrant abdominal pain. However, in a patient with a redundant sigmoid colon, an inflamed segment might present Bleeding with pain in the right lower quadrant, thus complicating the differential diagnosis with appendicitis. The pain is generally Bleeding is not recognized as a feature of diverticulitis. constant in nature, not colicky. Radiation may occur to the Bleeding related to diverticulosis is discussed in Chapter 20 back, ipsilateral flank, groin, and even down the leg. The pain (Lower Gastrointestinal Hemorrhage). may be preceded or accompanied by episodes of constipation or diarrhea. It often is progressive in nature if appropriate Perforation treatment is not instituted. Historically, age was used as a primary determinant in dis- Gross perforation can occur at two levels. If an abscess forms tinguishing the most likely etiology of such pain. However, as and then ruptures, purulent peritonitis is the result. If a large increasing numbers of young people are found to have diver- perforation occurs through the diverticulum directly into the ticular disease, the overlap between age groups has broadened peritoneum, fecal peritonitis is the result. Mixed fecal and and the need for diagnostic acumen has significantly sharp- purulent peritonitis may result from the rupture of an abscess ened. Classically, there is no prodromal epigastric pain with which has an ongoing communication with the bowel lumen. diverticulitis as one might expect to see with appendicitis. Clinically, the presentation is that of either abrupt onset of Nausea and vomiting are unusual in the absence of obstruc- abdominal pain for a free perforation or an abrupt exacerba- tion, although secondary ileus with abdominal distention is tion of progressive localized pain in the case of a ruptured common in more severe cases. Bleeding is not a typical abscess. A pneumoperitoneum is typically seen on abdominal associated finding, and, if present, suggests an alternative films or computed tomographic (CT) scan. Rapid progression diagnosis (e.g., cancer). Symptoms of dysuria or urgency to diffuse abdominal pain and rigidity can be expected. 274 A.G. Thorson and S.M. Goldberg

Abscess for management. The successful use of colonic stents to relieve obstruction secondary to diverticulitis has been An abscess most often results from the mechanism described described.53,54 In this setting, the stent is used as a bridge to above. Small abscesses less than 1 cm in diameter will fre- surgery with later elective resection. However, the use of quently resolve with antibiotic therapy. Larger abscesses may stents in benign disease is controversial. Some investigators require drainage. CT-guided percutaneous drainage is the pre- have found a high incidence of complications leading to ferred approach when possible because it can convert the high emergency surgery for removal of the stent and management risks of an urgent operation to a much safer elective operation. of complications when a stent is used in this setting.55

Fistula Ureteral Obstruction The incidence of fistulization reported in the literature ranges The ureter is infrequently involved with diverticular disease. from 5% to 33% depending largely on the type of referral cen- When involved, it is most frequently the left ureter. Rarely 52 ter making the report. Colovesical fistula is the most com- diverticular disease has been reported as fistulizing to the mon fistula associated with diverticular disease and ureter. A stricture may occur but compression is more com- diverticular disease is the most common cause of colovesical mon. This can result from retroperitoneal fibrosis secondary fistula. Other relatively common fistulas associated with to diverticular inflammation. Most often, this resolves with diverticular disease are colocutaneous, colovaginal, and resolution of the underlying inflammatory process although coloenteric. Most patients who develop a colovaginal fistula rarely ureterolysis has been advised.56 have had a previous hysterectomy. Other fistulas have rarely been described and include colocolic, ureterocolic, colouter- ine, colosaphingeal, coloperineal, sigmoido-appendiceal, Phlegmon colovenous, and even fistulas to the thigh (a variant of a colo- A phlegmon represents an inflammatory mass. It may or may cutaneous fistula). not be associated with a central abscess. A phlegmon can sig- The diagnosis of a diverticular fistula is generally clinical. nificantly complicate the technical aspects of resection. Many fistulas will not be directly identifiable by imaging stud- Many phlegmons will resolve with antibiotic therapy. If ies. Thus, excess efforts should not be undertaken to try to resection is planned because of recurrent episodes of disease, radiographically or otherwise demonstrate a fistula. Gas seen it is best to treat the acute phlegmon, to resolution if possi- in the bladder on a CT scan in a patient who has not had their ble, before resection. On occasion, operation becomes neces- urethra or bladder instrumented is the most sensitive/common sary in the face of an acute phlegmon. This situation may be finding with a colovesical fistula. The primary aim of a diag- the source of some descriptions of “malignant” diverticulitis nostic workup is not to see the fistula but to determine the eti- as earlier described. ology [diverticulitis, cancer, inflammatory bowel disease (IBD), etc.] so that appropriate therapy can be initiated. Saint’s Triad Stricture Saint’s triad is a described association of diverticulosis, cholelithiasis, and hiatal hernia. Although it has been sug- The development of a phlegmon with repeated attacks of acute gested that the triad occurs in 3%Ð6% of the general popula- disease or long-term persistent disease may result in a stric- tion,47 it is of unknown clinical significance and likely ture. Although a relatively uncommon complication, patients represents the normal concomitant distribution of these com- will present with constipation, abdominal pain, and bloating. It mon maladies. is necessary to rule out carcinoma as the true cause of the stricture. Colonoscopy is the first choice to help make this distinction; however, it is not uncommon for associated bowel angulation and fixation to prevent endoscopic visualization. Diagnostic Tests Contrast studies may assist the evaluation in such instances but resection may be necessary to make a diagnosis. Endoscopy Endoscopy in the face of acute diverticulitis must be under- Obstruction taken with extreme caution because of risk of gross perforation and decreased chance of success for complete colonic On rare occasions, complete obstruction may occur. If caused evaluation. It can provide important information before oper- by diverticular disease, most patients will respond to initial ation but will change acute management in less than 1% of medical management allowing an elective resection at a later cases.57 Generally, in the absence of an urgent indication, date. Persistence of an obstruction may require a Hartmann’s colonoscopy should be delayed until resolution of the acute procedure or primary anastomosis with proximal diversion episode is complete. 18. Benign Colon: Diverticular Disease 275

In the case of elective colonoscopy, the unexpected finding morbidity and mortality to the safety of an elective opera- of acute diverticulitis (manifested as erythema, edema, pus, or tion.59 In some selected cases, there may be no need for elec- granulation tissue at a diverticula opening) is distinctly tive resection. unusual, occurring in just 0.8% of patients. Treatment with antibiotic therapy for such findings is generally unnecessary Ultrasonography because follow-up has shown that symptoms of diverticulitis do not develop after the colonoscopy.58 Transrectal ultrasound (TRUS) has been used in the evaluation of diverticular disease in conjunction with transabdomi- Abdominal X-rays nal ultrasound (TAUS). Combining TRUS with TAUS reveals complications not visualized on TAUS alone including When used, plain films of the abdomen should be done supine inflamed diverticula. TRUS may be an accurate adjunct for and upright/left lateral decubitus because the primary value is confirming clinically suspected acute colonic diverticulitis to rule out pneumoperitoneum or to assess for a possible when the rectosigmoid or perirectal tissues are affected as one obstruction. However, either of these two complications can might see in the case of malignant diverticulitis. It helps avoid also be assessed with CT scan, so in many centers, the plain false-negative results and defines the severity of disease in the abdominal film is rarely used. lower sigmoid colon better than TAUS alone. TRUS may prove to be a useful adjunct in selected cases of rectosigmoid Contrast Studies diverticulitis and perirectal involvement by diverticular disease in centers where CT scanning is not readily available.60 Barium or water-soluble contrast studies have proponents for their use but CT scan offers an examination of much broader Magnetic Resonance Imaging scope in one evaluation making it the preferred imaging study in many centers. However, because of costs, some clinicians Preliminary studies using magnetic resonance imaging will use CT scan only if there is clinical suspicion of an colonography have shown a high correlation with CT findings abscess or other complicating feature for which an alternative in patients with diverticular disease without exposure to ion- to standard bowel rest and antibiotics might be applied. A izing radiation. Three-dimensional rendered models and vir- water-soluble contrast study can evaluate the lumen of the tual colonoscopy can be performed only in the nonacute bowel if there is concern about distal bowel obstruction. It setting. These comprehensive three-dimensional models, may be an important part of the assessment for the possible rather than BE, may have a role in presurgical planning with use of a stent if malignant disease is suspected. concurrent assessment of the residual colon.61 Contrast studies have been shown to identify fistulas, most often colovaginal or coloenteric. Some clinicians prefer the anatomic view of the entire colon provided by BE because it Differential Diagnosis distinguishes the extent of diverticulosis throughout the colon and can assess for stricture and colonic length. In most cen- The differential diagnosis for diverticular disease includes ters, contrast studies, if used at all, are used in a limited man- IBS, carcinoma, IBD, appendicitis, bowel obstruction, ner to evaluate the anatomy of the colon before an operation. ischemic colitis, gynecologic disease, and urologic disease. Of these, IBS is perhaps the most difficult to differentiate in CT Scan many patients. An important advantage to a CT scan is the ability to document Irritable Bowel Syndrome diverticulitis, even if uncomplicated, when the diagnosis is in doubt. Studies using CT scan as the initial diagnostic test have In many ways, the distinction between chronic diverticulitis shown that up to 5% of patients admitted for acute diverticuli- and noninflammatory diverticular disease relies on the pathol- tis have been hospitalized for the incorrect clinical diagnosis.59 ogist whereas the distinction between noninflammatory diver- It has been demonstrated that CT can recognize and strat- ticular disease and IBS relies on the diagnostic acumen of the ify patients according to the severity of their disease. It can clinician and the long-term outcomes of resection. Because of distinguish uncomplicated disease with predictably short the prevalence of diverticular disease, many patients with IBS length of stay from complicated disease as defined by will have concomitant diverticular disease. However, because abscess, fistula, peritonitis, or obstruction and a predictably diverticular disease is usually asymptomatic, the presence of long length of stay. It also provides information about extra- diverticulosis in these patients will often not be the source of colonic pathology and anatomic variation useful for surgical their symptoms but rather just a source of confusion in the dif- planning. Early CT-guided drainage of abscesses allows down- ferential. It is helpful to be familiar with the Rome II criteria staging of complicated diverticulitis to convert an otherwise (Table 18-2) for the diagnosis of IBS in order to sort through urgent or emergent operation with attendant increases in this differential. 276 A.G. Thorson and S.M. Goldberg

TABLE 18-2. The Rome II criteria for IBS similar complications including fistulas, phlegmons, and IBS can be diagnosed based on at least 12 weeks (which need not be consec- abscesses. Rectal involvement, anal disease, extracolonic utive) in the preceding 12 months, of abdominal discomfort or pain that signs, and bleeding suggest Crohn’s. Recurrent “diverticuli- has two of three of these features: tis” requiring a repeat resection should always raise the ques- 1. Relieved with defecation; and/or tion of possible Crohn’s disease.66 Ulcerative colitis is rarely 2. Onset associated with a change in frequency of stool; and/or 3. Onset associated with a change in form (appearance) of stool. a significant differential problem because bleeding is not a Symptoms that cumulatively support the diagnosis of IBS: prominent symptom of diverticulitis and a simple endoscopic 1. Abnormal stool frequency (>3 stools per day or <3 stools per week) examination showing inflammation within the rectum should 2. Abnormal stool form (lumpy/hard or loose/watery stool) suffice to rule out diverticular disease. In the unusual circum- 3. Abnormal stool passage (straining, urgency, or feeling of incomplete stance in which diverticulitis and ulcerative colitis both exist, evacuation); treatment should be targeted to both entities simultaneously. 4. Passage of mucus 5. Bloating or feeling of abdominal distension Red Flag symptoms that are not typical of IBS: Other Colitides, Appendicitis, Gynecologic 1. Pain that often awakens/interferes with sleep and Urologic Disease 2. Diarrhea that often awakens/interferes with sleep 3. Blood in stool (visible or occult) Endoscopy can be an important adjunct in differentiating 4. Weight loss IBD, ischemic colitis, and other forms of colitis although cau- 5. Fever tion must be used in the acute setting. A major advantage of 6. Abnormal physical examination the CT scan is the ability to evaluate for many of the other potential differentials including appendicitis, gynecologic and urologic disease. Colon Neoplasia Distinguishing diverticular disease from cancer can be diffi- Associated Conditions cult. Imaging techniques can provide significant diagnostic assistance, but occasionally a resection is necessary to be cer- There is such a high incidence of diverticulosis among tain. Several features of BE studies support a diagnosis of patients with autosomal dominant polycystic kidney disease diverticular disease including preservation of the mucosa, that some consider it an extrarenal manifestation.67 These long strictures, and the presence of diverticula. A BE is pre- patients undergoing renal transplantation are at particularly ferred by some clinicians to assess the extent of the divertic- high risk for devastating infectious complications because of ulosis and evaluate the length of the colon before resection. their immunocompromised state. Many transplant centers Although colonoscopy can frequently resolve this issue, it is recommend prophylactic sigmoid resection in those polycys- not always successful because of acute angulations or nar- tic kidney patients scheduled for transplantation with a docu- rowing of the lumen. CT evaluates the entire abdomen, can mented history of diverticulitis.67Ð70 identify concurrent disease, and may give clues as to the underlying colonic pathology. The increasing incidence of colonic neoplasia with increas- Uncommon Presentations ing age parallels that of diverticular disease. Polyps and cancer must be considered whenever a diagnostic workup for Diverticulitis in Young Patients diverticular disease is begun. Although unusual, cases of adenocarcinoma arising within a diverticulum have been Young patients with diverticular disease are usually male,45,71 reported.62 Because colonic diverticula are thin walled, con- obese,72,73 and have a higher incidence of right-sided diverti- taining only mucosa and serosa, early penetration by cancer is culitis.74,75 Young patients undergoing operation are fre- likely, leading to advanced stages with small primary lesions. quently misdiagnosed preoperatively72,73,76 with appendicitis Although historically diverticular disease is not believed to being the most common misdiagnosis.76 Historically, divertic- have an etiologic link to colon cancer, a causal association has ular disease in patients younger than 50 years of age has been been identified between left-sided colon cancer and divertic- described as more virulent and with more serious complica- ulitis. In a review of 7159 patients from the Swedish Cancer tions.45,72,77Ð79 Many recommend that patients younger than Registry, patients with diverticulitis had a long-term increased age 50 have an elective resection after a single episode of risk of left-sided colon cancer compared with patients with acute disease. Recent evidence is mixed. asymptomatic diverticulosis (odds ration = 4.2).63Ð65 In some series, young people present with more severe disease at first presentation74,77Ð79 but less frequently have a resection at that time. Reasons for this include missed diag- Inflammatory Bowel Disease noses and rapid response to therapy. With fewer resections for Crohn’s disease can be a particularly difficult differential to more complex disease, a higher percentage of young patients make. Both Crohn’s and diverticular disease may present with return with delayed complications and the appearance of 18. Benign Colon: Diverticular Disease 277 more aggressive disease. Elective resection after the first Rectal Diverticula episode of diverticulitis is thus advised.77Ð79 Others have recommended elective resections at a younger Rectal diverticula are rare. They are typically true diverticula age to avoid the increased morbidity and mortality associated because they include the muscular layer of the rectum in their with urgent or emergent surgery in the elderly (0% versus wall, and are frequently solitary. Inflammation can generally 34.9%).80 Some recommendations for elective resection in the be managed with antibiotics. young patient are based on cost savings related to definitive surgical management versus the higher costs of ongoing med- Cecal and Right-sided Diverticulitis ical treatment for recurring disease.81 These types of recommendations assume a high risk of recurrent disease. Right-sided diverticular disease is much more common in the There is evidence that diverticular disease in young patients Far East than in the West, representing 35%Ð84% of divertic- is changing. It is not as rare as it used to be72,82,83 and contin- ula in that region. Patients present an average of 20 years ues to become more common.83 Recent evidence suggests younger than with sigmoid diverticulitis. Classically, cecal there is not increased risk of complications from diverticular diverticula are described as true diverticula containing all lay- disease in the young.73,75,76,82Ð86 Based on these findings, ers of the bowel wall. However, most cecal diverticula actu- resection after a single episode of diverticulitis is not recom- ally are false and frequently not solitary. mended. It is estimated that 13% of patients with cecal diverticulo- Data are difficult to interpret because the presentations of sis develop diverticular inflammation. Cecal diverticulitis can diverticular disease are so varied and most studies are small be graded according to the extent of the inflammation. Grade and retrospective with risks of unrecognized selection bias. I disease refers to an easily recognizable projecting inflamed However, it does seem that diverticular disease is more com- cecal diverticulum. Grade II is an inflamed cecal mass. Grade mon in young patients than generally recognized. Obesity III encompasses a localized abscess or fistula. Grade IV is a may be a risk factor, probably related to diet. Diets high in free perforation or ruptured abscess with diffuse peritonitis. fiber are less likely to result in obesity as well as diverticular Cecal diverticulitis is correctly diagnosed preoperatively only disease. 5% of the time. Appendicitis is the preoperative diagnosis in 88 The issue of male predominance could be a result of missed more than two-thirds of cases. Intraoperative diagnosis is diagnoses in females. Young females frequently have a gyne- relatively easy with Grade I and to a lesser extent with Grade cologic focus of attention placed on causes of abdominal pain II disease. Most episodes of cecal diverticulitis presenting other than diverticular disease and accentuated by the general with Grade III or Grade IV disease are misdiagnosed intraop- poor recognition of the prevalence of diverticular disease in eratively as perforated carcinoma. younger patients. If a correct diagnosis of uncomplicated cecal diverticulitis Current recommendations for resection are based on the can be made preoperatively, then antibiotics and treatment predicted risk of developing a serious complication that similar to left-sided disease is appropriate. This is rare, how- would lead to emergency surgery with increased morbidity ever. When discovered intraoperatively, the options for treat- and mortality and frequent use of colostomy in this setting. ment include: 1) appendectomy, nonresection of the To improve management, we must become better at predict- diverticulum and postoperative antibiotic therapy; or 2) appen- ing who is at risk for recurrent disease. Age alone does not dectomy with diverticulectomy for Grade I and identifiable seem to be a reliable factor. The use of CT to identify Grade II disease. For not readily identifiable Grade II, Grade “severe” or “complex” diverticular disease seems most III, and Grade IV disease, failed treatment, or when cancer is promising. a consideration, right hemicolectomy is the procedure of The risk of complications within 5 years of a first attack of choice. Appendectomy should always accompany nonresec- diverticulitis exceeds 50% if CT shows severe diverticulitis at tion or diverticulectomy whenever the base of the appendix is 89,90 the initial episode.86 Mild findings on CT can be defined as not inflamed. This is to avoid confusion at a later date. localized thickening of colonic wall and inflammation of pericolic fat. Severe findings are defined as abscess and/or extra- Giant Colonic Diverticulum luminal air and/or extraluminal contrast. In a recent study, the incidence of remote complications was the highest (54% at 5 Giant diverticula of the colon are rare entities associated with years) for young patients with severe diverticulitis on CT and sigmoid diverticular disease. They are generally pseudo- the lowest (19% at 5 years) for older patients with mild dis- diverticula with inflammatory rather than colonic mucosal ease. Young age and severe diverticulitis taken separately walls. They usually arise off of the antimesenteric border of were both statistically significant factors of poor outcome (P the sigmoid colon. The mechanism of formation is unknown = .007 and .003, respectively), although age was no longer but they have been reported as large as 30Ð40 cm.91,92 Twelve significant after stratification for disease severity on CT (P = percent occur in patients younger than age 50. .07).86 Other studies have shown similar risks associated with Diagnosis is by plain film of the abdomen which shows a complex disease on CT.85,87 large, solitary, gas-filled cavity. Communication with the 278 A.G. Thorson and S.M. Goldberg colon can be demonstrated with contrast enema. The differential is usually restricted to low residue or clear liquids during the includes congenital duplication of the colon, cholecystenteric acute illness but with resolution of the acute symptoms, a high fistula, colonic volvulus, emphysematous cholecystitis, fiber diet should be instituted. There is no need to restrict the infected pancreatic pseudocyst, pneumatosis cystoides intesti- ingestion of seeds or hulls because there are no data to sub- nalis, Meckel’s diverticulum, intraabdominal abscess, giant stantiate this practice. duodenal diverticulum, dilated intestinal loop, gastric dilata- Appropriate antibiotics should be instituted to include cov- tion, tuboovarian abscess, and mesenteric cyst.93 erage of Gram-negative and anaerobic bacteria. The most pre- Most patients will present with vague symptoms of abdom- dominant organisms cultured from acute diverticular abscess inal discomfort or pain and a soft, mobile abdominal mass. A and peritonitis include the aerobic and facultative bacteria few patients will present with one of the known complications Escherichia coli and Streptococcus spp. The most frequently which include perforation, sepsis, intestinal obstruction, or isolated anaerobes include Bacteroides spp. (B. fragilis group), volvulus. The natural history is slow enlargement over Peptostreptococcus, Clostridium, and Fusobacterium spp.98 time. The treatment of choice is resection of the diverticulum The use of anticholinergics as adjunctive therapy is based and adjacent colon at time of diagnosis if the patient is on theoretically reducing pain related to spasm and hyper- symptomatic. motility in the sigmoid colon. Efficacy has not been proven. Signs of more advanced disease including marked leukocy- Diverticular Disease of the Transverse Colon tosis, high fever, tachycardia, or hypotension as well as a physical examination demonstrating more advanced intraab- This is an exceedingly rare condition. Clinical presentation dominal pathology, dictate a need for inpatient management. most often mimics appendicitis, cholecystitis, or, less fre- Patients admitted for inpatient care will usually undergo a quently, ischemic or Crohn’s colitis. It is reported to occur in baseline CT scan which can confirm the diagnosis, rule out a younger age group than sigmoid disease and is more com- potential alternative diagnoses, and evaluate for complicated mon in females. Treatment parallels that of sigmoid divertic- disease that would require a change in initial management.59 ulitis; however, resection is usually performed because a Antibiotics should be administered via an intravenous preoperative diagnosis is more difficult and a carcinoma fre- route. Generally the patient will be placed NPO (nothing by quently cannot be ruled out. mouth) until there is evidence that clinical progress is being made and surgery will not be necessary. The diet is then grad- ually advanced from clear liquids and then to low residue for Treatment a variable period of time before reinstituting a high fiber diet. Symptoms should improve within 24Ð72 hours. Failure to Medical and Dietary Management improve should prompt further diagnostic workup including repeat CT scan and reevaluation of the need for alternative The primary management of asymptomatic diverticular dis- interventions such as operation or abscess drainage. ease is diet. The goal of dietary manipulation is to increase the Worsening of the patient’s clinical condition, particularly pro- bulkiness of stool thus increasing lumen size, decreasing tran- gression to generalized peritonitis, should prompt urgent sit time, and decreasing intraluminal pressures. This operative management. decreases segmentation which has been described as a significant factor in the development of diverticular disease. The Surgical Management ideal amount of fiber is not known; however, the recommended daily amount is 20Ð30 g. In general, fiber can be The surgical management of diverticular disease is replete obtained by consuming foods high in fiber or through supple- with varied options that allow for customizing an operation to mentation with one or more of a large variety of bulk laxa- meet the needs of the individual patient. A thorough knowl- tives. Epidemiologic evidence strongly suggests a diet high in edge of these options and the indications for each are neces- fiber can reduce the risk of developing diverticulosis. What is sary for the surgeon managing these cases. The goal should less clear is whether a high fiber diet can prevent diverticuli- always be to manage a complex patient in a way that will tis and its complications in patients who already have diver- maximize the opportunity to avoid emergency surgery in ticulosis. Recent evidence is building in support of this favor of an elective resection. concept.94Ð97 Surgical options include primary resection with anastomosis with or without proximal diversion, resection with proximal colostomy, and oversewing of the rectal remnant Acute Diverticulitis (Hartmann’s procedure) or mucous fistula (Mikulicz opera- In the absence of systemic signs and symptoms (high fever, tion), simple diversion with drainage of the affected segment, marked leukocytosis, tachycardia, and hypotension), most diversion with oversewing of the perforation site, and, rarely, patients experiencing symptoms of diverticulitis will respond subtotal colectomy. Adjunctive measures include on-table to a regimen of bowel rest and antibiotics as outpatients. Diet lavage and the option of a laparoscopic approach. 18. Benign Colon: Diverticular Disease 279

The historical discussion of these options would include the use of a three-stage approach with diversion and drainage followed by a second operation for resection and a third operation for reestablishment of intestinal continuity. A modification of this approach includes oversewing of a visible site of perforation with an omental patch as a part of the initial operation.99 Alternatives include a two-stage approach consisting of a Hartmann’s or Mikulicz procedure followed by a second operation for reestablishment of intestinal continuity and resection with primary anastomosis, with or without proximal diversion, as a single operation. For the most part, today’s discussions revolve around the relative merits of a one-stage versus a two- stage approach in acute cases requiring urgent or emergent surgery.100Ð102 The three-stage approach is unlikely to be used except in the most extreme cases of medical instability.103,104 The following sections will discuss the applications of these approaches to the various presentations of diverticular disease including both chronic and acute forms. Special consideration will be given to the management of intraabdominal abscess.

Intraabdominal Abscess For a patient found to have an abscess, there is much clinical evidence supporting the advantages of percutaneous drainage and the conversion of an emergent operation with its attendant increased morbidity and mortality to the relative safety of elective operation.59,105 An abscess not responding to medical management should be drained percutaneously or transrec- tally as appropriate to its location (Figure 18-2). If drainage cannot be accomplished nonoperatively or if drainage is performed but fails to resolve systemic signs and symptoms, operation is indicated. Generally, the clinical sce- nario in this situation would be that of an advanced Hinchey class II. Although it is possible that intraoperative findings would support a resection with primary anastomosis with or without proximal diversion, it is more likely that a Hartmann’s resection will be required.

Indications for Surgery for Acute Disease The indications for surgery of acute disease include: 1) failure to respond to nonoperative management including a persistent phlegmon, failure of percutaneous or transrectal drainage of an abscess or increasing fever, leukocytosis, tachycardia, hypotension, signs of sepsis, or a worsening physical examination; 2) free perforation with peritonitis; and 3) obstruction that does not resolve with conservative therapy. Perforation without peritonitis may not require operation (Figure 18-3). FIGURE 18-2. A A centrally located pelvic diverticular abscess. B The same abscess after CT-guided percutaneous drainage. Surgical Procedures For acute disease, the choice of operation is highly dependent become necessary suggests rather advanced pathology and on the degree of inflammatory response encountered at the the need to be conservative. In general, most Hinchey class I time of operation. Because most acute disease can be and some class II disease can be managed with a one-stage managed nonoperatively (including the percutaneous procedure (resection and anastomosis) if the patient is stable, drainage of most abscesses), the fact that an operation has the extent of contamination is limited, and adequate bowel 280 A.G. Thorson and S.M. Goldberg

include anastomotic leak and hemorrhage. The prevalence of leak from a low intraperitoneal anastomosis is generally considered to be between 2% and 5%.113 Such leaks can lead to localized or systemic sepsis without an abscess, an abscess with or without sepsis, peritonitis, and stricture. The diagnosis is dependent on a high index of suspicion on the part of the surgeon and quick response to any unusual signs of sepsis. Fever, vague abdominal pain, diarrhea, obstructive symptoms, oliguria, prolonged postoperative ileus, and sepsis all should raise the concern of a leak. The diagnosis is usually confirmed by water-soluble contrast enema and/or CT scan with intravenous, oral, and rectal contrast. A contained leak without an abscess can usually be managed with intravenous antibiotics and response assessed. Free extravasation of contrast failure to respond to treatment within 24Ð48 hours or initial severe sepsis or peritonitis requires exploration with resection of the anastomosis and proximal diversion. Repair of the anastomosis with proximal diversion is usually unsatisfactory because of the high risk for recurrent leak in this inflammatory setting. An exception would be a “pin-hole” leak with limited inflammatory response which may be managed with repair, colonic lavage, and proximal diversion. A leak that results in an abscess can generally be managed

FIGURE 18-3. This CT scan shows a small pneumoperitoneum ante- with percutaneous or transrectal drainage. Again, failure to riorly. There was not physical evidence of peritonitis. This patient respond will require laparotomy, take down of the anastomo- was managed nonoperatively with intravenous antibiotics. sis, and proximal diversion. A colocutaneous fistula related to a diverticular resection will usually respond to nonoperative measures. Provided that there is no distal obstruction or foreign body and that Crohn’s preparation is possible,100,106 recognizing, however, that the was not the cause of the original symptoms, spontaneous clo- necessity of mechanical bowel preparation in elective colon sure should be anticipated. Important steps to take to facilitate resections has been recently questioned.107 Proximal diver- this closure include drainage of any undrained abscess, atten- sion may be appropriate. Most cases of Hinchey class III and tion to nutritional needs, and appropriate wound care. IV disease will require a two-stage approach. Some recent Stricture is an unusual complication related to diverticular evidence suggests a possible role for resection with primary resections unless the underlying process is Crohn’s disease. In anastomosis and proximal diversion in highly selected cases the rare instance when stricture does occur, the likely etiolo- without gross fecal contamination.100,103 gies include ischemia or localized sepsis caused by confined A major disadvantage of a two-stage procedure is that leak. Such strictures can usually be managed by dilatation 35%Ð45% of patients never have their colostomy closed. with a hydrostatic balloon or rigid proctoscopy but occasion- Women are more likely than men to not have closure.108,109 ally will require a formal restapling or resection. However, in patients with preexisting incontinence, a Ureteral injuries are reported to occur in 1%Ð10% of Hartman’s pouch should be the procedure of choice. For abdominal surgeries.114 Early identification of any injury is patients who do not undergo closure of their stoma, it is crit- the key to preventing significant morbidity. Although ureteral ical that their rectal stump undergo scheduled surveillance for stents have not been shown to decrease the rate of injury, they neoplasia as the remaining rectum has the same risk for neo- do improve intraoperative identification of the ureters and the plasia as the remainder of the colon.110 early identification of any ureteral injury.115 The decision to place ureteral stents before operation should be a function of clinical suspicion and the extent of retroperitoneal inflamma- Complications tion on CT scan. Predictors of complications from resection for diverticular General postoperative complications related to colon and disease include advanced age (older than 70Ð75 years), two or rectal surgery and specifics related to the recognition and more comorbid conditions, obstipation at initial examination, management of the specific complications mentioned above the use of steroids, sepsis, obesity,103,111,112 and emergent are discussed more thoroughly in Chapter 10, Postoperative rather than elective resection. Complications of resection Complications. 18. Benign Colon: Diverticular Disease 281

Indications for Surgery for Recurring and Surgical Procedures Chronic Disease Patients undergoing resection for chronic disease will almost always be candidates for single-stage resection with primary Patients with multiple, recurrent episodes of acute diverticuli- anastomosis. Additionally, patients returning for closure of a tis documented by CT scan should be considered for resec- colostomy after initial diversion and drainage, diversion with tion. The practice parameters of the American Society of oversew of perforation, or diversion with resection via either Colon and Rectal Surgeons states that elective resection Hartmann’s or a Mikulicz procedure, can all typically be man- should be considered after one or two well-documented aged with one additional operation only. attacks of diverticulitis depending on the severity of the attack and age and medical fitness of the patient. Patients with com- Complications plicated diverticulitis should be considered for resection after one attack.116 The ultimate goal is to perform an operation The complications related to operation for chronic disease in electively rather than as an emergency. This requires correctly many ways parallel those already discussed for acute disease. predicting those patients that are most likely to end up with a In addition, a noted complication of operating on chronic dis- serious complication as a result of their disease. One sugges- ease is failure to achieve symptomatic relief. This usually tion has been to resect after one episode of diverticulitis in results from a missed diagnosis of Crohn’s disease or IBS. young patients (generally younger than 40Ð50 years). Any “recurrence” of symptoms after resection for chronic It is now doubtful that age itself should be a primary con- diverticulitis should raise the suspicion of this possibility. The sideration in the decision to operate. The literature is mixed presence of functional bowel symptoms preoperatively in this with proponents of a more aggressive approach to the disease group of patients has been associated with poorer functional in young patients45,72,74,77Ð79,81 and those that believe age alone results postoperatively.121 does not significantly increase risk.71,73,75,76,80,82Ð84 Other factors apply, most of which are not age related. Management of Fistula CT evidence of complicated or “severe” disease has been The general principle of management is resection of the one of those criteria that have shown some promise in predict- colon, usually with primary anastomosis. Treatment of ing risk. Abscess, extraluminal air, and extraluminal contrast the other involved organ/site varies. For the bladder, simple have been associated with an increased risk of poor outcome drainage of the bladder with an indwelling urethral catheter from medical management regardless of age.85,87 for 5Ð7 days is advised. No treatment of the vagina is required Another approach is to identify specific groups of patients in most circumstances. Cutaneous fistulas will usually close (other than age) who are at increased risk. Immuno- by delay or secondary intention. Enteric fistulas require repair compromised patients are one group that is at particular risk or resection of the involved small bowel or colon. Ureteral for poor outcome.33 The risk is attributable to a higher inci- drainage for fistulas to the ureter, observation or hysterectomy dence of free perforation and more severe inflammatory com- for uterine fistulas, salpingo-oophorectomy for fistulas to the plications when perforation does occur. Patients with tubes, and appendectomy would be the most common treat- autosomal dominant polycystic kidney disease undergoing ments for uncomplicated fistulas of the other less common renal transplant are a very high risk group.67Ð70 Prophylactic varieties. If there is any question of cancer, an en bloc resec- resection in such patients with a history of any diverticulitis is tion of a portion of the involved organ must accompany the recommended. resection. Recent data have suggested that the recommendation for Occasionally nonoperative management is appropriate resection after two episodes of diverticulitis treated as an when symptoms are minor or when the patient is at otherwise inpatient may result in too many patients undergoing resec- too great a risk for other health reasons. The use of long-term tion thereby increasing the total cost of health care. suppressive antibiotic therapy in selected patients with Performing resection after the third episode of diverticulitis colovesical fistula has been shown to eliminate symptoms and results in significant cost savings.117 Performing resection prevent complications related to the fistula until death from after four documented episodes rather than after two results in other causes.122 fewer deaths, fewer colostomies, and additional cost savings of more than $5000 per patient in those younger than 50.118 Techniques for Appropriate Resection Others question the role of elective resection at all because of the high success rate of nonoperative management and the The practice parameters of the American Society of Colon large percentage of patients presenting with urgent surgical and Rectal Surgeons set out several general recommendations disease that have no previous history of diverticulitis.119,120 regarding resection of diverticular disease. For elective resec- This mirrors the experience of one of the authors (S.M.G.) in tions, all thickened, diseased colon, but not necessarily the which it has not been found necessary to resect all patients entire proximal diverticula-bearing colon, should be removed. with complicated disease, even after percutaneous drainage of It may be acceptable to retain proximal diverticular colon as diverticular abscesses. long as the remaining bowel is not hypertrophied. All of the 282 A.G. Thorson and S.M. Goldberg sigmoid colon should be removed. When anastomosis is culitis should be made on a case-by-case basis. Elective colon elected, it should be made to normal rectum and must be free resection should typically be advised if an episode of compli- of tension and well vascularized.123 The single most important cated diverticulitis is treated nonoperatively. The resection predictor of recurrence after sigmoid resection for uncompli- should be carried proximally to compliant bowel and extend cated diverticulitis is an anastomosis to the distal sigmoid distally to the upper rectum. When a colectomy for diverticu- colon rather than the rectum.124 lar disease is performed, a laparoscopic approach is appropriate in selected patients. Laparoscopic Surgery Reprinted from Dis Colon Rectum 2006; 49: 939Ð944. Copyright © 2006. All rights reserved. American Society of The role of laparoscopy in the management of diverticular Colon and Rectal Surgeons. disease is evolving. Recent data suggest decreased overall costs associated with laparoscopic resections when compared with open resections.125,126 Patients who are converted from References laparoscopic to open procedures are a concern with regard to 1. Almy TP, Howell DA. Diverticula of the colon. N Engl J Med added costs but conversion rates are less than 20% in experi- 1980;302:324Ð331. 125Ð131 128,131 enced centers, and are somewhat predictable and 2. Rankin FW, Brown PW. Diverticulitis of the colon. Surg 128 thus probably avoidable in many instances. Higher conver- Gynecol Obstet 1930;50:836Ð847. sion rates are associated with more complex disease.132 3. Heller SN, Hackler LR. Changes in the crude fiber content of Recurrence rates match those for open procedures,129,131,132 the American diet. Am J Clin Nutr 1978;31:1510Ð1514. and length of stay is shorter125,126 and complications fewer.126 4. Parks TG. Natural history of diverticular disease of the colon. As data continue to accumulate, it seems that laparoscopic Clin Gastroenterol 1975;4:53Ð69. surgery will have a significant role in the management of 5. Colcock BF. Diverticular Disease of the Colon. Philadelphia: diverticular disease. WB Saunders; 1971. 6. Schoetz DJ Jr. Diverticular disease of the colon: a century-old problem. Dis Colon Rectum 1999;42:703Ð709. Appendix: Practice Parameters 7. Corman ML. Colon and Rectal Surgery. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2005. for the Treatment of Sigmoid 8. Somasekar K, Foster ME, Haray PN. The natural history diver- Diverticulitis ticular disease: is there a role for elective colectomy? J R Coll Surg Edinb 2002;47:481Ð484. 9. Roberts PL, Veidenheimer MC. Current management of diver- Prepared by The Standards Task Force, The American ticulitis. Adv Surg 1994;27:189Ð208. Society of Colon and Rectal Surgeons. 10. Morris CR, Harvey IM, Stebbings WS, et al. Epidemiology of The initial evaluation of a new patient with suspected acute perforated colonic diverticular disease. Postgrad Med J 2002; diverticulitis should include a problem-specific history and 78:654Ð658. physical examination; a complete blood count, urinalysis, and 11. Painter NS, Truelove SC, Ardran GM, et al. Segmentation and plain abdominal radiographs may be useful in selected clini- the localization of intraluminal pressures in the human colon, cal scenarios. Computerized tomography scan of the with special reference to the pathogenesis of colonic divertic- abdomen and pelvis is usually the most appropriate imaging ula. Gastroenterology 1965;49:169Ð177. modality in the assessment of suspected diverticulitis. 12. Mann CV. Problems in diverticular disease. Proctology Contrast enema x-ray, cystography, ultrasound, and 1979;1:20Ð25. endoscopy are sometimes useful in the initial evaluation of a 13. Ryan P. Two kinds of diverticular disease. Ann R Coll Surg Engl 1991;73:73Ð79. patient with suspected acute diverticulitis. 14. Floch MH, Bina I. The natural history of diverticulitis: fact and Nonoperative treatment typically includes dietary modifi- theory. J Clin Gastroenterol 2004;38(suppl):S2ÐS7. cation and oral or intravenous antibiotics. Radiologically 15. Hinchey EJ, Schaal PG, Richards GK. Treatment of perforated guided percutaneous drainage is usually the most appropriate diverticular disease of the colon. Adv Surg 1978;12:85Ð109. treatment for patients with a large diverticular abscess. 16. Colecchia A, Sandri L, Capodicasa S, et al. Diverticular dis- After resolution of an initial episode of acute diverticulitis, ease of the colon: new perspectives in symptom development the colon should be adequately evaluated to confirm the diag- and treatment. World J Gastroenterol 2003;9:1385Ð1389. nosis. Colonoscopy or contrast enema x-ray (probably with 17. Huizinga JD, Waterfall WE, Stern HS. Abnormal response to flexible sigmoidoscopy) is appropriate to exclude other diag- cholinergic stimulation in the circular muscle layer of the noses, primarily cancer, ischemia, and inflammatory bowel disease. The practice parameters set forth in this document have been devel- Urgent sigmoid colectomy is required for patients with dif- oped from sources believed to be reliable. The American Society of Colon and Rectal Surgeons makes no warranty, guarantee, or repre- fuse peritonitis or for those who fail nonoperative manage- sentation whatsoever as to the absolute validity or sufficiency of any ment of acute diverticulitis. The decision to recommend parameter included in this document, and the Society assumes no elective sigmoid colectomy after recovery from acute diverti- responsibility for the use or misuse of the material contained herein. 18. Benign Colon: Diverticular Disease 283

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