Sean T. Martin
Jon D. Vogel
Presentation
A 65-year-old man presents to the emergency room with a 3-day history of severe, constant, worsening left lower-quadrant pain, with associated diarrhea, anorexia, and a fever of 102°F. His medical history is significantly for hypertension, mild angina pectoris, and hypothyroidism. Medications include hydralazine, aspirin, and levothyroxine. He lives alone but is independent and active.
He is febrile and tachycardic, at 110 beats per minute, with hypotension of 95/55 mm Hg. On clinical examination, he has generalized abdominal tenderness with signs of localized peritonitis in the left lower quadrant. His mucus membranes are dry and he is diaphoretic. He has no prior history of diverticulitis and has never had a colonoscopy.
Differential Diagnosis
This 65-year-old man presents with acute-onset left lower-quadrant abdominal pain. In this age group, the most likely diagnosis is acute diverticulitis, with an associated abscess or perforation. Important differential diagnoses, particularly in older patients with cardiovascular comorbidity, are intestinal ischemia and aortoiliac aneurysmal disease. Other diagnoses that should also be considered are perforated colon cancer, colonic volvulus, stercoral perforation of the colon, and acute manifestations of inflammatory bowel disease.
Diverticular disease, in the form of diverticulosis, is very common, affecting approximately 60% of 50-year-olds. However, only 10% to 20% of people with diverticular disease will develop diverticulitis, and of these, only 10% to 20% requires hospitalization. Of those hospitalized, 20% to 40% of patients will require operative intervention for “complicated diverticulitis,” defined as perforation of the colon with resultant abscess, pneumoperitoneum, or peritonitis; colonic obstruction; or fistulization of the diseased portion of the colon.
Workup
This gentleman presents with evidence of sepsis and possible early septic shock. The initial goal, after taking an accurate history and performing a focused clinical examination, is resuscitation. Adequate intravenous access is obtained and aggressive fluid resuscitation is pursued. A bladder catheter is inserted to monitor urinary output. Supplemental oxygen may be required and intravenous opioid analgesia is administered as necessary. Given the clinical picture and suspicion of intra-abdominal infection, intravenous broad-spectrum antibiotics are given to the patient. Once resuscitation is underway, the next step is to proceed with investigations that will aid diagnosis and guide treatment.
Laboratory investigations in this patient reveal a leukocytosis of 24 × 103/mm3, BUN of 30 mg/dL, and creatinine of 1.2 mg/dL. Amylase and lipase were within normal range. In patients with an acute abdominal presentation, plain film radiographs of abdomen and chest are of value in determining the presence of free intraperitoneal gas or concomitant pathology such as small bowel obstruction. Barring clear evidence of free air on abdominal radiograph, the diagnostic investigation of choice is a triple contrast (intravenous, oral, and rectal contrast) computed tomography (CT) of the abdomen and pelvis. Caution must be exercised when administering intravenous contrast to patients with renal compromise. The advantage of CT is that in addition to imaging all abdominal and pelvic organs, it can also facilitate therapeutic intervention; CT-guided drainage of a diverticular abscess allows control of sepsis, converting a potentially emergent scenario to an elective one.
In this case, plain abdominal radiograph showed no evidence of free air, and the abdominopelvic CT reveals sigmoid diverticulosis and an inflammatory phlegmon and associated mesenteric fat stranding in the region of the sigmoid colon, with extravasation of the rectally administered contrast, and free intraperitoneal gas (Figure 1). These findings are consistent with a diagnosis of perforated diverticular disease of the sigmoid colon.
FIGURE 1 • Abdominal CT image (axial) demonstrating perforated sigmoid diverticulitis. Note the extravasation of rectal contrast into the peridiverticular cavity. Also free gas is visible in the abdominal cavity (arrow), indicating a perforation.
Discussion
A diverticulum is a sac-like protrusion in the colonic wall that develops as a result of herniation of the mucosa and submucosa through points of weakness in the muscular bowel wall. Colonic diverticulae may be acquired or congenital. Acquired diverticulae are commonly seen in the sigmoid colon, and are considered “false diverticulae” as they are mucosal herniations through the muscle wall. Congenital diverticulae contain the full thickness of bowel wall, and are therefore considered “true diverticulae.” Classically, congenital diverticulosis affects the entire colon; right-sided and transverse colonic diverticulosis in isolation is rare.
Diverticular disease is relatively common in the western world. While the true prevalence is difficult to measure because most individuals are asymptomatic, it is estimated that in the United States, diverticulosis occurs in approximately one-third of the population older than age 45 and in up to two-thirds of the population older than 85 years. Incidence increases with age, and males and females are equally affected. A diet high in red meat and sugars but low in fiber (cereals, fruit, vegetables, brown bread) and water is postulated to be etiologic in acquired diverticulosis. With passage of hard, constipated stools, the intraluminal pressure in the sigmoid colon increases, causing segmentation. As a result, mucosal herniation occurs at the weakest point in the colonic wall, which is the point of entry of blood vessels and nerves supplying the colonic mucosa, between the mesenteric and antimesenteric teniae.
Men often require surgery for complicated disease earlier than women. Young men tend to develop fistulating disease; older male patients develop bleeding diverticulosis. In contrast, young women often present with perforated diverticulitis and older women with stricturing disease. Emergency surgery is typically indicated for management of perforated diverticulitis, which tends to occur on the index admission. In the elective setting, sigmoid colectomy may be required for recurrent episodes of uncomplicated diverticulitis (2 to 3 episodes) or a single episode of complicated diverticulitis, including micro perforation with abscess, sigmoid stricture, or the development of a colovesicle or colovaginal fistula.
Presentation Continued: Diagnosis and Treatment
Emergency surgery is required for this patient with perforated diverticulitis. The basic tenet of managing perforated diverticulitis is control of intra-abdominal sepsis with excision of the septic focus (e.g., source control), where possible. Firstly, appropriate resuscitation is required for this patient with septic shock and acute renal injury. Once resuscitation is underway, we proceed to surgery. The surgical options are diverse and varied; but typically in this situation, resection of the diseased segment of colon, with or without primary anastomosis, is favored.
Surgical Approach to Perforated Diverticulitis
The surgical procedure of choice in the management of perforated diverticulitis is dependent on the clinical condition of the patient at the time of emergency surgery. This patient has septic shock secondary to intraabdominal sepsis following a diverticular perforation. Historically, a Hartmann’s procedure was performed in this setting, by conventional open surgery or more recently using a minimally invasive approach. In this case, this 65-year-old man is significantly compromised by his condition and will benefit from an expeditious open operation. Additionally, in the setting of hypotension and shock, laparoscopy may further impair venous return and worsen hypotension.
The patient is placed on the operating table in the modified lithotomy position, facilitating transanal access to the rectum should it be required. Access to the peritoneal cavity is gained via a low midline laparotomy, extending from the umbilicus to pubic symphysis. Although it may be possible to complete the operation through this relatively small incision, if access is limited the incision can be extended cephalad. A wound protector is used to minimize risk of postoperative wound infection. The operation begins with a general laparotomy in which the four quadrants of the abdomen are inspected systematically. The stomach and duodenum are visualized for signs of perforation; the small bowel is palpated from the ligament of treitz to the ileocecal valve. Lastly, the colon and rectum are inspected. Frequently in this scenario, purulent or feculent peritonitis is encountered on entering the peritoneal cavity. In that setting, contaminants of the peritoneal cavity are thoroughly lavaged with warm sterile saline.
At laparotomy, an inflammatory phlegmon is noted in the region of the sigmoid colon and a perforation is visible in a diverticulum of the diseased bowel. The diseased sigmoid colon is adherent to the pelvic sidewall. It is critical to have optimal access to the diseased segment of colon, and packing the small bowel into the right upper quadrant with large moist packs before inserting a Balfour retractor can improve visualization and access to the colon. Surrounding tissues are typically quite friable and bleed easily. Sharp dissection in the area of the inflammatory segment is not advisable as the normal anatomical planes between the sigmoid mesentery and the retroperitoneum are obliterated. The left ureter may be pulled anteriorly into the inflammatory phlegmon and is in danger of iatrogenic injury particularly at the pelvic brim. The dissection should commence proximally, at a portion of nondiseased left colon by dividing the white line of Toldt, where the mesocolon fuses with the lateral abdominal wall. This can be carried out with electrocautery or Metzenbaum scissors. This allows the proximal colon to be mobilized and the correct anatomical plane to be entered between the mesocolon and the retroperitoneum. In this plane, we identify the left ureter and follow its course down toward the pelvis. As we approach the diseased phlegmon from above, the anatomical planes lose definition. We follow the course of the ureter and ensure it is not involved in the diseased segment of colon that will be excised. Should the ureter be adherent, we dissect it from the inflammatory phlegmon under direct vision using a combination of blunt and sharp dissection. At this point in the operation, with the ureter identified, we utilize blunt fingertip dissection to “pinch” the sigmoid colon from the pelvic sidewall. Once the sigmoid colon has been mobilized from the pelvis, we confirm the site of the perforation and decide how much colon to resect. At this point, a pitfall in the emergency setting is to attempt to resect the entire sigmoid colon with the aim of definitive treatment of the diverticular disease. This approach often requires mobilization of the splenic flexure to form a descending colostomy or both splenic flexure mobilization and entry into the pelvis for creation of a colorectal anastomosis. These extra steps should be avoided as they will increase the extent of the surgery, prolong the operation, and will expose previously unaffected tissue planes to the infectious process and the potential for a postoperative abscess.
After confirming the position of the left ureter, the sigmoid mesocolon is divided close to the bowel wall between hemostats, leaving the inferior mesenteric vein, inferior mesenteric and superior rectal arteries undisturbed. Next, we divide the colon proximal to the perforation with a linear stapling device. Distally, the sigmoid colon is divided above the pelvic brim, again using a linear stapling device, and the specimen is extracted. The distal staple line is reinforced with a hemostatic stitch. A marking, nonabsorbable stitch may be placed on the distal segment to facilitate identification of the stump when we return to close the colostomy at a later date. Proximally, a tension-free colostomy is passed through the rectus muscle and positioned at the apex of the infraumbilical fat pad. It may be necessary to mobilize the left colon proximally, particularly in obese patients, to facilitate formation of colostomy, but mobilization of the splenic flexure is rarely required. At the end of the procedure, we repeat a thorough peritoneal lavage. The abdominal wall is closed, the subcuticular fat and skin are irrigated, and the skin is closed with staples. The colostomy is then matured with interrupted rapidly absorbable suture.
Alternative Approaches to Perforated Diverticulitis
Several alternative approaches to perforated diverticulitis are available. Data exist to support performing a primary colorectal anastomosis after emergency sigmoid colectomy for perforated diverticulitis. However, this typically adds 40 to 60 minutes to the procedure as the splenic flexure is freed, the entire sigmoid colon is removed, and an anastomosis between the descending colon and the rectum is created. This one-stage procedure may be considered for fit patients with Hinchey grade 1 and 2 diverticulitis (Table 1), who are hemodynamically stable throughout the operation; there is minimal contamination of the operative field, and the surgery is completed without difficulties. The advantage of a one-stage procedure is that it obviates the need for a temporary stoma, which may be beneficial considering that up to 40% of patients having a two-stage procedure will elect not to have their stoma closed. Formal sigmoid resection with colorectal anastomosis may also be considered for select patients with Hinchey grade 3 and 4 diverticulitis (purulent and fecal peritonitis); however, we believe it is prudent to protect the anastomosis with a defunctioning loop ileostomy, which can be closed at a later date. In unusual situations, with patients who are unstable during the operation or with severe pericolinic inflammation that results in complete obliteration of tissue planes, it may be necessary to perform a proximal stoma, leaving the diseased segment in situ, with placement of appropriate drains to control the sepsis. Lastly, laparoscopic peritoneal lavage has been reported for treatment of Hinchey 3 diverticulitis (purulent peritonitis) with encouraging results. The obvious advantage of this technique is that it saves the patient an open operation, colonic resection, and possibly a stoma. However, this novel therapeutic strategy requires validation in a properly designed clinical trial. Key technical points of the various surgical approaches to managing perforated diverticular disease are summarized in Table 2.
TABLE 1. Intraoperative Hincheya Classification of Perforated Colonic Diverticulitis
aProposed by Hinchey EJ, Schaal PG, Richard GK. Treatment of diverticular disease of the colon. Adv Surg. 1978;12:85–109.
TABLE 2. Key Technical Steps and Potential Pitfalls to Approaching Perforated Diverticulitis
Special Intraoperative Considerations
On occasion, at emergency laparotomy for sigmoid perforation, we encounter a perforated sigmoid colon cancer. This unsuspected finding will alter the operative approach as it necessitates the performance of an oncologic resection (i.e., high ligation of the inferior mesenteric artery) rather than the more limited sigmoid resection described above. In this situation, the surgeon should consider which operation will result in the greatest benefit to the patient while minimizing the potential for risk. A sigmoid colectomy with end colostomy and closure of the rectal stump will eliminate the risk of anastomotic leak and may decrease the risk of postoperative abscess, both of which would interfere with or delay the use of chemotherapy. As with all cancer resections, any structure that is adherent to the perforated tumor mass (e.g., small bowel) must be resected en bloc to ensure radical clearance of all disease. We also lavage the peritoneal cavity with sterile water or dilute alcohol, in an attempt to eradicate any tumor cells that may have escaped from the area of perforation.
Another infrequently observed finding in association with sigmoid diverticular perforation and phlegmon is a right-sided colonic perforation. The inflammatory mass surrounding the perforated diverticulum compresses the colon, eventually obstructing the lumen. In the presence of a competent ileocecal valve, a closed loop obstruction ensues, with perforation occurring at the cecum as it is the portion of the colon with the thinnest wall. Classically, this patient presents with a history and clinical findings consistent with large bowel obstruction initially, or peritonitis at a later stage. In this setting, we perform a total abdominal colectomy with end ileostomy. Alternatively, in select fit patients with minimal peritoneal contamination and an uneventful operation, an ileorectal anastomosis with a proximal defunctioning ileostomy may be considered.
In the setting of a sigmoid colon perforation against a background of Crohn’s colitis, the surgical options depend on the extent of the colonic and rectal disease and the condition of the patient. In general, the surgical options in this setting are to perform a limited resection of the perforated colon with end colostomy, total abdominal colectomy with end ileostomy, or total abdominal colectomy with ileorectal anastomosis and proximal diverting loop ileostomy.
Postoperative Management
Most patients with perforated sigmoid diverticulitis will benefit from an initial stay in the Surgical Intensive Care Unit (SICU). Intravenous broad-spectrum antibiotics should be continued until culture results and sensitivities are available, after which time the antimicrobial regimen should be tailored according to the causative organisms. The duration of antibiotic therapy is determined by the patient’s clinical course. Both mechanical and pharmacologic venous thromboembolism prophylaxes are beneficial. For nutrition, the enteral route is favored. For patients who are alert and can protect their airway, a diet is started in the early postoperative period. Parenteral nutrition is reserved for patients who cannot tolerate enteral feeding for a prolonged postoperative period. Postoperative complications in the setting of intra-abdominal sepsis include intra-abdominal or pelvic abscess. Suspicion for abscess formation should be aroused by the occurrence of a prolonged ileus, nonfunctioning stoma, persistent fever, or leukocytosis. CT-guided drainage of intra-abdominal abscesses is typically successful in managing sepsis. Wound infections are common after a Hartmann’s procedure and are managed by removing clips from the wound and expressing underlying pus. If the skin defect is large, a vacuum-assisted closure device may be applied. Following laparotomy for intra-abdominal sepsis, abdominal compartment syndrome can occur. Increasing inotropic and ventilatory requirements with signs of impaired organ perfusion (oliguria or anuria) should alert the clinician to the diagnosis, and prompt measurement of intra-abdominal pressure via a transducer inserted into the bladder. Severe abdominal compartment syndrome warrants emergent laparostomy.
Case Conclusion
The patient undergoes a successful Hartmann’s procedure and is extubated in SICU the following day. His stoma functions on day 2 and he recommences diet on the fourth postoperative day. He spends 7 days in the hospital and is discharged well, without sequelae. He has his proximal colon assessed endoscopically prior to successful reversal of Hartmann’s procedure 6 months later.
TAKE HOME POINTS
· A small proportion (1%) of patients requires surgery for complications of diverticular disease.
· Complicated sigmoid diverticulitis that results in generalized peritonitis and hemodynamic instability requires prompt resuscitation, the administration of broad-spectrum antibiotics, and urgent surgical exploration.
· The standard of care for patients with complicated sigmoid diverticulitis who require urgent surgery is resection of the perforated segment of the colon with creation of an end colostomy.
· In select patients with complicated sigmoid diverticular disease who present with a pericolonic abscess (Hinchey 1) or abdominal/pelvic abscess (Hinchey 2), sigmoid colectomy with colorectal anastomosis and proximal diversion, may be considered.
· In patients with complicated sigmoid diverticular disease and purulent (Hinchey 3) or feculent (Hinchey 4) peritonitis, the current standard of care is open resection of the perforated segment of colon with end colostomy and closure of the rectal stump.
· In rare cases of complicated sigmoid diverticular disease, due to severe inflammation of the colon or the surrounding structures, or in patients who are unstable during the operation, it is necessary to perform a proximal diversion, without resection, leaving abdominal and pelvic drains to control sepsis.
· During surgery for suspected complicated sigmoid diverticular disease, the surgeon should be alert for the unsuspected finding of cancer or Crohn’s disease and modify the surgical approach accordingly.
SUGGESTED READING
Thorson AG, Beaty JS. Diverticular disease. In Beck DE, Roberts PL, Saclarides TJ, Senagore AJ, Stamos MJ, Wexner SD. The ASCRS textbook of colon and rectal surgery. New York: Springer, 2011:375–395.