Diverticulosis and its Complications

Complications of Diverticulosis

1. Hemorrhage
1. Pathogenesis
• develops in 15% of patients with diverticulosis
• as a diverticulum begins to herniate, one of the vasa recta may become draped over the dome of the diverticulum, predisposing it to injury and rupture
• usually occurs in the absence of acute and chronic inflammation



2. Clinical Manifestations and Diagnosis
• one-third of patients with diverticular hemorrhage will have massive, life-threatening bleeding
• overall mortality rate is 2% - 4%
• 50% of patients will have had a prior episode of colonic bleeding
• 80% to 85% of patients will stop bleeding spontaneously
• initial management revolves around resuscitation and replacement of blood loss
• nasogastric tube lavage or EGD may be required to exclude an upper GI source
• anoscopy and proctoscopy should be done to exclude an anal or rectal source


1. Localization of Bleeding
• hemodynamically stable patients who continue to bleed should have the bleeding site localized, if possible


1. Radioisotope Scans
• tagged red blood cell scan can detect bleeding rates as low as 0.1 to 0.4 ml per minute
• repeat scanning can be done every 2 - 3 hours over a 24 hour period, which is useful in the detection of chronic or intermittent bleeding
• localization accuracy rates have been reported from 24% to 91%
• reasons for the relatively low accuracy rates include: 1) extravasated blood may travel rapidly proximally or distally, 2) bleeding from an upper source may superimpose on the adjacent colon, 3) a redundant sigmoid colon may be falsely identified as bleeding from the right colon
• because of the low localization accuracy rates, performing a segmental colon resection based on a positive bleeding scan alone results in a high rate of rebleeding
• some centers use a positive bleeding scan as an indication for angiography



2. Angiography
• accurately localizes the bleeding site; however, the rate of bleeding must be very brisk (0.5 to 1.0 ml per minute)
• negative studies are common because of the delay inherent in arranging the procedure
• both the superior mesenteric and inferior mesenteric arteries must be studied
• has therapeutic value as well: vasopressin may be infused through the arterial catheter in order to stop the bleeding, but complications are high (cardiac arrhythmias, bowel ischemia, rebleeding)
• transcatheter embolization has largely replaced vasopressin infusion but is also associated with serious complications (bowel infarction, arterial injury and thrombosis







3. CT Angiography
• can detect bleeding rates of 0.3 – 0.5 ml/minute
• widely available, fast, noninvasive
• very accurate in identifying the site of active bleeding
• has no therapeutic capability
• major value is that surgeons can rely on the information to guide resection decisions in patients who require surgery



4. Colonoscopy
• should be the initial study in a patient who has stopped bleeding
• may be impossible to perform in a rapidly bleeding patient
• has therapeutic uses: angiodysplastic lesions may be cauterized or injected with vasoconstrictive agents


3. Treatment
• 10% to 20% of patients will continue to bleed and require emergent or urgent surgical intervention


1. Segmental Colectomy
• should be done only if the bleeding site has been confidently localized
• primary anastomosis is usually possible
• blind segmental resection is associated with a very high rate of rebleeding (~40%)
• intraoperative localization, either with multiple enterotomies, divided colostomies, or intraoperative colonoscopy, is usually unsuccessful


2. Subtotal Colectomy
• procedure of choice if the bleeding site has not been localized
• primary anastomosis with ileoproctostomy is usually performed




2. Acute Diverticulitis
1. Pathogenesis
• develops in 15% to 20% of patients with diverticulosis
• majority of cases (>90%) occur in the sigmoid colon; right-sided diverticulitis is very rare (and usually mistaken for appendicitis)
• results from perforation of a diverticulum, either macroscopic or microscopic
• in most cases the perforation is confined to the mesentery and pericolic fat
• if the inflammation does not subside, then a localized abscess will result
• if the perforation is not contained, then free perforation and peritonitis will result


2. Clinical Manifestations
• left lower quadrant pain is the most common symptom
• physical exam usually reveals abdominal distention and left lower quadrant tenderness
• fever and leukocytosis are usually present
• diffuse peritonitis indicates free perforation


1. Hinchey Classification



3. Diagnosis
• patients with mild symptoms may be diagnosed and treated as outpatients based on their history and physical exam alone
• most other patients should have confirmation of the diagnosis


1. Plain X-rays
• usually are unremarkable
• useful in excluding other acute surgical problems


2. Barium Enema and Colonoscopy
• should not be done in the acute setting
• increased luminal pressure may lead to the free rupture of a previously well-contained perforation
• these studies should be reserved for the elective workup of a patient after the acute episode has resolved


3. CT Scan
• diagnostic test of choice in the acute setting
• will show evidence of pericolic inflammation, abscess formation, phlegmon, and bowel wall edema
• accurate in identifying colovesical fistulas
• has a therapeutic role in draining abscesses



4. Management
1. Medical Treatment
• mild cases may be treated as outpatients with oral antibiotics and a clear liquid diet
• majority of patients will need to be admitted and treated with IV antibiotics, bowel rest, and pain medicine
• 70% of patients who have recovered from an uncomplicated episode of diverticulitis will not have another episode


2. Uncomplicated Diverticulitis
• absence of abscess, fistula, obstruction, or free perforation


1. Recurrent or Chronic Diverticulitis
• historically, most patients were recommended to have elective sigmoid resection after one or two episodes of diverticulitis
• the concern was for progression to complicated disease
• current thinking is that the recommendation for surgery should be individualized, based on frequency and severity of recurrences, as well as overall medical condition
• laparoscopic resection appears superior to traditional open surgery


2. Failure of Medical Management
• patients who do not respond or deteriorate within 24 to 48 hours after starting antibiotics usually require an emergency operation
• an exception is the patient who has an abscess that can be drained percutaneously
• since a preoperative bowel preparation is not possible, a two-stage procedure involving resection and end-colostomy followed by colostomy closure 3 months later is the usual operation chosen
• if the diseased colon is so densely adherent to the ureter or iliac vessels as to make resection dangerous, a three-stage approach may be chosen (diverting colostomy, resection with anastomosis, closure of colostomy 3 months later)
• a one-stage procedure with on-table bowel prep can be performed if the patient is hemodynamically stable and otherwise in suitable medical condition


3. Complicated Diverticulitis
1. Diverticular Abscesses
• may present as a mesocolic abscess (Hinchey I) or pelvic abscess (Hinchey II)
• small abscesses may be treated with IV antibiotics
• large abscesses are best treated with CT-guided drainage
• failure to improve or clinical progression are indications for surgery
• if the patient can tolerate a bowel prep, a resection with primary anastomosis is often possible, without or without a protective proximal ostomy


1. Healed Diverticular Abscesses
• asymptomatic patients appear to be at low risk for another complicated attack
• the decision of whether to offer elective sigmoidectomy must be made on a case by case basis


2. Diffuse Peritonitis
• requires an emergency operation following adequate resuscitation
• resection of the perforated segment of colon with end-colostomy is the most appropriate operation (Hartmann's procedure)
• in a stable patient with minimal contamination, a primary anastomosis with or without a defunctioning loop ileostomy is another option


1. Laparoscopic Lavage
• reserved for Hinchey III patients (purulent peritonitis)
• consists of diagnostic laparoscopy, irrigation of peritoneal cavity, placement of penrose drains adjacent to the perforation, antibiotics post op
• no resection or colostomy is performed
• treatment failure usually mandates colectomy
• studies have not demonstrated improved outcomes when compared to sigmoidectomy
• another concern is a missed sigmoid colon cancer
• successful treatment may obviate the need for elective resection in many patients




3. Obstruction
• may be difficult to distinguish from carcinoma preoperatively or intraoperatively
• a one-stage procedure with on-table bowel prep or a two-stage procedure are the operative options
• rarely, in a moribund patient, a decompressing colostomy (3-stage procedure) may be the initial procedure chosen


4. Fistula
• colovesical fistula is most common, followed by colocutaneous and colovaginal fistulas
• symptoms of colovesical fistula include multi-organism UTIs, pneumaturia, fecaluria
• cystoscopy shows localized inflammation and edema of the bladder mucosa; the fistula opening is rarely seen
• CT scan demonstrating air in the bladder is diagnostic
• treatment consists of an elective one-stage procedure
• bladder resection or repair is unnecessary – bladder catheterization for 7 days will allow the fistula site to heal
• for fistulas involving organs other than the bladder, management consists of a one-stage procedure with repair or resection of the involved organ







5. Diverticulitis in Young Patients
• historically, in patients < 50 years old, diverticulitis was considered more virulent and associated with more complications
• elective resection was usually recommended after the first episode in this age group
• current recommendations do not support routine elective resection in young patients


6. Immunocompromised Patients
• most should undergo elective surgery after a single episode of diverticulitis in order to avoid an emergency procedure after a delayed presentation from a second episode
• elective surgery is associated with a lower morbidity and mortality rate compared with emergency surgery in this group of patients