Definitions:

  • Diverticular disease is an umbrella term which encompasses any symptomatic condition resulting from the development of diverticulosis (blind ending sac-like protrusions of the colonic wall)
  • Includes:
    • Diverticular bleeding: painless hematochezia resulting from exposed blood vessels within the wall of diverticulum
    • Segmental colitis associated with diverticula (SCAD): inflammatory changes within the colon between uninvolved diverticulum
      • Poorly understood, but likely related to microbiome changes and fecal stasis resulting from colonic outpouching
    • Diverticulitis: inflammatory changes within the diverticulum itself, resulting in abdominal pain and bowel wall edema; often infectious in etiology
      • Can be simple or complicated if associated with obstruction, fistulization, abscess or perforation

Epidemiology:

  • Diverticulosis is a widespread but often asymptomatic condition, with prevalence highly dependent on age and patient population. Among patients in western industrialized nations:
    • <20% below age 40
    • Around 40% in ages 40-50
    • 60%+ over age 70
  • Diverticulitis occurs at a rate of 4-15% of patients with diverticula
    • Responsible for 60-75 hospitalizations per 100,000 people
    • Male predominant < age 45, female predominant > age 45
    • Growing rates among young patients
  • Diverticular bleeding occurs at similar rates (4-15%) among people with diverticulosis
  • Risk factors for all diverticular disease include diets high in red meat, low dietary fiber, high BMI, extensive smoking, chronic constipation and known diverticular disease
  • Eastern Asian populations experience much lower rates of diverticular disease, but have a comparatively higher rate of diverticula within the ascending colon

Pathogenesis:

  • Diverticulum typically develop at well-defined points around the colon where vasa recta penetrate the circular muscle layer
  • Considered a “false” diverticula if the inner layers of serosa are poking through the muscle
  • Most commonly (95%+) occurs in the sigmoid colon which experiences the highest colonic wall pressure during bowel movements
  • Bleeding and injury occur when penetrating vessels are superficially exposed within the colonic wall
  • Microperforations associated with luminal pressure, food particles and/or fecal obstruction of the diverticulum opening can lead to acute inflammation and complication
    • These microperforations are walled off by mesentery preventing frank perforation and leakage of bowel contents

Presentation:

  • Isolated diverticulosis is most often asymptomatic
  • Diverticular bleeding presents as painless hematochezia; bleeding can be mild but results in clinically significant hemorrhage/anemia in up to ⅓ of patients
  • Diverticulitis presents with fever, anorexia, constipation, and abdominal pain
    • Pain localizes to the area of colonic involvement, which will be LLQ in the preponderance of cases; pain is typically constant for days
    • May present with nausea, vomiting, and bowel habit changes
    • Chronic constipation is a predisposing condition, therefore in a patient with acute diverticulitis it can be difficult to determine the presence of bowel obstruction or ileus as a complicating feature of acute illness
    • Patients with the typical sigmoid involvement may experience dysuria, urinary frequency or urgency which results from bladder irritation due to close contact with the sigmoid colon anatomically
    • Recurrence is common

Diagnosis:

  • Diverticulosis can be seen incidentally on CT of the abdomen and pelvis
  • Diverticular bleeding
    • With report of rectal bleeding, reasonable to obtain CBC, T&S, coags if relevant
    • Acute bleeding should not cause immediate drop in hemoglobin, as patients will be losing whole blood; fluid shifts will result in normocytic anemia over the subsequent days
    • Clinically significant hemorrhage may cause expected vital sign changes, with initial tachycardia followed by hypotension (beware of bradycardic patients on beta blockers)
    • Anoscopy is a useful tool in the Emergency Department to rule out internal hemorrhoids as source of rectal bleeding
    • Gold standard (not in the Emergency Department) is direct visualization with colonoscopy (see image below), which will allow for intervention as well
    • Angiography or surgical exploration should be reserved for cases when emergent colonoscopy is unsuccessful
  • Diverticulitis
    • Initial labs may show evidence of inflammation including leukocytosis and elevated CRP, although these markers have only 45% sensitivity
    • Consider obtaining a hepatic panel and lipase which can narrow the differential in undifferentiated patients with abdominal pain
      • Mildly elevated lipase may be seen with peritoneal involvement or in cases where diverticulitis is complicated by perforation
    • UA may demonstrate sterile pyuria due to proximity of colon to bladder
    • CT is the gold standard for diagnosis with sensitivity of 94% and specificity of 99%
    • Graded, compressive ultrasound can detect acute colonic diverticulitis with similar rates, although user dependency and limited ability to identify alternative pathology limit its replacement of CT
    • Abdominal plain films may demonstrate air fluid levels suggestive of ileus or other nonspecific abnormalities, although utility is limited by low sensitivity and specificity

Complications:

  • Abscess:
    • Microperforations leading to diverticulitis can seed gut bacteria into the peritoneal cavity
    • Can be found in 16-40% percent of hospitalized patients
    • Identified on CT so unlikely to change diagnostic management
    • Drainage, usually percutaneous, is indicated for abscesses > 4cm in diameter due to high rate of failure of antibiotic management
    • Consider reimaging if a patient who was trialed on conservative management continues to have systemic signs of infection after 3 days
  • Obstruction:
    • Chronic inflammation from diverticulitis episodes can result in fibrosis of the colon leading to stricture
    • Diverticulitis alone can present with obstipation while inflammatory changes alter colonic motility, making it difficult to distinguish acute ileus from stricture
    • CT should include PO contrast if tolerated to best identify the presence of stricture
    • Requires surgical consult to consider stricture resection
  • Fistula:
    • Inflammation of the colon can lead to fistulization with contacting strictures
    • Most frequently, fistulization occurs with the bladder (65% of cases)
      • Consider colovesical fistula in patients with diverticulitis and recurrent UTI, air or feces in the urine or passage of urine per rectum
      • No clear gold standard imaging, can be diagnosed with CT, cystogram, cystoscopy
      • Importantly, fistula can be missed if IV and PO contrast given concurrently; if opting for CT imaging with high suspicion, choose PO contrast only
      • Typically requires repair by colorectal surgery
    • Colovaginal fistulas are less common and can be identified on a speculum exam
      • Symptoms are typically vaginal discharge or passage of gas/feces per vagina
    • Coloenteric fistulas are generally rare, but should be considered in patients with known diverticular disease and sudden onset diarrhea
  • Perforation:
    • Rare complication of diverticular disease but carries high overall mortality of 20%
    • Characterized by guarding, rebound tenderness, rigidity on abdominal exam or acute interval worsening of the exam
    • Vital signs abnormalities, most notably tachycardia and hypotension are usually present
    • Consider an upright chest/abdominal x-ray to detect extraluminal gas below the diaphragm early, although low sensitivity of 50-70%

Disposition:

  • Diverticular bleeding may be managed as an outpatient if hemodynamically stable healthy patient
    • Patients who are hemodynamically unstable, require transfusion, demonstrate symptomatic anemia, or are on anticoagulation (in select cases) should be admitted for serial hemoglobins and inpatient endoscopic management
    • Consider a higher level of care for patients requiring multiple transfusions or in whom bleeding remains brisk
  • Diverticulitis may be managed outpatient in select cases, however surgical admission is indicated for any patient with disease complicated by obstruction, fistula, abscess or perforation
    • Admission in uncomplicated diverticulitis is indicated for patients who have failed outpatient treatment, cannot tolerate PO, have significant comorbidities, show signs of peritonitis, or in whom sepsis is suspected
    • Patients with perforation may go directly to the operating room depending on clinical status

Treatment:

  • Diverticulosis does not require treatment unless associated with diverticulitis or significant diverticular bleeding
    • Avoidance of seeds, nuts and corn was previously advised to prevent development of diverticulitis, however data does not support this recommendation
  • Diverticular bleeding can often be treated at the time of diagnosis with colonoscopy; the mainstay of management in the Emergency Department is centered on resuscitation and assessment of hemorrhage
    • Slow rates of bleeding may be considered for outpatient management
    • Brisk bleeds should be treated as undifferentiated GI bleeds; place two large bore IVs, fluid resuscitate, and consider transfusion for patients with frank hemorrhage or hemoglobin below 7/ far below their baseline
    • Consult GI for emergent endoscopic intervention if bleeding is uncontrolled or the patient requires multiple transfusions
    • Further intervention with IR for embolization or colorectal surgery for operative management may be required
  • Diverticulitis may be managed differently depending on expected disposition, however the mainstay of treatment is fluid resuscitation, antibiotic treatment, and bowel rest in more severe cases.
    • Outpatient management:
      • Should receive 7-10 days of antibiotics with broad coverage of gram negative and anaerobic bacteria
        • Oral agents to consider are amoxicillin-clavulanate, fluoroquinolones or trimethoprim/sulfamethoxazole combined with metronidazole
      • In some cases of first time, uncomplicated diverticulitis, consider observation as studied in a randomized clinical trial of observational versus antibiotic treatment for a first episode of CT-proven uncomplicated acute diverticulitis
      • Dietary restrictions are not necessary, however some advocate for a clear liquid diet until reassessment in 2-3 days
      • Patients who improve do not require repeat imaging, but those who remain febrile, have worsening pain, or cannot tolerate oral intake after 3 days should be reimaged to rule out the development of complications
      • Only 6% of uncomplicated diverticulitis patients treated as outpatients will return to the Emergency Department or require admission for diverticulitis in the following 2 months
    • Inpatient management:
      • Start IV broad spectrum coverage of gram negative and anaerobic bacteria
        • Agents to consider include piperacillin-tazobactam or a combination of metronidazole plus a cephalosporin or a fluoroquinolone
      • Patients should be kept on a clear liquid diet or complete bowel rest for the first several days of admission, depending on severity
      • Intravenous resuscitation with crystalloid is indicated in volume depleted patients and maintenance fluids should be given for patients kept NPO
      • IV pain control in patients who are unable to tolerate oral medications

Key Points:

  • Diverticulosis:
    • although asymptomatic in most cases, is widespread and predisposes patients to acute diverticular disease
  • Diverticular bleeding:
    • common cause of lower GI bleeding, and although typically benign can result in significant hemodynamic compromise in some cases
    • Emergency management of diverticular bleeding is similar to other causes of gastrointestinal hemorrhage, with emphasis on early recognition and resuscitation
  • Diverticulitis:
    • CT A/P is the gold standard of imaging for patients with acute diverticulitis
    • Complications of diverticulitis including fistulization, abscess, obstruction, and perforation which all require surgical consultation
    • Diverticulitis may be managed as an outpatient in many cases with oral antibiotics and close follow-up with strict return precautions
    • Consider hospital admission for patients with diverticulitis and advanced age or medical comorbidities with definite admission for sepsis, peritonitis, diverticular complications, and hemodynamic instability
    • The mainstays of treatment for acute diverticulitis are appropriate antibiotics, fluid resuscitation and bowel rest

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