Diverticulitis

Aka: Diverticulitis

1. See Also
   1. Diverticulosis
2. Pathophysiology
   1. Complicates 5% of Diverticulosis
      1. Lifetime Prevalence of acute Diverticulitis: 25%
   2. Distribution
      1. Most often affects sigmoid colon (85% of Diverticuli in western societies)
      2. Right Diverticuli (ascending colon) seen in age <60 years and asian patients
   3. Inflammation of colonic Diverticula
      1. Impacted with fecal material (fecalith)
      2. Colon Perforation
         1. Microperforation (Simple, Uncomplicated Diverticulitis)
            1. Peridiverticulitis with localized phlegmon
            2. Infection walled off by pericolic fat
         2. Macroperforation (Complicated Diverticulitis)
            1. Pericolic abscess or
            2. Free perforation with generalized peritonitis
            3. Fistulas may form between adjacent structures
3. Risk Factors
   1. Increasing age over 45 years
   2. Obesity
   3. Women
   4. Sedentary
   5. Medications
      1. Aspirin
      2. NSAIDS
4. Symptoms
   1. Mild anorexia
   2. Nausea or Vomiting
   3. Chills
   4. Diarrhea or obstipation
   5. Abdominal Pain: Acute constant pain
      1. Initial: Hypogastric pain
      2. Later: Left Lower Quadrant Abdominal Pain (>92%)
5. Signs
   1. Fever
      1. Fever is typically <102 F
   2. Tenderness over left lower quadrant
      1. Isolated tenderness in Left lower quadrant is highly suggestive of Diverticulitis
   3. Guarding, abdominal rigidity and rebound tenderness
      1. Not sensitive or specific for Diverticulitis
      2. May suggest peritonitis
   4. Rectal mass or tenderness on rectal exam
      1. May suggest pelvic abscess
6. Labs
   1. Complete Blood Count
      1. Leukocytosis (>55-68% of cases)
   2. C-Reactive Protein
      1. C-RP >50 mg/L consistent with Diverticulitis (LR+ 2.2, LR- 0.3)
      2. C-RP >200 mg/L consistent with perforation (69% of cases)
   3. Urinalysis
      1. Dysuria and urinary frequency may occur
   4. Urinary Pregnancy Test
      1. Evaluate differential diagnosis in premenopausal women
7. Diagnosis
   1. Combination Criteria (LR+ 18, LR- 0.65)
      1. Left Lower Quadrant Abdominal Pain AND
      2. Vomiting absent AND
      3. C-RP >50 mg/L
   2. Symptoms and signs
      1. Localized left lower quadrant tenderness (LR+ 10.4, LR- 0.7)
      2. Left Lower Quadrant Abdominal Pain: (LR+ 3.3, LR- 0.5)
      3. Vomiting absent (LR+ 1.4, LR- 0.2)
      4. Fever (LR+ 1.4, LR- 0.8)
   3. Labs
      1. C-Reactive Protein (C-RP) > 50 mg/L (LR+ 2.2, LR- 0.3)
   4. Imaging
      1. CT Abdomen (LR+ 94, LR- 0.1)
      2. UltrasoundAbdomen (LR+ 9.2, LR- 0.09)
      3. MRI Abdomen (LR+ 7.8, LR- 0.07)
   5. References
      1. Lameris (2010) Dis Colon Rectum 53(6): 896-904
      2. Wilkins (2013) Am Fam Physician 87(9): 612-20
8. Differential Diagnosis
   1. See Left Lower Quadrant Abdominal Pain
   2. Appendicitis
   3. Small Bowel Obstruction
   4. Gastroenteritis
   5. Inflammatory Bowel Disease
   6. Inguinal Hernia (Incarcerated Hernia or Strangulated Hernia)
   7. Urinary Tract Infection
   8. Nephrolithiasis
   9. Ischemic Colitis
   10. Pancreatitis
   11. Women
       1. Ectopic Pregnancy
       2. Ovarian Torsion
       3. Ovarian Cancer
       4. Tubo-ovarian abscess (Pelvic Inflammatory Disease)
9. Imaging: Abdominal CT (preferred)
   1. Abdominal CT with oral contrast is the best overall imaging study to diagnose Diverticulitis
   2. Abdominal CT is best test to confirm sigmoid Diverticulitis
      1. Test Sensitivity: Approaches 100% (sigmoid involvement)
      2. Test Specificity: Approaches 100% (sigmoid involvement)
   3. Abdominal CT is best test to identify complications (perforation)
   4. Highest Test Sensitivity CT Findings suggestive of Diverticulitis
      1. Pericolic fat infiltration or stranding
      2. Bowel wall thickening
   5. Highest Test Specificity CT Findings suggestive of Diverticulitis
      1. Fascial thickening
      2. Free Air
      3. Inflamed diverticulum
      4. Intramural air or sinus tract
      5. Abscess or Phlegmon
      6. Muscle hypertrophy (Test Specificity 98% in Diverticulitis)
      7. Arrowhead sign
         1. Localized bowel wall thickening
         2. Bowel lumen resembles arrow shape at diverticulum
   6. Disadvantages
      1. See CT-associated Radiation Exposure
   7. References
      1. Kaiser (2005) Am J Gastroenterol 100(4): 910-7
      2. Lameris (2008) Eur Radiol 18(11): 2498-511
10. Imaging: Other
    1. Abdominal flat and upright Abdomen
       1. Observe for abdominal free air
       2. Small Bowel Obstruction
    2. Abdominal MRI
       1. Not routinely used in practice for this indication
          1. High cost
          2. Long scan times (unacceptable in critically ill patients)
       2. MRI findings are similar to CT, but with better resolution of soft tissue
          1. Buckley (2007) Eur Radiol 17(1): 221-7
    3. Abdominal Ultrasound
       1. Not routinely used in practice for this indication (Disadvantages when compared with CT)
          1. Does not evaluate alternative diagnoses for Abdominal Pain (outside the Pelvis)
          2. Does not well define abscess extent
          3. Does not identify free air
          4. Limited by overlying gas, Obesity and pain limiting examination
       2. Reliable for diagnosis of sigmoid Diverticulitis but variable efficacy due to technique, body habitus and acute pain
          1. Schwerk (1992) Dis Colon Rectum 35(11): 1077-84
       3. Consider in women for evaluating additional Pelvic Pain causes (including pregnancy-related)
    4. Avoid Colonoscopy in acute disease
       1. Risk of worsening perforation
    5. Avoid Barium Enema in acute disease
       1. Risk of extravasation if perforation
11. Management: Approach
    1. Indications for outpatient management
       1. Uncomplicated Diverticulitis with mild pain or well controlled on Oral Analgesics
       2. Stable clinically without signs of peritonitis
       3. Tolerating oral fluids
       4. Exercise caution in discharging patients at higher risk of failed outpatient management (abdominal free fluid on imaging, women)
    2. Advanced Imaging Indications (i.e. CT Abdomen for most patients)
       1. Diagnosis unclear
          1. Not classic Left Lower Quadrant Abdominal Pain with fever
          2. Other diagnoses are of similar likelihood
       2. Moderate to severe symptoms
       3. Inability to tolerate oral fluids
       4. Peritoneal signs
       5. Failure to improve in 2-3 days
12. Management: Outpatient
    1. General Measures
       1. Clear Liquid Diet (NPO in severe disease)
       2. Low fiber diet in acute phase
       3. Avoid Opioids as much as possible (most Opioids increase intracolonic pressure)
       4. Anticipate improvement within 48-72 hours
    2. Antibiotic regimen (Outpatient Mangement of mild disease)
       1. Consider no antibiotics for acute uncomplicated Diverticulitis
          1. Chabok (2012) Br J Surg 99(4): 532-9
       2. Primary protocol (requires 2 agents for 7-10 days)
          1. Antibiotic 1: Metronidazole (Flagyl) 500 mg orally every 6 hours AND
          2. Antibiotic 2 (choose one)
             1. Ciprofloxacin 500 mg orally twice daily OR
             2. Levofloxacin 750 mg orally every 24 hours OR
             3. Septra DS orally twice daily
       3. Alternative protocol (choose one antibiotic for 7-10 days)
          1. Augmentin 1000 mg orally twice daily OR
          2. Moxifloxacin 400 mg orally daily
13. Management: Inpatient
    1. Indications for hospitalization
       1. Age >85 years
       2. Significant inflammation, clinically unstable or with peritoneal signs
       3. Unable to take oral fluids
       4. Complicated Diverticulitis with moderate to severe pain
       5. Consider in patients at higher risk of failed outpatient management (abdominal free fluid on imaging, women)
    2. General measures
       1. Nothing by mouth initially
    3. Precautions
       1. E. coli resistance to Fluoroquinolones (e.g. Ciprofloxacin) is as high as 75% at some hospitals
    4. Antibiotic regimen for moderate disease
       1. Primary agents (choose one)
          1. Piperacillin-tazobactam (Zosyn) 3.375 g IV every 6 hours (or 4.5 g IV every 8 hours) or
          2. Ticarcillin-clavulanate (Timentin) 3.1 g IV every 6 hours or
          3. Ertapenem (Invanz) 1 g IV every 24 hours or
          4. Moxifloxacin 400 mg IV every 24 hours
       2. Alternative agents (choose one)
          1. Moxifloxacin 400 mg IV every 24 hours or
          2. Tigecycline (Tygacil) 100 mg IV for dose 1, then 50 mg IV every 12 hours
       3. Alternative agents: Combination (choose two agents)
          1. Antibiotic 1: Metronidazole (Flagyl) 500 mg IV every 6 hours (or 1 g IV every 12 hours) AND
          2. Antibiotic 2 (choose one)
             1. Ciprofloxacin 400 mg IV every 12 hours or
             2. Levofloxacin 750 mg IV every 24 hours
    5. Antibiotic regimen for severe disease (e.g. ICU, life-threatening)
       1. Primary agents (choose one)
          1. Imipenem-cilastin (Primaxin) 500 mg IV every 6 hours or
          2. Meropenem (Merrem) 1 g IV every 8 hours or
          3. Doripenem (Doribax) 500 mg IV every 8 hours
       2. Alternative agents: Three agent protocol (choose 3)
          1. Ampicillin 2 g IV every 6 hourss and
          2. Metronidazole 500 mg IV every 6 hours and
          3. Aminoglycoside (choose one, pharmacy to monitor levels)
             1. Gentamicin or
             2. Tobramycin or
             3. Amikacin
       3. Alternative agents: Three agent protocol (choose 3)
          1. Ampicillin 2 g IV q6 hours and
          2. Metronidazole 500 mg IV every 6 hours and
          3. Fluoroquinolone (choose one)
             1. Ciprofloxacin 400 mg IV every 12 hours or
             2. Levofloxacin 750 mg IV every 24 hours
14. Management: Complicated Diverticulitis requiring surgical intervention
    1. Surgical intervention is required in 15-30% of hospitalized patients with acute Diverticulitis
    2. CT-guided percutaneous drainage Indications
       1. Localized Abscess
    3. Laparoscopic or open surgery Indications
       1. Laparoscopy is preferred over open procedure (fewer complications, less mortality and faster recovery)
       2. Abscess drainage or Washout procedure
       3. Emergency Colectomy
          1. High morbidity (Pneumonia, Acute Coronary Syndrome or respiratory failure)
          2. Increased mortality (especially in elderly)
          3. Colectomy with primary anastomosis performed at initial procedure
             1. Safe despite Diverticulitis in selected patients
          4. Colectomy with multi-stage, delayed re-anastomosis (Hartmann Procedure)
15. Course
    1. Improves on antibiotics within 48 to 72 hours
16. Follow-up
    1. Colonoscopy
       1. Do not perform in acute Diverticulitis
          1. Risk of bowel perforation
       2. Obtain 6 weeks after complicated Diverticulitis episode
          1. May not be needed in uncomplicated first-episode empirically treated Diverticulitis
          2. Consider also if approaching routine screening or if findings suggest other indication
          3. lau (2011) Dis Colon Rectum 54(10): 1265-70
          4. Westwood (2011) Br J Surg 98(11): 1630-4
       3. Findings
          1. Define extent of Diverticulosis
          2. Evaluate for Colon Cancer
          3. Barium Enema may be used as alternative option
    2. Surgical indications
       1. Recurrent uncomplicated Diverticulitis requiring hospitalization following third episode
17. Complications
    1. Colonic perforation
       1. Increased risk in immunocompromised patients and in Chronic Opioid, Corticosteroid or NSAID use
    2. Colonic abscess (~10%)
    3. Generalized peritonitis
    4. Colonic fistula
18. Prevention
    1. High fiber diet (except in acute phase - see above)
    2. Maintain adequate hydration
    3. Exercise
    4. Weight loss (if BMI >30 kg/m2)
    5. Tobacco Cessation
       1. Tobacco use is associated with complicated Diverticulitis and worse outcomes
       2. Turunen (2010) Scand J Surg 99(1): 14-17
    6. No evidence that avoiding nuts, corn or popcorn decreases Diverticulitis risk
       1. Strate (2008) JAMA 300(8): 907-14
19. Prognosis
    1. Peritonitis Mortality
       1. See Mannheim Peritonitis Index (Clinical Scoring System to Predict Mortality in Peritonitis)
    2. Diverticulitis recurrence risk
       1. After first episode, recurs in 9-30% of cases
       2. After second episode, recurs in 50% of cases
20. References
    1. Gilbert (2011) Sanford Guide to Antimicrobials
    2. Simmang in Feldman (1998) Gastrointestinal, p. 1793-7
    3. Hammond (2010) Am Fam Physician 82(7): 766-70
    4. Salzman (2005) Am Fam Physician 72:1229-42
    5. Stollman (2004) Lancet 363(9409): 631-9
    6. Wilkins (2013) Am Fam Physician 87(9): 612-20