Diverticulitis

Background

• Prevalence of diverticulosis 30% by age 60, >70% by age 85
• 70% of pts w/ diverticulosis remain asymptomatic
• Diverticular disease is almost exclusively left-sided colon (USA) or right-sided (Asia)
• Pathogenesis
  • Erosion of diverticular wall by inspissated fecal material leads to microperforation
    • Most common pathogens are anaerobes, as well as gram-negative rods
• Diverticular bleeding (painless LGIB) is NOT associated w/ diverticulitis

Clinical Features

• LLQ abdominal pain
  • Asian pt may c/o RLQ or suprapubic pain
• Fever
• Leukocytosis
• Change in bowel habits: diarrhea (30%) or constipation (50%)
• N/V
• Anorexia

Differential Diagnosis

LLQ Pain

• Diverticulitis
• Kidney stone
• UTI
• Pyelonephritis
• Ectopic pregnancy
• Infectious colitis
• Inflammatory bowel disease (Crohn's Disease, Ulcerative Colitis)
• Inguinal hernia
• Mesenteric ischemia
• Epiploic appendagitis
• Mittelschmerz
• Ovarian cyst
• Ovarian torsion
• PID
• Psoas abscess
• Testicular torsion
• Appendicitis
• Abdominal aortic aneurysm
• Herpes zoster
• Endometriosis
• Colon cancer
• Irritable bowel syndrome
• Small bowel obstruction

Diagnosis

• Stable pt w/ h/o confirmed diverticulitis does not require further diagnostic evaluation
  • 1st time episode or current episode different from previous requires diagnostic imaging

Work-Up

1. Labs
   1. CBC
   2. Chemistry
   3. LFTs
   4. Lipase
   5. UA
2. Imaging
   1. CT w/ IV and PO contrast
      1. Sn 97%, Sp 100%

Treatment

• Antibiotics are aimed at treating Gram Negative organisms and Anerobes (Enterobacteriaceae, Pseudomonas aeruginosa, Bacteriodes sp., and Enterococci)

Uncomplicated

• Liquid diet and bowel rest are most important

Antibiotic First, consider whether antibiotics are needed:

• In immunocompetent patients with mild uncomplicated diverticulitis (no systemic signs, able to tolerate PO, reliable follow-up), a trial of supportive care alone (bowel rest, hydration, pain control) without antibiotics is reasonable
• Antibiotics ARE indicated if: immunocompromised, significant comorbidities/frailty, CRP >140 mg/L, WBC >15 × 10⁹/L, refractory symptoms, vomiting, or CT showing fluid collection or longer segment of inflammation

If antibiotics are prescribed (4-7 day course preferred):

Preferred:

• Amoxicillin/Clavulanate 875/125mg PO Q8hrs x 5 days (or Augmentin XR 2 tablets BID [each tablet 1gm amoxicillin 62.5mg clavulanate])
  • Equally effective as fluoroquinolone + metronidazole with lower C. difficile risk (especially in patients ≥65 years)
  • Avoids FDA black box fluoroquinolone risks (tendinopathy, neuropathy, aortic dissection, CNS effects)

Alternatives (penicillin allergy or intolerance):

• Trimethoprim/Sulfamethoxazole one double-strength tablet BID PLUS Metronidazole 500mg PO Q8h x 5 days
• Metronidazole 500mg PO Q8hrs PLUS Ciprofloxacin 500mg PO BID x 5 days (reserve for patients without non-fluoroquinolone options)
• Moxifloxacin 400mg PO QDaily (same fluoroquinolone cautions apply)

Current research suggests that antibiotics may not be necessary in uncomplicated diverticulitis if patient receives sufficient bowel rest in coordination with medicine observation and close follow up.

Complicated

• Defined as having a phlegmon, abscess, stricture, obstruction, fistula, or perforation
• Bowel rest in coordination with antibiotics
• Surgical consult for drainage of abscess or further surgical intervention

Antibiotics Options:

• Ticarcillin/Clavulanate 3.1 g IV Q6h or
• Piperacillin/Tazobactam 3.375 g IV q6 hours x 7-10 days
• Ciprofloxacin 400 mg IV q12h and Metronidazole 1 g IV Q12h
• Ampicillin 2 g IV Q6h and Metronidazole 500 mg IV q6h Plus (Gentamicin 7 mg/kg Q24h or Ciprofloxacin 400 mg IV Q12h)
• Imipenem/Cilastatin 500 mg IV Q6h

Disposition

1. Admit
   1. All complicated diverticulitis
   2. Intractable N/V, comborbid disease, high WBC, high fever, elderly, immunocompromised
   3. Failed outpt therapy (worsening symptoms or CT findings w/in 6wk of initial episode)
2. Discharge
   1. Well-appearing, immunocompetent pts w/ uncomplicated disease
   2. Refer all newly-diagnosed pts for f/u colonoscopy in 6 wk (CT cannot r/o carcinoma)
   3. Surgical referral should be made for all pts w/ 2nd episode of diverticulitis

Source

Tintinalli