Diverticulitis

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Pathophysiology - Gut Pouch Punch-Up

  • False diverticula: Mucosa and submucosa herniate through the muscularis propria.
  • Occur at weak points in the colonic wall where vasa recta penetrate.
  • 📌 Sigmoid Is The Site: Highest pressure area.

Diverticulosis, hemorrhage, and acute diverticulitis

⭐ The sigmoid colon is the most common site for diverticula (>90% of cases) because it's the narrowest colonic segment, generating the highest pressures via the Law of Laplace.

Presentation & Diagnosis - Bellyache Breakdown

  • Classic Presentation: Steady, deep LLQ pain, fever, and altered bowel habits (constipation > diarrhea). Nausea and anorexia are common.

    • Physical Exam: Localized tenderness, palpable mass (phlegmon/abscess), guarding.
    • 📌 Note: Right-sided diverticula (common in Asian populations) can mimic appendicitis.
  • Diagnostic Workup:

    • Labs: Leukocytosis (↑ WBC) is typical.
    • Imaging: Abdominal/Pelvic CT with contrast is the gold standard.
      • Key CT Findings: Sigmoid wall thickening (>4 mm), pericolic fat stranding, abscess, fistula.

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High-Yield: Never perform a colonoscopy or barium enema during an acute attack. It dramatically increases perforation risk. A colonoscopy should be done 6-8 weeks post-recovery to exclude underlying malignancy.

Staging & Management - Calming the Chaos

  • Hinchey Classification (Modified) for Complicated Diverticulitis:
    • Stage 1a: Pericolic inflammation/phlegmon
    • Stage 1b: Pericolic or mesocolic abscess (<5 cm)
    • Stage 2: Pelvic, distant intra-abdominal, or retroperitoneal abscess (≥5 cm)
    • Stage 3: Purulent peritonitis
    • Stage 4: Feculent peritonitis

CT scan of acute diverticulitis with pericolic abscess

Elective Sigmoidectomy: Consider after recovery in patients who are young, immunosuppressed, or after a complicated episode to prevent recurrence. The old "two-strikes" rule is no longer absolute; decisions are individualized.

Complications - When Guts Go Rogue

  • Abscess: Most common complication. Look for persistent fever despite antibiotics. Percutaneous drainage often required if > 4-5 cm.
  • Fistula: Abnormal connection to adjacent organs.
    • Colovesical: Most common; presents with pneumaturia, fecaluria.
    • Colovaginal: Passage of flatus/stool from vagina.
  • Obstruction: Partial or complete blockage from stricture formation due to chronic inflammation.
  • Perforation: Free perforation leads to purulent or feculent peritonitis (Hinchey stages III/IV).

High-Yield: The most common fistula type is colovesical, classically presenting with air in the urine (pneumaturia).

High‑Yield Points - ⚡ Biggest Takeaways

  • Classic triad: LLQ pain, fever, leukocytosis. Sigmoid colon is the most common site.
  • CT scan with contrast is the best diagnostic test.
  • Complications include abscess, fistula (colovesical is classic), obstruction, and perforation.
  • Uncomplicated cases: treat with bowel rest and oral antibiotics.
  • Complicated cases: require IV antibiotics. Abscesses >4 cm need percutaneous drainage.
  • Peritonitis or perforation mandates emergency surgery (e.g., Hartmann procedure).
  • Prevent recurrence with a high-fiber diet after resolution.

Practice Questions: Diverticulitis

Test your understanding with these related questions

A 46-year-old woman comes to the emergency department because of intermittent abdominal pain and vomiting for 2 days. The abdominal pain is colicky and diffuse. The patient's last bowel movement was 3 days ago. She has had multiple episodes of upper abdominal pain that radiates to her scapulae and vomiting over the past 3 months; her symptoms subsided after taking ibuprofen. She has coronary artery disease, type 2 diabetes mellitus, gastroesophageal reflux disease, and osteoarthritis of both knees. Current medications include aspirin, atorvastatin, rabeprazole, insulin, and ibuprofen. She appears uncomfortable. Her temperature is 39°C (102.2°F), pulse is 111/min, and blood pressure is 108/68 mm Hg. Examination shows dry mucous membranes. The abdomen is distended and tympanitic with diffuse tenderness; bowel sounds are high-pitched. Rectal examination shows a collapsed rectum. Her hemoglobin concentration is 13.8 g/dL, leukocyte count is 14,400/mm3, and platelet count is 312,000/mm3. An x-ray of the abdomen is shown. Which of the following is the most likely cause of this patient's findings?

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Flashcards: Diverticulitis

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Cholecystitis can cause _____ formation with the GI tract, resulting in air in the biliary tree (pneumobilia)

TAP TO REVEAL ANSWER

Cholecystitis can cause _____ formation with the GI tract, resulting in air in the biliary tree (pneumobilia)

fistula

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