Diverticular Disease

Intro & Pathophysiology - Gut's Little Outpouchings

• Diverticulosis: Presence of uninflamed diverticula (outpouchings).
• Diverticulitis: Inflammation and infection of diverticula.
• True vs. False Diverticula (📌 Key Difference):
  • True: Involves all three gut wall layers (mucosa, submucosa, muscularis propria). E.g., Meckel's diverticulum.
  • False (Pulsion/Pseudodiverticula): Herniation of mucosa and submucosa through the muscularis propria at weak points. Common in colon.

    ⭐ False diverticula (pulsion type) are common in the colon, lacking a muscularis propria layer.

• Commonest Location: Sigmoid colon (~95%); narrowest segment, highest intraluminal pressure (Law of Laplace).
• Epidemiology: ↑ with age; >50% by 60 years. Prevalence: Western > Asian populations.
• Risk Factors: Low-fibre diet, obesity, sedentary lifestyle, chronic constipation, smoking, NSAIDs.
• Pathophysiology:
  • Segmental ↑ intraluminal pressure (e.g., from straining with low-bulk stools).
  • Focal areas of weakness in colonic wall, typically where vasa recta penetrate the muscularis propria.
  • Altered colonic motility and structure (e.g., elastin changes).

Symptoms & Complications - When Pockets Inflame

• Diverticulosis:
  • Mostly asymptomatic.
  • May cause vague symptoms: bloating, chronic constipation, intermittent crampy LLQ discomfort.
• Acute Diverticulitis:
  • Acute, persistent LLQ pain (📌 'left-sided appendicitis').
  • Fever (often low-grade), nausea, vomiting.
  • Altered bowel habits (constipation > diarrhea).
  • Leukocytosis common.
• Complications: (Mnemonic: 📌 "FAB-PPHS" - Fistula, Abscess, Bleeding (Hemorrhage), Perforation, Phlegmon, Stricture)
  • Abscess: Most common; localized pus.
  • Phlegmon: Diffuse pericolic fat inflammation/cellulitis.
  • Fistula: 📌 Colovesical (most common; M>F) → pneumaturia, fecaluria, recurrent UTIs. Others: colovaginal, coloenteric.

  ⭐ The most common type of fistula in complicated diverticulitis is a colovesical fistula, presenting with pneumaturia or fecaluria.

  • Perforation: Contained (abscess) or Free (peritonitis → surgical emergency).
  • Stricture/Obstruction: Chronic inflammation → fibrosis, luminal narrowing.
  • Hemorrhage: Painless, arterial; often from right-sided diverticula (typically in diverticulOSIS).
• Hinchey Classification (Perforated Diverticulitis):

Diagnosis & Management - Spotting & Soothing Strategies

• Diagnosis: Diverticulosis
  • Often incidental finding (colonoscopy, barium enema).
• Diagnosis: Acute Diverticulitis
  • CT scan (abdomen/pelvis with contrast): Investigation of choice. Shows inflamed diverticula, wall thickening, pericolic fat stranding, abscess.
  • 
  • ⚠️ Avoid colonoscopy/barium enema in acute phase (risk of perforation).
  • Labs: CBC (↑leukocytosis), ↑CRP.

⭐ Contrast-enhanced CT scan of the abdomen and pelvis is the gold standard for diagnosing acute diverticulitis and its complications.

• Management: Asymptomatic Diverticulosis
  • High-fibre diet, hydration, physical activity.
• Management: Symptomatic Uncomplicated Diverticulosis
  • Fibre, antispasmodics (controversial).
• Management: Acute Diverticulitis

• Management: Acute Uncomplicated Diverticulitis
  • Outpatient: Clear liquid diet, oral broad-spectrum antibiotics (e.g., ciprofloxacin + metronidazole for 7-10 days).
• Management: Acute Complicated Diverticulitis
  • Hospitalization, NPO, IV fluids, IV antibiotics.
  • Percutaneous drainage for abscess >3-4 cm.
  • Surgery for perforation, obstruction, fistula, or failure of medical management (e.g., Hartmann's procedure).

High‑Yield Points - ⚡ Biggest Takeaways

• Diverticulosis: Acquired false diverticula (mucosa/submucosa herniation) of the colon.
• Sigmoid colon is the most common site due to highest intraluminal pressure.
• Low-fiber diet is a key etiological factor.
• Diverticulitis: Inflammation/infection of diverticula; presents with LLQ pain, fever, and leukocytosis.
• Most common complication: Diverticulitis; painless, massive lower GI bleeding also occurs.
• Colovesical fistula is the most frequent fistula type following diverticulitis.
• CT scan is preferred for diagnosing acute diverticulitis; colonoscopy is contraindicated in the acute phase due to perforation risk.