Diverticulitis

Introduction

• Low fibre, high fat, high refined carb diets promote decreased GI transit times leading to high intraluminal pressures and diverticula
• More common in obesity and sedentary lifestyles
• Central obesity in males increases risk of diverticulitis, complications and bleeding
• Also linked to smoking, alcohol, caffeine and ingestion of seeds and nuts but not causal
• Right sided disease in 2-5% in Western societies vs. left sided in Asian communities

Pathology

• Diverticula are small herniations at sites where the vasa recta penetrate the circular muscle layer of the colon
• True diverticula involve all layers, however, most are false diverticula involving only the mucosa and submucosa
• Diverticulitis thought to occur from inspissated faecal material leading to inflammation and microperforation
• Most common bacteria are anaerobes including Bacteroides, Peptostreptococcus, Clostridium and Fusobacterium + E. coli

Clinical presentation

• Classically LLQ pain, fever, leukocytosis
• RLQ or suprapubic pain seen with redundant colon, right-sided disease in Asian people
• May be intermittent or constant, diarrhoeal (30%) or constipation (50%)
• 50% have prior episodes of similar pain
• Nausea/vomiting in 60%, anorexia in 40%, urinary symptoms 10%

Diagnosis

• If stable, previously documented diverticulitis – no further Ix necessary
• If not previously confirmed or this presentation different to prior ones or failed conservative management – CT
• DDx is extensive including GI and GU pathologies
• CT with IV and oral contrast = 97% sensitivity and specificity nearing 100%
  • 98% will show fat stranding, 84% colonic diverticula, 70% bowel wall thickening >4mm and 35% of cases show soft tissue masses suggestive of phlegmon, pericolic fluid collections or abscesses
  • In 10% of cases, cannot be differentiated from carcinoma
• All patients should be referred for colonoscopy 6 weeks after resolution of symptoms to rule out carcinoma
• USS
  • Sensitivity 85-95% and specificity 80-98% and may be an option in pregnant females or younger non-obese individuals

Treatment

• Uncomplicated diverticulosis (70%) – High fibre diet, exercise
• Diverticular bleeding (5-15%)
  • Resuscitate, admit, colonoscopy
• Diverticulitis (15-25%)
  • Uncomplicated (nonsevere) (75%)
    • Well appearing, left-sided, immunocompetent, pain manageable and no perforation, peritonitis, sepsis or abscess >5cm
    • D/C home, clear diet
    • Has 90% success rate
    • 5-10% failure rate requiring admission and IV antibiotics
      • This failure rate is unchanged whether antibiotics are prescribed or not (Cochrane 2022)
    • NB: Antibiotics (Augmentin) are recommended if conservative treatment does not improve symptoms within 3 days
    • Colonoscopy required at 6-8 weeks only if imaging suggests possible malignancy, atypical sx (bleeding, narrowed stools) or delayed recovery (more than few days)
      • Risk of malignancy only 0.5% in uncomplicated diverticulitis (unless above criteria met)
  • Complicated (severe) (25%)
    • Ill-appearing, uncontrolled pain, vomiting, comorbidities, septic, perforated, abscess >5cm, right-sided or immunosuppressed
      • Admit, IV triple Abs/Augmentin/PipTaz, NBM, Surgical consultation
      • Need colonoscopy at 6-8 weeks after resolution due to 10% risk of carcinoma

Antibiotic regimes

• Outpatient (if symptoms persist despite conservative therapy)
  • Metronidazole 500mg q8h + Ciprofloxacin 500mg BD or
  • Clindamycin 300mg q6h or
  • Bactrim DS BD or
  • Augmentin BD or
  • Moxifloxacin 400mg PO OD
  • 7-14 day course
• Inpatient (moderate-severe)
  • Triples/PipTaz/IV Augmentin

Complications

• Phlegmon, abscess, stricture, obstruction, fistula or perforation
• Abscess can be drained percutaneously by radiology or surgically
• Perforation carries a high mortality rate
  • 13% for Hinchey Stage 3
  • 43% for Hinchey Stage 4

Disposition

• Discharge if well on clear diet uptitrating as tolerated
• Surgical referral
  • Second episode of diverticulitis
  • Extensive disease
  • Complicated first episode
  • Significant comorbidities
  • Immunosuppression

Young patients

• Patients <40 constitute <2% of cases
• Tend to be obese
• Disease is thought to be more virulent than older counterparts
• Show higher rates of recurrence, complications and surgical intervention
• Higher rates of re-admission
• Consider surgical referral in first presenters

Meckel diverticulitis

• True congenital diverticula
• Seen in 2% of population, 2ft from ileocaecal junction, symptomatic in 2% of patients
• Crampy abdo pain, nausea/vomiting and pR bleeding
• Often confused with appendicitis

Epiploic appendages

• Small fatty sacs near lining of colon that can become inflamed
• Typically afebrile, middle-aged, sharp abdominal pain with nausea/vomiting
• Usually benign, self-limiting course identified on CT

Diverticular bleeding

• Painless rectal bleeding usually self-limited
• Accounts for 23% of lower GI bleed
• Occurs when dome of diverticulum erodes into medial surface of vasa recta
• Not associated with diverticulitis

Last Updated on July 18, 2023 by Andrew Crofton