Special Surgery 19. Colon Diverticulosis, Diverticulitis: Symptoms, Diagnosis, Conservative Treatment, Surgical Indications

I. Colon Diverticulosis

Definitions and Classification

• Diverticulum: outpouching of gut wall
• Diverticulosis: presence of multiple diverticula
• Colonic diverticula are usually false diverticula / pulsion diverticula
• Most common site: sigmoid colon in Western countries; right-sided disease is more common in East Asia

1. According to Histology

• True diverticulum: all bowel wall layers protrude, usually congenital
• False diverticulum: only mucosa and submucosa protrude through muscle, usually acquired

2. According to Pathomechanism

• Pulsion diverticulum: increased intraluminal pressure + focal wall weakness → usually false
• Traction diverticulum: external traction pulls wall outward → usually true

Etiology

• Risk factors: low-fiber diet, constipation, increasing age, obesity, smoking, connective tissue disorders

Clinical Features

• Usually asymptomatic

Symptomatic Uncomplicated Diverticular Disease

• LLQ pain or cramps, often relieved by defecation
• Bloating
• Altered bowel habit
• No fever/leukocytosis/CT inflammation

Diverticular Bleeding

• Painless hematochezia, sometimes massive

Diagnosis

• Often incidental on colonoscopy or imaging
• Colonoscopy: detects diverticula and excludes cancer/polyps; avoid during acute diverticulitis
• CT colonography / barium enema can show diverticula if colonoscopy incomplete

Treatment

• High-fiber diet / lifestyle modification
• Weight reduction if obese
• Regular physical activity
• Smoking cessation
• No specific drug treatment unless complications occur

II. Diverticulitis: Symptoms and Diagnosis

Definition and Clinical Features

• Diverticulitis: inflammation/infection of one or more diverticula
• Often caused by fecalith obstruction of diverticular neck → microperforation → inflammation
• Classical triad: LLQ pain + fever + leukocytosis
• Other symptoms: altered bowel habit, nausea, vomiting, localized tenderness, palpable tender mass if abscess/phlegmon
• Generalized peritonitis suggests free perforation

Complications

• Abscess → sepsis
• Diverticular perforation → purulent/fecal peritonitis, sepsis
• Fistula, especially colovesical
• Stricture / obstruction
• Diverticular bleeding / hematochezia

Hinchey Classification

• Stage I: pericolic abscess/phlegmon
• Stage II: pelvic or distant intra-abdominal abscess
• Stage III: purulent peritonitis
• Stage IV: fecal peritonitis

Diagnosis

Laboratory

• Increased WBC/leukocytosis, increased CRP

Imaging

• Contrast-enhanced CT abdomen/pelvis: gold standard

• Bowel wall thickening
• Pericolic fat stranding
• Inflamed diverticula
• Abscess, extraluminal air/perforation, fistula or obstruction

Colonoscopy

• Colonoscopy: avoided during acute diverticulitis because of perforation risk
• Delayed colonoscopy after recovery, usually 6-8 weeks when indicated, to exclude cancer

III. Conservative Treatment

Uncomplicated Diverticulitis

• Uncomplicated = localized inflammation without abscess, free perforation, fistula, obstruction or sepsis

Mild Outpatient Treatment

• Clear fluids/light diet → gradual return to normal diet
• Pain management; avoid NSAIDs if possible
• Oral antibiotics when used: amoxicillin-clavulanate or ciprofloxacin + metronidazole depending on local protocol
• Close follow-up and return if fever, worsening pain, vomiting or sepsis signs

Hospitalization / Inpatient Treatment

When to Hospitalize

• Elderly/frail, immunocompromised, significant comorbidity, severe symptoms, sepsis concern, unable to tolerate oral intake/antibiotics, failed outpatient treatment, complicated CT finding

Inpatient Conservative Treatment

• Nil by mouth or clear liquids initially
• IV fluids and electrolyte correction
• IV antibiotics covering Gram-negative and anaerobic bacteria
• Analgesia, antiemetics, serial abdominal exams and labs

Abscess Management

• Small pericolic abscess: antibiotics and observation may be enough
• Larger or pelvic/intra-abdominal abscess: CT-guided/percutaneous drainage + antibiotics
• Emergency surgery if drainage impossible and sepsis persists or perforation/peritonitis develops

IV. Surgical Indications and Procedures

Surgical Indications

Emergency Surgery

• Diffuse peritonitis / Hinchey III-IV
• Free perforation with sepsis
• Failure of conservative treatment or worsening condition
• Large abscess not suitable for percutaneous drainage
• Obstruction, uncontrolled bleeding, or severe sepsis

Elective Surgery

• Recurrent attacks with significant symptoms / quality-of-life impairment
• Complicated diverticulitis after recovery: abscess, fistula, stricture/obstruction
• Suspicion of malignancy not excluded
• Decision individualized; not only by number of attacks

Operative Options

Hartmann Procedure

• Sigmoid/proctosigmoid colectomy + end colostomy + closed rectal stump

• Used especially in unstable patients, severe sepsis, fecal peritonitis, high operative risk or unsafe anastomosis
• Reanastomosis/stoma reversal can be considered later after recovery, but is not guaranteed

Primary Resection with Anastomosis

• Colectomy with colorectal anastomosis
• Stable patients with acceptable tissue quality and lower risk
• May include diverting loop ileostomy

Elective Sigmoid Colectomy

• Usually laparoscopic after inflammation resolves
• Resect diseased sigmoid segment and restore continuity with colorectal anastomosis