Diverticular disease

Presence of outpouchings (diverticula) in the colonic wall, most often in the sigmoid colon. Diverticulosis refers to these mucosal outpouchings (usually asymptomatic, but can cause bleeding), while diverticulitis refers to inflammation/infection of a diverticulum.

• Very common in older adults (over 50% of people >60 have diverticulosis), though only ~4% develop diverticulitis. It's a leading cause of lower GI bleeding and a frequent cause of left-sided abdominal pain on exams. Early recognition of diverticulitis (often called "left-sided appendicitis") and its complications (perforation, abscess, fistula, etc.) is crucial to prevent severe outcomes.

• Diverticulosis: usually asymptomatic; may be discovered incidentally on colonoscopy or CT. Can cause painless hematochezia (diverticular bleeding from stretched vessels). Risk factors include low-fiber diet, obesity, smoking, NSAIDs; most common in sigmoid colon in Western patients (right colon in Asian populations).
• Diverticulitis: steady, aching left lower quadrant (LLQ) pain, fever, and leukocytosis. Patients (often >50 years) may have constipation or diarrhea; LLQ tenderness on exam (sometimes a palpable mass if abscess). Peritoneal signs (guarding, rigidity) suggest perforation. Colovesical fistulas can cause urinary symptoms (dysuria or pneumaturia). Bleeding is usually minimal in diverticulitis (contrast with diverticulosis).
• Complicated cases: may present with abscess (continued fever despite antibiotics), peritonitis from perforation (diffuse abdominal pain), fistula (e.g., recurrent UTIs or gas in urine with colovesical fistula), or obstruction from chronic stricturing.

1. Diagnosis: CT scan of abdomen/pelvis is the test of choice to confirm diverticulitis and assess severity. Avoid colonoscopy during acute diverticulitis (risk of perforation); perform colonoscopy ~6 weeks after recovery to rule out colon cancer.
2. Outpatient vs. inpatient: Uncomplicated diverticulitis (localized inflammation, no abscess/perforation) in a stable patient can be managed outpatient with oral antibiotics and a clear liquid diet. Indications for hospitalization include inability to tolerate oral intake, high fever or sepsis, diffuse peritonitis, significant comorbidities, or immunocompromise.
3. Antibiotics: Regimens must cover Gram-negatives & anaerobes. Outpatient options include ciprofloxacin + metronidazole or monotherapy like amoxicillin-clavulanate. Inpatient IV options include piperacillin-tazobactam or a 3rd-gen cephalosporin + metronidazole. For mild cases in healthy patients, a selective no-antibiotic approach is sometimes used, but antibiotics are standard if any complication or risk factors.
4. Complications management: An abscess >4 cm often requires CT-guided percutaneous drainage in addition to antibiotics. Free perforation with peritonitis requires emergency surgery (typically sigmoid resection with diversion). Fistulas or strictures usually need elective surgical repair once inflammation settles.
5. After recovery: High-fiber diet is recommended to prevent recurrence. Counsel to avoid NSAIDs and smoking. Recurrent or persistent diverticulitis episodes — especially if complications occur — may warrant elective sigmoid colectomy, but decisions are individualized (no fixed "number of attacks" threshold).

1. Uncomplicated diverticulitis: outpatient antibiotics and clear liquid diet; if pain or fever is severe, hospitalize for IV antibiotics and analgesia.
2. Abscess complication: add percutaneous drainage (for abscess >4 cm) to antibiotic therapy.
3. Perforation or obstruction: urgent surgical intervention (e.g., Hartmann's procedure or primary resection) is often needed for free perforation (peritonitis), fistula, or obstruction.
4. Diverticular bleeding: most episodes resolve spontaneously; severe persistent bleeding may require colonoscopic intervention (e.g., cautery, clipping), arterial embolization, or surgical resection.

• Mnemonic: Osis = Oozes, Itis = Inflamed. Diverticulosis tends to ooze blood (painless bleeding), while diverticulitis is inflamed, causing pain ± fever.
• Diet myth: Patients with diverticulosis do not need to avoid nuts, seeds, or popcorn – these do *not* increase diverticulitis risk.

• Rigid abdomen, guarding, or rebound tenderness in diverticulitis → suspect perforation with peritonitis (surgical emergency).
• Air or feces in urine (pneumaturia or fecaluria) → likely colovesical fistula (colon-bladder connection), usually from prior diverticulitis.
• Profuse bright red rectal bleeding with hypotension → possible diverticular hemorrhage (lower GI bleed) needing rapid stabilization and intervention.

1. Incidental diverticulosis (no symptoms) → high-fiber diet and risk factor modification (exercise, weight management) to prevent diverticulitis.
2. Suspected diverticulitis (LLQ pain, fever) → labs (CBC, CRP) and CT scan to confirm & assess for complications (avoid colonoscopy in acute phase).
3. If uncomplicated diverticulitis confirmed: manage conservatively – oral antibiotics + liquid diet outpatient if stable; admit for IV antibiotics if high fever, significant pain, or unable to tolerate oral intake.
4. If complicated (abscess, perforation, fistula, obstruction): involve surgery. Drain abscesses >4 cm; emergency surgery for diffuse peritonitis; plan elective surgery for fistula or recurrent disease.
5. After resolution of diverticulitis: perform colonoscopy in ~6 weeks (especially if first episode or any atypical features) to exclude colon cancer. Discuss elective sigmoid resection for patients with frequent recurrences or complications (individualized decision).

• Older adult with LLQ pain, fever, and leukocytosis → Acute diverticulitis (likely sigmoid) requiring antibiotics and bowel rest.
• Elderly patient with sudden painless large-volume bright red hematochezia → Diverticular bleeding from colonic diverticulosis (often stops spontaneously).
• Patient with recurrent diverticulitis history now has pneumaturia (air in urine) and UTIs → Colovesical fistula formation (requires surgical repair).