What is the best management approach for a patient with diverticulosis, presenting with right flank pain, a negative computed tomography (CT) scan, and no significant past medical history?

Management of Diverticulosis with Right Flank Pain and Negative CT

For a patient with diverticulosis presenting with right flank pain and a negative CT scan, the diagnosis is NOT diverticulitis, and the focus should shift to identifying alternative causes of the pain while implementing preventive strategies to reduce future risk of diverticulitis. 1

Immediate Clinical Assessment

This patient does not have acute diverticulitis. A negative CT scan effectively rules out diverticulitis, as CT has 98-99% sensitivity and 99-100% specificity for this diagnosis. 1, 2 The right flank location further argues against typical left-sided diverticulitis, though right-sided disease occurs in less than 1% of Western patients. 3

Alternative Diagnoses to Consider

With diverticulosis present but CT negative for inflammation, evaluate for:

• Renal pathology: Nephrolithiasis, pyelonephritis, or renal infarction (right flank pain is classic) 1
• Gynecologic causes in women: Ovarian torsion, ruptured cyst, ectopic pregnancy 1
• Musculoskeletal pain: Costochondritis, muscle strain 1
• Visceral hypersensitivity: Approximately 45% of patients report ongoing abdominal pain after diverticular disease, usually attributable to visceral hypersensitivity rather than inflammation 1, 4

Order urinalysis, pregnancy test if applicable, and consider renal ultrasound if suspicion for renal pathology is high. 1

Management of Underlying Diverticulosis

Since this patient has documented diverticulosis (even without active diverticulitis), implement evidence-based preventive strategies to reduce the 10-25% lifetime risk of progression to diverticulitis. 2, 3

Dietary Modifications (Highest Priority)

Prescribe a high-fiber diet with >22.1 grams daily from fruits, vegetables, whole grains, and legumes. This threshold shows statistically significant protective effects against diverticulitis. 4, 5 Fiber from fruits appears most protective compared to other sources. 4, 5

• Start fiber gradually to minimize bloating 4, 5
• Dietary sources are preferred over supplements alone, though fiber supplementation can be beneficial as an adjunct 4, 5
• Explicitly counsel the patient that nuts, seeds, popcorn, and corn do NOT increase diverticulitis risk—this outdated restriction lacks evidence and may reduce overall fiber intake 1, 4, 5, 6

Lifestyle Modifications

Recommend regular vigorous physical activity to decrease diverticulitis risk. 4, 5

Advise achieving or maintaining BMI 18-25 kg/m², as obesity increases risk. 4, 5, 2

Strongly counsel smoking cessation if applicable, as smoking is an established risk factor for diverticulitis progression. 4, 5, 2, 3

Medication Review

Minimize NSAID use when possible, as these medications are associated with increased diverticulitis risk. 4, 5, 2, 3 Aspirin does not need to be routinely avoided. 4, 5

Minimize opioid use when possible, as opioids increase diverticulitis risk. 4, 2, 3

If the patient is on chronic corticosteroids, recognize this elevates both diverticulitis flare risk and complication risk including perforation. 4

What NOT to Do

Do not prescribe antibiotics. There is no role for prophylactic antibiotics in asymptomatic diverticulosis. 4, 5

Do not prescribe mesalamine or rifaximin for prevention—these have no proven benefit and the AGA strongly recommends against mesalamine. 4, 5

Do not prescribe probiotics for prevention—very low-quality evidence shows no benefit. 5

Do not order colonoscopy unless the patient is >50 years without recent screening or has alarm symptoms (rectal bleeding, iron deficiency anemia, weight loss, change in stool caliber). 1, 3 Routine colonoscopy is not indicated for asymptomatic diverticulosis. 5

Follow-Up Strategy

If pain persists beyond 7 days or worsens, re-evaluate with repeat imaging to exclude evolving pathology. 1, 4

If chronic abdominal pain develops after excluding structural causes, consider visceral hypersensitivity and treat with low-dose tricyclic antidepressants (e.g., amitriptyline 10-25 mg at bedtime). 1, 4

Educate the patient that approximately 50% of diverticulitis risk is genetic, so family history matters, but modifiable factors still play a crucial role. 4, 5

Critical Pitfall to Avoid

Do not treat this as diverticulitis simply because diverticulosis is present. The negative CT scan excludes active inflammation, and empiric antibiotics would be inappropriate, contributing to antibiotic resistance without clinical benefit. 1, 4