Can diverticulitis persist on imaging after treatment?

Can Diverticulitis Persist on Imaging After Treatment?

Yes, diverticulitis can persist on imaging after treatment, with approximately 5% of patients experiencing "smoldering diverticulitis"—characterized by continued abdominal pain and persistent inflammatory changes on CT scan despite initial treatment. 1

Understanding Persistent Imaging Findings

Smoldering Diverticulitis

• Smoldering diverticulitis is a distinct clinical entity where patients continue to have abdominal pain and CT evidence of inflammation after an acute episode, affecting approximately 5% of patients who undergo treatment for acute uncomplicated diverticulitis 1
• This represents a failure of complete resolution rather than recurrent disease, and is different from segmental colitis associated with diverticular disease (SCAD) 1

Timing of Imaging Resolution

• Colonoscopy should be delayed 6-8 weeks after acute diverticulitis or until complete resolution of acute symptoms, whichever is longer, indicating that inflammatory changes are expected to persist for at least this duration 1
• The severity and duration of the initial episode are relevant considerations for determining when imaging findings should normalize 1

Clinical Implications of Persistent Findings

When to Suspect Persistent Disease

• Patients with mean pain scores ≥3.75 during the first 10 days of disease have 2.77 times higher odds of persistent symptoms (OR = 2.77,95% CI 1.60-4.80) 2
• Prolonged time to recovery (≥28 days) increases the risk of persistent symptoms by 2.25-fold (OR = 2.25,95% CI 1.31-3.88) 2
• More than one-third (32.2%-38.2%) of patients experience persistent symptoms at 1-2 years after an episode of uncomplicated diverticulitis 2

Prognostic Value of CT Findings

• CT findings during the acute phase predict clinical outcomes: colonic wall thickness <9 mm correlates with only 19% recurrence risk, while more severe CT findings predict higher rates of treatment failure 3
• Severe diverticulitis on CT (presence of abscess, extraluminal air/contrast) has a 26% medical treatment failure rate compared to only 4% for moderate disease 4
• Patients with severe CT findings have significantly worse secondary outcomes after successful initial medical treatment (36% vs 17% for moderate disease, p<0.0001) 4

Management of Persistent Imaging Findings

Indications for Repeat Imaging

• CT should be considered in patients who fail to improve with therapy to confirm persistent inflammation and exclude complications 1
• Imaging is also indicated for patients with multiple recurrences who are contemplating prophylactic surgery to confirm diagnosis and location(s) of disease 1

Treatment Considerations for Persistent Disease

• Elective surgery should be discussed for patients with uncomplicated diverticulitis that is persistent or recurs frequently (conditional recommendation, low-certainty evidence) 1
• The decision for surgery should be personalized based on discussion of potential benefits, harms, costs, and patient preferences 1
• Patients with CT evidence of abscess have a 41.2% recurrence rate when treated conservatively, compared to 13% for mild cases, supporting consideration of elective surgery after resolution 5

Common Pitfalls and Caveats

Distinguishing Persistent Inflammation from Malignancy

• Absence of a mass lesion on CT does not exclude underlying colonic neoplasm, which is why colonoscopy is recommended after complicated diverticulitis and after first episodes of uncomplicated diverticulitis 1
• The pooled prevalence of colon cancer among patients with diverticulitis is 1.9%, but rises to 7.9% in complicated cases 1

Risk Factors for Persistent/Severe Disease

• Immunocompromised patients (corticosteroid use, chemotherapy, transplant recipients) are more likely to present with severe or complicated disease and may have persistent findings 1
• Risk factors for progression to complicated disease include ASA score III-IV, symptoms >5 days, vomiting, CRP >140 mg/L, WBC >15×10⁹/L, and longer segments of inflammation on baseline CT (86mm vs 65mm) 1

Long-term Symptom Burden

• The top 5 persistent complaints at 12-24 months are flatulence, rumblings, bloating, fullness, and frequent stools, even when acute inflammation has resolved 2
• Quality of life impairment persists in over one-third of patients regardless of whether initial treatment was with antibiotics or observation 2