Diverticulitis

Hinchey classification (modified)

Staging system for perforated diverticulitis, used to guide management and as the entry criterion for SCANDIV and related lavage-vs-resection trials:

Stage	Description
I	Pericolic/mesenteric abscess or phlegmon
II	Pelvic, distant intra-abdominal, or retroperitoneal abscess
III	Generalized purulent peritonitis
IV	Generalized fecal peritonitis

Stages I-II are generally amenable to non-operative or percutaneous management; III-IV are the surgical-emergency stages and the population studied in the lavage-vs-resection trials below. Note (per SCANDIV): preoperative differentiation between Hinchey III (purulent) and IV (fecal) is not reliably possible — patients selected for lavage should have consent for resection secured as a backup.

Modified CT-based Hinchey reclassification, per ASCRS Ch38 - Colonic Diverticular Disease: a more granular CT-imaging-specific system used clinically alongside the classic Hinchey stages above. Grade 0 — colonic wall thickening without pericolonic fat stranding. Grade 1a — wall thickening with pericolonic fat stranding. Grade 1b — pericolonic or mesocolic abscess. Grade 2 — distant intra-abdominal or pelvic abscess. Grade 3 — purulent peritonitis. Grade 4 — fecal peritonitis. (Grades 1a/1b/2/3/4 map onto classic Hinchey I/I/II/III/IV respectively, with grade 0 added as a distinct mild category below classic Hinchey I.) CT-graded severity correlates with postoperative morbidity/mortality and, in patients managed nonoperatively, with recurrence — one study found severe CT findings (wall thickening + abscess, extraluminal air, or extraluminal contrast) were associated with more frequent operative intervention (33% vs. 15%) than mild findings, and another found severe CT findings on an index attack predicted higher recurrence with antibiotic-only treatment (39% vs. 14%). CT is limited in distinguishing grade 3 from grade 4 peritonitis, mirroring the same preoperative Hinchey III-vs-IV ambiguity noted above.

Diagnostic evaluation

Per ASCRS Ch38 - Colonic Diverticular Disease: laboratory testing is of limited value — CRP, procalcitonin, and fecal calprotectin have all been studied as adjuncts for discriminating uncomplicated from complicated diverticulitis, but the evidence base is limited to small case series with inconsistent cutoff values; one study found CRP >150 mg/L (combined with free fluid on CT) associated with increased mortality. Not yet recommended for routine use, though may gain a larger evidence base over time.

CT is the imaging modality of choice for suspected acute diverticulitis, given superior performance over plain films and ultrasound (95% sensitivity/90% specificity for intestinal perforation, vs. 53%/53% for plain film and 92%/53% for ultrasound). MRI is comparable to CT for diagnosing obstruction/ischemia and useful when ionizing radiation should be avoided. A water-soluble contrast enema has 96% sensitivity/98% specificity but does not typically elucidate etiology, limiting its clinical usefulness relative to CT.

Endoscopic evaluation: colonoscopy 4–8 weeks after recovery (already noted above) is recommended primarily to exclude malignancy — quantified per Ch38: the pooled prevalence of colorectal cancer across a meta-analysis of 17 studies/3296 patients was 2.1% (95% CI 1.5–3.1%) overall, but rose sharply with complicated diverticulitis specifically — one study found 7.9% malignancy after a complicated attack vs. 1.3% after an uncomplicated one (another found 11% vs. 0.7%). This risk gradient is the practical rationale for the post-attack colonoscopy recommendation being strongest after complicated disease. Endoscopy is generally deferred during the acute episode itself (theoretical risk of converting a sealed microperforation into a free perforation), though this has been questioned by groups demonstrating safety of acute-phase colonoscopy in select cases; when performed acutely, a significant proportion of procedures cannot be completed.

Complicated diverticulitis short of generalized peritonitis (Hinchey Ib–III)

Per ASCRS Ch38 - Colonic Diverticular Disease: management of diverticular abscesses (Hinchey Ib/II) is difficult to compare across the literature owing to significant selection bias — smaller abscesses (<3cm) are predominantly treated with antibiotics alone, while larger abscesses are treated with percutaneous drainage or surgery. One large multicenter observational study of 447 patients found a significantly higher treatment-failure rate with percutaneous drainage vs. antibiotics alone (36% vs. 24%) — but with more complications in the subgroup with a large/distant abscess. A systematic review of 7653 antibiotic-treated patients found 25.5% overall recurrence (vs. 15% after percutaneous drainage). Practical synthesis: percutaneous drainage may be considered for abscesses >3cm; emergent surgery is reserved for patients who fail standard nonoperative management.

Hinchey III (purulent peritonitis) nonoperative management: appropriate in select clinically stable patients without fever, hemodynamic changes, or toxicity, tailored to CT findings — case series suggest this is effective in the majority of carefully selected patients, though CT with rectal contrast (an unproven potential refinement) may help rule out an overt bowel-lumen-to- peritoneal-cavity connection (Hinchey IV) before committing to a nonoperative course.

Perforated diverticulitis: lavage vs. resection

Central open question in managing Hinchey III perforated diverticulitis. Two strategies:

• Laparoscopic peritoneal lavage — washout + drainage, no resection. Faster, avoids stoma in most cases, but does not remove the diseased segment.
• Primary resection — sigmoid colectomy, with or without primary anastomosis (± diverting loop ileostomy) or as a Hartmann's procedure (resection + end colostomy). Definitive, but more morbid up front and (per SCANDIV) leaves ~1 in 3 patients with a stoma even at 5 years.

Two major RCTs now in this wiki, both comparing lavage to resection for Hinchey III:

SCANDIV 5-year data (Azhar 2021 - SCANDIV 5-Year Outcomes): no difference between lavage and resection in severe complications (29% vs 25%), mortality (32% vs 25%), or QoL. Lavage: much lower stoma prevalence (8% vs 33%) but higher recurrence (21% vs 4%) and higher unplanned reoperation rate (26% vs 12%); 30% of lavage patients eventually needed sigmoid resection anyway. Most events (both arms) occurred within year 1.

Ladies trial (LOLA group) (Vennix 2015 - Ladies Trial LOLA): more cautionary — stopped early after an interim safety signal (18 vs 2 in-hospital reinterventions, p=.001); 30-day major morbidity significantly higher with lavage (39% vs 19%, p=.043). No difference in the 12-month primary composite or in mortality/QoL. Recurrence: 20% vs 2% (p=.03).

DILALA trial (per ASCRS Ch38 - Colonic Diverticular Disease, cited at the textbook/ secondary level only — not yet independently ingested from Thornell et al. or Kohl et al.'s primary publications): the third major European lavage-vs-resection RCT, alongside SCANDIV and Ladies/LOLA above. No significant difference in early (30-day) reintervention rate (13.2% lavage vs. 17.1% Hartmann's, p=.67), but at 24-month follow-up the lavage group had a 45% relative risk reduction in the odds of undergoing any reoperation. This is a third distinct short-term-morbidity signal — neither replicating Ladies' stark early-morbidity harm signal nor SCANDIV's null finding, and if anything leaning toward benefit — deepening rather than resolving the cross-trial discordance noted below. A separate comparative figure (Fig. 38.1 in the source chapter) tracking all three trials' outcomes at 1 year shows a consistent pattern across all three: lavage → lower "never had a stoma" burden and higher "stoma-free and alive at one year," at the cost of more reoperation — broadly consistent with the SCANDIV/Ladies findings already detailed below. Lavage has also been shown more cost-effective than resection in at least one economic analysis.

Cross-trial synthesis: the recurrence-after-lavage finding is consistent and robust across both independent RCTs with recurrence data (~20-21% vs ~2-4%) — probably the most trustworthy single data point in this area so far. The short-term morbidity picture is not consistent across all three trials: stark and trial-stopping in Ladies, absent by SCANDIV's 5-year report, and directionally favorable (though not significant at 30 days) in DILALA. Not yet clear whether this is a real discordance (different patient selection, different Hinchey III confirmation protocols) or an artifact of different endpoints/timepoints — flagged as an open question, see SCANDIV Trial for detail.

Guideline positions diverge:

• ASCRS (2020) — strong recommendation for resection over lavage in purulent peritonitis.
• ESCP — considers lavage feasible in selected Hinchey III patients.

Framed by both trials' authors as a shared-decision-making trade-off (lower stoma risk vs. higher reoperation/recurrence risk, and in Ladies trial's case, higher short-term morbidity) rather than a settled question.

A recurring theme across both papers: Hinchey III (purulent) vs. IV (fecal) peritonitis cannot be reliably distinguished preoperatively or even at limited intraoperative exploration — a meaningful share of lavage "failures" in both trials trace back to misdiagnosed fecal peritonitis or an underlying perforated carcinoma. Both papers suggest CT with rectal contrast as an unproven potential fix, not routinely used.

Hartmann's procedure vs. primary anastomosis (given resection is happening)

A distinct question from lavage-vs-resection above: once the decision is made to resect, should the surgeon end with a stoma (Hartmann's) or restore continuity (primary anastomosis, ± defunctioning ileostomy)? The LADIES DIVA trial (Lambrichts 2019 - LADIES DIVA Trial) gives a clear answer, in contrast to the more contested lavage-vs-resection debate: primary anastomosis strongly favored — 12-month stoma-free survival 94.6% vs 71.7% (HR 2.79, p<0.0001) in hemodynamically stable, immunocompetent patients under 85. Benefit held (and was even larger) in Hinchey IV (fecal peritonitis) vs. Hinchey III, with no difference in short-term morbidity/mortality after the index procedure, and notably lower morbidity after stoma reversal with primary anastomosis (8% vs 30%) — reversing an ileostomy is a simpler procedure than reversing a Hartmann's colostomy. This is the wiki's first source covering Hinchey IV disease specifically.

Corroborating cohort data, per ASCRS Ch38 - Colonic Diverticular Disease (four RCTs' inclusion/exclusion criteria — Oberkofler, Binda, Bridoux, Lambrichts/DIVA itself — plus cumulative cohort data comparing primary anastomosis (PA) to Hartmann's procedure (HP) for Hinchey III/IV perforated diverticulitis): a large cohort series (n=529 PA / 366 HP) found significantly lower mortality with PA (7.9% vs. 19.5%, p<0.0001) and higher stoma closure rate (86% vs. 68%), though similarly comparing PA-selected to HP-selected populations carries the same selection-bias caveat as any non-randomized comparison (sicker/less stable patients more likely to receive a Hartmann's). Directionally consistent with DIVA's randomized findings above, but not independently randomized evidence itself.

Uncomplicated (non-perforated) diverticulitis

Per Sabiston Ch52 - Diverticular Disease, Obstruction & Pseudo-Obstruction (textbook reference, not primary literature): individualized outpatient management is now standard for most cases.

• Antibiotics controversy: a systematic review/meta-analysis found no benefit from antibiotics in uncomplicated diverticulitis, prompting some clinicians to stop prescribing them routinely — described as an evolving practice shift rather than a settled guideline mandate. Named trials now identified, per ASCRS Ch38 - Colonic Diverticular Disease (cited at the textbook/ secondary level only — DIABOLO and AVOD not yet independently ingested from their primary publications): two large RCTs in immunocompetent, stable patients — DIABOLO and AVOD — found no difference in development of complicated diverticulitis, short- or long-term, with vs. without antibiotics (antibiotic-related complications up to 8% in DIABOLO, which included some patients with small abscesses). Despite level I evidence from both trials, practice has not reached consensus — a combined SAGES/EASC guideline effort failed to reach agreement, while the ASCRS 2020 left-sided-diverticulitis guidelines (in press at the time of the source chapter) recommend that "selected patients with uncomplicated diverticulitis can be treated without antibiotics."
• Ambulatory management: most patients with uncomplicated diverticulitis can be treated entirely outside the hospital — general practitioners successfully manage many without admission, with low readmission rates (~7%) and considerable cost savings; outpatient candidates should be hemodynamically stable, generally healthy-appearing, and without major comorbidity or immunosuppression.
• Dietary changes: little evidence that dietary modification alters the disease course during an acute episode — patients should be allowed a normal diet as tolerated rather than a restrictive one.
• Colonoscopy recommended 4–8 weeks after recovery to rule out an underlying malignancy — performed with awareness that severe diverticular disease (muscular hypertrophy, luminal narrowing) is itself a colonoscopic perforation risk factor, per Colonoscopy & Lower GI Endoscopy. See the Diagnostic evaluation section above for the complicated-vs-uncomplicated malignancy-yield gradient underlying this recommendation.
• Recurrence after a first uncomplicated episode: 10–35%.
• Symptomatic uncomplicated diverticular disease (SUDD) / IBS overlap: recurrent abdominal symptoms with loose stools in the presence of localized diverticular disease but without acute diverticulitis — a controversial entity, per ASCRS Ch56 - Functional Disorders After Colorectal Surgery-IBS, that may not be fully separable from Irritable Bowel Syndrome (IBS). Persistent diverticulitis-associated visceral hypersensitivity is one proposed mechanism. Practically relevant to surgical decision-making: patients with IBS-like functional complaints before elective resection for diverticular disease are less likely to have satisfactory symptomatic outcomes afterward, and persistent post-resection symptoms resembling IBS occur in up to 25% of patients despite resolved inflammation on pathology — worth factoring into preoperative counseling for elective resection driven primarily by chronic symptoms rather than recurrent acute episodes.

Elective surgery timing/indications

Indications have shifted away from the old "number of prior attacks" threshold toward individualized assessment (severity, comorbidity, QoL impact). This also overturns the older teaching that patients under 50 have more "virulent" disease warranting resection after a single uncomplicated episode — current evidence does not show elevated recurrence or emergency-surgery rates in younger patients, and current guidelines do not recommend treating them differently.

DIRECT trial (per ASCRS Ch38 - Colonic Diverticular Disease, cited at the textbook/ secondary level only — not yet independently ingested): a randomized study specifically comparing elective surgery to optimal conservative management for patients with ongoing complaints or recurrent attacks (i.e., the population this section is about, not the acute-attack population above) found superior quality of life with surgery, despite a relatively high complication rate. Patients should have CT-confirmed diverticulitis before enrollment in this decision, since symptoms overlapping with irritable bowel syndrome can mimic ongoing inflammation or recurrent attacks.

Special populations

• Right-sided diverticulitis — common in Asian populations, rare in the West; can mimic acute appendicitis; recurrent/complicated disease or diagnostic uncertainty favors resection (right hemicolectomy). Corroborating detail, per ASCRS Ch38 - Colonic Diverticular Disease: right- and left-sided diverticular disease are pathologically distinct — left-sided diverticula are, by definition, false diverticula (mucosal herniation through the bowel wall only), while right-sided diverticula are most often true diverticula (all bowel-wall layers). Literature on right-sided diverticulitis is scarce, but suggests it's less often associated with a complicated course than left-sided disease; once complicated, management principles are generally the same regardless of side.
• Immunocompromised patients (transplant, diabetes, renal failure/cirrhosis, steroids/ chemotherapy) — similar baseline prevalence of diverticulitis, but more likely to present with free perforation and complicated disease due to blunted inflammatory response; lower threshold for resection after a single attack; primary anastomosis generally avoided if emergency resection is required, given impaired healing/immune status. Quantified per Preoperative Evaluation & Perioperative Risk Optimization (ASCRS Ch6, citing Biondo's review): emergent operation rate ~40% vs. 10–25% in the general population, with mortality 6.9%. Practice-changing nuance from the same review, contrary to older teaching: prophylactic colectomy in immunosuppressed patients with diverticulitis cannot be recommended — the lower threshold above applies to management of an active/recurrent attack, not to prophylactic resection in quiescent disease. Solid organ transplant recipients specifically are covered in more detail on that page, including the note that early elective resection for transplant patients with diverticulitis is "no longer the case" as a blanket recommendation. Corroborating detail, per ASCRS Ch38 - Colonic Diverticular Disease: complicated diverticulitis may be more aggressive in immunocompromised patients with a higher incidence of free perforation, but overall the incidence of complicated diverticulitis in this population is only slightly higher (1%) than baseline — broadly consistent with the "similar baseline prevalence, more likely complicated when it occurs" framing above.
• The young — corroborating detail, per ASCRS Ch38 - Colonic Diverticular Disease: younger patients do not appear to have more virulent disease than older counterparts (consistent with the Elective surgery section above), but do carry a higher lifetime risk of recurrent disease simply from having more remaining years at risk. A systematic review found a slightly higher relative risk of emergent operation in the younger cohort (7.3% vs. 4.9%) — though this may reflect a more aggressive treatment approach or a higher rate of misdiagnosis (e.g., appendicitis) in younger patients, rather than more virulent underlying disease.

Fistula

Per ASCRS Ch38 - Colonic Diverticular Disease: complicated diverticular disease can form fistulas to adjacent organs, typically arising when a diverticular abscess decompresses through a nearby viscus.

• Colovesical fistula: characterized by pneumaturia, fecaluria, and recurrent urinary tract infections; cross-sectional imaging showing air in the bladder, or a urinary culture with multiple gut organisms, is usually diagnostic. May also be identified on cystoscopy. Most medically fit patients should be offered surgery to avoid recurrent urosepsis.
• Colovaginal fistula: typically arises in patients with a prior hysterectomy (loss of the uterus as a barrier structure between colon and vagina). Most patients complain of passing gas or stool per vagina; cross-sectional imaging is usually sufficient for diagnosis. Most patients with a significant colovaginal fistula will desire repair given the associated distressing symptoms.
• Colocutaneous fistula: usually results from a longstanding abscess that drains through the abdominal wall. Can initially be managed expectantly; patients with significant symptoms usually require or wish to have an elective operation.

Obstruction

Per ASCRS Ch38 - Colonic Diverticular Disease: diverticulitis-related large bowel obstruction should be treated surgically — colonic stenting, unlike its role in malignant obstruction (see Endoscopic Polypectomy, EMR & ESD), is generally not successful in this benign condition. An important diagnostic task is differentiating a diverticular stricture from colorectal cancer, given the very different resection approach required for malignancy (oncologic resection with lymphadenectomy) — see the Diagnostic evaluation section above for the underlying malignancy-risk data that motivates this caution.

Technical aspects of surgery

Per ASCRS Ch38 - Colonic Diverticular Disease. See Anastomotic Construction for this wiki's fuller, anatomically-general treatment of mobilization/perfusion-assessment technique that this chapter also contributes to (IMA preservation vs. ligation, splenic flexure mobilization outcome data, ureteral stents, anastomotic leak testing) — not repeated here to avoid duplication.

• Approach: three randomized trials and three meta-analyses have evaluated laparoscopy for sigmoid colectomy in diverticulitis; two of the three RCTs showed superiority of the laparoscopic approach over open surgery. Laparoscopy within an enhanced-recovery program is usually preferred in suitable elective cases (fewer complications, earlier recovery); Pfannenstiel incisions are associated with lower incisional hernia rates. Evidence is accumulating that a laparoscopic approach may also benefit emergency surgery specifically.
• Transection margins: most literature on extent of resection is retrospective and not particularly robust. The distal margin should be the proximal rectum — colorectal anastomoses have a lower recurrence rate than colocolic anastomoses. The proximal margin should be chosen where the bowel is not diseased (absence of bowel-wall thickening) — the presence of diverticula themselves should not guide the proximal margin, since diverticula alone don't indicate disease requiring resection.

Related pages

• Anastomotic Construction — this wiki's fuller, anatomically-general treatment of IMA preservation vs. ligation, splenic flexure mobilization outcome data, ureteral stents, and anastomotic leak testing evidence contributed by ASCRS Ch38 - Colonic Diverticular Disease.
• SCANDIV Trial and Ladies Trial (LOLA) — full trial-level detail for the two independently- ingested lavage-vs-resection RCTs referenced throughout this page.
• Colonoscopy & Lower GI Endoscopy — general colonoscopic perforation-risk context for the post-attack colonoscopy recommendation above.
• Preoperative Evaluation & Perioperative Risk Optimization — fuller immunocompromised/ transplant-recipient perioperative risk detail than this page's Special populations section.
• Large Bowel Obstruction — the condition-focused counterpart to this page's brief Obstruction section; diverticulitis-related obstruction is one of several LBO etiologies covered there.
• Lower Gastrointestinal Hemorrhage — diverticular bleeding (a distinct presentation from the inflammatory diverticulitis this page focuses on) is the most common cause of severe acute LGIB; that page covers bleeding-specific evaluation/endoscopic hemostasis technique not covered here.
• Irritable Bowel Syndrome (IBS) — full detail on the SUDD/IBS overlap and post-resection persistent-symptom data noted above.

Open items / gaps

• ~~No primary trial data yet on the antibiotics-vs-no-antibiotics question for uncomplicated diverticulitis — only the textbook chapter's characterization of a systematic review.~~ Partially resolved by ASCRS Ch38 - Colonic Diverticular Disease: the two named trials (DIABOLO, AVOD) are now identified — still not independently ingested from their primary publications, which remains worth doing.
• ~~DILALA and LapLAND trial data are referenced in ingested trials' discussions but not yet ingested as their own sources.~~ Partially resolved: DILALA's headline results are now captured above at the textbook/secondary level, per Ch38 — still not independently ingested from Thornell et al. or Kohl et al.'s primary publications. LapLAND remains completely unaddressed.
• Resolve (or find a source that resolves) the short-term-morbidity discordance between Ladies LOLA and SCANDIV — now a three-way discordance including DILALA (see above), not two-way.
• Patient selection criteria for primary anastomosis (hemodynamic stability, immunocompetence, age <85) come from DIVA's inclusion/exclusion criteria — Ch38's Table 38.3 corroborates similar (though not identical) criteria across three further RCTs (Oberkofler, Binda, Bridoux), but exact cross-trial consistency has not been checked in detail.
• ~~Colovesical fistula management (mentioned in Sabiston as typically requiring resection with fistula takedown) not yet covered in depth — no dedicated source.~~ Resolved by ASCRS Ch38 - Colonic Diverticular Disease — see the new Fistula section above (colovesical, colovaginal, colocutaneous).
• DIRECT trial (elective surgery vs. conservative management for ongoing/recurrent symptoms) and the Ambrosetti/Kaiser CT-severity studies are all cited by Ch38 at the textbook/secondary level only — none independently ingested from primary literature.
• No data yet on right-sided diverticulitis recurrence rates specifically, or on how frequently it is misdiagnosed as appendicitis preoperatively.