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Acute diverticulitis
Background
Overview
Definition
Acute diverticulitis is a disease resulting from acute inflammation and/or micro-perforation of colonic diverticula.
1
Pathophysiology
The putative etiology of acute diverticulitis include alterations in colonic structure, colonic motility, microbiome, genetics, immune system, in addition to connective tissue disorders and environmental factors (obesity, smoking, NSAIDs).
2
Epidemiology
The incidence of acute diverticulitis has increased in the past several decades and is estimated at 188 cases per 100,000 person-years in the US.
3
Disease course
Alterations in gut motility, intraluminal pressure, and the accumulation of inspissated fecal particles in diverticula leads to erosion of the diverticular wall, causing inflammation that can progress to perforation and diffuse peritonitis. The sequelae of diverticula covered by mesentery may cause phlegmons or abscesses, as well as fistulas.
4
Prognosis and risk of recurrence
Acute diverticulitis has a recurrence rate of 13-23% in patients with uncomplicated disease, and around 40% in patients with complicated disease.
3
Guidelines
Key sources
The following summarized guidelines for the evaluation and management of acute diverticulitis are prepared by our editorial team based on guidelines from the European Society of Coloproctology (ESCP/EAES 2025), the Infectious Diseases Society of America (IDSA 2024), the American College of Radiology (ACR 2023,2022), the Academy of Emergency Medicine and Care (AcEMC/SIFIPAC/SICUT/WSES/ACOI/SICG 2022), the American College of Physicians (ACP 2022), ...
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Screening and diagnosis
Differential diagnosis
As per DGAV/DGVS 2022 guidelines:
Include diverticulitis in the differential diagnosis of acute abdominal pain, even in younger patients (< 40 years of age).
B
Include diverticulitis in the differential diagnosis of acute abdominal pain, even if the localization of pain is right-sided or suprapubic.
E
Classification and risk stratification
Risk assessment: as per IDSA 2024 guidelines, assess disease severity for risk stratification in patients with complicated intra-abdominal infections. Consider using the APACHE II as the preferred severity of illness score for risk stratification within 24 hours of hospital or ICU admission in adult patients with complicated intra-abdominal infection, if a severity of illness score is used.
B
APACHE II
Calculator
When to use
Age (years)
< 45
45-54
55-64
65-74
≥ 75
Rectal temperature (°C [°F])
< 30 [< 86]
30-31.9 [86-89.5]
32-33.9 [89.6-93.1]
34-35.9 [93.2-96.7]
36-38.4 [96.8-101.2]
38.5-38.9 [101.3-102.1]
39-40.9 [102.2-105.7]
≥ 41 [≥ 105.8]
Mean arterial pressure (mmHg)
≥ 160
130-159
110-129
70-109
50-69
< 50
Arterial pH
≥ 7.7
7.6-7.69
7.5-7.59
7.33-7.49
7.25-7.32
7.15-7.24
< 7.15
Heart rate (bpm)
≥ 180
140-179
110-139
70-109
55-69
40-54
< 40
Respiratory rate (rpm)
≥ 50
35-49
25-34
12-24
10-11
6-9
< 6
Serum sodium (mEq/L)
≥ 180
160-179
155-159
150-154
130-149
120-129
111-119
< 111
Serum potassium (mEq/L)
≥ 7.0
6.0-6.9
5.5-5.9
3.5-5.4
3.0-3.4
2.5-2.9
< 2.5
Serum creatinine (mg/dL)
≥ 3.5
2.0-3.4
1.5-1.9
0.6-1.4
< 0.6
Acute renal failure
No
Yes
Hematocrit (%)
≥ 60
50-59.9
46-49.9
30-45.9
20-29.9
< 20
White blood cell count (×10**3/mcL)
≥ 40
20-39.9
15-19.9
3-14.9
1-2.9
< 1
Glasgow Coma Scale (GCS)
Oxygenation (use PaO₂ if FiO₂ < 50% or non-intubated, otherwise use A-a gradient; mmHg)
PaO₂ > 70
PaO₂ 61-70
PaO₂ 55-60
PaO₂ < 55
A-a < 200
A-a 200-349
A-a 350-499
A-a ≥ 500
Setting
Nonoperative
Emergency surgery
Elective surgery
Severe organ failure (liver cirrhosis, congestive heart failure, chronic lung disease, chronic kidney disease on dialysis) or immunocompromise
No
Yes
Calculation
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Diagnostic investigations
Initial evaluation: as per DGAV/DGVS 2022 guidelines, elicit medical history
B
and perform a physical examination in patients with suspected diverticulosis. B
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Poppy seed test
Diagnostic imaging
Blood cultures
Diagnostic procedures
Medical management
Setting of care: as per ACP 2022 guidelines, manage most patients with acute uncomplicated left-sided colonic diverticulitis in an outpatient setting.
B
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Indications for nonoperative management
Antibiotic therapy
NSAIDs
Inpatient care
Nonpharmacologic interventions
Dietary modifications: as per AGA 2021 guidelines, offer a clear liquid diet during the acute phase of uncomplicated diverticulitis. Advance diet as symptoms improve.
E
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Physical activity
Therapeutic procedures
Percutaneous drainage of diverticular abscesses: as per ASCRS 2020 guidelines, perform image-guided percutaneous drainage in stable patients with an abscess > 3 cm.
B
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Laparoscopic lavage and drainage
Intra-abdominal culture
Perioperative care
Surgical interventions
Emergency colectomy: as per DGAV/DGVS 2022 guidelines, consider performing surgical exploration, possibly with colectomy (dissection at the terminal ileum and in the upper third of the rectum), in the threatening situation of severe active bleeding that cannot be either endoscopically or angiographically located.
E
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Elective colectomy
Technical considerations for surgery
Specific circumstances
Patients with complicated diverticulitis, general indications
As per JGA 2019 guidelines:
Consider administering antibiotic therapy combined with bowel rest in patients with complicated colonic diverticulitis, localized peritonitis, and an abscess ≤ 3 cm. Consider performing ultrasound- or CT-guided drainage combined with antibiotic therapy and bowel rest in patients with an abscess ≥ 5 cm. Individualize treatment in patients with an abscess measuring 3-5 cm based on clinical status, feasibility of drainage, and resource availability. (Strength of recommendation: Probably do it, Quality of evidence: C).
C
Perform colectomy when antibiotic therapy and drainage are ineffective.
B
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Patients with complicated diverticulitis (abscess and localized peritonitis)
Patients with complicated diverticulitis (fistula)
Patients with complicated diverticulitis (stricture)
Elderly patients (diagnosis)
Elderly patients (diagnostic imaging)
Elderly patients (indications for nonoperative management)
Elderly patients (antibiotic therapy)
Elderly patients (percutaneous drainage of diverticular abscesses)
Elderly patients (laparoscopic lavage and drainage)
Elderly patients (emergency colectomy)
Elderly patients (elective colectomy)
Elderly patients (follow-up)
Patients with immunocompromising conditions
Patient education
General counseling
As per AGA 2021 guidelines:
Counsel patients that approximately 50% of the risk for diverticulitis is attributable to genetic factors.
E
Counsel patients that complicated diverticulitis is most often the first presentation of diverticulitis and the risk of complicated diverticulitis decreases with recurrences.
E
Preventative measures
Secondary prevention, aminosalicylates: as per ACP 2022 guidelines, do not offer mesalamine for the prevention of recurrent diverticulitis.
D
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Secondary prevention (rifaximin)
Secondary prevention (probiotics)
Secondary prevention (lifestyle modifications)
Follow-up and surveillance
Endoscopic follow-up, uncomplicated diverticulitis: as per AGA 2021 guidelines, obtain a colonoscopy after a first episode of uncomplicated diverticulitis based on the patient's history, most recent colonoscopy, and the severity and course of the disease. Consider deferring colonoscopy if a high-quality examination was performed within the past year, or performing it sooner if alarm symptoms are present.
E
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Endoscopic follow-up (complicated diverticulitis)
Management of persistent symptoms
Management of recurrent diverticulitis