Diverticulitis
Diverticulitis is inflammation and micro- or macro-perforation of a colonic diverticulum, most often sigmoid, presenting with left lower quadrant pain, fever, and altered bowel habits. CT abdomen and pelvis with contrast confirms the diagnosis, separates uncomplicated from complicated disease, and grades complicated disease by the modified Hinchey classification to guide antibiotics, drainage, or surgery.
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What this article covers
- Overview
Definition: diverticulitis is inflammation, with microperforation or macroperforation, of one or more colonic diverticula, the acquired herniations of mucosa and submucosa through the muscular wall that define diverticulosis.
- Epidemiology
Age-related prevalence: diverticulosis, the substrate for diverticulitis, is very common in older adults, with a reported prevalence up to 80% by ages 40 to 85 years and older.
- Risk factors
Low-fiber, high-fat diet: the dominant dietary risk factor for diverticulosis and progression to diverticulitis.
- Pathophysiology
Diverticulum formation: diverticula are acquired outpouchings of mucosa and submucosa through points of relative weakness in the colonic muscular wall, most concentrated in the sigmoid colon where intraluminal pressure is highest.
- Clinical features
Left lower quadrant pain: the hallmark symptom, reflecting the sigmoid predominance of diverticular disease; pain is typically constant and may be accompanied by a palpable tender mass.
- Differential diagnosis
Acute appendicitis: right lower quadrant pain and tenderness; a left-sided mirror-image presentation is unusual, discriminated by pain location and CT findings.
- Diagnosis
Establish the diagnosis with clinical features plus confirmatory CT, then classify and stage: acute diverticulitis is diagnosed clinically in a patient with left lower quadrant pain, fever, and…
- Management
Assess severity first to select a treatment track: uncomplicated disease in a reliable, stable, immunocompetent outpatient tolerating oral intake is managed as an outpatient; complicated disease…
- Complications
Free perforation with generalized peritonitis: the most severe complication, with sudden severe pain, sepsis, and free air on imaging, requiring immediate surgery.
- Prognosis
Uncomplicated disease has a favorable course: most episodes resolve with bowel rest and, when indicated, antibiotics, without progression to complication.
- Prevention
High-fiber diet: a high-fiber diet is recommended to reduce the risk of recurrent diverticulitis after an acute episode.
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Related articles
- Diverticulosis
Diverticulosis is the acquired presence of uninflamed mucosal and submucosal herniations through the colonic wall, overwhelmingly asymptomatic and usually found incidentally on colonoscopy or CT, that serves as the anatomic substrate for diverticulitis and diverticular bleeding rather than a disease in itself. Management of uncomplicated diverticulosis is a high-fiber diet with no restriction of nuts, seeds, or popcorn, plus routine age-based colorectal cancer screening.
- Diverticular bleeding
Diverticular bleeding is painless arterial hematochezia from rupture of a vasa recta at the neck or dome of a colonic diverticulum, the most common cause of severe acute lower gastrointestinal bleeding, and it stops spontaneously in about 75% of episodes. Diagnosis rests on hemodynamic triage followed by urgent colonoscopy or CT angiography to localize the source, and management combines resuscitation with a restrictive transfusion threshold, endoscopic hemostasis, and angiographic embolization or surgery for refractory bleeding.
- Colorectal cancer
Colorectal cancer is an adenocarcinoma that arises through the adenoma-carcinoma sequence and presents differently by location, with right-sided tumors causing occult bleeding and iron-deficiency anemia and left-sided tumors causing obstruction and hematochezia. Colonoscopy with biopsy confirms the diagnosis, TNM staging on CT chest/abdomen/pelvis with CEA guides treatment, and management ranges from surgical resection alone for localized disease to adjuvant FOLFOX for node-positive colon cancer, neoadjuvant chemoradiation for rectal cancer, and molecularly targeted systemic therapy for metastatic disease.