What is acute colitis?

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Last updated: May 28, 2025View editorial policy

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From the Guidelines

Acute colitis is a serious condition that requires prompt medical attention, and the most effective treatment approach is often a tailored one, involving initial conservative management with bowel rest, parenteral nutrition, parenteral steroids, and broad-spectrum antibiotics, with close monitoring for signs of progressive deterioration 1. Acute colitis is inflammation of the colon (large intestine) that develops suddenly, causing symptoms like abdominal pain, diarrhea (sometimes with blood or mucus), urgency to have bowel movements, and possibly fever. This condition can result from infections (bacterial, viral, or parasitic), certain medications (especially antibiotics), inflammatory bowel disease flares, or reduced blood flow to the colon.

Key Considerations

  • The diagnostic criteria for acute severe colitis include bloody stool frequency ≥ 6/day and at least one additional criterion such as tachycardia, temperature >37.8°C, anemia, or elevated ESR 1.
  • Treatment depends on the cause, but often includes rest, increased fluid intake, and a temporary bland diet avoiding spicy foods, dairy, and high-fiber items.
  • For infectious colitis, antibiotics may be prescribed, but their use should be judicious and based on the severity of the condition and the presence of systemic inflammatory response or immunosuppression 1.

Management Approach

  • A tailored approach to the patient with acute severe colitis is recommended, with an attempt at initial conservative management and close monitoring for signs of progressive deterioration 1.
  • Surgical options or therapeutic alternatives for rescue therapy should be considered early (on or around day 3 of corticosteroid therapy) by a multidisciplinary team that includes both a surgeon and gastroenterologist 1.
  • The use of biologic therapy has opened new perspectives for salvage therapy in steroid-refractory patients, and may help avoid emergent colectomy 1.

Important Considerations

  • Post-operative morbidity is higher after emergency surgery compared to elective surgery, suggesting that the increased use of rescue therapy may contribute to reducing emergency surgical interventions and improving outcomes 1.
  • Delay in surgery and prolonged intravenous immunosuppressive therapy are associated with increased morbidity and mortality following subsequent surgery, emphasizing the need for prompt and effective management 1.

From the Research

Definition and Symptoms of Acute Colitis

  • Acute colitis, specifically acute severe ulcerative colitis (ASUC), is a potentially life-threatening condition that requires early recognition and treatment 2.
  • Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by continuous mucosal inflammation extending from the rectum to the more proximal colon, with variable extents 3.
  • The classic presentation of UC includes bloody diarrhea with or without mucus, rectal urgency, tenesmus, and variable degrees of abdominal pain that is often relieved by defecation 3.

Diagnosis of Acute Colitis

  • The diagnosis of UC is made on the basis of presenting symptoms consistent with UC as well as endoscopic evidence showing continuous and diffuse colonic inflammation that starts in the rectum 4.
  • Biopsies of the colon documenting chronic inflammation confirm the diagnosis of UC 4.
  • Ileocolonoscopy with biopsy is the only way to make a definitive diagnosis of UC 3.

Treatment of Acute Colitis

  • The goals of treatment in UC are to improve quality of life, achieve steroid-free remission, and minimize the risk of cancer 3.
  • For mild to moderate UC, oral and rectal 5-aminosalicylates are typically used 4.
  • In moderate to severe colitis, medication classes include thiopurines, biological agents targeting tumor necrosis factor and integrins, and the small-molecule Janus kinase inhibitors 4.
  • Intravenous corticosteroids are the first-line treatment for acute severe ulcerative colitis (ASUC) 2.
  • Rescue treatment with ciclosporin or infliximab is indicated in patients who do not sufficiently respond to corticosteroids after 3-5 days 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Acute severe ulcerative colitis: from pathophysiology to clinical management.

Nature reviews. Gastroenterology & hepatology, 2016

Research

Ulcerative Colitis.

Mayo Clinic proceedings, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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