Infectious colitis

COVID-19 associated colitis

Editorial Board Member: Aaron R. Huber, D.O.
Deputy Editor-in-Chief: Catherine E. Hagen, M.D.
Isma Perveze, M.D.
Feng Yin, M.D., Ph.D.

Last author update: 27 July 2021
Last staff update: 26 April 2022

Copyright: 2021-2024,, Inc.

PubMed Search: COVID-19 associated colitis

See Also: COVID-19 convalescent plasma, COVID-19 lung pathology, COVID-19 testing, COVID-19 viral hepatitis

Isma Perveze, M.D.
Feng Yin, M.D., Ph.D.
Page views in 2023: 1,061
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Cite this page: Perveze I, Yin F. COVID-19 associated colitis. website. Accessed February 26th, 2024.
Definition / general
  • Colonic mucosal damage associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection
Essential features
ICD coding
  • ICD-10:
    • U07.1 - COVID-19
    • B34.2 - coronavirus infection, unspecified
    • B97.2 - coronavirus as the cause of disease classified elsewhere
  • WHO declared the COVID-19 outbreak, caused by SARS-CoV-2, a global pandemic
  • Primarily affecting the respiratory system, COVID-19 can also lead to gastrointestinal symptoms
  • Common comorbidities: hypertension, diabetes mellitus, chronic cardiac disease, chronic respiratory disease, chronic renal disease (Clin Gastroenterol Hepatol 2020;18:2378, BMJ Open Gastroenterol 2021;8:e000578)
  • SARS-CoV-2 binds to the angiotensin converting enzyme 2 (ACE2) receptor through its surface spike protein for host entry
  • ACE2 receptor is highly expressed in the intestinal epithelial cells
  • Potential mechanisms for COVID-19 associated colitis:
  • SARS-CoV-2, an enveloped positive stranded RNA virus related to the severe acute respiratory syndrome (SARS) virus and the Middle East respiratory syndrome (MERS) virus
Clinical features
  • Common clinical presentation:
  • Gastrointestinal symptoms typically develop within 1 week of onset of COVID-19 infection
  • Diffuse abdominal pain / tenderness, metabolic acidosis and hypotension indicate worsening clinical course and potential need for surgical intervention
  • Elevation of prothrombin time and international normalized ratio (INR)
  • D dimer > 1,850 ng/mL and presence of at least 1 gastrointestinal symptom were independently associated with major endoscopic abnormalities (BMJ Open Gastroenterol 2021;8:e000578)
  • Elevation of liver function test (aspartate aminotransferase [AST], alanine aminotransferase [ALT]) (Am J Gastroenterol 2020;115:766)
Radiology description
Radiology images

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CT scan

CT scan

Case reports
  • Supportive care, bowel rest and close observation
  • Surgical intervention is indicated if there is evidence of perforation, infarction and necrosis (Am J Emerg Med 2020;38:2758.e1)
Clinical images

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Colonoscopic findings

Colonoscopic findings

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Feng Yin, M.D., Ph.D.
Ischemic injury with microthrombi

Ischemic injury
with microthrombi

Withered crypts with neutrophils

Withered crypts with neutrophils

Positive stains
Electron microscopy description
Electron microscopy images

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Virion particles

Virion particles

Sample pathology report
  • Colon, biopsy:
    • Ischemic colitis consistent with clinical history of SARS-CoV-2 infection
Differential diagnosis
  • Inflammatory bowel disease (IBD):
    • Personal or family history of IBD or other autoimmune disorders
    • Onset tends to be subacute to chronic
    • Marked architectural distortion and prominent acute inflammation
  • Ischemic colitis, NOS:
    • Noninfectious colitis
    • Watershed areas most commonly affected
    • Clinical correlation essential
  • Medication associated mucosal damage:
    • History of medication (such as NASID) use
    • May present as chronic mucosal injury pattern
  • Acute infectious colitis (other than COVID-19):
    • Caused by bacteria or virus
    • Acute cryptitis, crypt abscess
    • May present with ischemic injury pattern
    • Bacterial culture, PCR and sequencing diagnostic
Board review style question #1

A 71 year old man with a medical history of diabetes mellites type 2, coronary artery disease and morbid obesity was hospitalized for COVID-19 pneumonia. On day 3 of hospital stay, he developed left sided abdominal pain and hematochezia. Endoscopy showed mucosal erosions and ulceration at the splenic flexure. A representative photomicrograph of the biopsy is shown. Which is the most likely diagnosis?

  1. COVID-19 associated colitis
  2. Diverticulitis
  3. Inflammatory bowel disease
  4. Mesenteric ischemia
  5. Pseudomembranous colitis
Board review style answer #1
A. COVID-19 associated colitis. The biopsy reveals colonic mucosa with focal epithelial mucin depletion, withered crypts, mildly hyalinized stroma, mucosal microthrombi and patchy acute inflammatory infiltrate. In the current clinical setting (patient with COVID-19 pneumonia followed by abdominal pain and hematochezia), this is most compatible with COVID-19 associated ischemic colonic mucosal injury. Clinical correlation is essential.

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Reference: COVID-19 associated colitis
Board review style question #2
What is the most common histologic feature of COVID-19 associated colitis?

  1. Basal lymphoplasmacytosis and crypt architectural distortion
  2. Eosinophilic cryptitis and abscess
  3. Intraepithelial lymphocytosis
  4. Pseudomembrane material composed of fibrin, mucin, neutrophils and inflammatory debris
  5. Withered crypts, lamina propria hyalinization and microthrombi
Board review style answer #2
E. Withered crypts, lamina propria hyalinization and microthrombi. The most common histologic feature of COVID-19 associated colitis is ischemic colitis pattern, including withered crypts, lamina propria hyalinization and microthrombi.

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