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10.7: Toxic Megacolon

  • Page ID
    14850
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    ACR – Gastrointestinal – Acute (non-localized) Abdominal Pain and Fever

    Case

    Toxic Megacolon

    Clinical:

    History –This patient had been in the hospital for 5 days after an acute stroke. A urinary tract infection developed secondary to the urinary bladder catheter. The patient was treated with antibiotics and the bladder infection improved.

    Transfer to a rehabilitation unit was completed. The patient developed intractable diarrhea and became obtunded, febrile, and seemed very unwell. General surgery was asked to assess the patient.

    Symptoms – Poor historian due to stroke and diminished consciousness.

    Physical – The abdomen was extremely distended. The patient was in severe pain. Bowel sounds were enhanced. There was guarding but no rebound. Skin turgor was poor suggesting dehydration.

    Laboratory– The patient was hypernatremic. The urea and creatinine were elevated. The white cell count was very high. Mild macrocytic anemia was noted.

    DDx:

    Colitis

    Abscess

    Enteritis

    Perforation

    Imaging Recommendation

    ACR – Gastrointestinal – Acute (non-localized) Abdominal Pain and Fever, Variant 3

    CT Abdomen and Pelvis with Intravenous Contrast

    ODIN Link for Toxic Megacolon images (X-rays and CT of the Abdomen), Figure 10.11A and B: mistr.usask.ca/odin/?caseID=20160330231305076

    gi-8-2-1.jpg
    Figure 10.11A Abdominal x-ray of Toxic Megacolon
    gi-8-3-1024x813.jpg
    Figure 10.11B Axial CT of Toxic Megacolon

    Imaging Assessment

    Findings:

    Contrast could not be given intravenously due to the poor renal function. There was patchy consolidation in the lung bases and small pleural effusions. The colon was generally, massively, distended. There was marked colonic wall thickening in the pelvis. No evidence of pneumatosis of the bowel or pneumoperitoneum. No evidence of obstruction.

    Interpretation:

    Toxic Megacolon

    Diagnosis:

    Clostridium Difficile Colitis

    Discussion:

    Toxic megacolon is the clinical term for an acute, toxic, colitis, with dilatation of the colon. The dilatation can be either total or segmental. A more contemporary term for toxic megacolon is simply toxic colitis, because patients may develop toxicity without megacolon.

    The hallmarks of toxic megacolon (toxic colitis), a potentially lethal condition, are non-obstructive colonic dilatation and signs of systemic toxicity.

    Any of the following may predispose an individual to toxic megacolon – Dehydration, altered mental status, electrolyte abnormality, or hypotension.

    TM (TC) was first thought to be a complication only of ulcerative colitis. In fact, TM (TC) may complicate any number of colitides, including inflammatory, ischemic, infectious, radiation, and pseudomembranous. Any three of the following supports the diagnosis of a toxic component – Fever (>38°C), tachycardia (>120 beats/min), leukocytosis (>10.5 x 10 3/µL), or anemia.

    Imaging findings may include:

    • Evidence of colonic dilation – more than 6 cm diameter of the transverse colon, and/or 10 cm diameter of the cecum.
    • Thumb printing, thickening of the bowel wall which projects into the lumen (especially the colon)
    • Perforation may be focal, contained, or disseminated.
    • Pneumatosis intestinalis (gas bubbles in the bowel wall) may be seen
    • Gas in the portal venous system is a rare, and very serious, complication.

    Attributions

    Figure 10.11A Supine Abdominal X-Ray of Toxic Megacolon by Dr. Brent Burbridge MD, FRCPC, University Medical Imaging Consultants, College of Medicine, University of Saskatchewan is used under a CC-BY-NC-SA 4.0 license.

    Figure 10.11B Axial CT of Toxic Megacolon by Dr. Brent Burbridge MD, FRCPC, University Medical Imaging Consultants, College of Medicine, University of Saskatchewan is used under a CC-BY-NC-SA 4.0 license.


    This page titled 10.7: Toxic Megacolon is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Brent Burbridge and Evan Mah via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.