Toxic megacolon: Difference between revisions
 
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==Background==
==Background==
*Inflammation of intestinal smooth muscle causes colon dilation
[[File:Diameters of the large intestine.png|thumb|Average inner diameters and ranges of different sections of the large intestine.<ref> Nguyen H, Loustaunau C, Facista A, Ramsey L, Hassounah N, Taylor H, et al. (July 2010). "Deficient Pms2, ERCC1, Ku86, CcOI in field defects during progression to colon cancer". Journal of Visualized Experiments (41). doi:10.3791/1931. PMC 3149991. PMID 20689513.</ref>]]
*Untreated, can lead to perforation
*Colonic Dilation ≥6cm
*Usually associated with infectious colitis or [[Crohn's disease]] or [[Ulcerative Colitis]]
*Therapy: Fluids, Electrolyte Repletion, Steroids, Antibiotics, Surgical Consultation
*AVOID anticholingerics, anti-motility agents, opioids
 
===Causes===
*Most commonly IBD ([[Ulcerative Colitis]] >>> [[Crohn's disease]])
*Bacterial ([[Salmonella]], [[Shigella]], [[Campylobacter]], [[C. Diff]], [[Yersinia]], [[E. Coli]])
*Viral ([[CMV]], [[Rotavirus]])
*Fungal/Protozoa ([[Aspergillus]], [[Entamoeba]], [[Cryptosporidium]])
*Drugs (Anti-motility agents, [[anticholinergics]], [[opioids]])
*Less Common Causes (Ischemic [[Colitis]], Collagenous Colitis, Obstructive Colorectal Cancer, Colonic Lymphoma, [[Kaposi's Sarcoma]], Chemotherapy)
*Pediatric Population ([[Hirschsprung's Disease]], [[Hemolytic Uremic Syndrome]])
*[[HIV]]/AIDS Population ([[CMV]], [[C. Diff]])


==Clinical Features==
==Clinical Features==
*Abdominal Pain
*[[Abdominal Pain]] ± Distention
*Fever
*[[Fever]]
*Tachycardia
*[[Tachycardia]]
*Distended abdomen
*[[Diarrhea]], ± Bloody
*Hypokalemia
*[[Hypotension]]
*Hypomagnesemia
*[[Altered Mental Status]] (AMS)
*[[Bowel perforation]]
**[[Peritonitis]]
**[[Septicemia]]


==Differential Diagnosis==
==Differential Diagnosis==
*SBO
*[[Small bowel obstruction]]
*LBO
*[[Large bowel obstruction]]
*Constipation
**[[Volvulus]], Neoplastic Disease, Paralytic [[ileus]], [[ogilvie's syndrome|Pseudo-obstruction]]
*C. difficile colitis
*[[Colitis]]
**Infectious, Inflammatory, Ischemic


==Diagnosis==
==Evaluation==
*X-ray showing colon > 6 cm diameter
[[File:Toxisches Megacolon bei Colitis ulcerosa.jpg|thumb|Toxic megacolon on [[KUB]]]]
[[File:PMC2365454 ci08001303.png|thumb|CT with toxic megacolon showing submucosal edema and mucosal enhancement of the ascending and descending colon giving the appearance of the “target sign”.]]
[[File:MPX1359 synpic29148.png|thumb|CT showing is diffuse dilation of the colon with air and fluid levels present. There is diffuse wall thickening and enhancement in the rectosigmoid colon. The descending, transverse, and ascending colon are dilated to as much as 8.5cm. These features are consistent with a diagnosis of toxic megacolon.]]
*[[Plain abdominal radiographs]]:
**Colonic Dilation ≥6 cm diameter
**Loss of haustra, "thumb-printing" (bowel edema)
**Air-fluid levels
*[[Ultrasound: Abdomen|Abdominal Ultrasound]]:
**Thin colonic walls with loss of haustra coli
**Diameter ≥6cm with gaseous content
*Labs:
**[[Leukocytosis]]
**[[Electrolyte derangements]]: [[Hypokalemia]], [[Hypomagnesemia]]
**Elevated ESR/CRP
**[[Anemia]]
**[[Hypoalbuminemia]]


==Management==
==Management==
*[[Fluid resuscitation]]
*IV [[corticosteroids]]
**[[Hydrocortisone]] IV 100mg q6h
*Triple Antibiotic Therapy
**[[Ampicillin]] 2 g IV q6h '''PLUS''' [[Metronidazole]] 500mg IV q6h '''PLUS''' [[Gentamicin]] 7mg/kg q24h or [[Ciprofloxacin]] 400mg IV q12h '''OR'''
**[[Imipenem]] 500mg IV q6h
*[[Electrolyte repletion]]
**Aggressively treat hypokalemia and hypomagnesemia because these can exacerbate dilation
*Emergent Surgical Consultation
*Obtain blood cultures, stool cultures, C. Diff Toxin
*If known cause is C. Diff treat with [[Vancomycin]] or [[Metronidazole]]
*If known cause is CMV can add Ganciclovir
*Avoid
**Anticholinergics, anti-motility agents, opioids which can worsen dilation
**Sulfasalazine or 5-aminosalicylate (5-ASA) unhelpful
**Nasogastric (NG) Tube NOT effective in reducing colonic distention


==Disposition==
==Disposition==
*Admit


==See Also==
==See Also==
 
*[[Crohn's disease]]
==External Links==
*[[Ulcerative Colitis]]


==References==
==References==
<references/>
<references/>
[[Category:GI]]
[[category:Surgery]]

Latest revision as of 21:02, 24 September 2025

Background

Average inner diameters and ranges of different sections of the large intestine.[1]
  • Colonic Dilation ≥6cm
  • Therapy: Fluids, Electrolyte Repletion, Steroids, Antibiotics, Surgical Consultation
  • AVOID anticholingerics, anti-motility agents, opioids

Causes

Clinical Features

Differential Diagnosis

Evaluation

Toxic megacolon on KUB
CT with toxic megacolon showing submucosal edema and mucosal enhancement of the ascending and descending colon giving the appearance of the “target sign”.
CT showing is diffuse dilation of the colon with air and fluid levels present. There is diffuse wall thickening and enhancement in the rectosigmoid colon. The descending, transverse, and ascending colon are dilated to as much as 8.5cm. These features are consistent with a diagnosis of toxic megacolon.

Management

  • Obtain blood cultures, stool cultures, C. Diff Toxin
  • If known cause is C. Diff treat with Vancomycin or Metronidazole
  • If known cause is CMV can add Ganciclovir
  • Avoid
    • Anticholinergics, anti-motility agents, opioids which can worsen dilation
    • Sulfasalazine or 5-aminosalicylate (5-ASA) unhelpful
    • Nasogastric (NG) Tube NOT effective in reducing colonic distention

Disposition

  • Admit

See Also

References

  1. ↑ Nguyen H, Loustaunau C, Facista A, Ramsey L, Hassounah N, Taylor H, et al. (July 2010). "Deficient Pms2, ERCC1, Ku86, CcOI in field defects during progression to colon cancer". Journal of Visualized Experiments (41). doi:10.3791/1931. PMC 3149991. PMID 20689513.
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