Toxic megacolon classification

Toxic Megacolon Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Toxic Megacolon from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic study of choice

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

Abdominal X Ray

Ultrasound

MRI

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Toxic megacolon classification On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Toxic megacolon classification

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Toxic megacolon classification

CDC on Toxic megacolon classification

Toxic megacolon classification in the news

Blogs on Toxic megacolon classification

Directions to Hospitals Treating Toxic megacolon

Risk calculators and risk factors for Toxic megacolon classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:  Farima Kahe M.D. [2]

## Overview

[edit | edit source]

Toxic megacolon may be classified according to etiology into two groups including toxic megacolon associated with inflammatory bowel disease and toxic megacolon associated with Clostridium difficile pseudomembranous colitis.

## Classification

[edit | edit source]

* There is no established system for the classification of toxic megacolon but it may be classified according to etiology into 2 groups:[1][2][3][4][5][6][7][8][9][10]

Etiology of toxic megacolon  | Pathological evolution  | CT scan findings  | MRI findings

|
|
|

Toxic megacolon associated with inflammatory bowel disease | Toxic megacolon associated with ulcerative colitis |

* Rapid damage involving all layers of the colonic wall
* Toxins cause a breach in the protective mucosal barrier leading to exposure of muscularis propria

* Colonic dilation

* Mucosal edema (thumbprint sign)

* Contrast MRI is superior to CT for visualization of the anal sphincter complex and the pelvis (especially in case of Crohn's disease
* Bowel wall hyperintensity and hyper-enhancement
* Bright enhancement of mucosa (due to inflammation) and hypoenhancing submucosa (due to edema)

Toxic megacolon associated with Crohn's disease |

* Occurs early in the course of Crohn's disease
* Develops more commonly in pancolitis than in segmental disease
* Cytomegalovirus infection may be a trigger

* Colonic dilation
* Mucosal edema (thumbprint sign)
* Lead-pipe appearance of the colon

Toxic megacolon associated with Clostridium difficile pseudomembranous colitis |

* 0.3-4 percent of cases of pseudomembranous colitis may develop toxic megacolon
* Toxic megacolon is thought to develop secondary to inflammatory changes that penetrate into the muscularis propria leading to neural injury, altered colonic motility and colonic dilation

* Colonic dilation
* Mucosal edema (thumbprint sign)
* Circumferential colonic wall thickening (accordion sign) consistent with a pancolitis

Toxic megacolon associated with ischemic colitis |  |

* Colonic dilation
* Mucosal edema (thumbprint sign)

## References

[edit | edit source]

1. ↑ Morón C (1992). "[The street sales of food and the cholera epidemic in Latin America]". Arch Latinoam Nutr (in Spanish; Castilian). 42 (3 Suppl): 36S–40S. PMID 1344622.CS1 maint: Unrecognized language (link)
2. ↑ Sheth SG, LaMont JT (1998). "Toxic megacolon". Lancet. 351 (9101): 509–13. doi:10.1016/S0140-6736(97)10475-5. PMID 9482465.
3. ↑ "Toxic Megacolon Complicating a First Course of Crohn's Disease: About Two Cases (PDF Download Available)".
4. ↑ Croswell SC, Lei KY (1985). "Effect of copper deficiency on the apolipoprotein E-rich high density lipoproteins in rats". J. Nutr. 115 (4): 473–82. PMID 3981266.
5. ↑ Earhart MM (2008). "The identification and treatment of toxic megacolon secondary to pseudomembranous colitis". Dimens Crit Care Nurs. 27 (6): 249–54. doi:10.1097/01.DCC.0000338869.70035.2b. PMID 18953191.
6. ↑ Berman L, Carling T, Fitzgerald TN, Bell RL, Duffy AJ, Longo WE, Roberts KE (2008). "Defining surgical therapy for pseudomembranous colitis with toxic megacolon". J. Clin. Gastroenterol. 42 (5): 476–80. doi:10.1097/MCG.0b013e31804bbe12. PMID 18277885.
7. ↑ Grieco MB, Bordan DL, Geiss AC, Beil AR (1980). "Toxic megacolon complicating Crohn's colitis". Ann. Surg. 191 (1): 75–80. PMC 1344622. PMID 7352781.
8. ↑ Imbriaco M, Balthazar EJ (2001). "Toxic megacolon: role of CT in evaluation and detection of complications". Clin Imaging. 25 (5): 349–54. PMID 11682295.
9. ↑ "www.ncbi.nlm.nih.gov" (PDF).
10. ↑ Maccioni F, Viscido A, Broglia L, Marrollo M, Masciangelo R, Caprilli R, Rossi P (2000). "Evaluation of Crohn disease activity with magnetic resonance imaging". Abdom Imaging. 25 (3): 219–28. PMID 10823437.

Template:WH Template:WS