eMedicine Specialties > Gastroenterology > Colon

Megacolon, Toxic: Differential Diagnoses & Workup

Author: Deepika Devuni, MBBS, Resident Physician, Department of Internal Medicine, University Of Connecticut
Coauthor(s): Lisa M Rossi, MD, Fellow, Department of Gastroenterology-Hepatology, University of Connecticut School of Medicine; George Y Wu, MD, PhD, Professor, Department of Medicine, Director, Hepatology Section, Herman Lopata Chair in Hepatitis Research, University of Connecticut School of Medicine; Jerome H Liu, MD, Staff Physician, Department of Surgery, University of California at Los Angeles Medical Center; Clifford Y Ko, MD, MS, Assistant Professor, Department of Surgery, University of California at Los Angeles School of Medicine
Contributor Information and Disclosures

Updated: Apr 14, 2009

Differential Diagnoses

Crohn Disease
Pseudomembranous Colitis
Cytomegalovirus
Ulcerative Colitis
Cytomegalovirus Colitis
Megacolon, Acute
Megacolon, Chronic

Workup

Laboratory Studies

  • Complete blood cell (CBC) count
    • Patients with toxic megacolon (toxic colitis) may develop leukocytosis with a left shift. Patients can also present with leukemoid reaction.
    • Additionally, bloody diarrhea results in anemia.
    • In immunosuppressed or extremely toxic patients, the white blood cell count actually may be normal or low.
  • Chemistry panel
    • Electrolyte disturbances are very common in toxic megacolon (toxic colitis) secondary to inflammatory diarrhea, steroid use, and ongoing gastrointestinal losses.
    • The inflamed colon is unable to reabsorb salt and water.
  • Nutritional and coagulation panel
    • A coagulation panel should be ordered in the event that surgery is required.
    • A nutrition panel, in accordance with the physician's practice, is helpful to determine treatment (eg, albumin vs prealbumin) and to assess nutritional status.
  • Other
    • Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels are usually elevated.
    • Although these findings may support the diagnosis of toxic megacolon (toxic colitis), they are not specific.

Imaging Studies

  • Plain abdominal radiographs are essential for the diagnosis and management of toxic megacolon (toxic colitis). Repeated abdominal plain films are necessary to evaluate the efficacy and progress of treatment.
  • Radiographic findings include the following:
    • Dilated (>6 cm) transverse colon
      A 22-year-old man presented with abdominal pain, ...

      A 22-year-old man presented with abdominal pain, passage of blood and mucus per rectum, abdominal distention, fever, and disorientation. Findings from sigmoidoscopy confirmed ulcerative colitis. Abdominal radiographs obtained 2 days apart show mucosal edema and worsening of the distention in the transverse colon. The patient's clinical condition deteriorated over the next 36 hours despite steroid and antibiotic therapy, and the patient had to undergo a total colectomy and ileostomy.

      [ CLOSE WINDOW ]
      A 22-year-old man presented with abdominal pain, ...

      A 22-year-old man presented with abdominal pain, passage of blood and mucus per rectum, abdominal distention, fever, and disorientation. Findings from sigmoidoscopy confirmed ulcerative colitis. Abdominal radiographs obtained 2 days apart show mucosal edema and worsening of the distention in the transverse colon. The patient's clinical condition deteriorated over the next 36 hours despite steroid and antibiotic therapy, and the patient had to undergo a total colectomy and ileostomy.

    • Loss of colonic haustrations, possible "thumbprinting"
      Plain abdominal radiograph from a patient with kn...

      Plain abdominal radiograph from a patient with known ulcerative colitis who presented with an acute exacerbation of his symptoms. This image shows thumbprinting in the region of the splenic flexure of the colon.

      [ CLOSE WINDOW ]
      Plain abdominal radiograph from a patient with kn...

      Plain abdominal radiograph from a patient with known ulcerative colitis who presented with an acute exacerbation of his symptoms. This image shows thumbprinting in the region of the splenic flexure of the colon.

    • Presence of intraluminal soft-tissue masses (ie, pseudopolyps)
    • Free intraperitoneal air – Possible finding, best seen on upright chest x-ray or left lateral decubitus abdominal film
  • Comparison with old baseline films, if available, is helpful.
  • Avoid barium studies in a patient who is severely toxic. The potential for perforation is considerable.
  • Maconi et al showed intestinal ultrasonography as a potential diagnostic test for toxic megacolon.13  The investigators demonstrated similar findings in 4 cases. The findings, including the following, need further evaluation by more studies.
    • Complete loss of haustra coli of the colon
    • Hypoechoic and thickened bowel walls with irregular internal margins in the sigmoid and descending colon
    • Marked dilation of the transverse colon (>6 cm), a finding that correlated well with the plain X-ray of the abdomen
    • Hypoechoic and thin (<2-mm) bowel walls without haustra coli in the dilated colon—in patients who underwent surgery, the postoperative pathohistologic findings of the bowel walls correlated with the ultrasonographic features observed before surgery
    • Slight dilation of ileal bowel loops (diameter >18 mm) with increased intraluminal gas and fluid

A computed tomography (CT) scan should probably be obtained in patients for whom the diagnosis of toxic megacolon (toxic colitis) is considered. A CT scan may identify a local or contained perforation. If the diagnosis remains unclear or the cause of toxicity is thought to be an abscess, a CT scan may be helpful. There is little literature on the role of CT scanning  in toxic megacolon (toxic colitis), but further studies may help further define the role of this imaging modality in the diagnosis and prognosis.

Computed tomography scan from a patient with pseu...

Computed tomography scan from a patient with pseudomembranous colitis demonstrating the classic accordion sign.

[ CLOSE WINDOW ]
Computed tomography scan from a patient with pseu...

Computed tomography scan from a patient with pseudomembranous colitis demonstrating the classic accordion sign.


Procedures

  • If the diagnosis of toxic megacolon (toxic colitis) is in doubt and the patient's condition is not toxic or unstable, endoscopy may be attempted by appropriately trained personnel.
    • Endoscopy may take the form of flexible sigmoidoscopy or colonoscopy. If clinical concern of toxic megacolon (toxic colitis) exists, the examination should not progress beyond sigmoidoscopy, if at all. The scope should only be advanced as far as is needed for diagnosis. Air insufflation should be a minimal. According to some experts, colonoscopy is generally justified only if the patient has no or minimal inflammation of the sigmoid or rectum.
    • Perforation is an obvious potential complication with this approach.

Histologic Findings

Pathology in cases of toxic megacolon (toxic colitis) demonstrates acute inflammation involving all layers of the colon. Variable amounts of necrosis and degeneration are present. Infiltration by inflammatory cells (neutrophils, macrophages, and lymphocytes) is noted. The myenteric and submucosal plexi are usually preserved.

More on Megacolon, Toxic

Overview: Megacolon, Toxic
Differential Diagnoses & Workup: Megacolon, Toxic
Treatment & Medication: Megacolon, Toxic
Follow-up: Megacolon, Toxic
Multimedia: Megacolon, Toxic
References
Further Reading
[ CLOSE WINDOW ]

References

  1. Marshak RH, Lester LJ. Megacolon a complication of ulcerative colitis. Gastroenterology. Dec 1950;16(4):768-72. [Medline].

  2. Jalan KN, Sircus W, Card WI, et al. An experience of ulcerative colitis. I. Toxic dilation in 55 cases. Gastroenterology. Jul 1969;57(1):68-82. [Medline].

  3. Mourelle M, Casellas F, Guarner F, et al. Induction of nitric oxide synthase in colonic smooth muscle from patients with toxic megacolon. Gastroenterology. Nov 1995;109(5):1497-502. [Medline].

  4. Mourelle M, Vilaseca J, Guarner F, Salas A, Malagelada JR. Toxic dilatation of colon in a rat model of colitis is linked to an inducible form of nitric oxide synthase. Am J Physiol. Mar 1996;270(3 pt 1):G425-30. [Medline].

  5. Guslandi M. Nitric oxide and inflammatory bowel diseases. Eur J Clin Invest. Nov 1998;28(11):904-7. [Medline].

  6. Greenstein AJ, Sachar DB, Gibas A, et al. Outcome of toxic dilatation in ulcerative and Crohn's colitis. J Clin Gastroenterol. Apr 1985;7(2):137-43. [Medline].

  7. Jalan KN, Sircus W, Card WI, et al. An experience of ulcerative colitis. I. Toxic dilation in 55 cases. Gastroenterology. Jul 1969;57(1):68-82. [Medline].

  8. Roy MA. Inflammatory bowel disease. Surg Clin North Am. Dec 1997;77(6):1419-31. [Medline].

  9. Bartlett JG, Perl TM. The new Clostridium difficile--what does it mean?. N Engl J Med. Dec 8 2005;353(23):2503-5. [Medline].

  10. Shimada Y, Iiai T, Okamoto H, et al. Toxic megacolon associated with cytomegalovirus infection in ulcerative colitis. J Gastroenterol. 2003;38(11):1107-8. [Medline].

  11. Wodzinski MA, Snowden JA, Reilly JT. Toxic megacolon complicating chemotherapy for acute myeloid leukaemia. Postgrad Med J. Dec 1994;70(830):921-3. [Medline].

  12. Fitzgerald SC, Conlon S, Leen E, Walsh TN. Collagenous colitis as a possible cause of toxic megacolon. Ir J Med Sci. Mar 2009;178(1):115-7. [Medline].

  13. Maconi G, Sampietro GM, Ardizzone S, et al. Ultrasonographic detection of toxic megacolon in inflammatory bowel diseases. Dig Dis Sci. Jan 2004;49(1):138-42. [Medline].

  14. Panos MZ, Wood MJ, Asquith P. Toxic megacolon: the knee-elbow position relieves bowel distension. Gut. Dec 1993;34(12):1726-7. [Medline]. [Full Text].

  15. Present DH, Wolfson D, Gelernt IM, et al. Medical decompression of toxic megacolon by "rolling." A new technique of decompression with favorable long-term follow-up. J Clin Gastroenterol. Oct 1988;10(5):485-90. [Medline].

  16. Actis GC, Ottobrelli A, Pera A, et al. Continuously infused cyclosporine at low dose is sufficient to avoid emergency colectomy in acute attacks of ulcerative colitis without the need for high-dose steroids. J Clin Gastroenterol. Jul 1993;17(1):10-3. [Medline].

  17. Sriram PV, Reddy KS, Rao GV, Santosh D, Reddy DN. Infliximab in the treatment of ulcerative colitis with toxic megacolon. Indian J Gastroenterol. Jan-Feb 2004;23(1):22-3. [Medline]. [Full Text].

  18. Sawada K, Egashira A, Ohnishi K, et al. Leukocytapheresis (LCAP) for management of fulminant ulcerative colitis with toxic megacolon. Dig Dis Sci. Apr 2005;50(4):767-73. [Medline].

  19. Kuroki K, Masuda A, Uehara H, Kuroki A. A new treatment for toxic megacolon. Lancet. Sep 5 1998;352(9130):782. [Medline].

  20. Heppell J, Farkouh E, Dube S, et al. Toxic megacolon. An analysis of 70 cases. Dis Colon Rectum. Dec 1986;29(12):789-92. [Medline].

  21. Lee EC, Truelove SC. Proctocolectomy for ulcerative colitis. World J Surg. 1980;4(2):195-201. [Medline].

  22. Grant CS, Dozois RR. Toxic megacolon: ultimate fate of patients after successful medical management. Am J Surg. Jan 1984;147(1):106-10. [Medline].

  23. Gan SI, Beck PL. A new look at toxic megacolon: an update and review of incidence, etiology, pathogenesis, and management. Am J Gastroenterol. Nov 2003;98(11):2363-71. [Medline].

  24. Levine CD. Toxic megacolon: diagnosis and treatment challenges. AACN Clin Issues. Nov 1999;10(4):492-9. [Medline].

  25. Morris JB, Zollinger RM Jr, Stellato TA. Role of surgery in antibiotic-induced pseudomembranous enterocolitis. Am J Surg. Nov 1990;160(5):535-9. [Medline].

  26. Present DH. Toxic megacolon. Med Clin North Am. Sep 1993;77(5):1129-48. [Medline].

  27. Sheth SG, LaMont JT. Toxic megacolon. Lancet. Feb 14 1998;351(9101):509-13. [Medline].

  28. Shetler K, Nieuwenhuis R, Wren SM, Triadafilopoulos G. Decompressive colonoscopy with intracolonic vancomycin administration for the treatment of severe pseudomembranous colitis. Surg Endosc. Jul 2001;15(7):653-9. [Medline].

  29. Weissleder, R, Rieumont MJ, Wittenberg J. Primer of Diagnostic Imaging. 2nd ed. St. Louis, Mo: Mosby; 1997:192.

  30. [Best Evidence] Andrews JM, Travis SP, Gibson PR, Gasche C. Systematic review: does concurrent therapy with 5-ASA and immunomodulators in inflammatory bowel disease improve outcomes?. Aliment Pharmacol Ther. Mar 1 2009;29(5):459-69. [Medline].

  31. [Best Evidence] Bossa F, Latiano A, Rossi L, et al. Erythrocyte-mediated delivery of dexamethasone in patients with mild-to-moderate ulcerative colitis, refractory to mesalamine: a randomized, controlled study. Am J Gastroenterol. Oct 2008;103(10):2509-16. [Medline].

  32. [Best Evidence] Feagan BG, Panaccione R, Sandborn WJ, et al. Effects of adalimumab therapy on incidence of hospitalization and surgery in Crohn's disease: results from the CHARM study. Gastroenterology. Nov 2008;135(5):1493-9. [Medline].

  33. [Best Evidence] Kruis W, Kiudelis G, Racz I, et al. Once daily versus three times daily mesalazine granules in active ulcerative colitis: a double-blind, double-dummy, randomised, non-inferiority trial. Gut. Feb 2009;58(2):233-40. [Medline]. [Full Text].

  34. [Best Evidence] Lichtenstein GR, Bengtsson B, Hapten-White L, Rutgeerts P. Oral budesonide for maintenance of remission of Crohn's disease: a pooled safety analysis. Aliment Pharmacol Ther. Mar 15 2009;29(6):643-53. [Medline].

[ CLOSE WINDOW ]

Further Reading

Related eMedicine Topics

Best Evidence

Clinical Trials

National Guidelines Clearinghouse

[ CLOSE WINDOW ]

Keywords

toxic megacolon, megacolon, dilated toxic colitis, fulminant dilated colitis, colonic dilatation, colitides, Hirschsprung disease, ulcerative colitis, Crohn disease, amebic dysentery, clostridium enterocolitis, idiopathic megacolon, chronic constipation, intestinal pseudoobstruction, intestinal pseudo-obstruction, Ogilvie syndrome, acute toxic colitis

[ CLOSE WINDOW ]

Contributor Information and Disclosures

Author

Deepika Devuni, MBBS, Resident Physician, Department of Internal Medicine, University Of Connecticut
Disclosure: Nothing to disclose.

Coauthor(s)

Lisa M Rossi, MD, Fellow, Department of Gastroenterology-Hepatology, University of Connecticut School of Medicine
Disclosure: Nothing to disclose.

George Y Wu, MD, PhD, Professor, Department of Medicine, Director, Hepatology Section, Herman Lopata Chair in Hepatitis Research, University of Connecticut School of Medicine
George Y Wu, MD, PhD is a member of the following medical societies: American Association for the Study of Liver Diseases, American Gastroenterological Association, American Medical Association, American Society for Clinical Investigation, and Association of American Physicians
Disclosure: Humana Press Consulting fee Consulting; Novartis Consulting fee Review panel membership

Jerome H Liu, MD, Staff Physician, Department of Surgery, University of California at Los Angeles Medical Center
Disclosure: Nothing to disclose.

Clifford Y Ko, MD, MS, Assistant Professor, Department of Surgery, University of California at Los Angeles School of Medicine
Clifford Y Ko, MD, MS is a member of the following medical societies: American College of Surgeons, American Medical Association, American Society of Colon and Rectal Surgeons, Association for Academic Surgery, California Medical Association, and New York Academy of Sciences
Disclosure: Nothing to disclose.

Medical Editor

Terence David Lewis, MBBS, FRACP, FRCPC, FACP, Program Director, Internal Medicine Residency, & Assistant Chairman, Associate Professor, Department of Internal Medicine, Division of Gastroenterology, Loma Linda University Medical Center
Terence David Lewis, MBBS, FRACP, FRCPC, FACP is a member of the following medical societies: American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Medical Association, California Medical Association, Royal College of Physicians and Surgeons of Canada, and Sigma Xi
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Douglas M Heuman, MD, FACP, Director of Hepatology, McGuire Veterans Affairs Medical Center, Professor, Department of Internal Medicine, Division of Gastroenterology, Virginia Commonwealth University School of Medicine
Douglas M Heuman, MD, FACP is a member of the following medical societies: American Association for the Study of Liver Diseases, American College of Physicians, and American Gastroenterological Association
Disclosure: Nothing to disclose.

CME Editor

Alex J Mechaber, MD, FACP, Associate Dean for Undergraduate Medical Education, Associate Professor of Medicine, University of Miami Miller School of Medicine
Alex J Mechaber, MD, FACP is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians-American Society of Internal Medicine, and Society of General Internal Medicine
Disclosure: Nothing to disclose.

Chief Editor

Julian Katz, MD, Clinical Professor of Medicine, Drexel University College of Medicine; Consulting Staff, Department of Medicine, Section of Gastroenterology and Hepatology, Hospital of the Medical College of Pennsylvania
Julian Katz, MD is a member of the following medical societies: American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Geriatrics Society, American Medical Association, American Society for Gastrointestinal Endoscopy, American Society of Law Medicine and Ethics, American Trauma Society, Association of American Medical Colleges, and Physicians for Social Responsibility
Disclosure: Nothing to disclose.

 
 
HONcode

We subscribe to the
HONcode principles of the
Health On the Net Foundation

All material on this website is protected by copyright, Copyright© 1994- by Medscape.
This website also contains material copyrighted by 3rd parties.

DISCLAIMER: The content of this Website is not influenced by sponsors. The site is designed primarily for use by qualified physicians and other medical professionals. The information contained herein should NOT be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for educational and informational purposes only. In no way should it be considered as offering medical advice. Please check with a physician if you suspect you are ill.