Toxic megacolon

Toxic megacolon

Micrograph of pseudomembranous colitis, a cause of toxic megacolon. H&E stain.
Classification and external resources
Specialty	gastroenterology
ICD-10	K59.3
ICD-9-CM	556.9
DiseasesDB	27702
MedlinePlus	000248
eMedicine	med/1418 radio/702
MeSH	D008532

Toxic megacolon (megacolon toxicum) is an acute form of colonic distension.^[1] It is characterized by a very dilated colon (megacolon), accompanied by abdominal distension (bloating), and sometimes fever, abdominal pain, or shock.

Toxic megacolon is usually a complication of inflammatory bowel disease, such as ulcerative colitis and, more rarely, Crohn's disease, and of some infections of the colon, including Clostridium difficile infections, which have led to pseudomembranous colitis. Other forms of megacolon exist and can be congenital (present since birth, such as Hirschsprung's disease). Also, it can be caused by Entamoeba histolytica and Shigella.

Signs and symptoms

Abdominal pain
Abdominal bloating
Abdominal tenderness
Fever
Tachycardia (rapid heart rate)
Dehydration

There may be signs of septic shock. A physical examination reveals abdominal tenderness and possible loss of bowel sounds. An abdominal radiography shows colonic dilation. White blood cell count is usually elevated. Severe sepsis may present with hypothermia or leukopenia.

Treatment

Toxic megacolon in a patient with ulcerative colitis: The patient subsequently underwent a colectomy.

The objective of treatment is to decompress the bowel and to prevent swallowed air from further distending the bowel. If decompression is not achieved or the patient does not improve within 24 hours, a colectomy (surgical removal of all or part of the colon) is indicated. When surgery is required the recommended procedure is a subtotal colectomy with end ileostomy.^[2] Fluid and electrolyte replacement help to prevent dehydration and shock. Use of corticosteroids may be indicated to suppress the inflammatory reaction in the colon if megacolon has resulted from active inflammatory bowel disease. Antibiotics may be given to prevent sepsis.^[3]

Prognosis

If the condition does not improve, the risk of death is significant. In case of poor response to conservative therapy, a colectomy is usually required.^[4]

Complications

A pathological specimen showing toxic megacolon

Perforation of the colon^[5]
Sepsis
Shock

Emergency action may be required if severe abdominal pain develops, particularly if it is accompanied by fever, rapid heart rate, tenderness when the abdomen is pressed, bloody diarrhea, frequent diarrhea, or painful bowel movements.

Colonoscopy is contraindicated, as it may rupture the dilated colon resulting in peritonitis and septic shock.

Footnotes

↑ "Toxic megacolon" at Dorland's Medical Dictionary
↑ Seltman, AK (December 2012). "Surgical Management of Clostridium difficile Colitis". Clinics in Colon and Rectal Surgery. 25 (4): 204–9. doi:10.1055/s-0032-1329390. PMC 3577611. PMID 24294121.
↑ Autenrieth, DM; Baumgart, DC (August 2011). "Toxic megacolon". Inflammatory Bowel Diseases. 18: 584–91. doi:10.1002/ibd.21847. PMID 22009735.
↑ Benchimol, EI; Turner, D; Mann, EH; Thomas, KE; et al. (June 2008). "Toxic megacolon in children with inflammatory bowel disease: Clinical and radiographic characteristics". The American Journal of Gastroenterology. 103 (6): 1524–31. doi:10.1111/j.1572-0241.2008.01807.x. PMID 18510624.
↑ Panos, MZ; Wood, MJ; Asquith, P (December 1993). "Toxic megacolon: The knee-elbow position relieves bowel distension". Gut. 34 (12): 1726–7. doi:10.1136/gut.34.12.1726. PMC 1374472. PMID 8282262.

References

This article incorporates text from the United States National Library of Medicine (Toxic megacolon), which is in the public domain.

Ausch, C; Madoff, RD; Gnant, M; Rosen, HR; Garcia-Aguilar, J; Hölbling, N; Herbst, F; Buxhofer, V; Holzer, B; Rothenberger, DA; Schiessel, R (March 2006). "Aetiology and surgical management of toxic megacolon". Colorectal Disease. 8 (3): 195–201. doi:10.1111/j.1463-1318.2005.00887.x. PMID 16466559.
Toxic Megacolon at eMedicine

Diseases of the digestive system (primarily K20–K93, 530–579)

Upper GI tract

Esophagus	Esophagitis Candidal Eosinophilic Herpetiform Rupture Boerhaave syndrome Mallory-Weiss syndrome UES Zenker's diverticulum LES Barrett's esophagus Esophageal motility disorder Nutcracker esophagus Achalasia Diffuse esophageal spasm Gastroesophageal reflux disease (GERD) Laryngopharyngeal reflux (LPR) Esophageal stricture Megaesophagus

Stomach	Gastritis Atrophic Ménétrier's disease Gastroenteritis Peptic (gastric) ulcer Cushing ulcer Dieulafoy's lesion Dyspepsia Pyloric stenosis Achlorhydria Gastroparesis Gastroptosis Portal hypertensive gastropathy Gastric antral vascular ectasia Gastric dumping syndrome Gastric volvulus

Lower GI tract:
Intestinal/
Enteropathy

Small intestine (Duodenum/Jejunum/Ileum)	Enteritis Duodenitis Jejunitis Ileitis Peptic (duodenal) ulcer Curling's ulcer Malabsorption: Coeliac Tropical sprue Blind loop syndrome Small bowel bacterial overgrowth syndrome Whipple's Short bowel syndrome Steatorrhea Milroy disease Bile acid malabsorption

Large intestine (Appendix/Colon)	Appendicitis Colitis Pseudomembranous Ulcerative Ischemic Microscopic Collagenous Lymphocytic Functional colonic disease IBS Intestinal pseudoobstruction / Ogilvie syndrome Megacolon / Toxic megacolon Diverticulitis/Diverticulosis

Large and/or small	Enterocolitis Necrotizing Gastroenterocolitis IBD Crohn's disease Vascular: Abdominal angina Mesenteric ischemia Angiodysplasia Bowel obstruction: Ileus Intussusception Volvulus Fecal impaction Constipation Diarrhea Infectious Intestinal adhesions

Rectum	Proctitis Radiation proctitis Proctalgia fugax Rectal prolapse Anismus

Anal canal	Anal fissure/Anal fistula Anal abscess Anal dysplasia Pruritus ani

GI bleeding/BIS

Accessory

Liver	Hepatitis Viral hepatitis Autoimmune hepatitis Alcoholic hepatitis Cirrhosis PBC Fatty liver NASH Vascular Budd-Chiari syndrome Hepatic veno-occlusive disease Portal hypertension Nutmeg liver Alcoholic liver disease Liver failure Hepatic encephalopathy Acute liver failure Liver abscess Pyogenic Amoebic Hepatorenal syndrome Peliosis hepatis Metabolic disorders Wilson's disease Hemochromatosis

Gallbladder	Cholecystitis Gallstones/Cholecystolithiasis Cholesterolosis Rokitansky-Aschoff sinuses Postcholecystectomy syndrome Porcelain gallbladder

Bile duct/ Other biliary tree	Cholangitis Primary sclerosing cholangitis Secondary sclerosing cholangitis Ascending Cholestasis/Mirizzi's syndrome Biliary fistula Haemobilia Gallstones/Cholelithiasis Common bile duct Choledocholithiasis Biliary dyskinesia Sphincter of Oddi dysfunction

Pancreatic	Pancreatitis Acute Chronic Hereditary Pancreatic abscess Pancreatic pseudocyst Exocrine pancreatic insufficiency Pancreatic fistula

Abdominopelvic

Hernia	Diaphragmatic Congenital Hiatus Inguinal Indirect Direct Umbilical Femoral Obturator Spigelian Lumbar Petit's Grynfeltt-Lesshaft Undefined location Incisional Internal hernia Richter's

Peritoneal	Peritonitis Spontaneous bacterial peritonitis Hemoperitoneum Pneumoperitoneum

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