Toxic megacolon is an acute form of colonic distension. It is characterized by a very dilated colon

Colon (anatomy)

The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...

 (megacolon

Megacolon

Megacolon is an abnormal dilation of the colon . The dilatation is often accompanied by a paralysis of the peristaltic movements of the bowel...

), accompanied by abdominal distension (bloating

Bloating

Bloating is any abnormal general swelling, or increase in diameter of the abdominal area. As a symptom, the patient feels a full and tight abdomen, which may cause abdominal pain sometimes accompanied by increased borborygmus or more seriously the total lack of borborygmus.-Symptoms:The most common...

), and sometimes fever

Fever

Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

, abdominal pain

Abdominal pain

Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem...

, or shock.

Toxic megacolon is usually a complication

Complication (medicine)

Complication, in medicine, is an unfavorable evolution of a disease, a health condition or a medical treatment. The disease can become worse in its severity or show a higher number of signs, symptoms or new pathological changes, become widespread throughout the body or affect other organ systems. A...

 of inflammatory bowel disease

Inflammatory bowel disease

In medicine, inflammatory bowel disease is a group of inflammatory conditions of the colon and small intestine. The major types of IBD are Crohn's disease and ulcerative colitis.-Classification:...

, such as ulcerative colitis

Ulcerative colitis

Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...

 and, more rarely, Crohn’s disease, and of some infections of the colon, including Clostridium difficile

Clostridium difficile

Clostridium difficile , also known as "CDF/cdf", or "C...

infections which have led to Pseudomembranous colitis

Pseudomembranous colitis

Pseudomembranous colitis, a cause of antibiotic-associated diarrhea , is an infection of the colon. It is often, but not always, caused by the bacterium Clostridium difficile. Because of this, the informal name C. difficile colitis is also commonly used. The illness is characterized by...

. Other forms of megacolon exist and can be congenital (present since birth, such as Hirschsprung's disease

Hirschsprung's disease

Hirschsprung's disease , or congenital aganglionic megacolon is a serious medical problem where the enteric nervous system is missing from the end of the bowel. The enteric nervous system is a complex network of neurons and glia that controls most aspects of intestinal function...

).

Signs and symptoms

• Abdominal pain
  Abdominal pain
  Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem...
  
  
• Abdominal bloating
  Bloating
  Bloating is any abnormal general swelling, or increase in diameter of the abdominal area. As a symptom, the patient feels a full and tight abdomen, which may cause abdominal pain sometimes accompanied by increased borborygmus or more seriously the total lack of borborygmus.-Symptoms:The most common...
  
  
• Abdominal tenderness
• Fever
  Fever
  Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
  
  
• Tachycardia
  Tachycardia
  Tachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...
  
   (rapid heart rate)
• Dehydration
  Dehydration
  In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...
  
  

There may be signs of septic shock

Septic shock

Septic shock is a medical emergency caused by decreased tissue perfusion and oxygen delivery as a result of severe infection and sepsis, though the microbe may be systemic or localized to a particular site. It can cause multiple organ dysfunction syndrome and death...

. A physical examination

Physical examination

Physical examination or clinical examination is the process by which a doctor investigates the body of a patient for signs of disease. It generally follows the taking of the medical history — an account of the symptoms as experienced by the patient...

 reveals abdominal tenderness and possible loss of bowel sounds. An abdominal radiography

Radiography

Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....

 shows colonic dilation. There is usually an elevated white blood cell

White blood cell

White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...

 count. Severe sepsis may present with hypothermia or leukopenia

Leukopenia

Leukopenia is a decrease in the number of white blood cells found in the blood, which places individuals at increased risk of infection....

.

Treatment

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

Colectomy

Colectomy consists of the surgical resection of any extent of the large intestine .-History:Sir William Arbuthnot-Lane was one of the early proponents of the usefulness of total colectomies, although his overuse of the procedure called the wisdom of the surgery into question.-Indications:Some of...

 (surgical removal of all or part of the colon) is indicated. Fluid and electrolyte replacement help to prevent dehydration and shock. Use of corticosteroid

Corticosteroid

Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...

s may be indicated to suppress the inflammatory

Inflammation

Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 reaction in the colon if megacolon has resulted from active inflammatory bowel disease. Antibiotics may be given to prevent sepsis

Sepsis

Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...

.

Prognosis

If the condition does not improve, there is a significant risk of death. In case of poor response to conservative therapy a colectomy is usually required. This may involve all or part of the colon being removed, with the resulting option of anastomosis

Surgical anastomosis

In surgical jargon, to create an anastomosis is to join together two hollow organs , usually to restore continuity after resection, or to bypass an unresectable disease process. Historically such procedures were performed with suture material, but increasingly mechanical staplers and biological...

 or ileostomy

Ileostomy

An ileostomy is a surgical opening constructed by bringing the end or loop of small intestine out onto the surface of the skin. Intestinal waste passes out of the ileostomy and is collected in an external pouching system stuck to the skin...

. Ileostomy carries far less risk of infection and post-operative complications because the risk of deterioration of sutures within the intestinal tract (as a result of anastomosis) is not present. The risk of death and shock has been reported to be lower in children, however most children required colectomy in one case-control study .

Complications

• Sepsis
• Shock
• Perforation of the colon

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

Diarrhea

Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

, frequent diarrhea, or painful bowel movements.

Colonoscopy is contra-indicated, as it may rupture the dilated colon, thus causing severe hemorrhage.

External links

• Toxic megacolon. National Institutes of Health. Used as the public domain source for this article. Update on 1/26/2004 by: Sreeni Jonnalagadda, M.D., Interventional and Pancreatobiliary Endoscopy, Washington University School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network.