Toxic megacolon

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Toxic megacolon
Other namesMegacolon toxicum
Colonic pseudomembranes low mag.jpg
Micrograph of pseudomembranous colitis, a cause of toxic megacolon. H&E stain.
Specialty Gastroenterology
Symptoms Swelling of the belly, Pain in the belly, Fever, Rapid heart rate, Shock, Diarrhea. [1]
Complications Septic shock, perforation of the colon
Risk factors Chronic bowel disease
Prognosis Fatal without treatment

Toxic megacolon is an acute form of colonic distension. [2] It is characterized by a very dilated colon (megacolon), accompanied by abdominal distension (bloating), and sometimes fever, abdominal pain, or shock.

Contents

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). It can also be caused by Entamoeba histolytica and Shigella . It may also be caused by the use of loperamide.

Signs and symptoms

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.[ citation needed ]

Complications

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.

Pathophysiology

Toxic megacolon in a patient with ulcerative colitis: The patient subsequently underwent a colectomy. Toxisches Megacolon bei Colitis ulcerosa.jpg
Toxic megacolon in a patient with ulcerative colitis: The patient subsequently underwent a colectomy.
A pathological specimen showing toxic megacolon Toxic megacolon 1.JPG
A pathological specimen showing toxic megacolon

The pathological process involves inflammation and damage to the colonic wall with unknown toxins breaking down the protective mucosal barrier and exposing the muscularis propria. [4] There is relative destruction of the ganglion cells and swelling of the nerve fibers in the myenteric plexus, with concomitant damage to the colonic musculature. [4] This results in almost complete paralysis of the diseased segment of the colon with loss of smooth muscle substance, tone and motility. [4] This can lead to further complications as pressure builds up in the colon due to relative fecal stasis including sepsis, intestinal hemorrhage or free perforation and spontaneous decompression. [4]

Diagnosis

Massively dilated colon with air-fluid level can be seen on abdominal radiograph or CT scan. [5] [6]

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 with medical management, surgery is indicated. When surgery is required the recommended procedure is a colectomy (surgical removal of all or part of the colon) with end ileostomy. [7] 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. [8]

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. [9]

Related Research Articles

<span class="mw-page-title-main">Ulcerative colitis</span> Inflammatory bowel disease that causes ulcers in the colon

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD). It is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and anemia may also occur. Often, symptoms come on slowly and can range from mild to severe. Symptoms typically occur intermittently with periods of no symptoms between flares. Complications may include abnormal dilation of the colon (megacolon), inflammation of the eye, joints, or liver, and colon cancer.

<span class="mw-page-title-main">Defecation</span> Expulsion of feces from the digestive tract via the anus

Defecation follows digestion, and is a necessary process by which organisms eliminate a solid, semisolid, or liquid waste material known as feces from the digestive tract via the anus. The act has a variety of names ranging from the common, like pooping or crapping, to the technical, e.g. bowel movement, to the obscene (shitting), to the euphemistic, to the juvenile. The topic, usually avoided in polite company, can become the basis for some potty humor.

<span class="mw-page-title-main">Bowel obstruction</span> Medical condition

Bowel obstruction, also known as intestinal obstruction, is a mechanical or functional obstruction of the intestines which prevents the normal movement of the products of digestion. Either the small bowel or large bowel may be affected. Signs and symptoms include abdominal pain, vomiting, bloating and not passing gas. Mechanical obstruction is the cause of about 5 to 15% of cases of severe abdominal pain of sudden onset requiring admission to hospital.

<span class="mw-page-title-main">Diverticulitis</span> Digestive disease of the large intestine

Diverticulitis, also called colonic diverticulitis, is a gastrointestinal disease characterized by inflammation of abnormal pouches—diverticula—that can develop in the wall of the large intestine. Symptoms typically include lower abdominal pain of sudden onset, but the onset may also occur over a few days. There may also be nausea, diarrhea or constipation. Fever or blood in the stool suggests a complication. People may experience a single attack, repeated attacks, or ongoing "smouldering" diverticulitis.

<span class="mw-page-title-main">Colitis</span> Inflammation of the colon (large intestine)

Colitis is swelling or inflammation of the large intestine (colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases.

In medicine, the ileal pouch–anal anastomosis (IPAA), also known as restorative proctocolectomy (RPC), ileal-anal reservoir (IAR), an ileo-anal pouch, ileal-anal pullthrough, or sometimes referred to as a J-pouch, S-pouch, W-pouch, or a pelvic pouch, is an anastomosis of a reservoir pouch made from ileum to the anus, bypassing the former site of the colon in cases where the colon and rectum have been removed. The pouch retains and restores functionality of the anus, with stools passed under voluntary control of the person, preventing fecal incontinence and serving as an alternative to a total proctocolectomy with ileostomy.

<span class="mw-page-title-main">Volvulus</span> Twisting of part of the intestine, causing a bowel obstruction

A volvulus is when a loop of intestine twists around itself and the mesentery that supports it, resulting in a bowel obstruction. Symptoms include abdominal pain, abdominal bloating, vomiting, constipation, and bloody stool. Onset of symptoms may be rapid or more gradual. The mesentery may become so tightly twisted that blood flow to part of the intestine is cut off, resulting in ischemic bowel. In this situation there may be fever or significant pain when the abdomen is touched.

<span class="mw-page-title-main">Fecal impaction</span> Medical condition

A fecal impaction or an impacted bowel is a solid, immobile bulk of feces that can develop in the rectum as a result of chronic constipation. Fecal impaction is a common result of neurogenic bowel dysfunction and causes immense discomfort and pain. Its treatment includes laxatives, enemas, and pulsed irrigation evacuation (PIE) as well as digital removal. It is not a condition that resolves without direct treatment.

<span class="mw-page-title-main">Colectomy</span> Surgical removal of any extent of the colon

Colectomy is bowel resection of the large bowel (colon). It consists of the surgical removal of any extent of the colon, usually segmental resection. In extreme cases where the entire large intestine is removed, it is called total colectomy, and proctocolectomy denotes that the rectum is included.

<span class="mw-page-title-main">Megacolon</span> Medical condition

Megacolon is an abnormal dilation of the colon. This leads to hypertrophy of the colon. The dilation is often accompanied by a paralysis of the peristaltic movements of the bowel. In more extreme cases, the feces consolidate into hard masses inside the colon, called fecalomas, which can require surgery to be removed.

Pouchitis is an umbrella term for inflammation of the ileal pouch, an artificial rectum surgically created out of ileum in patients who have undergone a proctocolectomy or total colectomy. The ileal pouch-anal anastomosis is created in the management of patients with ulcerative colitis, indeterminate colitis, familial adenomatous polyposis, cancer, or rarely, other colitides.

<span class="mw-page-title-main">Neutropenic enterocolitis</span> Medical condition

Neutropenic enterocolitis, also known as typhlitis, is an inflammation of the cecum that may be associated with infection. It is particularly associated with neutropenia, a low level of neutrophil granulocytes in the blood.

<span class="mw-page-title-main">Abdominal distension</span> Physical symptom

Abdominal distension occurs when substances, such as air (gas) or fluid, accumulate in the abdomen causing its expansion. It is typically a symptom of an underlying disease or dysfunction in the body, rather than an illness in its own right. People with this condition often describe it as "feeling bloated". Affected people often experience a sensation of fullness, abdominal pressure, and sometimes nausea, pain, or cramping. In the most extreme cases, upward pressure on the diaphragm and lungs can also cause shortness of breath. Through a variety of causes, bloating is most commonly due to buildup of gas in the stomach, small intestine, or colon. The pressure sensation is often relieved, or at least lessened, by belching or flatulence. Medications that settle gas in the stomach and intestines are also commonly used to treat the discomfort and lessen the abdominal distension.

<span class="mw-page-title-main">Stercoral perforation</span> Medical condition

Stercoral perforation is the perforation or rupture of the intestine's walls by its internal contents, such as hardened feces or foreign objects. Hardened stools may form in prolonged constipation or other diseases which cause obstruction of transit, such as Chagas disease, Hirschprung's disease, toxic colitis, hypercalcemia, and megacolon.

<span class="mw-page-title-main">Ogilvie syndrome</span> Medical condition

Ogilvie syndrome is the acute dilatation of the colon in the absence of any mechanical obstruction in severely ill patients.

<span class="mw-page-title-main">Ischemic colitis</span> Medical condition

Ischemic colitis is a medical condition in which inflammation and injury of the large intestine result from inadequate blood supply. Although uncommon in the general population, ischemic colitis occurs with greater frequency in the elderly, and is the most common form of bowel ischemia. Causes of the reduced blood flow can include changes in the systemic circulation or local factors such as constriction of blood vessels or a blood clot. In most cases, no specific cause can be identified.

<span class="mw-page-title-main">Descending colon</span>

In the anatomy of humans and homologous primates, the descending colon is the part of the colon extending from the left colic flexure to the level of the iliac crest. The function of the descending colon in the digestive system is to store the remains of digested food that will be emptied into the rectum.

Management of ulcerative colitis involves first treating the acute symptoms of the disease, then maintaining remission. Ulcerative colitis is a form of colitis, a disease of the intestine, specifically the large intestine or colon, that includes characteristic ulcers, or open sores, in the colon. The main symptom of active disease is usually diarrhea mixed with blood, of gradual onset which often leads to anaemia. Ulcerative colitis is, however, a systemic disease that affects many parts of the body outside the intestine.

Stercoral ulcer is an ulcer of the colon due to pressure and irritation resulting from severe, prolonged constipation due to a large bowel obstruction, damage to the autonomic nervous system, or stercoral colitis. It is most commonly located in the sigmoid colon and rectum. Prolonged constipation leads to production of fecaliths, leading to possible progression into a fecaloma. These hard lumps irritate the rectum and lead to the formation of these ulcers. It results in fresh bleeding per rectum. These ulcers may be seen on imaging, such as a CT scan but are more commonly identified using endoscopy, usually a colonoscopy. Treatment modalities can include both surgical and non-surgical techniques.

Checkpoint inhibitor induced colitis is an inflammatory condition affecting the colon (colitis), which is caused by cancer immunotherapy. Symptoms typically consist of diarrhea, abdominal pain and rectal bleeding. Less commonly, nausea and vomiting may occur, which may suggest the present of gastroenteritis. The severity of diarrhea and colitis are graded based on the frequency of bowel movements and symptoms of colitis, respectively.

References

  1. "Toxic Megacolon". Johns Hopkins Medicine. 19 November 2019. Retrieved 15 March 2023.
  2. "Toxic megacolon" "at Dorland's Medical Dictionary
  3. 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.
  4. 1 2 3 4 Michael B; et al. (1980). "Toxic megacolon complicating Crohn's Colitis". Ann. Surg. 191 (1): 75–80. doi:10.1097/00000658-198001000-00015. PMC   1344622 . PMID   7352781.
  5. "Toxic megacolon: MedlinePlus Medical Encyclopedia". medlineplus.gov. Retrieved 2022-11-18.
  6. "Toxic megacolon httpsmedlineplus.govencyarticle000248.htm". profilpelajar.com. Retrieved 2022-11-18.
  7. 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.
  8. Autenrieth, DM; Baumgart, DC (August 2011). "Toxic megacolon". Inflammatory Bowel Diseases. 18 (3): 584–91. doi:10.1002/ibd.21847. PMID   22009735. S2CID   32866477.
  9. 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. S2CID   23729183.

Further reading