Megacolon, toxic

Antidiarrheal medications that reduce GI motility, such as loperamide, diphenoxylate/atropine, or codeine should be avoided in patients with active IBD due to the risk of precipitating acute colonic dilation (toxic megacolon). 

A serious complication of UC is toxic megacolon, defined as dilation of the transverse colon of greater than 6 cm. Patients... 

Toxic megacolon (primarily in the setting of S. dysenteriae 1 infection)... 

Rifaximin is likely to be effective in the treatment of milder forms of shigellosis and has been shown to be effective at preventing infection owing to S. flexneri.10 Antimotility agents are not recommended because they can worsen dysentery and may be related to the development of toxic megacolon. No vaccines are licensed currently for the prevention of shigellosis. 

Toxic megacolon Suggested by acute dilatation of the colon to a diameter greater than 6 cm, associated systemic toxicity, and the absence of mechanical obstruction. It carries a high mortality rate. 

Fulminant colitis Acute abdomen and systemic symptoms such as fever, tachycardia, dehydration, and hypotension. Some patients have marked leukocytosis (up to 40,000 white blood cells/mm3). Diarrhea is usually prominent but may not occur in patients with paralytic ileus and toxic megacolon. 

Severe disease is defined as the presence of complications of colitis, such as sepsis, volume depletion, electrolyte imbalance, hypotension, paralytic ileus, and toxic megacolon. Patients with signs of severe disease should receive oral vancomycin as initial therapy. Surgical intervention may be indicated and lifesaving, particularly in cases complicated by toxic megacolon or colonic perforation. 

In circumstances where oral therapy cannot be given, intravenous metronidazole (500 mg every 6-8 hours), vancomycin retention enemas (500 mg every 4-8 hours), or vancomycin via colonic catheter should be considered.38 Antiperistaltic agents should not be given because the use of these agents is associated with the development of toxic megacolon. 

Signs and Symptoms Abdominal pain, cramps, diarrhea, fever, vomiting, tenesmus, and blood, pus, or mucus in stools. Infections also cause mucosal ulceration, rectal bleeding, drastic dehydration. Serious less frequent complications include sepsis, seizures, convulsions, rectal prolapse, toxic megacolon, intestinal perforation, renal failure, and hemolytic uremic syndrome. 

A major complication is toxic megacolon, a severe condition that occurs in up to 7.9% of ulcerative colitis patients admitted to hospitals. The patient with toxic megacolon usually has a high fever, tachycardia, distended abdomen, elevated white blood cell count, and a dilated colon. 

The treatment required for toxic megacolon includes general supportive measures to maintain vital functions, consideration for early surgical intervention, and antimicrobials. 

Gi disorders Doses administered to patients with ulcerative colitis may suppress Gl motility and produce paralytic ileus and precipitate or aggravate toxic megacolon. Administer ER tablets with caution to patients with Gl obstructive disorders because of the risk of gastric retention. 

Constipation Serious complications of constipation, including obstruction, perforation, impaction, toxic megacolon, secondary colonic ischemia, and death have been reported with use of alosetron. Immediately discontinue alosetron treatment in patients who develop constipation. 

Gl Obstructive disease (eg, achalasia, pyloroduodenal stenosis or pyloric obstruction, cardiospasm) paralytic ileus intestinal atony of the elderly or debilitated severe ulcerative colitis toxic megacolon complicating ulcerative colitis hepatic disease. 

Uicerative coiitis Agents that inhibit intestinal motility or delay intestinal transit time have induced toxic megacolon. Consequently, carefully observe patients with acute ulcerative colitis. 

Diarrhea Diphenoxylate may prolong or aggravate diarrhea associated with organisms that penetrate intestinal mucosa (ie, toxigenic Escherichia coli, Salmonella, Shigella) or in pseudomembranous enterocolitis associated with broad-spectrum antibiotics. Do not use diphenoxylate in these conditions. In some patients with acute ulcerative colitis, diphenoxylate may induce toxic megacolon. Fluid/Electrolyte balance Dehydration, particularly in younger children, may... 

Adverse reactions may include dry skin and mucous membranes, flushing, hyperthermia, tachycardia, urinary retention (especially in children), pruritus, gum swelling, angioneurotic edema, urticaria, anaphylaxis, dizziness, drowsiness, sedation, headache, malaise, lethargy, restlessness, euphoria, depression, numbness of extremities, confusion, anorexia, nausea, vomiting, abdominal discomfort, toxic megacolon, and pancreatitis. 

VIII.b.1.3. Extensive disease. Rectal therapies are insufficient, and patients should receive, if outpatients, oral corticosteroids, and if in-patients oral or parenteral corticosteroids with full supportive treatment including parenteral fluids and blood transfusion. The need for intensive in-patient treatment is indicated by the presence of severe diarrhoea, anaemia, fever and tachycardia with radiographic evidence of colonic mucosal oedema on plain X-ray, or of toxic megacolon. 

Contraindications Bladder neck obstruction due to prostatic hypertrophy, cardiospasm, intestinal atony, myasthenia gravis in those not treated with neostigmine, narrow-angle glaucoma, obstructive disease of the GI tract, paralytic ileus, severe ulcerative colitis, tachycardia secondary to cardiac insufficiency or thyrotoxicosis, toxic megacolon, unstable cardiovascular status in acute hemorrhage... 

Paralytic ileus and toxic megacolon (marked by constipation, decreased appetite, and stomach pain with nausea or vomiting) occur rarely. 

Contraindications Glaucoma, obstructive uropathy, obstructive disease of Gl-anti-cholinergic tract, paralytic ileus, intestinal atony of the elderly or debilitated patient, unstable cardiovascular status in acute hemorrhage, severe ulcerative colitis especially if complicated by toxic megacolon, myasthenia gravis, hiatal hernia associated with reflux esophagitis, hypersensitivity to any component of f he formulaf ion, acuf e infermiffenf porphyria. 

I Contraindications Acute ulcerative colitis (may produce toxic megacolon), diarrhea associated with pseudomembranous enterocolitis due to broad-spectrum antibiotics or to organisms that invade intestinal mucosa (such as Escherichia coli, shigella, and salmonella), patients who must avoid constipation... 

Hypotension, paralytic ileus, respiratory depression, and toxic megacolon rarely occur. 

Contraindications GI or genitourinary (GU) obstruction, myasthenia gravis, narrow-angle glaucoma, toxic megacolon, severe ulcerative colitis, unstable cardiovascular adjustment in acute hemorrhage, hypersensitivity to propantheline or other anticholinergics... 

Loperamide and codeine are preferred to diphenoxylate in chronic diarrhoea, because they have less tendency to produce drug dependence. Long-term use of these drugs may aggravate irritable bowel syndrome. These drugs are used cautiously in attacks of colitis because there is increased risk of toxic megacolon. Also all these drugs should be used with caution in elderly because faecal impaction... 

A possible risk of glucocorticoid treatment of ulcerative colitis is the development of toxic megacolon or colonic... 

Two drugs widely used to control diarrhea are diphenoxylate [di PHEN ox a late and loperamide [loe PER a mide]. Both are analogues of meperidine (see p. 138) and have opioid-like actions on the gut, activating presynaptic opioid receptors in the enteric nervous system to inhibit acetylcholine release and decrease peristalsis. Side effects include drowsiness, abdominal cramps and dizziness. Since these drugs can cause toxic megacolon, they should not be used in young children or patients with severe colitis. 

Severe ulcerative cohtis or toxic megacolon Unstable cardiovascular status in acute hemorrhage... 

Hypersensitivity to hyoscyamine products or other anticholinergic drugs Intestinal obstruction, intestinal atony (in elderly, debilitated), severe ulcerative colitis, paralytic ileus, toxic megacolon Myasthenia gravis Obstructive uropathy... 

Gastrointestinal Abdominal discomfort, nausea and vomiting, pancreatitis, toxic megacolon... 

History of Crohn s disease, diverticulitis, G1 perforation and/or adhesions, impaired intestinal circulation or ischemic colitis, intestinal obstruction, intestinal stricture, or toxic megacolon... 

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