Signs and symptoms of pseudomembranous colitis may include:

• Watery diarrhea
• Abdominal cramps, pain or tenderness
• Fever
• Pus or mucus in your stool
• Nausea
• Dehydration

Symptoms of pseudomembranous colitis can begin as soon as one to two days after you start taking an antibiotic, or as long as several months or longer after you finish taking the antibiotic.

Your body usually keeps the many bacteria in your colon in a naturally healthy balance, but antibiotics and other medications can upset this balance. Pseudomembranous colitis occurs when certain bacteria — usually C. difficile — rapidly outgrow other bacteria that normally keep them in check. Certain toxins produced by C. difficile, which are usually present in only tiny amounts, rise to levels high enough to damage the colon.

While almost any antibiotic can cause pseudomembranous colitis, some antibiotics are more commonly linked to pseudomembranous colitis than others, including:

• Fluoroquinolones, such as ciprofloxacin (Cipro) and levofloxacin
• Penicillins, such as amoxicillin and ampicillin
• Clindamycin (Cleocin)
• Cephalosporins, such as cefixime (Suprax)

Other causes

Other medications besides antibiotics can sometimes cause pseudomembranous colitis. Chemotherapy drugs that are used to treat cancer may disrupt the normal balance of bacteria in the colon.

Certain diseases that affect the colon, such as ulcerative colitis or Crohn's disease, may also predispose people to pseudomembranous colitis.

C. difficile spores are resistant to many common disinfectants and can be transmitted from the hands of health care professionals to patients. Increasingly, C. difficile has been reported in people with no known risk factors, including people with no recent health care contact or use of antibiotics. This is called community-acquired C. difficile.

Factors that may increase your risk of pseudomembranous colitis include:

• Taking antibiotics
• Staying in the hospital or a nursing home
• Increasing age, especially over 65 years
• Having a weakened immune system
• Having a colon disease, such as inflammatory bowel disease or colorectal cancer
• Undergoing intestinal surgery
• Receiving chemotherapy treatment for cancer

Treatment of pseudomembranous colitis is usually successful. However, even with prompt diagnosis and treatment, pseudomembranous colitis can be life-threatening. Possible complications include:

• Dehydration. Severe diarrhea can lead to a significant loss of fluids and electrolytes. This makes it difficult for your body to function normally and can cause blood pressure to drop to dangerously low levels.
• Kidney failure. In some cases, dehydration can occur so quickly that kidney function rapidly deteriorates (kidney failure).
• Toxic megacolon. In this rare condition, your colon is unable to expel gas and stool, causing it to become greatly distended (megacolon). Left untreated, your colon may rupture, causing bacteria from the colon to enter your abdominal cavity. An enlarged or ruptured colon requires emergency surgery and may be fatal.
• A hole in your large intestine (bowel perforation). This is rare and results from extensive damage to the lining of your large intestine or after toxic megacolon. A perforated bowel can spill bacteria from the intestine into your abdominal cavity, leading to a life-threatening infection (peritonitis).
• Death. Even mild to moderate C. difficile infections can quickly progress to a fatal disease if not treated promptly.