Question

Case Study:

An 83-year-old female patient presented in the ER with signs of dehydration such as sunken eyes, dry mucus membranes and low urinary output due to frequent watery diarrhea (five to 10 times a day), for two days. Her stools had turned bloody with mucus in them. At the start of her diarrhea she was given Loperamide at the nursing home she lived in, but the frequency of her diarrhea increased, and she started developing abdominal cramps and bloating .When the doctor took her medical history, she discovered that her patient had completed a course of Clindamycin for a bad sinus infection. The doctor immediately ordered stool tests, enzyme immunoassays for toxins and a colonoscopy. The colonoscopy revealed yellowish adherent plaques, 2–10 mm, called pseudomembranes with a few areas of normal mucosa between them. Her doctor immediately started her on aggressive antibiotic therapy with Metronidazole and Vancomycin. The patient subsequently recovered well enough to be discharged

1) What disease did the doctor suspect?

2) What is the casual organism for this disease?

3) What are the pre-disposing or risk factors for this disease?

4) What toxins would the ELISA test detect?

5) What were the other tests done?

Answer 1

1) Pseudomembranous Colitis - Due to the presence of yellowish plaques during colonoscopy, the doctor has suspected it to be Pseudomembranous Colitis.

2) Clostridium difficile - The condition is also known as Clostridium difficile colitis. It is caused by this spore forming bacteria.

3) Clostridium difficile are resistant to fluoroquinolones, cephalosporins and clindamycin. When taking these antibiotics for treating other conditions, C. difficile may overgrow and produce toxin that results in Pseudomembranous Colitis. This disease occurs mostly in patients who are living in a hospital environment or a nursing home, due to incresed colonization.

4) Toxins A and toxin B of C. difficile are assessed using ELISA. Out of the many toxins produced by the bacteria, these two toxins are tested to confirm the infection.

5) Cytotoxicity assay is done to detect the bacteria. C.difficile toxins have a cytopathic effect in cell culture and are tested for toxin production in toxigenic culture. Stool tests such as Stool leukocyte measurements and stool lactoferrin levels are also used in diagnosis. Colonoscopy and sigmoidoscopy are also done to detect the yellow plaques adhered to the walls of the colon.