A 66-year-old woman comes to the office due to 4 days of watery diarrhea and abdominal cramps. The patient has had 7-10 loose stools daily with no blood or mucus. She has a history of constipation requiring frequent laxative use but last took a laxative 6 days ago. The patient received oral antibiotics for acute sinusitis 3 weeks ago. She has a history of gastroesophageal reflux disease and type 2 diabetes mellitus. The patient takes omeprazole and metformin daily. She smokes a pack of cigarettes daily. Temperature is 38 C (100.4 F). The abdomen is soft with mild distension and mild diffuse tenderness. No guarding or rebound tenderness is present. Stool testing for Clostridioides difficile is positive. In addition to recent antibiotic use, which of the following most likely predisposed this patient to her current condition?

Question

A 66-year-old woman comes to the office due to 4 days of watery diarrhea and abdominal cramps.  The patient has had 7-10 loose stools daily with no blood or mucus.  She has a history of constipation requiring frequent laxative use but last took a laxative 6 days ago.  The patient received oral antibiotics for acute sinusitis 3 weeks ago.  She has a history of gastroesophageal reflux disease and type 2 diabetes mellitus.  The patient takes omeprazole and metformin daily.  She smokes a pack of cigarettes daily.  Temperature is 38 C (100.4 F).  The abdomen is soft with mild distension and mild diffuse tenderness.  No guarding or rebound tenderness is present.  Stool testing for Clostridioides difficile is positive.  In addition to recent antibiotic use, which of the following most likely predisposed this patient to her current condition?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d0cd_1258_bc81_595923b06190_MD0003_00 Clostridioides difficile is a gram-positive, anaerobic bacterium that causes infectious diarrhea in nosocomial and outpatient settings. Hardy, antibiotic-resistant spores are ingested and convert to fully functional bacilli in the colon. Although the organism is noninvasive, pathogenic strains produce exotoxins (enterotoxin A, cytotoxin B) that penetrate colonic epithelial cells, resulting in apoptosis and loss of tight junctions. The greatest risk factor for C difficile-associated diarrhea is recent antibiotic use (eg, fluoroquinolones, clindamycin, cephalosporins, penicillins). Antibiotics disrupt the normal colonic flora (eg, Bacteroides), eliminating a crucial epithelial barrier and freeing nutrients that C difficile uses to proliferate. Other common risk factors include the following: Gastric acid suppression: C difficile spores are acid resistant, but proton pump inhibitors (PPIs) are thought to alter the colonic microbiome, which increases the risk for C difficile proliferation. Recent hospitalization: C difficile transmission is most common in the hospital setting, particularly when patients are severely ill. Advanced age (eg, >65): Older individuals often have diminished colonic immunity and greater exposure to antibiotics, PPIs, and hospitals. Less common risk factors include inflammatory bowel disease and cancer chemotherapy, both of which can alter the gut microbiome. (Choice A) This patient discontinued laxatives 6 days ago; they are unlikely to cause diarrhea several days later. Laxative use is not typically associated with increased risk for C difficile-associated diarrhea; gastric acid suppression is a much stronger risk factor. (Choice B) Metformin can cause gastrointestinal adverse effects, including watery diarrhea; however, these adverse effects more commonly occur at the start of therapy, rather than from chronic use. Metformin use is not associated with an increased risk of C difficile infection. (Choice C) Cigarette smoking is not considered a major risk factor for the development of C difficile infection. In contrast, it has been shown to negatively impact the development, severity, and progression of Crohn disease. (Choice E) Small bowel dysmotility (eg, due to diabetes mellitus) and gastric hypochlorhydria (eg, PPI use) can lead to small intestinal bacterial overgrowth, which can manifest as chronic watery diarrhea. However, bloating and flatulence are also commonly present, and fever is unexpected. Educational objective: Clostridioides difficile is a common cause of nosocomial and outpatient infectious diarrhea. Major risk factors include recent antibiotic use, age >65, and gastric acid suppression (eg, proton pump inhibitors). Less common risk factors include underlying inflammatory bowel disease and cancer chemotherapy. References: Proton pump inhibitors therapy and risk of Clostridium difficile infection: systematic review and meta-analysis. (http://www.ncbi.nlm.nih.gov/pubmed/29085200) Association of gastric acid suppression with recurrent Clostridium difficile infection: a systematic review and meta-analysis. (http://www.ncbi.nlm.nih.gov/pubmed/28346595) Acute diarrhea. (http://www.ncbi.nlm.nih.gov/pubmed/24506120)

A 66-Year-Old Woman Comes to the Office Due to 4