A 50-year-old man undergoes surgery for a peptic ulcer perforation. The patient's early postoperative course is complicated by fever and hypotension, which are treated with broad-spectrum antibiotics and intravenous fluid support. He recovers until postoperative day 7, when he develops nausea, abdominal cramps, and profuse watery diarrhea. The patient is not currently on antibiotics. Temperature is 38.9 C (102 F), blood pressure is 112/70 mm Hg, pulse is 120/min and regular, and respirations are 18/min. The lungs are clear to auscultation. Abdominal examination shows a well-healing midline scar and no distension. Tenderness is present in the left lower quadrant. Testing of stool for occult blood is negative. Laboratory results are as follows: Which of the following is the most appropriate next step in management of this patient?

Question

A 50-year-old man undergoes surgery for a peptic ulcer perforation.  The patient's early postoperative course is complicated by fever and hypotension, which are treated with broad-spectrum antibiotics and intravenous fluid support.  He recovers until postoperative day 7, when he develops nausea, abdominal cramps, and profuse watery diarrhea.  The patient is not currently on antibiotics.  Temperature is 38.9 C (102 F), blood pressure is 112/70 mm Hg, pulse is 120/min and regular, and respirations are 18/min.  The lungs are clear to auscultation.  Abdominal examination shows a well-healing midline scar and no distension.  Tenderness is present in the left lower quadrant.  Testing of stool for occult blood is negative.  Laboratory results are as follows: Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d91c_9a4d_bc81_412a10364e4c_MD0003_00 This hospitalized patient, who recently completed a course of broad-spectrum antibiotics, has new-onset, profuse watery diarrhea accompanied by abdominal cramping, fever, and leukocytosis. This presentation is concerning for Clostridioides difficile infection (CDI), and the most appropriate next step is confirmation of the diagnosis with one of the following stool studies: Stool PCR for C difficile: PCR assesses for genes specific to toxigenic strains. It is highly sensitive but cannot differentiate active CDI from colonization (affecting up to 20% of hospitalized patients), in which C difficile is present without active toxin production. Enzyme immunoassay for C difficile toxins and glutamate dehydrogenase antigen (a protein present on all C difficile strains): These tests are not as sensitive as PCR; however, stool toxin testing is more specific than PCR for active infection because it detects active toxin production. When symptoms of active CDI are present (ie, infection rather than colonization is already suspected), the more sensitive PCR test is typically preferred. (Choice A) Blood cultures are indicated in a patient with new-onset fever due to suspected bacteremia. However, given this patient's classic symptoms (eg, profuse watery diarrhea) and risk factors (eg, recent antibiotics), empiric broad-spectrum antibiotics should not be given because they can worsen CDI. Bacteremia is uncommon in CDI. (Choice B) CT scan of the abdomen can diagnose diverticulitis, which can present with fever, left lower quadrant pain, and diarrhea. However, this patient already received broad-spectrum antibiotics, making diverticulitis less likely. Even if the CT scan reveals colitis, the finding is nonspecific. (Choice C) Patients with significant abdominal pain from an acute abdominal process (eg, pancreatitis) are often NPO, and parenteral feeding may be required for those on prolonged bowel rest. However, bowel rest is usually not required for patients with CDI, who typically require oral antibiotics. (Choice D) Stool anerobic culture is rarely used to diagnose CDI; it takes days for results, and culture cannot distinguish between toxigenic and nontoxigenic strains. Stool PCR is ready within hours and is more specific for toxigenic CDI. (Choice E) Although parasitic infection (eg, giardiasis) can cause watery diarrhea and abdominal pain, it is rare for hospitalized patients to acquire such infections. When suspected, stool PCR testing is the preferred method of diagnosis; microscopy has lower sensitivity and is more labor intensive and technician dependent. Educational objective: Clostridioides difficile infection is diagnosed via stool testing with either stool PCR (for genes specific to toxigenic strains) or enzyme immunoassay (for C difficile toxins and glutamate dehydrogenase antigen). References: ACG clinical guidelines: prevention, diagnosis, and treatment of Clostridioides difficile infections. (http://www.ncbi.nlm.nih.gov/pubmed/34003176)

A 50-Year-Old Man Undergoes Surgery for a Peptic Ulcer Perforation