Infectious diarrhea

Question 1

Diagnostic tests of CDI

Answer 1

1) Gold standard: stool culture
2) Enzyme immunoassay (EIA): for toxins (lack sensitivity), for glutamate dehydrogenase (sensitive, not specific)
3) PCR: for gene tcdB, tcdC is alternative to stool culture, high sen/spec, preferred over EIA

Question 2

CDI treatment

Answer 2

1) 1st episode, mild-moderate disease: metronidazole 500mg po QID, reassess for response in 72 hrs
2) 1st episode, severe disease or in critically ill: oral vancomycin 125mg QID +/- IV metronidazole, titrate to 250-500mg QID. Vanco enema if ileus. 97% vs. 72% cure rate compared to metronidazole, recurrent rate same
3) 2nd episode or more: vancomycin

Question 3

RF severe/complicated CDI

Answer 3

Older age, comorbidities, use of immunosupression, abx, narcotics, anti peristaltic medications, fever, severe abdominal pain, lab abnormalities, (WBC >15, Cr 1.5x BL, low albumin),