A Review on Clostridioides Difficile Testing and How to Approach Patients With Multiple Negative Tests: A Case Report.

Clostridioides difficile (C. difficile) is an important nosocomial infection that is commonly associated with antibiotic use with pseudomembranous colitis being present in only 13% of cases. Disease severity ranges from asymptomatic carriers to severe complicated disease, based on clinical and laboratory findings. There is no single rapid FDA-approved test to diagnose C. difficile infections (CDI) and diagnosis usually requires a multi-step diagnostic approach. C. difficile testing usually begins with the C. difficile toxin and glutamate dehydrogenase antigen screen (GDH). If testing is negative for either, then nucleic acid amplification testing (NAAT) is done to confirm the diagnosis. Endoscopic evaluation may be required in rare instances when there is a high clinical suspicion of disease with negative testing. Here, we present an interesting case of a patient with multiple negative C. difficile toxin and GDH tests. Given the high index of clinical suspicion of CDI, the patient underwent a colonoscopy which revealed diffuse pseudomembranous colitis. The patient was then appropriately treated with oral vancomycin. We aim to shed light on the different testing modalities available to clinicians and the indications for doing a colonoscopy to delineate between false positive testing and active CDI.

ANCA-Associated Intrahepatic Duct Injury Associated with Levamisole-Adulterated Cocaine.

Damage to the liver or kidney can occur through direct toxic effects; however, damage can also be drug-induced immune-mediated. Levamisole-adulterated cocaine (LAC) is known to cause antineutrophil cytoplasmic antibody- (ANCA-) associated vasculitis and glomerulonephritis leading to acute kidney injury and end-stage renal disease. It remains unclear whether LAC is associated with hepatic duct damage. Here, we report a case with biopsy-proven evidence of intrahepatic duct damage months after being diagnosed with ANCA-associated crescentic and sclerosing glomerulonephritis caused by LAC use. This case represents the first report of LAC-induced ANCA-associated hepatic duct cholestasis in the setting of previous LAC-induced ANCA-positive glomerulonephritis.