WebM&M: Case Studies

This case describes a man in his 70s with a history of multiple myeloma and multiple healthcare encounters for diarrhea in the previous five years, which had always been attributed to viral or unknown causes, without any microbiologic or serologic testing. The patient was admitted to the hospital with gastrointestinal symptoms and diagnosed with cholecystitis and gangrenous gallbladder. Two months after his admission for cholecystitis, he was readmitted for severe vomiting and hypotension. An upper gastrointestinal endoscopy with biopsy unexpectedly showed that his duodenum was heavily infiltrated with a parasitic helminth (worm) called Strongyloides stercoralis. He was treated with the anti-parasitic drug ivermectin and eventually improved enough to be discharged from the hospital. The commentary summarizes factors contributing to the missed diagnosis of strongyloidiasis, potential consequences of a failure to diagnose this infection, and approaches to identify patients who should be tested for Strongyloides infection.

A pregnant patient was admitted for scheduled Cesarean delivery, before being tested according to a universal inpatient screening protocol for SARS-CoV-2. During surgery, the patient developed a fever and required oxygen supplementation. Due to suspicion for COVID-19, a specimen obtained via nasopharyngeal swab was sent to a commercial laboratory for reverse transcriptase polymerase chain reaction (RT-PCR) testing. However, due to delays in receiving those results, another sample was tested two days later with a newly developed in-house test, and a third sample was sent to the state public health laboratory. The in-house test returned as positive for SARS-CoV-2. The patient was discharged in stable clinical condition but was advised to quarantine for 14 days. Two days after the patient’s discharge, the commercial and state lab tests were both reported as negative. A root-cause analysis subsequently determined that the positive test run on the in-house platform was due to cross-contamination from a neighboring positive sample. The commentary discusses the challenges associated with SARS-CoV-2 testing, the unprecedented burden faced by health systems, and downstream consequences of false positive tests.