COVID-19: The Great Masquerader

Introduction Reverse-transcriptase polymerase chain reaction testing (RT-PCR) remains the mainstay in diagnosing SARS-CoV-2. Though a positive result is highly specific for the virus, the false negative rate of the test can vary from 20% to 100%. This can have implications including, but not limited to, delay in treatment, improper management, and more costly and invasive testing. We present a case of a 54 year old male who presented for hypoxic respiratory failure diagnosed with SARS-CoV-2 on bronchoalveolar lavage (BAL) after extensive workup including 5 negative nasopharyngeal RT-PCR SARS-CoV-2 tests (NP RT-PCR). Case The patient is a 54 year old male with a past medical history significant for morbid obesity and well controlled asthma who presented for dyspnea on exertion. Throughout the patient's hospitalization, his oxygen requirements rapidly increased leading to a short course of ventilator support. CT angiogram of the chest on presentation did not show evidence of pulmonary embolism however did show bilateral multi-lobar ground glass opacities. The patient admitted to recently removing an old carpet at work but denied any other significant inhalational exposures. Dozens of his co-workers recently tested positive for SARS-CoV-2. Extensive workup including respiratory virus panel, 5 NP RT-PCR tests one week apart, basic rheumatologic serologies, and hypersensitivity pneumonitis panel were all unremarkable. Treatment for community acquired pneumonia was completed without improvement. Empiric treatment with steroids was started. BAL and trans-bronchial biopsies were initially unremarkable (Table 1). Repeat imaging demonstrated multiple sub-segmental pulmonary emboli. RT-PCR of the BAL specimen and serum antibodies for SARS-CoV-2 were collected, both of which resulted positive. The patient was eventually discharged on oral anticoagulation, a short prednisone taper, and 2L oxygen via nasal cannula on exertion with scheduled outpatient follow-up. Conclusion NP RT-PCR has become the gold standard diagnostic test for SARS-CoV-2, but it does not come without imperfections. Timing of the test in relation to symptoms, assay limit of detection, and sample collection technique all affect the results. Our patient's clinical presentation, known recent exposure, and imaging findings increased his probability of having SARS-CoV-2. However, NP RT-PCR was negative on 5 separate occasions. Limitations of this test may therefore extend beyond our current understanding. After obtaining SARS-CoV-2 diagnosis from the BAL, this obviated the need for a thoracoscopic biopsy and treatment with prolonged steroids. BAL RT-PCR SARS-CoV-2 testing consequently may play a necessary role in such patients with negative NP RT-PCR testing.