SARS-CoV-2 infection in a 76-year-old man with initially negative nasopharyngeal swabs

Abstract

A 76-year-old man presented to a quaternary care hospital with a 6-day history of respiratory symptoms, fatigue and a fainting episode. The patient had a resolving postinfectious dry cough from an upper respiratory infection that occurred 3 months before presentation. He had hypertension, gastritis, diabetes, sciatica, a remote 30 pack-year smoking history and no history of recreational drug use. His medications included metformin and rosuvastatin. He worked as a professor and attended language classes.In early March, our patient was informed of a potential classroom exposure to coronavirus disease 2019 (COVID-19). One week after this exposure, he had an outpatient nasopharyngeal swab for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after 2 days of worsening cough. The results were negative for both the envelope and RNA-dependent RNA polymerase genes, which are common targets for polymerase chain reaction (PCR) amplification of SARS-CoV-2. A worsening dry cough, fatigue, exertional dyspnea, fevers, low appetite and diarrhea developed over the next 4 days. He presented to the emergency department 4 days after his first swab for SARS-CoV-2 (11 d after his potential exposure).The patient was admitted to hospital and placed under droplet and contact precautions. His initial vital signs included a body temperature of 38.6°C, blood pressure of 98/55 mm Hg with an orthostatic drop, pulse 94 beats/min, and a respiratory rate of 18 breaths/ min with an oxygen saturation of 96% on room air. A physical examination showed flat neck veins, and he had mild inspiratory bibasilar crackles. Bloodwork showed lymphopenia, but electrolytes and hepatic and renal function tests were normal. Chest radiography showed ill-defined right basal airspace opacification.We started treatment with crystalloids administered intravenously and ceftriaxone and azithromycin for pneumonia. Blood and stool culture tests performed on admission were negative; influenza A, influenza B and respiratory syncytial virus were not present; and a repeat nasopharyngeal swab for SARS-CoV-2 on admission also returned a negative result.On day 3 after admission, our patient became hypoxemic and he required 2 L/min of oxygen. Repeat radiography of the chest showed new bilateral, ill-defined patchy opacities. Results for an extended viral panel, legionella urinary antigen and a third nasopharyngeal swab for SARS-CoV-2 were negative. Consequently, we stopped droplet and contact precautions on day 3 of admission. A computed tomography (CT) scan of the chest showed bilateral ground glass opacification and septal lines (Figure 1). This was consistent with atypical bacterial or viral infection, and our differential diagnosis included edema, hemorrhage, drug reaction and connective tissue disease.On day 4 of admission, our patient's hypoxemia worsened and he required 5 L/min of oxygen. We consulted our respirology department. Given his history of progressive symptoms, persistent lymphopenia and potential exposure to a student with COVID-19, we were advised to...

Determining the period of communicability of SARS-CoV-2: A rapid review of the literature

“…The relationship between viral viability and symptom presentation was inconsistent. Some studies reported successful viral isolation from individuals who did not have symptoms at the time of sample collection [12,15,20,22], others isolated viable virus from individuals who were symptomatic at the time of sample collection [23,24], while other studies were unable to isolate virus from symptomatic individuals [13,25] (Table 3). There were inconsistent data available on viral load and/or RT-PCR cycle threshold (Ct) values and duration of viability, though a number of studies reported an upper limit on these measures for virus viability [12,22,23,25–28].…”

“…Notably, these positive findings were from individuals with mixed levels of underlying comorbidities, and who presented with heterogeneous disease profiles, from mild symptoms to severe complications and death associated with infection with SARS-CoV-2. An additional impetus for taking a precautionary approach is the inconsistency from studies reporting on symptomatology and viable virus; while some studies were not able to successfully culture virus from asymptomatic or post-symptomatic individuals [13,14], others successfully cultured virus from individuals who were not symptomatic at the time of specimen collection [12,15].…”

RSNA Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19: Interobserver Agreement Between Chest Radiologists

“…In cases where RT-PCR is initially negative, typical findings on CT may encourage maintenance of infection control mechanisms and prompt repeat testing. 8,24,25 In cases of high clinical suspicion but negative RT-PCR, a combination of repeated swab tests and CT imaging may be useful to reach the diagnosis and assist management. 9,26 With many countries beginning to ease lockdown restrictions and health care systems returning to near prepandemic levels of operation, it is important that radiologists remain vigilant to the typical COVID-19 CT imaging findings with the almost inevitable anticipated second wave of the pandemic.…”

Radiological Society of North America (RSNA) Expert Consensus Statement Related to Chest CT Findings in COVID-19 Versus CO-RADS: Comparison of Reporting System Performance Among Chest Radiologists and End-User Preference

“…It is unclear whether these systems are applicable to patients with incidental chest CT findings on an examination performed for another purpose. Particularly, a patient with typical CT findings in whom subsequent RT-PCR testing comes back negative poses a clinical dilemma-some of these cases eventually test positive bronchoalveolar lavage alone, 22 and this may be due to variability in test accuracy. Both systems are also deficient in providing recommendations for management and follow-up, unlike the widely adopted TI-RADS and CAD-RADS systems, and ultimately require more definitive testing with RT-PCR regardless of imaging findings.…”