Peripheral, bilateral ground-glass opacity with out without consolidation or visible intralobular lines (crazy paving)
Multifocal rounded GGO with or without consolidation or crazy paving
Reverse halo sign or other findings of organizing pneumonia (later finding)
Indeterminate appearance:
Multifocal, diffuse, perihilar, or unilateral GGO with or without consolidation lacking a specific distribution and are non-rounded or non-peripheral
Few very small GGO with a non-rounded and non-peripheral distribution
Atypical appearance, which suggests unlikely to be COVID-19:
Isolated lobar or segmental consolidation without GGO
Discrete small nodules (centrilobular, tree-in-bud)
Lung cavitation
Smooth interlobular septal thickening with pleural effusion
Diagnosis
PCR from NP swab
Highest sensitivity within 5 days of symptom onset, with decreasing sensitivity as the disease enters the immune-mediated phase
May be positive long after no longer infectious
Diagnostic accuracy of PCR by sample site (below) has a lot of heterogeneity among the studies
Sensitivity
Specificity
Upper Respiratory Samples
Oral
56
99
Nasal
76
100
NP
97
100
Nasal
95
100
Saliva
85
100
Mid-turbinate
100
100
Upper Versus Lower Tract
Upper respiratory tract
57
100
Lower respiratory tract
81
100
Single Versus Repeat Testing
Single test
71
100
Repeat testing
100
100
Serology (IgM and IgG)
Total antibodies have poor sensitivity (51%) in first week, and increases to about 90% by week 3
Management
For patients no requiring supplemental oxygen, the focus is on supportive care
Remdesivir 200 mg IV once followed by 100 mg IV daily for 2 more days may be used within 7 days of symptom onset who have at least one risk factor for disease progression (age ≥60 years, obesity, or other medical conditions)3
Consideration of monoclonal antibodies such as casirivimab-imdevimab (Regeneron), depending on the variant
Use in patients who are anti-spike protein seronegative and within 9 days of symptom onset
May reduce hospitalization of high risk patients (hypertension, diabetes, chronic lung disease, congestive heart failure, of immunodeficiency) with ARR of 2 to 3%
For patients requiring supplemental oxygen or with oxygen saturation less than 94%:
Dexamethasone 6 mg PO/IV daily for 10 days, which has a mortality benefit
Remdesivir 200 mg IV once on day one followed by 100 mg PO daily for 5-10 days, which has not been shown to have a mortality benefit
Tocilizumab indicated if progressing despite dexamethasone, still requiring oxygen and CRP ≥75 mg/L, per RECOVERY trial
ARR for 28-day mortality of about 4%
If tocilizumab is unavailable, then baricitinib 4 mg p.o. daily for 14 days or until hospital discharge
If unvaccinated/no prior infection, declining clinically, and within 9 days of symptom onset, casirivimab-imdevimab (Regeneron) 8000 mg IV once
If asymptomatic, HCWs may return to work while awaiting results, depending on the reason for testing and the staffing needs
Positive but asymptomatic: in exceptional circumstances, may return to work early
Clearance
Non-test based (preferred)
Asymptomatic: isolate for 10 days from swab
Mild to moderate symptoms in immunocompetent person: 10 days from onset of symptoms, as long as afebrile (without antipyretics) and clinically improving
Severe (i.e. ICU-level care) or immunocompromised: 20 days from onset of symptoms, as long as afebrile (without antipyretics) and clinically improving
Test based (alternative): 2 negative swabs at least 24 hours apart (if still positive, repeat in 3 to 4 days), as long as afebrile and clinically improving
Further Reading
Pathophysiology, Transmission, Diagnosis, and Treatment of Coronavirus Disease 2019 (COVID-19): A Review. JAMA. doi: 10.1001/jama.2020.12839
^Louise Lansbury, Benjamin Lim, Vadsala Baskaran, Wei Shen Lim. Co-infections in people with COVID-19: a systematic review and meta-analysis. Journal of Infection. 2020;81(2):266-275. doi:10.1016/j.jinf.2020.05.046.
^Scott Simpson, Fernando U. Kay, Suhny Abbara, Sanjeev Bhalla, Jonathan H. Chung, Michael Chung, Travis S. Henry, Jeffrey P. Kanne, Seth Kligerman, Jane P. Ko, Harold Litt. Radiological Society of North America Expert Consensus Document on Reporting Chest CT Findings Related to COVID-19: Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA. Radiology: Cardiothoracic Imaging. 2020;2(2):e200152. doi:10.1148/ryct.2020200152.
^Robert L. Gottlieb, Carlos E. Vaca, Roger Paredes, Jorge Mera, Brandon J. Webb, Gilberto Perez, Godson Oguchi, Pablo Ryan, Bibi U. Nielsen, Michael Brown, Ausberto Hidalgo, Yessica Sachdeva, Shilpi Mittal, Olayemi Osiyemi, Jacek Skarbinski, Kavita Juneja, Robert H. Hyland, Anu Osinusi, Shuguang Chen, Gregory Camus, Mazin Abdelghany, Santosh Davies, Nicole Behenna-Renton, Frank Duff, Francisco M. Marty, Morgan J. Katz, Adit A. Ginde, Samuel M. Brown, Joshua T. Schiffer, Joshua A. Hill. Early Remdesivir to Prevent Progression to Severe Covid-19 in Outpatients. New England Journal of Medicine. 2021. doi:10.1056/nejmoa2116846.
