COVID-19 (summary)

This summary article is intended to be used as a quick reference guide. Please see our complete COVID-19 article for more detail. 

COVID-19 (coronavirus disease 2019) is a viral infectious disease caused by SARS-CoV-2 and is currently a World Health Organization (WHO) declared pandemic.

Clinical presentation

Many people with SARS-CoV-2 infection are asymptomatic ⁹. Symptoms and signs of COVID-19 are non-specific ¹ but in symptomatic individuals most commonly include:

• fever (85-90%)
• cough (65-70%)
• fatigue (35-40%)
• sputum production (30-35%)
• shortness of breath (15-20%)

The likelihood of severe illness requiring hospitalization correlates closely with advanced age and presence of co-morbidities. 

Pathology

SARS-CoV-2 is a member of the Betacoronavirus genus, one of the genera of the Coronaviridae family of viruses. SARS-CoV-2 is indirectly zoonotic, i.e. it originally arose from an animal species, but transmission is now primarily interhuman. The closest animal coronavirus by genetic sequence is a bat coronavirus ⁵.

Radiographic features

The primary findings of COVID-19 on are those of atypical or organizing pneumonia ^2,3.  Up to 18% of cases demonstrate normal chest x-rays or CT when mild/early in the disease course ¹⁰. Bilateral and/or multilobar involvement is common, more often with a lower zone distribution.

Plain radiograph

• patchy or diffuse airspace opacities, whether consolidation or ground-glass opacity ^10,11
• pleural effusion is rare ¹¹

CT

The primary findings on CT in adults have been reported ^2,3:

• ground-glass opacities (GGO)
• crazy paving appearance (GGOs and inter-/intra-lobular septal thickening)
• air space consolidation
• bronchovascular thickening in the lesion
• traction bronchiectasis

Treatment and prognosis

Treatment is currently supportive including ventilation for some patients. No specific treatment or vaccine is currently available but this area is being actively researched (March 2020). The mortality rate is estimated to be 3.6% ¹⁰. 

Differential diagnoses

• viral or other causes of atypical pneumonia ^7,8
• interstitial lung disease (ILD) ⁹
• pulmonary edema ⁷