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. As of April 2021, over 120 million people had been infected globally with over 2.5 million deaths 13.
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%) with sputum (30-35%)
- smell and taste disturbances (50%) 12
- fatigue (35-40%)
- shortness of breath (15-20%)
The likelihood of severe illness requiring hospitalization correlates closely with male sex, advanced age and presence of comorbidities.
- ~5% admitted patients require ICU admission
Multiple serious sequelae have been reported including:
- acute respiratory distress syndrome (ARDS)
- coagulopathy: including PE and DIC
- secondary infections, e.g. bacterial pneumonia
- myocardial injury
- acute kidney injury (AKI)
- multiorgan failure
- secondary hemophagocytic lymphohistiocytosis
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, but transmission is now primarily interhuman. The closest animal coronavirus by genetic sequence is a bat coronavirus 5. The cause of death is usually respiratory failure secondary to massive alveolar injury.
The primary findings of COVID-19 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.
- patchy or diffuse airspace opacities, whether consolidation or ground-glass opacity 10,11
- pleural effusion is rare 11
The primary findings on CT in adults have been reported as 2,3,16:
- ground-glass opacities (GGO)
- crazy paving appearance (GGOs with inter-/intra-lobular septal thickening)
- air space consolidation
- bronchovascular thickening in the lesion
- traction bronchiectasis
- subpleural sparing
Treatment and prognosis
There are several therapeutic approaches: some of them inhibit the replication of the virus, others reduce the inflammatory response, still others inhibit coagulation 17,18.
Treatment is primarily supportive including ventilation for some patients. Dexamethasone has been shown to reduce mortality in ventilated patients or those on oxygen therapy 14.
Several highly-effective vaccines have now received regulatory approval in multiple territories 15.
The mortality rate is estimated to be 3.6% 10.
- 1. WHO. Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19). Report. World Health Organization (WHO); 2020 16-24.02.2020. https://www.who.int/publications-detail/report-of-the-who-china-joint-mission-on-coronavirus-disease-2019-(covid-19)
- 2. Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, Zhang L, Fan G, Xu J, Gu X, Cheng Z, Yu T, Xia J, Wei Y, Wu W, Xie X, Yin W, Li H, Liu M, Xiao Y, Gao H, Guo L, Xie J, Wang G, Jiang R, Gao Z, Jin Q, Wang J, Cao B. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. (2020) Lancet (London, England). doi:10.1016/S0140-6736(20)30183-5 - Pubmed
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- 5. Ng LFP, Hiscox JA. Coronaviruses in animals and humans. (2020) BMJ (Clinical research ed.). 368: m634. doi:10.1136/bmj.m634 - Pubmed
- 6. Yan-Rong Guo, Qing-Dong Cao, Zhong-Si Hong, Yuan-Yang Tan, Shou-Deng Chen, Hong-Jun Jin, Kai-Sen Tan, De-Yun Wang, Yan Yan. The origin, transmission and clinical therapies on coronavirus disease 2019 (COVID-19) outbreak – an update on the status. (2020) Military Medical Research. 7 (1): 1. doi:10.1186/s40779-020-00240-0 - Pubmed
- 7. Wei-cai Dai, Han-wen Zhang, Juan Yu, Hua-jian Xu, Huan Chen, Si-ping Luo, Hong Zhang, Li-hong Liang, Xiao-liu Wu, Yi Lei, Fan Lin. CT Imaging and Differential Diagnosis of COVID-19:. (2020) Canadian Association of Radiologists Journal. doi:10.1177/0846537120913033 - Pubmed
- 8. Yan Li, Liming Xia. Coronavirus Disease 2019 (COVID-19): Role of Chest CT in Diagnosis and Management. (2020) American Journal of Roentgenology. doi:10.2214/AJR.20.22954 - Pubmed
- 9. Kenji Mizumoto, Katsushi Kagaya, Alexander Zarebski, Gerardo Chowell. Estimating the asymptomatic proportion of coronavirus disease 2019 (COVID-19) cases on board the Diamond Princess cruise ship, Yokohama, Japan, 2020. (2020) Eurosurveillance. 25 (10): 2000180. doi:10.2807/1560-7917.ES.2020.25.10.2000180 - Pubmed
- 10. Rodrigues, J.C.L. et al. An update on COVID-19 for the radiologist - A British society of Thoracic Imaging statement. (2020) Clinical Radiology. https://doi.org/10.1016/j.crad.2020.03.003
- 11. Wong HYF, Lam HYS, Fong AH, Leung ST, Chin TW, Lo CSY, Lui MM, Lee JCY, Chiu KW, Chung T, Lee EYP, Wan EYF, Hung FNI, Lam TPW, Kuo M, Ng MY. Frequency and Distribution of Chest Radiographic Findings in COVID-19 Positive Patients. (2019) Radiology. doi:10.1148/radiol.2020201160 - Pubmed
- 12. Tong JY, Wong A, Zhu D, Fastenberg JH, Tham T. The Prevalence of Olfactory and Gustatory Dysfunction in COVID-19 Patients: A Systematic Review and Meta-analysis. (2020) Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery. doi:10.1177/0194599820926473 - Pubmed
- 13. Wuhan Coronavirus (2019-nCoV) Global Cases (by Johns Hopkins CSSE). Case Dashboard. [accessed 31 March 2021].
- 14. Horby P, Lim WS, Emberson JR, Mafham M, Bell JL, Linsell L, Staplin N, Brightling C, Ustianowski A, Elmahi E, Prudon B, Green C, Felton T, Chadwick D, Rege K, Fegan C, Chappell LC, Faust SN, Jaki T, Jeffery K, Montgomery A, Rowan K, Juszczak E, Baillie JK, Haynes R, Landray MJ. Dexamethasone in Hospitalized Patients with Covid-19 - Preliminary Report. (2020) The New England journal of medicine. doi:10.1056/NEJMoa2021436 - Pubmed
- 15. Ledford H. US authorization of first COVID vaccine marks new phase in safety monitoring. (2020) Nature. 588 (7838): 377-378. doi:10.1038/d41586-020-03542-4 - Pubmed
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