SARS-CoV-2

Background

Microbiology

• Coronavirus related to SARS-CoV
• Virion consists of:
  • Spike glycoprotein (S)
  • Membrane protein (M)
  • Nucleocapsid protein (N)
  • Hemagglutinin esterase (He)
  • Envelope protein (E)

Epidemiology

• First cases detected Dec 2019 related to likely exposure in wet market in Wuhan, Hubei, China, and declared a pandemic in 2020
• Secondary household attack rate of 12-17%

Risk Factors for Mortality

• Greater age
• Male sex
• COPD
• Dyslipidemia
• Diabetes

Clinical Manifestations

• Incubation period 4 to 5 days (range 2 to 11 days), possibly as long as 14 days in some cases
• Main presenting symptoms were fever and cough, followed by myalgia, fatigue, headache, dyspnea
• Other symptoms include dyspnea, rhinorrhea, vomiting, diarrhea, anosmia/hyposmia
• Lymphopenia is common, as is hypoalbuminemia, elevated D-dimer, CRP, LDH, AST/ALT
• Viral load detectable before symptom onset and peaks around the time of symptom onset

Pregnancy

• Please refer to a living systematic review on the topic
• Slightly less reported fever and myalgias
• Slightly more ICU admissions and mechanical ventilation
  • Risk factors included age, obesity, hypertension, and diabetes
• With regards to the fetus, there were more preterm deliveries (6%) and more needed NICU admission (25%)

Complications

• In critically ill patients:
  • ARDS (75%)
  • AKI (40%)
  • Thrombosis (10%)

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

Management

• For patients no requiring supplemental oxygen, the focus is on supportive care
• For patients requiring supplemental oxygen:
  • Dexamethasone 6 mg PO/IV daily for 10 days, which has a mortality benefit
  • Remdesivir 200 mg PO once on day one followed by 100 mg PO daily for 5-10 days, which has not been shown to have a mortality benefit
• Avoid hydroxychloroquine/chloroquine, lopinavir-ritonavir
• Other investigational therapeutics include tocilizumab

Further Reading

• Pathophysiology, Transmission, Diagnosis, and Treatment of Coronavirus Disease 2019 (COVID-19): A Review. JAMA. doi: 10.1001/jama.2020.12839
• UHN-MSH Ontario Clinical Practice Guidelines
• PHAC Interim guidelines for the clinical management of patients with moderate to severe COVID-19