COVID-19

Infectious Disease / Pulmonology

Overview

Definition

A highly contagious respiratory disease caused by the SARS-CoV-2 virus.

Epidemiology

Responsible for the global pandemic starting in late 2019.

Etiology & Risk Factors

  • Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), a single-stranded RNA virus.
  • Transmitted primarily via respiratory droplets and aerosols.

Clinical Symptoms

  • Fever, dry cough, shortness of breath
  • Anosmia (loss of smell) and ageusia (loss of taste)
  • Fatigue, myalgias, headache
  • Severe disease: Hypoxia, Acute Respiratory Distress Syndrome (ARDS)

Clinical Approach

Diagnosis

  • Reverse Transcription Polymerase Chain Reaction (RT-PCR) of a nasopharyngeal swab (Gold Standard)
  • Rapid Antigen Tests (highly specific, but lower sensitivity than PCR)
  • Chest X-ray/CT: Bilateral peripheral ground-glass opacities

Management

  • Mild/Moderate: Supportive care. Antiviral therapy (e.g., Nirmatrelvir/Ritonavir [Paxlovid]) for high-risk patients to prevent progression.
  • Severe (Requiring oxygen): Systemic Corticosteroids (Dexamethasone) are proven to reduce mortality. Remdesivir, IL-6 inhibitors (Tocilizumab).
  • Prevention: mRNA vaccines

Complications

  • ARDS and respiratory failure
  • Hypercoagulability (DVT/PE, strokes)
  • Long COVID (Post-Acute Sequelae of SARS-CoV-2)