Updated: 3/1/2022

COVID-19/SARSCOV2

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  • Snapshot
    • A 35-year-old man presents to the emergency department with cough and progressively worsening shortness of breath. He recently returned from a medical mission in East Asia approximately 10 days ago, where he was managing multiple patients with respiratory symptoms. His temperature is 101°F (38.3°C), blood pressure is 135/85 mmHg, pulse is 100/min, and respirations are 20/min with an oxygen saturation of 92%. A CT of the chest demonstrates ground glass opacities, fine reticular opacities, and vascular thickening.
  • SUMMARY
    • Condition is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 
      • a novel betacoronavirus
        • positive sense single-stranded RNA virus
    • Diagnosed by a positive nasal swab
    • Treatment is observation and isolation for mild cases, while severe cases require hospitalization and pulmonary support
  • Epidemiology
    • Incidence
      • United States cases
      • worldwide cases
    • Risk factors
      • close contact with suspected or confirmed cases of COVID-19
      • residence or travel to areas with high incidence of COVID-19
  • Etiology
    • Incubation
      • enters cells via the angiotensin-converting enzyme 2 receptors, especially on epithelium that line the respiratory tract
      • TMPRSS2 primes spike protein on SARS-CoV-2 for entry
      • The incubation period is thought to be 2-14 days post-exposure
      • Illness severity of this infection ranges from mild to critical
        • mild (~81% of cases)
          • no dyspnea
        • severe (~14%)
          • dyspnea
          • respiratory rate ≥ 30/min
          • hypoxia
        • critical (~5%)
          • respiratory failure
          • shock
          • multiorgan dysfunction
    • Transmission
      • person-to-person tramission
        • thought to mainly occur via respiratory droplets
          • the virus can be released into the air when the infected person coughs or sneezes
          • the virus reaching the host's mucous membrane can result in infection
        • can also be transmitted longer distances via airborne route
          • studies suggest that droplets may get aerosolized and be carried > 6 ft (2 meters) with speaking, coughing, or sneezing
      • fomite transmission
        • touching an infected surface and subsequently touching one's eyes, nose, or mouth can result in infection
          • therefore, disinfectant is recommended
      • fecal-oral transmission
        • the SARS-CoV-2 RNA has been detected in stool, so fecal-oral transmission is possible
  • Classification
    • SARS-CoV-2 is in the same subgenus as severe acute respiratory syndrome corona virus (SARS-CoV)
  • Presentation
    • Symptoms
      • often asymptomatic
      • common symptoms
        • fever (~99% of cases)
        • fatigue (~70%)
        • dry cough (~60%)
      • rare symptoms
        • myalgias (~35%)
        • dyspnea (~30%)
        • sputum (~27%)
        • anosmia (10-50%)
        • gastrointestinal symptoms
          • nausea (~12%)
          • diarrhea (~19%)
    • Physical exam
      • fever
      • tachycardia
      • tachypnea
  • Imaging
    • Radiographs
      • CXR
        • often normal
    • CT
      • chest CT
        • findings
          • ground-glass opacification (GGO)
            • consolidative abnormalities may or may not be present
            • more likely to affect both lungs, particularly in the lower lobes, and in a peripheral distribution
  • Studies
    • Diagnostic tests
      • Reverse-transcription PCR (RT-PCR) for SARS-CoV-2
        • procedure
          • nasopharyngeal swab
          • sputum collection in patients with a productive cough
        • positive test indicates detection of viral genome regions specific to SARS-CoV-2
      • Antigen test
        • procedure
          • nasal swab
        • positive result indicates detection of SARS-CoV-2 antigens
    • Serum labs
      • WBC count
        • variable (leukopenia, leukocytosis, and lymphopenia)
          • lymphopenia is more common
      • lactate dehydrogenase and ferritin level are commonly elevated
      • IL-6 may be elevated
  • Differential
      • COVID-19 Differential Diagnosis
      • Virus
      • Fever
      • Cough
      • Fatigue
      • Myalgia
      • Headache
      • Rhinitis
      • Sore Throat
      • COVID-19
      • ↑↑↑
      • ↑↑↑
      • ↑↑↑
      • ↑↑
      • Rare
      • Influenza
      • ↑↑↑
      • ↑↑↑
      • ↑↑↑
      • ↑↑↑
      • ↑↑↑
      • Common cold
      • Rare
      • ↑↑
      • ↑↑
      • ↑↑↑
      • ↑↑↑
  • Treatment
    • Medical
      • supportive care and isolation
        • indications
          • for mild cases, patients are isolated to their homes and symptomatically managed
            • adults with mild-to-moderate COVID-19 infection typically remain infectious for up to ~10 days after symptom onset
      • pharmacologic
        • indications
          • remains controversial without clear evidence supporting
        • medications
          • lopinavir-ritonavir
            • a combined protease inhibitor
          • remdesivir
            • a novel nucleotide analog that impairs RNA-dependent polymerases
          • IL-6 pathway inhibitors
            • tocilizumab
            • siltuximab
            • sarilumab
      • hospitalization with potential oxygen supplementation or mechanical ventilation
        • indications
          • for severe disease, characterized by hypoxia (O2 saturation ≤ 94% on room air), an oxygen requirement, or ventilatory support
            • hospitalized patients with severe disease but not yet on oxygen supplementation
              • remdesivir only
            • hospitalized patients with severe disease who are receiving supplemental oxygen (including high-flow oxygen and non-invasive ventilation)
              • low-dose dexamethasone AND remdesivir
            • hospitalized patients with severe disease who require mechanical ventilation
              • low-dose dexamethasone only
    • Operative
      • indications
        • rarely plays a role in treatment
  • Prevention
    • Hand hygiene
      • should be washed with water and soap or virucidal hand disinfectant
      • avoid face touching
    • Respiratory hygiene
      • maintain 6 feet of distance from others
      • masks (N95 respirators) and face shields or goggles for health care personnel or persons taking care of infected individuals in a health care facility or home
    • Face coverings
      • the CDC and WHO recommend wearing masks when in public spaces and when in the presence of individuals outside of one's household
    • Social and physical distancing
      • Avoidance of crowds and non-essential travel
    • Screening in high-risk settings 
      • (e.g. nursing facilities, college campuses, hospital employees)
      • testing-based screening is advantageous compared to symptom-based screening in that it allows identification of asymptomatic infections
    • Vaccines
      • primary antigenic target: surface spike protein
      • multiple vaccine candidates have shown efficacy without major adverse effects in early-phase human clinical trials
      • two mRNA vaccines have over 95% vaccine efficacy in preventing symptomatic COVID-19
        • BNT162b2 (Pfizer-BioNTech) COVID-19 mRNA vaccine
          • two intramuscular injections administered 3 weeks apart
        • mRNA-1273 (Moderna) COVID-19 mRNA vaccine
          • two intramuscular injections administered 4 weeks apart
        • Janssen Biotech viral vector vaccine
          • one intramuscular injection
  • Complications
    • Acute respiratory distress syndrome
      • has been associated with
        • older age (≥ 65 years of age)
        • diabetes mellitus
        • hypertension
    • Pneumonia
    • Septic shock
    • Cardiac arrhythmia
    • Cardiac injury
  • Prognosis
    • Poor Prognostic Predictors
      • older age (≥ 65 years of age)
        • more likely to develop severe disease
      • chronic medical conditions
        • diabetes
        • cardiovascular disease
        • hypertension
        • chronic lung disease
        • chronic kidney disease
        • cancer
        • body mass index ≥ 30
      • immunocompromising conditions
        • transplant patients on immunosuppressant drugs
      • certain laboratory derrangements
        • ↑ D-dimer
        • ↑ ferritin and C-reactive protein
        • ↑ creatine phosphokinase
        • ↑ troponin
        • ↑ lactate dehydrogenase
        • ↑ prothrombin time
        • acute kidney injury
        • severe lymphopenia

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