Course 04: Respiratory Medicine and Infectious Disease
Lesson 8 of 14. Explore the diagnostic and management frameworks, work through the case, and finish the linked 10-question practice set. Urgent presentations require an emergency-care pathway and review of local professional scope.
Clinical overlap and testing
- Influenza, SARS-CoV-2, RSV and other viruses can produce overlapping fever, cough and respiratory symptoms; symptoms alone do not reliably distinguish the pathogen.
- Choose testing based on severity, high-risk status, outbreak setting, availability and whether results affect therapy or precautions; multiplex NAAT can be useful.
- Assess for bacterial coinfection or alternate causes in severe, focal, recurrent or worsening presentations.
Timely treatment and risk assessment
- High-risk or hospitalized influenza patients may need prompt antiviral therapy based on clinical suspicion; do not wait unnecessarily for a test when treatment is indicated.
- COVID-19 antiviral eligibility depends on disease severity, timing, renal function and major interactions (especially with ritonavir-containing regimens).
- RSV in older adults and immunocompromised patients can cause severe disease; supportive care and escalation are often central.
Prevention and reporting
- Review current province-specific vaccination schedules for influenza, COVID-19, RSV and pneumococcus; eligibility and timing can change by season and population.
- Use hand hygiene, ventilation, source control, appropriate masks/PPE, illness precautions and institutional outbreak policies.
- Discuss vulnerable household contacts and the rationale for staying away from high-risk environments while contagious, aligned with current local public-health advice.
Complications and communication
- Worsening dyspnea, hypoxemia, chest pain, confusion, dehydration or clinical relapse are red flags for urgent assessment.
- Explain that antibiotics do not treat uncomplicated viral illness; provide symptomatic care and clear return precautions.
- Avoid blanket statements about test sensitivity, isolation dates or vaccine eligibility without checking the current local guidance.
Applied clinical case
A 69-year-old receiving immunosuppressive therapy has 24 hours of fever, myalgia and cough during influenza season; rapid antigen testing is negative.
Show model clinical reasoning and disposition
Risk is elevated and a negative rapid antigen test may not exclude influenza. Arrange prompt clinical assessment, appropriate molecular testing if available and consideration of antiviral treatment without harmful delay.
Clinical self-check
- When is empiric antiviral treatment reasonable?
- Why must interactions be checked for COVID therapy?
- Which infection-control practices protect vulnerable patients?
Current guidance and further learning
- CDC: Clinical guidance for influenza, SARS-CoV-2 and RSV (external)
- Canadian Thoracic Society guideline library (external)