Chapter 30: Infectious Respiratory Disorders

Upper respiratory infections, predominantly viral in origin, present with inflammation of the upper airway and generally resolve with supportive care; however, bacterial superinfections can develop, particularly with influenza, which causes more severe systemic symptoms and carries risk for secondary pneumonia. Acute epiglottitis represents a medical emergency requiring immediate airway intervention. Cystic fibrosis emerges as a chronic, genetically inherited condition resulting from CFTR gene mutations that produce abnormally thick secretions affecting multiple organ systems; modern CFTR modulators have substantially improved outcomes by addressing the underlying molecular defect rather than merely treating symptoms. Pneumonia involves alveolar inflammation and exudate formation that impairs gas exchange, with community-acquired cases typically caused by bacterial pathogens like Streptococcus pneumoniae and atypical organisms, while hospital-acquired pneumonia involves different pathogenic organisms and warrants broader antimicrobial coverage; chest imaging patterns help differentiate bacterial from atypical or viral etiologies, and severity assessment tools guide hospitalization decisions and treatment intensity. COVID-19, caused by SARS-CoV-2 virus, demonstrates the spectrum of viral respiratory infection from asymptomatic presentation to severe acute respiratory distress, with diagnosis confirmed through molecular testing and management primarily supportive except in severe disease. Tuberculosis, transmitted via aerosolized droplets from individuals with active disease, establishes latent infection through granuloma formation in immunocompetent hosts but can reactivate when immunity declines; diagnosis distinguishes latent from active disease using skin testing, interferon-gamma assays, and microbiologic confirmation, with treatment strategies varying between preventive therapy for latent infection and prolonged multidrug regimens for active disease, emphasizing directly observed therapy to ensure compliance and prevent antimicrobial resistance.