URI Differentiation

URI symptoms describe a syndrome, not a single disease. Rhinorrhea, cough, sore throat, fever, fatigue, and congestion may reflect a self-limited viral infection, influenza, COVID-19, RSV, GAS pharyngitis, acute bacterial rhinosinusitis, or the early catarrhal phase of pertussis. Symptoms overlap enough that the first clinical question is not simply which virus is present; it is whether the illness has a dangerous airway feature, a time-sensitive antiviral indication, a testable bacterial pattern, or a course that requires public-health action. For the nurse practitioner, the most informative clues are the illness trajectory, the dominant symptom pattern, the patient’s age and risk factors, and what the examination shows. A gradual cold with clear rhinorrhea is managed differently from abrupt influenza-like illness, but neither can be reliably separated from COVID-19 by symptoms alone. A sore throat with cough and rhinorrhea points away from GAS, whereas abrupt isolated throat pain with fever and exudates warrants microbiologic assessment. A cough that outlasts the expected URI course changes the differential again.