What is the likely diagnosis and management for a patient presenting with sneezing, coryza, itchy throat, fever, tachypnea, and decreased activity, with a recent history of similar symptoms in a family member?

Viral Upper Respiratory Tract Infection as Primary Diagnosis

The clinical presentation is most consistent with a viral upper respiratory tract infection (URI) that has progressed to involve the lower respiratory tract, evidenced by the sequential symptom development, household exposure, typical viral URI timeline, and absence of features suggesting bacterial superinfection. 1

Key Diagnostic Features Supporting Viral URI

Timeline and Symptom Progression

• The 2-day prodrome of sneezing and clear rhinorrhea represents the classic early phase of viral URI, which typically begins with these upper respiratory symptoms before systemic manifestations develop 1, 2
• Fever onset on day 3 of illness (afternoon of consult) aligns with the typical viral URI pattern, where fever commonly appears during the first 3 days in children and may persist for this duration 2
• The absence of purulent nasal discharge is significant - while colored secretions can occur with viral infections due to neutrophil influx, the clear discharge throughout the initial course supports ongoing viral rather than bacterial etiology 1, 3

Epidemiological Context

• The household contact (auntie) with fever, cough, and sore throat one week prior provides clear viral exposure history, establishing a transmission chain consistent with person-to-person viral spread 2
• The contact's illness resolved spontaneously in approximately one week, which is the typical self-limited course of adult viral URIs 2
• This temporal relationship (exposure 1 week prior, symptom onset 2 days ago) fits the incubation period of common respiratory viruses 2

Clinical Features Distinguishing Viral from Bacterial Infection

• The itchy throat is more characteristic of viral URI or allergic rhinitis than bacterial infection 1
• Absence of purulent nasal discharge argues strongly against acute bacterial rhinosinusitis (ABRS), as nasal purulence is considered essential for ABRS diagnosis - specificity for ABRS increases only when nasal obstruction or facial pain occurs with purulent discharge 1
• The symptom duration of only 2-3 days is too short to meet criteria for ABRS, which requires either symptoms persisting ≥10 days, worsening within 10 days after initial improvement, or severe symptoms (high fever >39°C with purulent discharge and facial pain) in the first 3-4 days 1
• While fever reached 39°C, the absence of unilateral facial/tooth pain, purulent discharge, and the presence of good appetite and activity until the afternoon of consult do not meet criteria for "particularly severe" presentation 1

Lower Respiratory Tract Involvement

• The development of tachypnea and decreased activity represents progression to lower respiratory tract involvement, which commonly occurs with viral URIs in children, particularly with viruses like respiratory syncytial virus (RSV) 1, 2
• Viral URIs in preschool children last 10-14 days compared to less than a week in adults, and the paranasal sinuses and middle ear are commonly involved during viral colds even without bacterial superinfection 2
• The absence of cough throughout the initial course is notable - while cough typically develops with viral URIs, its absence doesn't exclude the diagnosis, and tachypnea may represent early lower airway involvement before cough becomes prominent 1, 2

Features That Do NOT Suggest Bacterial Superinfection

Timing Considerations

• Bacterial rhinosinusitis typically requires ≥10 days of persistent symptoms or a "double-worsening" pattern (initial improvement followed by worsening), neither of which is present in this 2-3 day illness 1
• The guideline consensus indicates that persistent symptoms between days 5-10 are most difficult to assess, as they can represent either lingering viral disease or beginning bacterial infection - this patient hasn't reached that timeframe 1

Symptom Characteristics

• Fever alone at any point, including day 3, is not suggestive of ABRS 1
• The color of nasal discharge (which remained clear) and presence of fever are not useful in differentiating bacterial from viral disease according to multiple guidelines 1
• Good appetite and activity maintained until the afternoon of consult argues against severe bacterial infection 2

Clinical Reasoning for Tachypnea Development

The acute onset of tachypnea with decreased activity represents a concerning development requiring immediate evaluation, but this is consistent with viral lower respiratory tract extension rather than bacterial pneumonia given: 4, 2

• The short overall illness duration (2-3 days total)
• Absence of productive cough with purulent sputum
• The typical progression pattern of pediatric viral URIs to involve lower airways
• The household viral exposure history

Management Implications

This diagnosis supports symptomatic management rather than immediate antibiotic therapy, as the vast majority of acute URIs are viral and antibiotics are the most common reason for inappropriate prescribing in these cases 4, 3

However, the tachypnea and decreased activity warrant:

• Immediate assessment of respiratory rate, oxygen saturation, and work of breathing
• Evaluation for hypoxemia requiring supplemental oxygen
• Assessment for dehydration given fever and decreased oral intake
• Close monitoring for bacterial superinfection, which would be suggested by worsening after initial improvement or persistence beyond 10 days 1

The paracetamol dosing (5 mL of 120 mg/5 mL = 120 mg) appears appropriate for symptom management, though the every-4-hour frequency should be monitored to avoid exceeding maximum daily dosing 5