In a 5-year-old female weighing 27 kg with a 2‑day history of fever and productive cough producing green sputum, what is the most likely diagnosis and the appropriate antibiotic and paracetamol dosing?

Diagnosis and Treatment of Acute Bacterial Pneumonia in a 5-Year-Old

This 5-year-old with fever and productive cough with green sputum most likely has acute bacterial community-acquired pneumonia, and should receive high-dose amoxicillin 90 mg/kg/day (2,430 mg/day for 27 kg) divided into two doses of 1,215 mg twice daily for 10 days, plus paracetamol 15 mg/kg (405 mg) every 4–6 hours as needed for fever and discomfort, not exceeding 60 mg/kg/day (1,620 mg/day). 1

Clinical Diagnosis

The combination of fever and productive cough with greenish phlegm in a young child strongly suggests bacterial pneumonia rather than a viral infection. 2, 1 While viral infections account for the majority of lower respiratory tract infections in children under 5 years, the presence of purulent (green) sputum is a key distinguishing feature that warrants antibiotic therapy. 1, 3

Critical Assessment Points

Before initiating treatment, evaluate for signs requiring immediate hospitalization: 1

• Respiratory rate: >50 breaths/min in children this age indicates severe disease
• Oxygen saturation: ≤92% on room air mandates hospital admission and oxygen therapy
• Work of breathing: Grunting, cyanosis, or severe respiratory distress
• Hydration status: Inability to feed or signs of dehydration
• General condition: Lethargy or altered mental status

If any of these features are present, the child requires hospital admission with intravenous antibiotics. 2, 1

Antibiotic Management

First-Line Treatment: High-Dose Amoxicillin

For this 27 kg child, prescribe amoxicillin 90 mg/kg/day = 2,430 mg/day, divided into 1,215 mg twice daily (approximately 12 mL of 200 mg/5 mL suspension per dose) for 10 days. 1, 4

Rationale for High-Dose Regimen

The 90 mg/kg/day dosing (rather than the standard 45 mg/kg/day) is specifically indicated because: 1, 4

• Age <5 years is itself a risk factor for penicillin-resistant Streptococcus pneumoniae
• This dose achieves tissue concentrations sufficient to overcome resistant strains with MICs up to 2–4 mg/L
• Current guidelines from the Infectious Diseases Society of America and Pediatric Infectious Diseases Society mandate this higher dose for presumed bacterial pneumonia in children

Important: The maximum single dose is 2,000 mg and maximum daily dose is 4,000 mg, so this child's calculated dose is well within safe limits. 4

When to Consider Amoxicillin-Clavulanate Instead

Switch to amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component) if the child has: 1, 4

• Incomplete vaccination against Haemophilus influenzae type b
• Concurrent purulent acute otitis media
• Recent antibiotic use within the past 30 days
• Known exposure to β-lactamase-producing organisms

Alternative for Atypical Pathogens

If clinical features suggest atypical pneumonia (Mycoplasma or Chlamydophila)—such as gradual onset, low-grade fever, or predominantly dry cough that has become productive—consider adding or switching to: 1

• Azithromycin: 10 mg/kg (270 mg) on day 1, then 5 mg/kg (135 mg) once daily on days 2–5

However, given the 2-day history with fever and purulent sputum, typical bacterial pneumonia is more likely, making amoxicillin the appropriate first choice. 2, 1

Paracetamol (Acetaminophen) Dosing

Recommended Regimen

For this 27 kg child, give paracetamol 15 mg/kg per dose = 405 mg every 4–6 hours as needed for fever or discomfort. 5, 6

• Practical dosing: 400 mg (8 mL of standard 250 mg/5 mL suspension) every 4–6 hours
• Maximum daily dose: 60 mg/kg/day = 1,620 mg/day (do not exceed four doses in 24 hours)
• Duration: Continue as needed for symptom relief; fever typically resolves within 24–48 hours with appropriate antibiotic therapy 1

Safety Considerations

Paracetamol is the first-line antipyretic and analgesic in children with an excellent safety profile when used at recommended doses. 5, 7 Chronic overdosing (>140 mg/kg/day for several days) carries risk of hepatotoxicity, but the recommended 60 mg/kg/day maximum provides a substantial safety margin. 5

Monitoring and Follow-Up

Expected Clinical Response

• Fever resolution: Should occur within 24–48 hours of starting appropriate antibiotics 1
• Overall improvement: Clinical improvement should be evident within 48–72 hours 2, 1
• Cough: May persist longer than fever but should gradually improve

When to Re-Evaluate

Reassess the child after 48 hours if: 2, 1

• Fever persists or worsens
• Respiratory symptoms deteriorate
• No clinical improvement is observed
• New symptoms develop (e.g., increased work of breathing, decreased oral intake)

If no improvement occurs within 48–72 hours, consider: 1

1. Atypical pathogens: Add azithromycin to amoxicillin or switch to azithromycin monotherapy
2. Complications: Perform chest radiography if not already done; evaluate for empyema or other complications
3. Alternative diagnosis: Reconsider the diagnosis (e.g., aspirated foreign body, tuberculosis)

Critical Pitfalls to Avoid

• Do not use chest physiotherapy—it provides no benefit and should be omitted in pediatric pneumonia 2, 1
• Do not prescribe antibiotics for mild lower respiratory symptoms without clear evidence of bacterial infection, as most cases in young children are viral 1
• Do not use outdated lower amoxicillin doses (e.g., 40–50 mg/kg/day from older guidelines); current resistance patterns mandate 90 mg/kg/day for pneumonia 1, 4
• Ensure adequate hydration but avoid fluid overload; if IV fluids are needed, give at 80% of maintenance 2

Treatment Duration

Complete the full 10-day course of amoxicillin regardless of symptom improvement to ensure complete eradication of S. pneumoniae and prevent relapse. 1, 4 Continue therapy for at least 48–72 hours after complete resolution of clinical symptoms. 1