What is the appropriate antibiotic treatment for a 15.2kg child with cough and tonsillitis, suspected to be a bacterial infection?

Antibiotic Treatment for Pediatric Tonsillitis with Cough

For a 15.2kg child with bacterial tonsillitis and cough, amoxicillin 45 mg/kg/day divided into two doses (approximately 340mg twice daily) for 10 days is the first-line treatment, targeting the most common pathogen, Group A Streptococcus. 1, 2, 3

Initial Assessment and Diagnosis

Before prescribing antibiotics, confirm bacterial etiology using a validated scoring system:

• Apply the Centor or McIsaac score to estimate probability of Group A Streptococcus (GAS) infection 4
• In ambiguous cases, perform a point-of-care GAS rapid antigen test 4
• Only prescribe antibiotics if bacterial tonsillitis is confirmed or highly probable, as 70-95% of tonsillitis cases are viral 5

First-Line Antibiotic Therapy

Standard Dosing for Amoxicillin

For this 15.2kg child:

• Amoxicillin 45 mg/kg/day divided into 2 doses (approximately 340mg twice daily, can round to 350mg BID) 2, 3
• Alternative dosing: 40 mg/kg/day divided into 3 doses 2
• Treatment duration: 10 days to prevent complications including rheumatic fever and acute glomerulonephritis 1, 5

When to Use Higher Doses

Consider amoxicillin 90 mg/kg/day (approximately 685mg twice daily) if: 2, 3

• The child received antibiotics within the previous 4-6 weeks
• Local prevalence of penicillin-resistant S. pneumoniae is high
• Severe infection is present

Alternative Antibiotic Options

For Penicillin Allergy

If the child has a documented penicillin allergy: 1, 6

• Azithromycin: 12 mg/kg once daily for 5 days (approximately 180mg daily for this child) 6
• Clarithromycin: 15 mg/kg/day divided into 2 doses 7
• Cephalexin or clindamycin (if non-severe allergy) 1

For Treatment Failures or Chronic Carriers

If the child fails initial amoxicillin therapy or is a chronic GAS carrier: 1

• Amoxicillin-clavulanate (Augmentin): 40-45 mg/kg/day of amoxicillin component divided into 2-3 doses, maximum 2000mg amoxicillin per day 1, 3
• For this 15.2kg child: approximately 300-340mg amoxicillin component twice daily

Clinical Monitoring

Assessment Timeline

• Evaluate response at 48-72 hours 2, 3
• Fever should resolve within 24-48 hours for bacterial tonsillitis 7
• Cough may persist longer than fever 7

Signs of Treatment Failure

If no improvement after 48-72 hours, consider: 7, 2

• Atypical bacteria (Mycoplasma pneumoniae, Chlamydophila pneumoniae) - switch to macrolide monotherapy
• Viral etiology - discontinue antibiotics
• Complications (peritonsillar abscess) - refer for evaluation
• Non-compliance - reassess and reinforce importance of completion

Important Clinical Caveats

Antibiotic Stewardship

• Complete the full 10-day course even if symptoms resolve earlier to prevent recurrence and complications 1
• Avoid antibiotics if viral etiology is suspected, as this promotes resistance without benefit 7, 5
• Recent antibiotic exposure (within 4-6 weeks) increases risk of resistant organisms 2

Combination Therapy

• Initial combination therapy is NOT justified in children without risk factors 7
• Reserve combination therapy (amoxicillin + macrolide) only for ambiguous cases with no improvement on monotherapy 7

When to Consider Hospitalization

Hospitalization is warranted if: 7

• Severe respiratory distress with elevated PaCO2 (>6.5 kPa)
• Inability to maintain oxygen saturation >92%
• Signs of shock or encephalopathy
• No improvement after 5 days of appropriate therapy 7

Dosing Precision

For this specific 15.2kg child, the weight falls into the "15-23kg" category in most dosing tables, which typically corresponds to: 7

• Co-amoxiclav: 5ml of 125/31 suspension three times daily
• Clarithromycin: 62.5mg twice daily (if needed as alternative)

The key to successful treatment is confirming bacterial etiology before prescribing, using appropriate weight-based dosing, and ensuring completion of the full antibiotic course. 1, 5, 4