What is the differential diagnosis and treatment for a 14-year-old patient presenting with a 1-week cough producing greenish-brown sputum and a red tympanic membrane?

Differential Diagnosis and Treatment for a 14-Year-Old with 1-Week Productive Cough and Red Tympanic Membrane

This 14-year-old requires a 2-week course of amoxicillin-clavulanate 45 mg/kg/day divided every 12 hours targeting protracted bacterial bronchitis, with concurrent treatment for acute otitis media if the tympanic membrane is bulging. 1

Differential Diagnosis

Primary Considerations

• Protracted bacterial bronchitis (PBB) is the most likely diagnosis given the 1-week duration of wet/productive cough with greenish-brown (purulent) sputum, which indicates bacterial infection requiring antibiotic therapy 1
• Acute otitis media (AOM) must be differentiated from otitis media with effusion by assessing tympanic membrane position—if bulging, this confirms AOM requiring antibiotics; if neutral or retracted, this suggests effusion alone 2
• Acute bacterial sinusitis should be considered if symptoms include purulent nasal discharge for ≥3 consecutive days with high fever (≥39°C/102.2°F), though this is less likely with only 1-week duration 3

Important Exclusions

• Pneumonia should be ruled out by assessing for tachypnea, tachycardia, dyspnea, or lung findings suggestive of consolidation; if present, obtain chest radiograph 4, 5
• Pertussis is unlikely at 1 week but should be considered if cough becomes paroxysmal with post-tussive vomiting or inspiratory "whoop" develops 3, 6
• Acute viral bronchitis is less likely given the purulent (greenish-brown) sputum character, which suggests bacterial rather than viral etiology 4, 6

Treatment Protocol

Antibiotic Therapy

• Prescribe amoxicillin-clavulanate 45 mg/kg/day divided every 12 hours for 2 weeks as first-line therapy targeting the three most common respiratory bacteria: Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis 1, 7
• This dosing regimen provides adequate coverage for both protracted bacterial bronchitis and acute otitis media if both conditions are present 1, 7
• If cough persists after 2 weeks of appropriate antibiotics, extend treatment for an additional 2 weeks (total 4 weeks) 8
• If cough persists after 4 weeks of appropriate antibiotics, proceed to further investigations including flexible bronchoscopy with quantitative cultures and sensitivities with or without chest CT 8

Critical Monitoring Parameters

• Reassess clinical status at 48-72 hours to monitor for improvement in cough character and frequency, resolution of fever, and evaluation of respiratory status 1
• Immediate return is necessary if:
  • High fever ≥39°C (102.2°F) develops or persists 1, 3
  • Respiratory distress develops (increased respiratory rate, retractions, grunting) 1, 3
  • No improvement after 48-72 hours of antibiotics 1
  • Worsening clinical status or deteriorating respiratory function 3

Supportive Care Measures

• Eliminate tobacco smoke exposure as this is a major contributor to chronic cough in children 1, 9
• Ensure adequate hydration to thin secretions and facilitate clearance 1, 3
• Elevate the head of bed during sleep to improve breathing 1, 3
• Do not use over-the-counter cough medications as they lack proven efficacy and carry risk of serious adverse effects 9, 5

Common Pitfalls and Caveats

Diagnostic Errors to Avoid

• Do not rely solely on tympanic membrane redness to diagnose acute otitis media—assess for bulging position using pneumatic otoscopy to confirm middle ear effusion and distinguish AOM from otitis media with effusion 2
• Do not assume viral etiology based on cough duration alone—greenish-brown (purulent) sputum at 1 week indicates bacterial infection requiring antibiotics, not viral bronchitis 1, 4
• Do not wait for chronic cough criteria (>4 weeks) to initiate antibiotics when purulent sputum is present, as this indicates active bacterial infection 1

Treatment Errors to Avoid

• Do not use azithromycin as first-line therapy—while FDA-approved for acute otitis media in children, amoxicillin-clavulanate provides superior coverage for protracted bacterial bronchitis and has lower resistance rates 1, 10, 7
• Do not prescribe antibiotics for less than 2 weeks—shorter courses are inadequate for protracted bacterial bronchitis and increase risk of treatment failure 8, 1
• Do not empirically treat for asthma, GERD, or upper airway cough syndrome unless specific clinical features support these diagnoses 8, 9

When to Escalate Care

• Consider antibiotic resistance or alternative diagnosis if no improvement after 48-72 hours of appropriate antibiotics 3
• Refer to pediatric pulmonology if cough persists after 4 weeks of appropriate antibiotics or if specific cough pointers develop (digital clubbing, coughing with feeding, hemoptysis) 8, 9
• Obtain chest radiograph and spirometry if cough becomes chronic (>4 weeks) to guide further workup 9