What is the best course of treatment for a congested adult patient with a history of respiratory or sinus issues, presenting with symptoms of nasal congestion, productive cough with thick green-dark mucus, left-sided sinus blockage, and fatigue?

Acute Bacterial Rhinosinusitis: Antibiotic Therapy Required

This patient meets diagnostic criteria for acute bacterial rhinosinusitis (ABRS) and requires antibiotic therapy with amoxicillin 500mg three times daily for 10 days, along with symptomatic management. 1, 2, 3

Diagnostic Reasoning

The constellation of symptoms lasting >10 days without improvement establishes the diagnosis of ABRS:

• Thick green-dark purulent nasal discharge is a cardinal feature of bacterial sinusitis 1, 3
• Unilateral (left-sided) sinus blockage with facial pressure/pain strongly suggests bacterial infection 1, 3
• Fatigue is a common systemic symptom in ABRS 1
• Productive cough with purulent mucus represents postnasal drainage from infected sinuses 1, 2

The key diagnostic criterion is symptom persistence beyond 10 days without improvement, which distinguishes bacterial superinfection from viral upper respiratory infection 1, 2, 3. Viral URIs typically peak at 3-5 days and improve by day 10, whereas bacterial sinusitis either persists beyond 10 days or worsens after initial improvement at 5-7 days 1.

First-Line Antibiotic Treatment

Prescribe amoxicillin 500mg orally three times daily for 10 days as first-line therapy 2, 3. This recommendation is based on:

• Efficacy against the most common pathogens: Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis 1, 3
• Superior safety profile and cost-effectiveness compared to broader-spectrum agents 2
• Strong guideline consensus from the Infectious Diseases Society of America and American Academy of Otolaryngology 2, 3

Alternative if penicillin allergy: Use doxycycline or a respiratory fluoroquinolone (levofloxacin) 2, 3. Macrolides are less preferred due to increasing resistance in S. pneumoniae 1.

Essential Symptomatic Management

Intranasal corticosteroids (fluticasone propionate 2 sprays per nostril once daily) significantly reduce inflammation and improve symptoms 2, 4. The FDA-approved fluticasone regimen provides maximum benefit within several days and can be continued throughout the antibiotic course 4.

Additional symptomatic measures:

• Saline nasal irrigation to clear purulent secretions 2, 3
• Oral decongestants or short-term topical decongestants (≤3-5 days only to avoid rebound congestion) 5, 2
• Analgesics (acetaminophen or NSAIDs like naproxen 220-440mg twice daily) for facial pain 3
• Adequate hydration and sleeping with head elevated 2

Critical Follow-Up Parameters

Reassess in 3-5 days if symptoms worsen or fail to improve 2, 3. Treatment failure at 72 hours indicates need for broader-spectrum coverage with amoxicillin-clavulanate 875mg twice daily 2, 3.

Red flags requiring immediate evaluation:

• High fever with severe headache 2
• Visual changes or periorbital swelling (suggests orbital complications) 3
• Severe worsening after initial improvement 2

Expected timeline: Symptoms should begin improving within 3-5 days, with complete resolution taking 10-14 days even with appropriate treatment 2.

Common Pitfalls to Avoid

Do not confuse this with acute bronchitis, which would contraindicate antibiotics 5. The key distinguishing features here are unilateral sinus involvement, purulent nasal discharge (not just bronchial secretions), and facial pressure—all pointing to sinusitis rather than bronchitis 1, 3.

Do not order imaging (CT or plain radiographs) for uncomplicated ABRS, as it does not change management and adds unnecessary cost 2, 3.

Do not use topical decongestant sprays beyond 3-5 days due to risk of rebound congestion (rhinitis medicamentosa) 5.

Do not prescribe antibiotics for <10 days of symptoms unless there is clear worsening after initial improvement at 5-7 days, as most viral URIs resolve spontaneously 1, 5.

Bacterial Resistance Considerations

Be aware that approximately 15% of S. pneumoniae are penicillin-intermediate and 25% are penicillin-resistant, with common resistance to macrolides and TMP/SMX 1. Additionally, 30% of H. influenzae produce β-lactamases 1. However, standard-dose amoxicillin remains first-line because it achieves adequate sinus tissue concentrations for most strains 2, 3. Reserve amoxicillin-clavulanate for treatment failures or recent antibiotic exposure within 4-6 weeks 1, 2.