Management of Rhinosinusitis (Sinusitis): Stepwise Approach from First Stage to Antibiotic Therapy
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1. Definition and Classification
Rhinosinusitis refers to inflammation of the mucosa of the nasal cavity and paranasal sinuses.It often begins as viral rhinosinusitis and may progress to bacterial sinusitis in a small percentage of cases.
| Type | Duration | Typical Cause |
| Acute | ≤ 4 weeks | Usually viral; bacterial if severe/persistent |
| Subacute | 4–12 weeks | Unresolved infection |
| Chronic | > 12 weeks | Multifactorial (inflammation, allergy, biofilm, polyp) |
2. Common Etiologic Agents
Viral (Most Common, ~90%)
- Rhinovirus, Influenza, Parainfluenza, Coronavirus
Bacterial (Secondary infection)
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
3. Diagnostic Criteria: When to Suspect Bacterial Sinusitis
Antibiotics are NOT first-line for all sinusitis.They are reserved for bacterial cases based on these IDSA criteria:
Acute Bacterial Rhinosinusitis (ABRS) criteria
At least one of the following:
- Persistent symptoms > 10 days without improvement
- Severe symptoms: high fever ≥ 39 °C + purulent nasal discharge + facial pain lasting ≥ 3–4 days
- Double sickening: worsening symptoms after initial improvement (after 5–6 days)
If none of these are present → Viral rhinosinusitis → treat supportively only.
4. Stepwise Management Approach
Stage 1: Viral / Early Non-Severe Sinusitis (Day 1–10)
🧠 “Supportive Care First”
A. Non-Pharmacologic Management
- Nasal saline irrigation
- Isotonic (0.9%) preferred for daily use
- Hypertonic (2–3%) short-term use for severe congestion
- Clears mucus, allergens, and pathogens
- Enhances steroid absorption
- Steam inhalation / humidified air→ Relieves congestion and sinus pressure
- Adequate hydration→ Thins mucus and improves drainage
- Rest and sleep hygiene
B. Pharmacologic Supportive Treatment
| Medication | Example & Dose | Role |
| Intranasal corticosteroid | Budesonide (Bunase®) 1–2 sprays/nostril OD–BID | Reduces inflammation, edema, and congestion |
| Analgesic / Antipyretic | Paracetamol 500 mg q6h prn or Ibuprofen 400 mg tid pc | For facial pain, fever |
| Antihistamine (if allergic) | Loratadine 10 mg od or Cetirizine 10 mg od | For rhinorrhea, sneezing |
| Decongestant (short-term only) | Oxymetazoline spray bid ≤ 3 days | Opens nasal airway, avoid prolonged use (rebound rhinitis) |
🩸 No antibiotic at this stage.
Stage 2: Bacterial Sinusitis Confirmed or Highly Suspected
🦠 “Start Antibiotic + Continue Supportive”
A. First-line Antibiotic Therapy
| Drug | Dose | Duration | Remarks |
| Amoxicillin–Clavulanate | 875/125 mg po bid pc | 5–7 days | First choice (covers S. pneumoniae & H. influenzae) |
| Amoxicillin | 1 g po tid pc | 7–10 days | If low resistance risk |
| Doxycycline (if penicillin-allergic) | 100 mg po bid | 5–7 days | Alternative agent |
| Levofloxacin / Moxifloxacin | 500 mg po qd | 5 days | Reserve for resistant or recurrent cases |
❌ Avoid macrolides (Azithromycin, Clarithromycin) — due to high resistance of S. pneumoniae and H. influenzae.
B. Continue Adjunctive Therapies
- Nasal saline irrigation (daily)
- Intranasal corticosteroid (Budesonide / Mometasone)
- Pain control with NSAIDs or acetaminophen
- Antihistamines if allergic component present
Stage 3: Non-Responsive or Complicated Sinusitis
🏥 “Re-evaluate and escalate care”
If no improvement after 7 days of ATB or symptoms > 4 weeks:
- Reassess diagnosis – exclude dental origin or fungal sinusitis
- Obtain CT paranasal sinus for anatomical obstruction (In Thai, we order a film, PNS paranasal sinus)
- ENT referral for:
- Nasal endoscopy
- Possible sinus drainage or culture
- Consider a short-course oral corticosteroid if a nasal polyp is present
5. Chronic Rhinosinusitis (>12 weeks)
Usually inflammatory rather than infectious.Mainstay of treatment:
- Intranasal corticosteroids daily
- Saline irrigation
- Treat underlying allergy/asthma
- Antibiotics only if acute bacterial exacerbation
If persistent → CT scan → ENT evaluation for Functional Endoscopic Sinus Surgery (FESS)
6. Monitoring and Follow-up
| Parameter | Time frame | Action |
| Mild viral case | 7–10 days | Continue supportive care |
| Bacterial case on ATB | Reassess after 5–7 days | If no response → change antibiotic or ENT referral |
| Chronic / recurrent case | 4–6 weeks | ENT assessment ± imaging |
7. Patient Education
✅ Use nasal spray correctly (angle away from septum) ✅ Avoid using decongestant > 3 days ✅ Continue saline irrigation daily ✅ Complete full course of antibiotics ✅ Return if: fever > 39 °C, visual changes, periorbital swelling, or confusion
Clinical Pearls for Exams
- >10 days or double sickening = Bacterial sinusitis
- First-line antibiotic: Amoxicillin–Clavulanate
- Saline + Steroid are foundation for all stages
- Do not use macrolides or decongestants long-term
- Chronic sinusitis → anti-inflammatory (steroid), not antibiotic
📚 References
- IDSA Guidelines for Acute Bacterial Rhinosinusitis in Adults and Children, Clin Infect Dis. 2021
- EPOS 2020: European Position Paper on Rhinosinusitis and Nasal Polyps
- Thai Clinical Practice Guideline for Rhinosinusitis (2022), Royal College of Otolaryngologists of Thailand
- CDC Sinus Infection Treatment Guidelines, 2023