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Rhinosinusitis - Everything You Need to Know (Simply)

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1. What Is It?

• Nasal congestion/blockage
• Nasal discharge (front or back of throat - "postnasal drip")
• Facial pain or pressure
• Reduced or lost sense of smell (hyposmia/anosmia)

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2. The Sinuses Involved

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3. Classification by Duration

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4. Causes

Viral (Most Common - ~90% of Acute Cases)

• Rhinovirus, adenovirus, influenza, parainfluenza
• Self-limiting; peak 2-3 days, resolve by 7-10 days
• Viral infection causes mucosal edema → blocks sinus ostia → traps fluid → sets stage for bacterial superinfection

Bacterial (Complicates ~0.5-2% of viral URIs)

1. Streptococcus pneumoniae (~30%)
2. Non-typeable Haemophilus influenzae (~20%)
3. Moraxella catarrhalis (~20%)

Allergic

• Mucosal edema from allergic inflammation obstructs drainage
• Associated with eosinophilic inflammation
• Linked to CRS with nasal polyps (CRSwNP)

Odontogenic

• Infection from maxillary molar roots extends directly into maxillary sinus
• Classic cause of unilateral maxillary sinusitis - don't miss this!

Fungal (see Section 7 below)

Other predisposing factors:

• Nasal septal deviation
• Concha bullosa (air cell in turbinate)
• Cystic fibrosis, primary ciliary dyskinesia
• Immunodeficiency

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5. Pathophysiology (Simply)

Viral URI / Allergen / Structural blockage
        ↓
Mucosal edema and inflammation
        ↓
Ostiomeatal unit obstructed
        ↓
Mucus trapped in sinus cavity
        ↓
Impaired mucociliary clearance
        ↓
Bacterial overgrowth (superinfection)
        ↓
Acute Bacterial Rhinosinusitis

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6. Clinical Features

Symptoms

Signs

• Turbinate swelling and erythema on anterior rhinoscopy
• Purulent discharge in middle meatus
• Sinus tenderness on percussion (especially maxillary)
• Facial erythema/swelling if complicated

Key clinical rule: You CANNOT reliably distinguish viral from bacterial rhinosinusitis based on symptoms alone (color of mucus does NOT mean bacterial). Diagnosis relies on time course.

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7. Fungal Rhinosinusitis

Non-Invasive (Normal/Near-normal immunity)

Invasive (Immunocompromised)

Red flag: Diabetic or immunosuppressed patient with high fever, nasal crusting, black eschar, or rapid progression = invasive fungal sinusitis until proven otherwise - call ENT immediately.

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8. Diagnosis

Clinical Diagnosis of Bacterial Rhinosinusitis - 3 Criteria (any 1 of 3)

1. Symptoms persist ≥ 10 days without improvement
2. Severe symptoms from onset: fever >39°C + purulent nasal discharge or facial pain for 3-4 days
3. Double sickening - initial improvement then worsening

When to Image?

• Routine imaging NOT indicated for uncomplicated acute rhinosinusitis
• CT is the gold standard when needed:
  • Suspected complications (orbital/intracranial spread)
  • Chronic sinusitis (to assess extent)
  • Pre-surgical planning
  • Immunocompromised with suspected fungal disease

Gold Standard for Diagnosis

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9. Complications (Rare but Serious)

Orbital Complications (most common serious complication)

• Periorbital/preseptal cellulitis → orbital cellulitis → subperiosteal abscess → orbital abscess
• Symptoms: proptosis, ophthalmoplegia, visual changes

Intracranial Complications

• Meningitis, epidural/subdural abscess, brain abscess
• Cavernous sinus thrombosis (from sphenoid/ethmoid sinusitis)
• Pott's puffy tumor (frontal osteomyelitis with subperiosteal abscess)

Any neurological symptoms, visual changes, or periorbital swelling in sinusitis = emergency - get CT and call ENT/neurosurgery.

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10. Treatment

Acute Viral Rhinosinusitis (the majority!)

• Symptomatic only - antibiotics NOT indicated
• Saline nasal irrigation (1-2 sprays each nostril every 4 hours)
• Intranasal corticosteroids (fluticasone or mometasone, 2 sprays/nostril daily) - reduces swelling, aids drainage
• Analgesics: paracetamol 650 mg q6-8h or ibuprofen 400-800 mg q8h
• Decongestants and mucolytics: not recommended (insufficient evidence)
• Systemic corticosteroids: not recommended for acute rhinosinusitis
• Antihistamines: only if concurrent allergic symptoms

Acute Bacterial Rhinosinusitis

• Antibiotics: indicated when criteria met (see Section 8)
• First line: Amoxicillin-clavulanate (adults: 875/125 mg twice daily for 5-7 days)
• Penicillin allergy: Doxycycline or fluoroquinolone (levofloxacin)
• Duration: 5 days for uncomplicated adults; 10 days for children or recurrent/prior antibiotic use
• Continue saline irrigation + intranasal steroids alongside

Note: Benefit of antibiotics is modest - cure rates only slightly higher than placebo at 7-15 days. Watchful waiting for 7 days is acceptable for well-appearing adult patients.

Chronic Rhinosinusitis (CRS)

• Mainstay: Saline nasal irrigation + intranasal corticosteroids (long-term)
• Antibiotics: prolonged courses (3-6 weeks) sometimes used in CRS with neutrophilic/purulent pattern
• Nasal polyps (CRSwNP): intranasal steroids, short oral steroid courses; newer biologics (dupilumab, mepolizumab) for refractory cases
• Surgery: Functional Endoscopic Sinus Surgery (FESS) for patients failing medical therapy - opens sinus drainage pathways

Fungal Rhinosinusitis

• Non-invasive (fungus ball/AFRS): Surgery is primary treatment; antifungals secondary
• Acute invasive: Emergency - IV antifungal (amphotericin B) + aggressive surgical debridement + treat underlying immunosuppression

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11. CRS - Two Phenotypes (Important!)

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12. Quick Summary Flowchart

Nasal symptoms + facial pain/pressure
            ↓
     Duration < 10 days
     AND improving?
       /        \
     YES          NO (or worsening)
      ↓                ↓
  Viral ARS      Bacterial ARS
  (symptomatic    (antibiotics +
   treatment)      symptomatics)
                      ↓
              Not improving after
              antibiotics?
                      ↓
              CT scan + ENT referral
                      ↓
              Consider CRS, fungal,
              anatomical causes

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13. Key Points to Remember

1. 90% of rhinosinusitis is viral - don't reflexively prescribe antibiotics
2. Color of mucus is NOT diagnostic - doesn't distinguish viral from bacterial
3. Duration and time course are the key diagnostic criteria
4. The OMU is the key - block the drainage pathway, sinusitis follows
5. CRS > 12 weeks requires objective evidence (CT or endoscopy) to confirm - symptoms alone are unreliable
6. Odontogenic sinusitis = think of it when sinusitis is unilateral maxillary
7. Immunocompromised + rapid progression + black eschar = invasive fungal = ENT emergency
8. Complications are rare but include orbital cellulitis, meningitis, cavernous sinus thrombosis
9. FESS is the surgical solution for CRS failing medical therapy
10. Unified airway - always check for asthma in CRS, and treat both

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