Acute Sinusitis

I. Introduction and Definitions

• Definition: Inflammation of the mucosal lining of one or more paranasal sinuses. Since the nasal mucosa is almost always involved, the preferred term is Acute Rhinosinusitis (ARS).
• Acute Bacterial Rhinosinusitis (ABRS): Bacterial superinfection of a viral URI.
• Chronology:
  • Acute: Symptoms lasting < 30 days.
  • Subacute: 30–90 days.
  • Chronic: > 90 days.
  • Recurrent Acute: ≥ 4 episodes per year with complete resolution in between.

II. Development of Paranasal Sinuses

Understanding development predicts the site of infection by age.

1. Ethmoid & Maxillary: Present at birth (pneumatized).
   • Clinical: Primary sites of sinusitis in infants/toddlers.
2. Sphenoid: Pneumatization starts at 3–5 years.
3. Frontal: Pneumatization starts at 6–8 years; fully developed in adolescence.
   • Clinical: Frontal sinusitis/Pott’s puffy tumor is rare before 10 years.

III. Etiopathogenesis

A. Pathophysiology

Obstruction of the Ostiomeatal Complex (drainage pathway) is the central event.

1. Mucosal Swelling: Viral URI or Allergy causes edema.
2. Ostial Obstruction: Impaired drainage and aeration.
3. Ciliary Dysfunction: Stasis of secretions.
4. Bacterial Overgrowth: The static, hypoxic environment favors bacterial proliferation.

B. Microbiology

• Viral (Most Common): Rhinovirus, Influenza, Adenovirus, Parainfluenza.
• Bacterial (ABRS):
  • Streptococcus pneumoniae (30%).
  • Haemophilus influenzae (non-typeable) (30%).
  • Moraxella catarrhalis (10–20%).
  • Staphylococcus aureus (Significant in orbital complications).

C. Predisposing Factors

• Allergic Rhinitis: Most common risk factor.
• Anatomical: Septal deviation, Adenoid hypertrophy, Nasal polyps.
• Systemic: Cystic Fibrosis (bilateral polyps), Primary Ciliary Dyskinesia, Immunodeficiency.

IV. Clinical Presentation & Diagnosis (AAP Guidelines 2013)

Differentiation between simple Viral URI and Bacterial Sinusitis (ABRS) is strictly clinical.

Diagnostic Criteria for ABRS (Any of the following 3):

1. Persistent Symptoms:
   • Nasal discharge (any quality) or daytime cough for > 10 days without improvement.
2. Severe Onset:
   • High fever (>39°C) AND purulent nasal discharge/facial pain for at least 3–4 consecutive days at the beginning of illness.
3. Worsening Course ("Double Sickening"):
   • Initial improvement of a viral URI followed by new onset of fever, cough, or discharge (Day 6–7).

• Physical Signs:
  • Anterior rhinoscopy: Purulent discharge, mucosal edema.
  • Sinus tenderness (unreliable in young children).
  • Periorbital edema (suggests ethmoiditis).

V. Investigations

• Clinical Diagnosis: Imaging is NOT indicated for uncomplicated acute sinusitis.
• CT Scan (Contrast-Enhanced):
  • Indication: Suspected orbital/intracranial complications or frank sepsis.
  • Gold Standard for viewing anatomy and extent of disease.
• X-ray PNS: Obsolete in pediatrics (high rate of false positives/negatives due to small sinuses).
• Nasal Endoscopy/Aspiration: Reserved for immunocompromised hosts or failures of therapy (to get precise cultures).

VI. Complications

Sinusitis in children is prone to extension due to thin bony walls (lamina papyracea).

A. Orbital Complications (Chandler Classification)

Most common complication (usually from Ethmoiditis).

1. Stage I (Preseptal Cellulitis): Eyelid edema, erythema. Eye movement normal.
2. Stage II (Orbital Cellulitis): Inflammation post-septal. Proptosis, Chemosis, Ophthalmoplegia.
3. Stage III (Subperiosteal Abscess): Pus between lamina papyracea and periorbita. Globe displaced laterally/downward.
4. Stage IV (Orbital Abscess): Pus within orbital fat. Severe visual threat.
5. Stage V (Cavernous Sinus Thrombosis): Bilateral symptoms, cranial nerve palsies (III, IV, VI).

B. Intracranial Complications (From Frontal/Sphenoid)

• Meningitis.
• Epidural/Subdural empyema.
• Brain Abscess.

C. Bony Complications

• Pott’s Puffy Tumor: Osteomyelitis of the frontal bone presenting as a subgaleal abscess (doughy swelling on forehead).

VII. Management

A. Medical Management

1. Observation vs. Antibiotics:

• Children with Persistent symptoms (Criterion 1) may be observed for 3 more days (Watchful waiting).
• Children with Severe or Worsening symptoms require immediate antibiotics.

2. Antibiotic Therapy:

• First Line: Amoxicillin (Standard dose 45 mg/kg/day).
  • High Dose (80-90 mg/kg/day): If high resistance prevalence, recent antibiotic use, or daycare attendance.
• Second Line (Beta-lactamase coverage): Amoxicillin-Clavulanate.
• Penicillin Allergy:
  • Type 1 (Anaphylaxis): Levofloxacin or Clindamycin + Cefixime.
  • Non-Type 1: Cefdinir or Cefpodoxime.
• Duration: 10–14 days (or 7 days past symptom resolution).

3. Adjuvant Therapy:

• Saline Irrigation: Helpful to clear secretions.
• Intranasal Steroids: Modest benefit, especially if underlying allergic rhinitis exists.
• Decongestants/Antihistamines: NOT recommended (thicken secretions, no proven benefit).

B. Surgical Management

Indications:

• Orbital complications (Stage III onwards usually require drainage).
• Intracranial complications.
• Failure of maximal medical therapy.

Procedures:

• FESS (Functional Endoscopic Sinus Surgery): To restore drainage and ventilation.
• Trephination: Rarely used for frontal sinus.

VIII. Prognosis

• Uncomplicated ABRS has an excellent prognosis.
• Recurrent cases require evaluation for underlying anatomy (polyps/adenoids) or immunity.