ACUTE MASTOIDITIS ent

Definition: Inflammation of the mucosal lining of antrum and mastoid air cell system plus invasion of the bony walls (osteitis).

Aetiology

• Context: Follows Acute Suppurative Otitis Media (ASOM).
• Predisposing Factors:
  • High virulence of organism (e.g., Measles, Exanthematous fevers).
  • Lowered resistance (Diabetes, Poor nutrition).
  • Anatomy: Well-developed air cell system (common in children).
• Organisms: Beta-haemolytic Streptococcus (Most common), often mixed with Anaerobes.

Pathology

The transition from ASOM to Mastoiditis involves two main processes:

1. Production of Pus under Tension

• Inflammation extends to mucoperiosteum of air cells → Increased pus production (large surface area).
• Blockage: Swollen mucosa of antrum/attic blocks drainage to the middle ear.
• Result: Pus accumulates under tension as drainage through the TM perforation is insufficient.

2. Bony Destruction

• Hyperaemic Decalcification: Engorged mucosa causes dissolution of calcium.
• Osteoclastic Resorption: Break down of bony septae.
• Result: Coalescence of air cells into a single irregular cavity filled with pus (Empyema of Mastoid).

Clinical Features

Key Concept: Change in character of symptoms (Persistence, Increase, or Recurrence) in a case of ASOM.

Symptoms

• Pain: Behind the ear. Persists or recurs after subsiding.
• Fever: Recurrence or persistence despite antibiotics.
• Ear Discharge:
  • Becomes profuse and purulent ("Creamy").
  • May cease (if blocked) while other symptoms worsen.
  • *Red Flag: Discharge persisting > 3 weeks.

Signs

• Mastoid Tenderness: Elicited over:
  • Middle of mastoid process.
  • Tip of mastoid.
  • Root of zygoma.
  *Note: Tenderness over Suprameatal triangle is NOT diagnostic (seen in simple antritis).
• Sagging of Posterosuperior Meatal Wall: Due to periostitis of the bony party wall.
• Swelling:
  • Initially: Smooth "Ironed out" feel (Periosteal oedema).
  • Later: Pinna pushed forwards and downwards (Obliterated retroauricular sulcus).
• Perforation: Nipple-like protrusion often seen.
• General: Patient looks ill/toxic; high pulse rate in children.

Investigations

• Blood: Polymorphonuclear leukocytosis; Raised ESR.
• Ear Swab: For culture and sensitivity.
• CT Scan / X-ray:
  • Clouding of air cells (exudate).
  • Loss of bony septae (partition walls).
  • Sinus plate seen as a distinct outline.

Differential Diagnosis

1. Furunculosis vs Mastoiditis

2. Suppuration of Mastoid Lymph Nodes

• Caused by scalp infection.
• Abscess is usually superficial.
• Differentiation: No history of otitis media, ear discharge, or deafness.

3. Infected Sebaceous Cyst

• Local examination differentiates.

Treatment

1. Medical

• Hospitalization.
• Antibiotics: Amoxicillin/Ampicillin. Add Chloramphenicol/Metronidazole for anaerobes.

2. Surgical Interventions

• Myringotomy: Wide incision to relieve pus under tension (if drum is bulging).
• Cortical Mastoidectomy (Schwartze's Op):
  • Aim: Exenterate all mastoid air cells and remove pus pockets.
  • Post-op: Antibiotics continued for at least 5 days.

Complications

• Subperiosteal Abscess / Extradural / Subdural Abscess.
• Labyrinthitis / Facial Paralysis / Petrositis.
• Meningitis / Brain Abscess / Lateral Sinus Thrombophlebitis.
• Otitic Hydrocephalus.