Otology: Periostitis
High-Yield Revision for NEET PG
In the context of ENT, periostitis most commonly refers to the inflammatory process involving the periosteum of the mastoid process, often a precursor or concurrent finding in acute mastoiditis.
1. Clinical Correlation: Mastoid Periostitis
- The “Masked” Mastoiditis: Often follows inadequate antibiotic treatment of AOM, where the acute symptoms are suppressed, but subclinical osteitis/periostitis continues.
- Physical Signs: The characteristic post-auricular swelling and tenderness in mastoiditis are essentially manifestations of acute mastoid periostitis.
- Pathophysiology: Infection spreads from the mastoid air cells through the cortex, lifting the periosteum and creating a subperiosteal abscess.
2. Differential Diagnosis
| Condition | Key Differentiator |
|---|---|
| Mastoid Periostitis | Associated with AOM, loss of the retroauricular sulcus, and displaced pinna. |
| Post-auricular Lymphadenitis | Usually distinct/palpable nodes; the pinna is NOT displaced outward. |
| Furunculosis of EAC | Pain on moving the pinna; canal wall tenderness is superior. |
3. NEET PG High-Yield Pearls
- Subperiosteal Abscess: If periostitis is not managed, it evolves into a collection of pus between the mastoid bone and the periosteum.
- Imaging: CT scans are crucial to differentiate simple periostitis/edema from coalescent mastoiditis requiring surgical intervention.
- Management: Aggressive IV antibiotics are the first line; surgical cortical mastoidectomy is indicated if subperiosteal abscess formation is confirmed.