ENT (Otorhinolaryngology) · MU Sofia

14. Mastoiditis.

Explains mastoiditis as an infection of the mastoid air cells that usually follows acute otitis media, with its common organisms and the stages of spread from the middle ear to bone destruction and abscess. Covers a classification into acute, chronic, coalescent, masked and incipient forms, the clinical picture with physical findings such as Macewen's triangle and auricle displacement, and imaging with HRCT. Treatment, local and intracranial complications, and a differential diagnosis table are also set out.

Inside: 8 sections · 3 labelled pictures · 1 table · 15 flashcards · 6 min

Topic 14 of 52 in the MU Sofia syllabus for ENT (Otorhinolaryngology) (Medicine, Year 4). The free AceMed note covers it in 8 sections, about 712 words (6 min of reading), with 15 flashcards.

In this note

  1. Mastoiditis
  2. Etiopathogenesis
  3. Classification
  4. Clinical Picture
  5. Paraclinical and Radiological Examinations
  6. Treatment Options
  7. Possible Complications
  8. Differential Diagnosis

Mastoiditis

1. Definition - Mastoiditis is an infection and inflammation of the mastoid air cell system, usually arising as a complication of acute otitis media (AOM), and is characterized by accumulation of purulent exudate, destruction of the bony septa within the mastoid, and possible extension to surrounding structures.

Etiopathogenesis

The organisms are the same as those causing AOM:

  • Streptococcus pneumoniae (Most common)
  • Haemophilus influenzae
  • Streptococcus pyogenes (Group A Strep)
  • Poor Eustachian tube function
  • Virulent organisms
  • Children (poor mastoid pneumatization)

Pathogenesis

  1. 1. AOM Extension: A severe or untreated AOM infection spreads from the middle ear cavity into the mastoid antrum and surrounding mastoid air cell system.
  2. 2. Hyperemia & Edema: The mucosa lining the air cells becomes inflamed and thickened, leading to the accumulation of pus and secretions, and blocking the communication between the air cells and the middle ear (aditus ad antrum).
  3. 3. Bone Resorption (Coalescence): The trapped pus and increased pressure within the bony air cells cause osteitis (bone inflammation) and osteoclast activation, leading to the destruction (coalescence) of the thin bony septa, forming a large, infected cavity. This is termed Coalescent or Acute Necrotizing Mastoiditis.
  4. 4. Abscess Formation: If the infection breaks through the cortical bone of the mastoid, it forms a subperiosteal abscess (eg, post-auricular abscess).

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