Definition: Acute mastoiditis is a complication of acute suppurative otitis media, where the infection spreads from the mucosal lining of the antrum to involve the bony walls of the mastoid air system. Aetiology: Acute mastoiditis usually follows an attack of Acute suppurative otitis media due to:
- Lowered resistance of patient due to measles, exanthematous fever, poor nutrition and immunocompromising systemic disease.
- High virulence of organism. The most common organism infecting children is beta hemolytic streptococcus.
- Streptococcus pneumoniae.
- Streptococcus pyogenes.
- Staphylococcus aureus.
- Haemophilus influenzae.
- Moraxella catarrhalis.
- Pseudomonas aeruginosa.
- Gram-negative aerobic bacilli, and anaerobic bacteria.
- Pseudomonas aeruginosa.
- Production of pus under tension– If an Acute suppurative otitis media is untreated, or fails to respond, the inflammatory process persists and there is accumulation of pus in the mastoid air cells. The Eustachian tube or perforation in the tympanic membrane is not sufficient to drain the pus produced.
- Hyperemic decalcification– Hyperemia and engorgement of mucosa causes dissolution of calcium from the bony walls of mastoid air cells.
Both these processes combine and it causes destruction and coalescence of mastoid air cells, converting them into a single irregular cavity filled with pus (Empyema of mastoid). Eventually the pus can break through the bone:
- Laterally: causing subperiosteal abscess.
- Superiorly: causing brain abscess.
- Medially: Petrositis and Labyrinthitis.
- Inferior: through mastoid tip causing Bezold’s abscess, Citelli’s abscess.
- Anteriorly: causing facial paralysis.
- Fever and malaise: Fever is persistent, inspite of adequate antibiotics. It can be as high as 40-degree Celsius.
- Pain: It is usually post-aural. The presence of unilateral headache is suggestive of impending intracranial complications
- Ear discharge: The discharge is purulent, profuse and foul smelling.
- Sagging of postero-superior canal wall.
- Perforation of the tympanic membrane.
- Mastoid tenderness elicited by pressure over the Macewan’s triangle.
- Conductive hearing loss.
- Protuberance of the pinna.
- Routine blood counts show polymorphonuclear leukocytosis with raised Erythrocyte sedimentation rate.
- X-ray mastoid lateral oblique view shows clouding of air cells, lysis of bony partitions between air cells, but the sinus plate is seen as a distinct outline. In later stages, a cavity may be seen in the mastoid.
- HRCT temporal bone indicates the extent of the disease, status of the middle ear, mastoid, ear ossicles, and the facial nerve. It also gives idea of any impending complications.
- Ear swab for culture and sensitivity.
- The primary treatment for mastoiditis is administration of intravenous antibiotics.
- In the absence of culture sensitivity, start with amoxicillin or ampicillin.
- Since anaerobic organisms are often present, chloramphenicol or metronidazole is added.
- As culture results comes, treatment can be switched to more specific antibiotics directed at the eradication of the recovered aerobic and anaerobic bacteria.
- If the condition does not quickly improve with antibiotics, surgical procedures need to be performed (while continuing the medication).
Complications of Acute Mastoiditis
- Subperiosteal abscess.
- Facial paralysis.
- Extradural abscess.
- Subdural abscess.
- Brain abscess.
- Lateral sinus thrombophlebitis.
- Otitic hydrocephalous.
- Suppuration of mastoid lymph nodes.
- Furunculosis of meatus.
- Infected sebaceous cyst.