Malignant otitis externa

Malignant otitis externa is defined as rapidly progressive infection of external auditory meatus spreading to surrounding soft tissues and bones of skull base
Malignant is a misnomer (Chandler 1968):
Aggressive clinical behavior, poor treatment outcome and high mortality in elderly uncontrolled diabetics
Synonyms :
Invasive/ granulomatous/ necrotizing otitis externa
Skull base osteomyelitis
Predisposing factors
Elderly , poorly controlled diabetics, prolonged steroid use, atherosclerosis, immunosuppressed, AIDS
Causative organisms
Pseudomonas aeruginosa (95%)
Staph. epidermidis
Aspergillus fumigatus
Hallmark of disease
Granulation tissue at the junction of cartilaginous and bony EAC

1. •Rapidly progressive infection of external auditory meatus
spreading to surrounding soft tissues and bones of skull
base
•Malignant is a misnomer (Chandler 1968)
–Aggressive clinical behavior, poor treatment outcome
and high mortality in elderly uncontrolled diabetics
•Synonyms :
–Invasive/ granulomatous/ necrotizing otitis externa
–Skull base osteomyelitis
Malignant Otitis externa

2. •Predisposing factors
−Elderly , poorly controlled diabetics, prolonged steroid
use, atherosclerosis, immunosuppressed, AIDS
•Causative organisms
–Pseudomonas aeruginosa (95%)
–Staph. epidermidis
–Aspergillus fumigatus
•Hallmark of disease
–Granulation tissue at the junction of cartilaginous and
bony EAC

3. Pathogenesis
•Trauma to EAC Granuloma between the bony and cartilaginous
portion of the EAC
–Parotid gland ,TMJ and adjacent soft tissues through fissures of
Santorini
–Tympanomastoid suture and adjacent soft tissues: Erosion of
tympanic plate and mastoid tip leading to facial nerve palsy
–Secondary osteomyelitis of skull base and petrous apex IX, X,
XI,XII cranial nerve palsy and intracranial extension
–Thrombosis of lateral sinus, IJV, superior and inferior petrosal sinus

4. Trauma to EAC Granuloma between the bony and
cartilaginous portion of the EAC
Secondary osteomyelitis of
petrous Apex
Thrombosis of lateral sinus, IJV,
superior and inferior petrosal sinus
IX, X, XI,XII cranial nerve
palsy
Erosion of Tympanic plate,
Mastoid tip
Tympanomastoid suture, Adjacent soft tissues
Parotid gland ,TMJ and adjacent soft
tissues through fissures of Santorini
Facial Palsy
Pathogenesis
Floor of MCF, Basisphenoid.
Intracranial extension

5. Clinical features
•Severe earache in predisposed individuals more during
night time (pain out of proportion of the disease in EAC)
•Swelling of pinna/ face
•Ear discharge: Initially mucopurulent and later blood
stained and purulent
•Hearing loss : CHL/ SNHL
•VII nerve palsy/polyneuropathy
•Fever/ headache /neck stiffness
•Tender pinna/ mastoid
•Swollen EAC and granulations between the cartilaginous
and bony EAC (Hallmark of disease)

6. Investigations
•CBC:raisedtotalcounts
•ESR:raisedESRsignifiesactivedisease
•FBS/PPBS:Indicatorofdiabeticcontrol
•EarswabcultureforPseudomonas
•CTScan/MRI:Extentofdisease,boneandsofttissue
involvement
•GalliumandTechnetiumbonescan:
–BetterthanCT/MRI
–Radiotracerconcentratesinareaswithincreasedosteoblastic
activity

7. Treatment
•Controlofdiabetesandotherpredisposingfactors
•Debridementofnecrotictissues
•Administrationofantibioticsagainstpseudomonas(high
dose,broadspectrum)
–Piperacillin-tazobactam:4to6gIVevery4to6hours
–Ciprofloxacin750mgtwicedailyfor6-12weeks
–Ceftazidime2gmivTDS
•Hyperbaricoxygentherapy???
–Improveshypoxiaandleadstogreateroxidativekilling
ofbacteria