Malignant Otitis Externa
Dr. T. Balasubramanian M.S. D.L.O.
Malignant otitis externa is a inflammatory disorder involving the
external auditory canal caused by pseudomonas organism. Majority
of these patients are elderly diabetics. This condition is termed
as malignant otitis externa because of its propensity to cause
complications. Hence the term malignant must not be construed in
a histological sense.
1838 - Toulmousch reported the first case of otitis
1959 - Meltzer reported a case of pseudomonas osteomyelitis of temporal
1968 - Chandler discussed the various clinical features and described
it as a distinct clinical entity
effectiveness of present day antibiotics in the management of this
condition should provoke the physicians to abandon the term malignant
while describing this condition.
The typical patient with malignant otitis externa is an elderly
diabetic, with males outnumbering females by twice the number.
This could be due to the possibility of males being more prone to
secrete wax which are more acidic in nature. Malignant otitis
externa is very rare in children; if present it will be associated with
malnutrition or HIV infection.
otitis externa is known to affect the external auditory canal and
temporal bone. The causative organism being pseudomonas
aeruginosa. These patients are invariably elderly
diabetics. This disorder usually begins as otitis externa and
progresses to involve the temporal bone. Spread of this disease
occurs through the fissures of Santorini and osteo cartilagenous
junction. This disorder could be caused by a combination of poor
immune response and peculiar characteristics of the offending microbe.
Immunity is reduced in patients with :
1. Diabetes mellitus
2. Blood cancer
3. HIV infections
4. Patients on anticancer drugs
should also be remembered that diabetic patients have impaired
phagocytosis, poor leukocytic response, and impaired intracellular
digestion of bacteria. Diabetic patients secrete wax which has
less lysozyme content than normal thereby reducing the effectiveness of
wax as an antimicrobial agent.
aeruginosa is a gram negative aerobe with polar flagella. It is
found on the skin. It invariably behaves like an opportunistic
pathogen. The pathogenicity of this organism is due to ability to
secrete exotoxin and various enzymes like lecithinase, lipase,
esterase, protease etc. Since this organism is clothed by a
mucoid layer it is resistant to digestion by macrophages.
The patient gives history of trivial trauma to the ear often by ear
buds, followed by pain and swelling involving the external auditory
canal. Pain is often the common initial presentation. It is
often severe, throbbing and worse during nights. It needs
increasing doses of analgesics. On examination granulation tissue
may be seen occupying the external canal. It often begins at the bony
cartilaginous junction of the external canal. Discharge emanating
from the external canal is scanty and foul smelling in nature.
When the discharge is foul smelling it indicates the onset of
osteomyelitis. Ironically the patient does not have fever or
other constitutional symptoms.
Reveals granulation tissue at the bony cartilaginous junction.
The ear drum is usually normal. The external auditory canal skin
is soggy and edematous.
Cranial nerve palsies are common when the
disease affects the skull base. The facial nerve is the most
common nerve affected. As the disease progresses the lower three
cranial nerves are affected close to the jugular foramen.
Intracranial complications like meningitis and brain abscess are also
known to occur.
Picture showing patient with
malignant otitis externa with facial palsy left side
Spread of infection:
1. Inferiorly through the stylomastoid foramen to involve the facial
2. Anteriorly to the parotid
3. Posteriorly to the mastoid and sigmoid sinus
4. Superiorly to the meninges and brain
5. Medially to the sphenoid
6. Spread through vascular channels are also common
Role of imaging:
radiology is of no use.
* CT scan is useful in assessing bone destruction.
* MRI is useful in assessing soft tissue involvement.
* Radionucleotide scans with Technetium 99 helps in
assessing bone involvement
Imaging algorithm in these patients
1. TC99 scan to seek evidence of bone involvement
2. If this is positive CT scan and MRI scan is a must to rule out bone
and soft tissue involvement
3. Serial Ga 67 scans to assess the efficacy of treatment modality.
Levenson's criteria for diagnosis of
malignant otitis externa:
* Refractory otitis
* Severe nocturnal otalgia
* Purulent otorrhoea
* Granulation tissue in the external canal
* Growth of Pseudomonas aeruginosa from external
* Presence of diabetes and and other
Staging & classification:
Extent of Disease
Soft tissue (Necrotising
Ear & Mastoid
(Skull base osteomyelitis)
Extensive skull base
surgical procedures have failed miserably to cure this condition.
The role of surgery is confined to only exclusion of malignancy by
biopsy. Wound debridement is a possibility in advanced cases.
Carbenicillin, Pipercillin, Ticarcillin can be used. Third and
forth generation cephalosporins can be used.
Ciprofloxacillin in doses of 1.5 g - 2.5 g /day in divided doses
can be administered for a period of 2 weeks.
Gentamycin can also be administered parenterally in doses of 80 mg iv
two times a day in adults.
You can take CME quiz on this subject by
clicking the image below:
Copyright drtbalu 2007