Dr. T. Balasubramanian M.S. D.L.O.
Malignant otitis externa is a inflammatory
disorder involving the external auditory canal caused by psuedomonas
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 constured 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
The 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.
Malignant otitis externa
is knwon to affect the external auditory canal and temporal bone.
The causative oraganism 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. Diabetis mellitus
2. Blood cancer
3. HIV infections
4. Patients on anticancer drugs
It 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
Pseudomonas 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 cloathed 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
cartilagenous junction of the external canal. Discharge eminating
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.
granulation tissue at the bony cartilagenous junction. The ear
drum is usually normal. The external auditory canal skin is soggy
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.
Figure showing granulation tissue in the
Figure showing malignant otitis externa
patient with facial palsy
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 alogrithm 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 Otitis)
(Skull base osteomyelitis)
skull base osteomyelitis
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.
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