A 65-year-old diabetic presents with necrosis of the external auditory meatus with foul smelling discharge. The probable organism associated with the condition is
Correct Answer: Pseudomonas aeruginosa
Description: Malignant Otitis externa o Malignant otitis externa,
also called necrotizing external otitis, is a misnomer as it is not a neoplastic condition, rather it is an infectious condition.
Malignant otitis externa is a disorder involving inflammation and damage of the bones and cartilage at the base of the skull in temporal bone as a result of the spread of infection from the outer ear.
Malignant otitis externa is often caused by difficult to treat bacteria such as Pseudomonas aeruginosa.
Only rare cases of malignant otitis externa due to S.aureus, Proteus mirabilis and Aspergillus fumigatus have been reported.
The infection spreads from the floor of the ear canal to the nearby tissues and into the bones at the base of the skull.
The infection and inflammation may damage or destroy the bones. The infection may spread more and affect the cranial nerves, brain, or other parts of the body. Predisposing factors for malignant otitis externa o Elderly diabetics (most common predisposing factor)
Individuals with altered immune function (immunodeficiency)
Chemotherapy Clinical features of malignant otitis externa
The severe pain inside the ear and may get worse when moving the head.
Granulation tissue in the external auditory canal,
at the junction of a bony and cartilaginous part
Drainage from the ear - yellow, yellow-green, foul-smelling, persistent
Fever o Itching of the ear or ear canal
Troubled swallowing & weakness of face.
Complications Cranial nerve palsies most commonly facial nerve is involved.
Other cranial nerves can also be involved (glossopharyngeal, vagus, spinal accessory, hypoglossal,
abducens, trigeminal),
Jugular venous thrombosis Cavernous sinus thrombosis Meningitis Treatment of malignant otitis externa In all cases,
the external ear canal is cleansed and a biopsy specimen of the granulation tissue sent for culture. IV antibiotics are directed against the offending organism.
For Pseudomonas aeruginosa, the most common pathogen,
the regimen involves an antipseudomonal penicillin or cephalosporin (3rd generation piperacillin or ceftazidime) with an aminoglycoside.
A fluoroquinolone antibiotic can be used in place of the aminoglycoside.
Ear drops containing antipseudomonal antibiotic e.g. ciprofloxacin plus a glucocorticoid is also used. Early cases can be managed with oral and otic fluoroquinolones only.
Extensive surgical debridement once an important part of the treatment is now rarely needed.
Category:
ENT
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