78.NERVE COMMONLY INVOLVED IN MALIGNANT OTITIS EXTERNA
A.FACIAL
B.TRIGEMINAL
C.ABDUCENT
D.VESTIBULO COCHLEAR
ANS:FACIAL
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.
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.
Clinical features:
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.
Otoscopy: Reveals granulation tissue at the bony cartilagenous 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.
A.FACIAL
B.TRIGEMINAL
C.ABDUCENT
D.VESTIBULO COCHLEAR
ANS:FACIAL
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.
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.
Clinical features:
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.
Otoscopy: Reveals granulation tissue at the bony cartilagenous 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.
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