Answers:
All of the following contribute to sensory innervation of the external ear except...
A) CNV
B) CNVII
C) CNVIII
D) CNX
E) Great Auricular nerve
The vestibulocochlear nerve does not contribute to sensory innervation of the external ear. The great auricular nerve, the vagus (via Arnold's nerve), the trigeminal (via auriculotemporal of V3) and the glossopharyngeal (although this is somewhat controversial) all contribute to sensory innervation.
Name the vascular supply to the external ear.
-Posterior auricular artery/superficial temporal artery (from external carotid) supply auricle and lateral EAC.
-Deep auricular branch of maxillary artery supplies medial aspects of canal and external TM.
-Deep auricular branch of maxillary artery supplies medial aspects of canal and external TM.
Risk factors for otitis externa include all of the following except.
A) Excess cerumen
B) Exposure to heat
C) Excess humidity
D) Alkaline pH
E) All of the above are risk factors for OE.
Free Response Question:
Describe the differences between Grade I, II and III microtia.
Quick Facts:
Describe the differences between Grade I, II and III microtia.
Quick Facts:
Skull Base Osteomyelitis:
-aka malignant otitis externa or necrotizing otitis externa (NOE)
-Most common in elderly diabetics or immunocompromised pts.
-Begins as external otitis and progresses to cellulitis, chondritis, osteitis and osteomyelitis.
-OE spread through pneumatized temporal bone but NOE moves though haversian canals and vascularized bone of skull base.
-Can affect facial, hypoglossal, abducens, trigeminal, glossopharyngeal and spinal accessory nerves.
-Most common organism is Pseudomonas which is often abx resistant.
-Pts present with otalgia, otorrhea, aural fullness, pruritus and hearing loss.
-Granulation tissue is often seen on the floor of the EAC at osteocartilaginous junction.
-Progression can lead to sigmoid sinus thrombosis, meningitis, sepsis and death.
-ESR/CRP will be elevated.
-Draw Cx to help target Abx therapy.
-CT/MRI help determine extent of disease. Bone scans are sensitive but not specific.
-Use gallium scans to track resolution of infection as bone scans remain positive for a long time.
-DDX includes CA of EAC, chronic granulomatous disease, paget disease, fibrous dysplasia, nasopharyngeal carcinoma.
-Do biopsy to r/o CA.
-Treat w/ longterm pIC Abx.
-Can use outpatient oral fluoroquinolones in pts with early presentation and close follow up.
-Control hyperglycemia and immunosuppression.
-May need surgical debridement (circumferential petrosectomy)
-aka malignant otitis externa or necrotizing otitis externa (NOE)
-Most common in elderly diabetics or immunocompromised pts.
-Begins as external otitis and progresses to cellulitis, chondritis, osteitis and osteomyelitis.
-OE spread through pneumatized temporal bone but NOE moves though haversian canals and vascularized bone of skull base.
-Can affect facial, hypoglossal, abducens, trigeminal, glossopharyngeal and spinal accessory nerves.
-Most common organism is Pseudomonas which is often abx resistant.
-Pts present with otalgia, otorrhea, aural fullness, pruritus and hearing loss.
-Granulation tissue is often seen on the floor of the EAC at osteocartilaginous junction.
-Progression can lead to sigmoid sinus thrombosis, meningitis, sepsis and death.
-ESR/CRP will be elevated.
-Draw Cx to help target Abx therapy.
-CT/MRI help determine extent of disease. Bone scans are sensitive but not specific.
-Use gallium scans to track resolution of infection as bone scans remain positive for a long time.
-DDX includes CA of EAC, chronic granulomatous disease, paget disease, fibrous dysplasia, nasopharyngeal carcinoma.
-Do biopsy to r/o CA.
-Treat w/ longterm pIC Abx.
-Can use outpatient oral fluoroquinolones in pts with early presentation and close follow up.
-Control hyperglycemia and immunosuppression.
-May need surgical debridement (circumferential petrosectomy)
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