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Malignant Otitis Externa and Osteomyelitis of the Temporal Bone
Built from Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
What’s inside
10 sections · 83 slides
Overview
- Scope of this presentation
Definition and terminology
- Definition of malignant otitis externa
- Historical origin of the term
- Alternative names for the condition
Predisposing factors
- Diabetes mellitus as the dominant risk factor
- Non-diabetic causes of immunocompromise
- Fungal disease as a marker of immunodeficiency
- Age distribution and paediatric disease
- Local initiating events in the ear canal
- Sequence from canal injury to osteomyelitis
Pathways of spread
- Routes of spread of infection from the ear canal
- Anterior and inferior spread to parotid and TMJ
- Inferior spread to the stylomastoid foramen
- Spread to the jugular foramen and lower cranial nerves
- Posterior and medial extension
- Contrast with acute mastoiditis
- Middle ear changes in chronic disease
- Isolated temporal bone, lateral aspect
- Cranial nerves at the base of the skull
Pathogens
- Pseudomonas aeruginosa as the leading pathogen
- Isolated colonies of Pseudomonas aeruginosa
- Virulence factors of Pseudomonas aeruginosa
- Gram stain appearance of Pseudomonas aeruginosa
- Antimicrobial resistance in Pseudomonas
- Bacterial pathogens other than Pseudomonas
- Fungal malignant otitis externa
- Classification of causative organisms
Clinical presentation
- Presenting symptoms and diagnostic delay
- Other symptoms and the absence of fever
- Hearing loss in malignant otitis externa
- Findings on otoscopic and physical examination
- Cranial nerve involvement
Diagnosis
- Differential diagnosis
- Laboratory markers in malignant otitis externa
- Cohen criteria as a diagnostic framework
- The major and minor signs of MOE as defined by and adapted from Cohen et al. [ 22 ]
- The major and minor signs of MOE as defined by and adapted from Cohen et al. [ 22 ] (continued)
- Diagnostic criteria used in recent published studies
- Diagnostic criteria used in studies published within the last 5 years a
- Culture and tissue sampling
Imaging
- Role and limitations of computed tomography
- Coronal high-resolution CT in malignant otitis externa
- Magnetic resonance imaging in soft tissue assessment
- Diffusion-weighted MRI monitoring of petrous apex disease
- Technetium-99m MDP scintigraphy
- Technetium-99m MDP scintigraphy of left-sided disease
- Gallium-67 scintigraphy
- Technetium versus gallium in clinical use
- Sequence of imaging in suspected disease
Treatment
- Medical therapy as the mainstay
- Indications for surgical intervention
- Facial nerve decompression in facial paralysis
- Management of the underlying predisposing condition
- Culture-directed antibiotic therapy and duration
- Antibiotic classes used against Pseudomonas
- Ciprofloxacin and fluoroquinolone safety
- Culture-negative disease
- Treatment of fungal disease
- Hyperbaric oxygen therapy
Prognosis and treatment endpoints
- Historical and contemporary mortality
- Prognostic significance of cranial neuropathies
- Determining resolution of infection
- Laboratory and MRI markers of treatment response
- Summary of key points
- References
- References (continued)
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- References (continued)
- Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
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