Infections of the External Ear
http://www.tjdxdlec.com 天津电线电缆电力电缆低烟无卤电缆http://www.u51688.com http://www.qiwhy.comAnatomy and Physiology
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Consists of the auricle and EAMSkin-lined apparatus
Approximately 2.5 cm in lengthEnds at tympanic membrane
Anatomy and Physiology
•Auricle is mostly skin-lined cartilage
•External auditory meatus
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Cartilage: ~40%Bony: ~60%S-shaped
Narrowest portion at bony-cartilage junction
Anatomy and Physiology
Anatomy and Physiology
•EAC is related to various contiguous structures
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Tympanic membraneMastoid
Glenoid fossaCranial fossa
Infratemporal fossa
Anatomy and Physiology
•Innervation: cranial nerves V, VII, IX, X, and greater auricular nerve
•Arterial supply: superficial temporal, posterior and deep auricular branches
•Venous drainage: superficial temporal and posterior auricular veins•Lymphatics
Anatomy and Physiology
•Squamous epithelium•Bony skin –0.2mm•Cartilage skin
–0.5 to 1.0 mm
–Apopilosebaceous unit
Otitis Externa
•Bacterial infection of external auditory canal•Categorized by time course
–Acute–Subacute–Chronic
Acute Otitis Externa (AOE)
•“swimmer’s ear”•Preinflammatory stage•Acute inflammatory stage
–Mild
–Moderate–Severe
AOE: Preinflammatory Stage
•Edema of stratum corneum and plugging of apopilosebaceous unit
•Symptoms: pruritus and sense of fullness•Signs: mild edema
•Starts the itch/scratch cycle
AOE: Mild to Moderate Stage
•Progressive infection•Symptoms
–Pain
–Increased pruritus
•Signs
–Erythema
–Increasing edema
–Canal debris, discharge
AOE: Severe Stage
•Severe pain, worse with ear movement•Signs
–Lumen obliteration–Purulent otorrhea–Involvement of
periauricular soft tissue
AOE: Treatment
•Most common pathogens: P. aeruginosaand S. aureus•Four principles
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Frequent canal cleaningTopical antibioticsPain control
Instructions for prevention
Chronic Otitis Externa (COE)
•Chronic inflammatory process•Persistent symptoms (> 2 months)
•Bacterial, fungal, dermatological etiologies
COE: Symptoms
•Unrelenting pruritus•Mild discomfort
•Dryness of canal skin
COE: Signs
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AsteatosisDry, flaky skin
Hypertrophied skin
Mucopurulent otorrhea (occasional)
COE: Treatment
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Similar to that of AOE
Topical antibiotics, frequent cleaningsTopical SteroidsSurgical intervention
–Failure of medical treatment
–Goal is to enlarge and resurface the EAC
Furunculosis
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Acute localized infection
Lateral 1/3 of posterosuperior canalObstructed apopilosebaceous unitPathogen: S. aureus
Furunculosis: Symptoms
•Localized pain•Pruritus
•Hearing loss (if lesion occludes canal)
Furunculosis: Signs
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EdemaErythemaTenderness
Occasional fluctuance
Furunculosis: Treatment
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Local heatAnalgesics
Oral anti-staphylococcal antibiotics
Incision and drainage reserved for localized abscessIV antibiotics for soft tissue extension
Otomycosis
•Fungal infection of EAC skin•Primary or secondary
•Most common organisms: Aspergillusand Candida
Otomycosis: Symptoms
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Often indistinguishable from bacterial OEPruritus deep within the earDull pain
Hearing loss (obstructive)Tinnitus
Otomycosis: Signs
•Canal erythema•Mild edema
•White, gray or black fungal debris
Otomycosis
Otomycosis: Treatment
•Thorough cleaning and drying of canal•Topical antifungals
Granular Myringitis (GM)
•Localized chronic inflammation of pars tensa with granulation tissue
•Toynbee described in 1860
•Sequela of primary acute myringitis, previous OE, perforation of TM
•Common organisms: Pseudomonas, Proteus
GM: Symptoms
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Foul smelling discharge from one earOften asymptomatic
Slight irritation or fullness
No hearing loss or significant pain
GM: Signs
•TM obscured by pus •“peeping”granulations•No TM perforations
GM: Treatment
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Careful and frequent debridementTopical anti-pseudomonalantibioticsOccasionally combined with steroidsAt least 2 weeks of therapy
May warrant careful destruction of granulation tissue if no response
Bullous Myringitis
•Viral infection
•Confined to tympanic membrane•Primarily involves younger children
Bullous Myringitis: Symptoms
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Sudden onset of severe painNo fever
No hearing impairment
Bloody otorrhea (significant) if rupture
Bullous Myringitis: Signs
•Inflammation limited to TM & nearby canal•Multiple reddened, inflamed blebs
•Hemorrhagic vesicles
Bullous Myringitis: Treatment
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Self-limitingAnalgesics
Topical antibiotics to prevent secondary infectionIncision of blebs is unnecessary
Necrotizing External Otitis(NEO)
•Potentially lethal infection of EAC and surrounding structures
•Typically seen in diabetics and immunocompromised patients
•Pseudomonas aeruginosa is the usual culprit
NEO: History
•Meltzer and Kelemen, 1959
•Chandler, 1968 –credited with naming
NEO: Symptoms
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Poorly controlled diabetic with h/o OEDeep-seated aural painChronic otorrheaAural fullness
NEO: Signs
•Inflammation and granulation
•Purulent secretions•Occluded canal and obscured TM•Cranial nerve involvement
NEO: Imaging
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Plain films
Computerized tomography –most usedTechnetium-99 –reveals osteomyelitis Gallium scan –useful for evaluating RxMagnetic Resonance Imaging
NEO: Diagnosis
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Clinical findings
Laboratory evidenceImaging
Physician’s suspicion
Cohen and Friedman –criteria from review
NEO: Treatment
•Intravenous antibiotics for at least 4 weeks –with serial gallium scans monthly
•Local canal debridement until healed•Pain control
•Use of topical agents controversial•Hyperbaric oxygen experimental
•Surgical debridement for refractory cases
NEO: Mortality
•Death rate essentially unchanged despite newer antibiotics (37% to 23%)
•Higher with multiple cranial neuropathies (60%)•Recurrence not uncommon (9% to 27%)•May recur up to 12 months after treatment
Perichondritis/Chondritis
•Infection of perichondrium/cartilage•Result of trauma to auricle
•May be spontaneous (overt diabetes)
Perichondritis: Symptoms
•Pain over auricle and deep in canal•Pruritus
Perichondritis: Signs
•Tender auricle•Induration•Edema
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Advanced cases
–Crusting & weeping
–Involvement of soft tissues
Relapsing Polychondritis
•Episodic and progressive inflammation of cartilages•Autoimmune etiology?
•External ear, larynx, trachea, bronchi, and nose may be involved
•Involvement of larynx and trachea causes increasing respiratory obstruction
Relapsing Polychondritis
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Fever, pain
Swelling, erythemaAnemia, elevated ESRTreat with oral corticosteroids
Herpes Zoster Oticus
•J. Ramsay Hunt described in 1907
•Viral infection caused by varicella zoster
•Infection along one or more cranial nerve dermatomes (shingles)
•Ramsey Hunt syndrome: herpes zoster of the pinna with otalgia and facial paralysis
Herpes Zoster Oticus: Symptoms
•Early: burning pain in one ear, headache, malaise and fever
•Late (3 to 7 days):
vesicles, facial paralysis
Herpes Zoster Oticus: Treatment
•Corneal protection
•Oral steroid taper (10 to 14 days)•Antivirals
Erysipelas
•Acute superficial cellulitis•Group A, beta hemolytic streptococci
•Skin: bright red; well-demarcated, advancing margin
•Rapid treatment with oral or IV antibiotics if insufficient response
Perichondritis: Treatment
•Mild: debridement, topical & oral antibiotic•Advanced: hospitalization, IV antibiotics
•Chronic: surgical intervention with excision of necrotic tissue and skin coverage
Radiation-Induced Otitis Externa
•OE occurring after radiotherapy
•Often difficult to treat•Limited infection treated like COE
•Involvement of bone requires surgical
debridement and skin coverage
Conclusions
•Careful History
•Thorough physical exam
•Understanding of various disease processes common to this area
•Vigilant treatment and patience
