necrotizing otitis externa
TRANSCRIPT
NECROTIZING OTITIS EXTERNA
Prof. Céline PULCINI
Infectious Diseases specialist (Nancy, France)
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Background
• Necrotizing otitis externa (NOE) = Malignant
otitis externa (or external otitis) = Invasive
otitis externa
• Rare but severe infectious disease
• Around 300 articles available on Pubmed,
mostly published in ENT journals, only small
case seriesESCMID eLibrary
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Why did I get interested in NOE?
+
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Main references
• Necrotizing otitis externa: a systematic review. Mahdyoun P, Pulcini C, Gahide
I, Raffaelli C, Savoldelli C, Castillo L, Guevara N. Otol Neurotol.
2013;34(4):620-9
• Antibiotic therapy in necrotising external otitis: case series of 32 patients and
review of the literature. Pulcini C, Mahdyoun P, Cua E, Gahide I, Castillo L,
Guevara N. Eur J Clin Microbiol Infect Dis. 2012;31(12):3287-94
• Aspergillus spp. invasive external otitis: favourable outcome with a medical
approach. Marchionni E, Parize P, Lefevre A, Vironneau P, Bougnoux ME,
Poiree S, Coignard-Biehler H, DeWolf SE, Amazzough K, Barchiesi F, Jullien V,
Alanio A, Garcia-Hermoso D, Wassef M, Kania R, Lortholary O, Lanternier F.
Clin Microbiol Infect. 2016. pii: S1198-743X(16)00021-5ESCMID eLibrary
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Introduction
• First described in 1959
• First case series published by Chandler in 1968
• NOE = osteomyelitis of the skull base
– typically due to Pseudomonas aeruginosa
– following a skin infection in the external auditory canal
(= otitis externa)ESCMID eLibrary
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Anterior
extension
Inferior
extension
Posterior
extension
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Pathogenesis
• Contact with water, hot and humid months
• + Trauma of the skin of the EAC
• Leading to otitis externa
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Clinical diagnosis
• Otalgia (97%) and otorrhea (79%) = most frequent clinical signs, but
non specific
• More specific signs :
– (i) granulation tissue or polyp of the EAC (80%), caused by the underlying osteitis
– (ii) cranial nerve (CN) palsies (46%)
• + absence of response to topical treatment of the initial otitis externa
Systematic review
Mean age 62 years old 992 cases
Men 69% 974 cases
Diabetic 81% 1234 cases
Facial palsy 31% 985 casesESCMID eLibrary
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Microbiology
• Rarely:
– Other bacteria
– Aspergillus
– Candida
– Nontuberculous mycobacteria ?
Systematic review
Pseudomonas
aeruginosa76% 1185 cases
Negative cultures 16% 447 cases
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Microbiological samples
• Swab or pus aspiration of EAC drainage
• Biopsy of polyp or granulation tissue
• In appropriate media
• After stopping any topical and/or systemic antibiotic
therapy
• If negative: minimally invasive surgery in order to obtain
specimens for histopathological and microbiological
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Surgical samples
• Multiple surgical bone and ear tissue biopsies
to be sent to:
– Histology
– Bacteriology (including anaerobes, panbacterial
16sRNA polymerase chain reaction)
– Mycobacteria
– Mycology (culture + PCR)ESCMID eLibrary
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Imaging: CT scan– 1st intention exam (thin section CT)
– Bone erosion
– Can be normal if done at an early stage
First CT 2 months later
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Imaging: scintigraphy
• Tc99 scintigraphy lacks spatial
resolution, but can detect osteitis at
an early stage, before bone erosion
becomes visible on CT images
• Ga67 scintigraphy is suggested by some
authors for diagnosis, but with a very low
level of evidence
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Imaging: MRI– Better sensitivity for soft tissues
– May be useful at an early stage
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Diagnostic work-up
• The clinical suspicion of NOE must be confirmed:
- by positive microbiological samples (after stopping any topical
and/or systemic antibiotics)
- and appropriate imaging (computed tomography of the petrous
temporal bone, ± 99mTc scintigraphy or MRI if early stage + normal CT-scan)
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Antibiotic therapy• Comparable to other bone infections
• 6 weeks of culture-directed systemic antibiotics
• With good bone diffusion, optimized PK/PD
• Start with a combination for at least 3 weeks
• Total duration: 6 weeks
• Antibiotic therapy duration might be reduced to 4 weeks in some
cases, but shorter durations appear to predispose to relapse.
• The optimal duration of combination therapy remains unknown.ESCMID eLibrary
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Antibiotic therapy:
monotherapy vs combination therapy
• Low level of evidence
• Systematic literature review (Pulcini et al., EJCMID
2012): 115/119 (97 %) patients had a favorable
outcome with initial combination therapy versus 242/293
(83 %) with single therapy (P<.0.001).ESCMID eLibrary
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Antibiotic therapy:
example of guidelines
• 80-kg adult male patient, no allergy, normal renal function
• Ceftazidime 2 g loading dose then 6 g/day continuous infusion
(adapted to TDM) 3 weeks (OPAT)
• + Ciprofloxacin 1 gramme bd orally 6 weeks (replaced by IV
fosfomycin if contra-indication or resistance)
• 100% cure rate with that regimen in our experienceESCMID eLibrary
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Antifungal therapy
• Voriconazole for Aspergillus NOE
• Several months of treatment
• Beta-D-glucan levels may be helpful in the diagnosis
and follow-up
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Adjuvant treatments– Surgery
• No indication for curative therapy
• Can be needed if superficial samples are negative, to send bone and tissue samples for
microbiological and histological investigations
– Hyperbaric oxygen
• No indication (Phillips, J.S. and S.E. Jones, Hyperbaric oxygen as an adjuvant treatment for malignant otitis externa.
Cochrane Database Syst Rev, 2005(2): p. CD004617)
– Cranial nerve palsies, comorbidities and pain management
– No need for topical antibioticsESCMID eLibrary
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OutcomeP
reva
len
ce
of fa
vo
ura
ble
ou
tco
me
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Follow-up
• Follow up criteria– Need for a long-term follow-up, but there is no agreement on
which criteria should be used
– Patient’s compliance to antibiotic therapy is critical
– Relapse rate around 10% in the literature
– Clinical examination: always
– Imaging ?
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Multidisciplinary management
• Six weeks of antibiotic therapy is sufficient in NOE
• Collaboration between ID and ENT specialists
• Long-term follow up, based mostly on clinical examination
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Prevention
At-risk patients should avoid humidity in the EAC, as
well as iatrogenic or self-inflicted EAC trauma.
The prevention of “diabetic ear” complications should
also be explained to patients and physicians, as it is
the case for “diabetic foot”.
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Perspectives
• Need for a standardized management of NOE
• And for additional large prospective multicenter
clinical studies
• Infection specialists should be part of it !ESCMID eLibrary
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