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Invasive Aspergillus Masquerading as Chronic Otitis Externa:
A Case Report and Review of the Literature
1
MD ;
2
MD ;
2
FRCSC
Nipun Chhabra,
Philip E. Zapanta,
Nader Sadeghi, MD,
1University Hospitals Case Medical Center, Cleveland, OH 44106
2George Washington University Medical Center, Washington, DC 20037
ABSTRACT
INTRODUCTION
Objectives
In select hosts fungal species may
become invasive and opportunistic,
resulting in severe morbidity and
mortality. We report a rare case of
invasive Aspergillus, diagnosed on initial
presentation as chronic fungal otitis
externa.
Invasive mycotic infections of the head and
neck have been steadily increasing over the past
several decades. Otomycosis is the term generally
used to describe fungal infections of the ear.1
Diabetes and the increasing global incidence of
acquired immunodeficiency syndrome (AIDS) are
major contributors.
Methods
An elderly gentleman’s clinical course is
presented and discussed. We review
the pertinent etiology, clinical
manifestations, histopathology,
diagnosis, and treatment of this
aggressive mycosis and its associated
complications.
Fungal infection of the external auditory canal is
common and generally managed conservatively.
Malignant or necrotizing otitis externa is a rare,
potentially fatal entity involving the external auditory
canal and surrounding tissue, mastoid, or skull base.
This disease most commonly affects elderly males
with underlying diabetes mellitus, but has been
described
in
children,
immunocompromised
individuals, and very rarely in immunocompetent
adults.
Invasive fungal otitis externa mandates
aggressive treatment as it may result in cranial nerve
palsies,
perilymphatic
fistula,
hearing
loss,
osteomyelitis, great vessel thrombosis, or mortality.
Results
After invasive mycosis was suspected by
radiographic imaging, surgical
exploration and biopsy confirmed
Aspergillus species. The patient’s
treatment was modified to include
amphotericin B lipid complex and the
patient symptomatically improved,
eventually demonstrating clinical
resolution of further fungal disease.
Aspergillus is ubiquitous in nature and generally
does not cause symptoms in immunocompetent
individuals. Otologic and skull base Aspergillus
infections are extremely uncommon; with the first
case described only 25 years ago.2,3 We report on a
case of Aspergillus of the infratemporal fossa
masquerading as chronic otitis externa that was
ultimately recognized through surgical exploration
and successfully managed with aggressive antifungal
therapy, including intravenous amphotericin B.
Study Design
Single case report and review of the
literature.
Conclusions
The occurrence of invasive mycotic
infections of the head and neck has
been steadily increasing over the past
several decades. Aspergillus, a less
common but highly destructive species
in acute disease, employs a variety of
immunoevasive mechanisms to gain
advantage over its host. A high level of
clinical suspicion along with a prompt
multidisciplinary team approach can help
improve the outcome of afflicted patients.
A combination of medical therapy, early
and aggressive surgical intervention, and
an understanding of the underlying
immunologic competency of the patient
is the best regimen to achieve effective
treatment.
CONTACT
Nipun Chhabra, MD
Case Western Reserve University,
University Hospitals Case Medical Center
Cleveland, OH 44106
Email: [email protected]
Poster Design & Printing by Genigraphics® - 800.790.4001
CASE REPORT
A 70-year-old man with type II diabetes mellitus
presented with progressively worsening left sided
otalgia and bloody otorrhea. He had a known history
of fungal otitis externa, which had been managed
with local debridement and topic antifungals.
Examination demonstrated tenderness over the left
temporomandibular joint (TMJ) and a grossly
edematous left external auditory canal with necrotic
and squamous debris. Temporal bone computed
tomography (CT) scans revealed left-sided
mastoiditis and concern for bony dehiscence in the
left TMJ. Gadolinium enhanced magnetic resonance
imaging (MRI) showed enhancement and thickening
of the external auditory canal, osteomyelitis of the left
condylar head, and extension of disease to the left
pterygomasseteric space (Figures 1 & 2). Empiric
intravenous treatment was commenced and a CT
guided needle aspiration of the TMJ space was
performed but did not reveal any pathogens.
Subsequently, open biopsies were obtained from the
left parotid, mandibular condyle, external auditory
canal, and preauricular regions.
Final biopsy
specimens did not reveal any organisms but the ear
canal
swab
grew
a
methicillin-resistant
Staphylococcus aureus.
He was subsequently
discharged on long term antibiotics after showing
improvement.
One month after discharge, the patient presented
with increasing left sided facial pain and severe otalgia.
Repeat imaging was obtained, including MRI, CT, and
gallium scans, and persistent infection in the auricular
region and infratemporal fossa was noted. The patient
underwent extensive surgical exploration via a combined
preauricular and infratemporal fossa approach. Multiple
biopsies of the left tympanic bone and mandibular condyle
were taken, in addition to exploration of the left middle ear,
TMJ, and jugular vein at the skull base to determine
patency.
The deep tissue biopsies of the left tympanic bone
and TMJ later yielded a focal Aspergillus organism
(Figure 3). Thereafter the patient’s therapeutic regimen
was modified to include intravenous amphotericin B and
later oral voriconazole. Clinical symptoms and exam
findings rapidly improved and in follow-up the patient
demonstrated complete resolution of disease.
DISCUSSION
Otomycoses are almost always limited to the external
auditory canal. In rare instances, the organisms may
become invasive. Aspergillus niger is most commonly
involved in uncomplicated otitis externa while malignant
disease is often due to Aspergillus fumigatus.6 Invasive
Aspergillus can present in a similar manner as other
organisms, but has a worse overall prognosis.2,4
Aspergillus was first described in 1729 by the Italian
botanist Micheli.7 It is a filamentous and ubiquitous
saprophyte.
Invasive disease is most commonly
associated with immunocompromised patients and
disorders.5 Oxygen tension is low in diseased tissue and
Aspergillus utilizes gliotoxin and proteases to impair host
defenses.5,9 The degree of host immunosuppresion may
determine the speed and extent of infection.10
Diagnosis is augmented by radiologic imaging.
MRI is best for soft tissue delineation and may reveal
a hyperintense signal within fatty marrow spaces or
along the dura. CT detects bone erosion, abscess
formation, and mastoid involvement and predicts
chronicity and recurrence of disease. 1 Nuclear
imaging including gallium and technetium scan has
been the mainstay for diagnosis and follow-up of
malignant otitis externa of any etiology.1,2
Aggressive tissue biopsy is the definitive
method for diagnosis. Aspergillus is best identified
using
potassium
hydroxide
staining
which
demonstrates septate hyphae with 45-degree
branching.
Mortality from invasive otitic Aspergillus is
approximately 20%, thus necessitating early
recognition and treatment.6
Aggressive, early
surgical debridement is a cornerstone, along with
parenteral antifungal therapy and control of the
underlying immunologic condition.
Hyperbaric
oxygen has shown promise in recent select cases.4,5
Available systemic antifungals are abundant, and
newer agents such as voriconazole have replaced
older, more toxic drugs. Within the last decade,
national infectious disease recommendations have
been published for invasive fungal infection, thus a
multidisciplinary team approach is recommended.11
CONCLUSIONS
Aspergillus species is an uncommon cause of
malignant otitis externa, and occurs primarily in
immunocompromised patients. The organism is
usually indolent, but invasive disease can be life
threatening.
Tissue biopsy is necessary for diagnosis, and
the best management consists of aggressive surgical
debridement, systemic antifungals, and treatment of
the underlying immunologic deficiency. A high level
of clinical suspicion along with a multidisciplinary
team approach can help improve the outcome of
patients afflicted with invasive otitic Aspergillus, and
survival rates can approach 85%.
REFERENCES
Figure 1: Coronal T1-weighted post
gadolinium MRI showing involvement
of left infratemporal fossa and pterygoid
musculature
Figure 2: Axial T1-weighted post
gadolinium MRI with diffuse
enhancement and thickening of the left
external auditory canal and around
condylar process
Figure 3: High-powered, methenamine-silver nitrate
stain demonstrating focal Aspergillus
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