Transcript Fungal Sinusitis - AJNR Blog | American Journal of

Fungal Sinusitis: An Overview
Cade Martin, MD
Fungal Sinusitis
• 400,000 known fungal species or which 400
are human pathogens and 50 of which cause
systemic or CNS infection
• Clinical presentation, imaging features, and
treatment differ based on type of fungal
sinusitis
• Broadly categorized into invasive and
noninvasive
Fungal Sinusitis
• Invasive
– Presence of fungal hyphae within the mucosa,
submucosa, bone, or blood vessels of the
paranasal sinuses
• Noninvasive
– Absence of fungal hyphae within the mucosa
and other structures of the paranasal sinuses
Fungal Sinusitis - Classification
• Invasive
– Acute Invasive Fungal Sinusitis
– Chronic Invasive Fungal Sinusitis
– Chronic Granulomatous Invasive Fungal
Sinusitis
• Noninvasive
– Allergic Fungal Sinusitis
– Fungus Ball (fungus mycetoma)
Acute Invasive Fungal Sinusitis
• Most lethal form of fungal sinusitis – mortality 5080%
• Rare in immunocompetent patients
• Two clinical populations
– Poorly controlled Diabetics – ususally caused by fungi
of order Zymocycetes (Rhizopus, Rhizomucor, Absidia,
and Mucor)
– Immunocompromised with severe neutropenia
(chemotheraphy patients, BMT, organ transplants,
AIDS) – Aspergillus accounts for 80% of infection in
this group
Acute Invasive Fungal Sinusitis Clinical
• Necrotic nasal septum ulcer (eschar), sinusitis,
rapid orbital and intracranial spread resulting in
death
• Angioinvasion and hematogenous dissemination
common
• Present with fever, facial pain, nasal congestion,
epistaxis progressing to proptosis, visual
disturbance, headache, mental status changes,
seizures as spread occurs
• 73% of patients with intracranial spread die
Acute Invasive Fungal Sinusitis Imaging
• Noncontrast CT
– Severe unilateral nasal cavity soft tissue thickening is
most consistent (but nonspecific) early CT finding
– Hypoattenuating mucosal thickening within lumen of
paranasal sinus with rapid aggressive bone destruction
of sinus walls occurs as disease progresses
– Often unilateral involvement of ethmoids, sphenoids
– These Fungi can also spread along vessels with spread
beyond the sinus with intact bony walls
– Intracranial extension can result in cavernous sinus
thrombosis, carotid artery invasion, occlusion, or
pseudoaneurysm
Acute Invasive Fungal Sinusitis - CT
• Unilateral ethmoid involvement with bone
destruction, intraorbital spread and proptosis
Acute Invasive Fungal Sinusitis - MRI
Aspergillus involving the sphenoid sinus with invasion of the left
cavernous sinus, thrombosis, extension to the left sylvian fissure and
infratemporal fossa with cerebral infarctions.
Acute Invasive Fungal Sinusitis Imaging
• MRI – better for evaluating intracranial and
intraorbital extension
– Evaluate for inflammatory change in orbital fat
and extraocular muscles
– Obliteration of periantral fat is a subtle sign of
extension
– Leptomeningeal enhancement progressing to
cerebritis and abscess
Aspergillus in left maxillary sinus with extension anterior and
posterior to the retroantral space. There is diffuse involvement of
the muscles of mastication.
Acute Invasive Fungal Sinusitis Treatment
• Aggressive surgical debridement and
systemic antifungal therapy
• Reversal of underlying cause of
immunosuppression if possible
• Recovery from neutropenia is most
predictive of survival
• Intracranial spread is most predictive of
mortality
Chronic Invasive Fungal
Sinusitis
• Inhaled fungal organisms deposited in nasal
passageways and paranasal sinuses
• Progression over months to years with
fungal organisms invading mucosa,
submucosa, blood vessels, and bony walls
• Organisms – Mucor, Rhizopus, Aspergillus,
Bipolaris, and Candida
Chronic Invasive Fungal
Sinusitis – Clinical Features
•
•
•
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Usually immunocompetent
History of chronic rhinosinusitis
Usually persistent and recurrent disease
Maxillofacial soft tissue swelling, orbital
invasion with proptosis, cranial
neuropathies, decreased vision, can invade
cribiform plate causing headaches, seizures,
decreased mental status
Chronic Invasive Fungal
Sinusitis – Imaging
• Noncontrast CT – Hyperattenuating soft tissue
mass withing one or more of paranasal sinuses,
bone involvement often gives mottled appearance
with or without sclerosis
– May mimic malignancy with masslike appearance and
extension beyond sinus confines
• MRI – decreased signal on T1, markedly
decreased signal on T2 weighted images
Chronic Invasive Fungal Sinusitis
Chronic Invasive Fungal Sinusitis –
Treatment
• Surgical exenteneratin of affected tissues
and systemic antifungal
• Needs aggressive treatment
Chronic Granulomatous Invasive
Fungal Sinusitis
• AKA primary paranasal granuloma and
indolent fungal sinusitis
• Primarily found in Africa (Sudan) and
Southeast Asia, only few case reports in US
• Immunocompetent
• Caused by Aspergillus flavus
• Characterized by noncaseating granulomas
in the tissues
Chronic Granulomatous Invasive
Fungal Sinusitis
• Chronic indolent course similar to chronic
invasive fungal sinusitis
• Considered by some as same entity as
chronic invasive fungal sinusitis
• Imaging characertistics are similar to those
of chronic invasive fungal sinusitis
• Often resembles a mass/neoplasms
• Treatment is surgical debridement and
systemic antifungals
Allergic Fungal Sinusitis
• Most common form of fungal sinusitis
• Common in warm, humid climates of Southern US
• Hypersensitivity reaction to inhaled fungal
organisms resulting in chronic noninfectious
inflammatory reaction - IgE type I immediate
hypersensitivity and type III hypersensitivity are
involved
• Common organisms implicated – Bipolaris,
Curvularia, Alternaria, Aspergillus, and Fusarium
• “Allergic mucin” within affected sinus which is
inspissated mucous the consistency of peanut
butter with eosinophils on histology
Allergic Fungal Sinusitis Clinical
• Younger individuals, third decade,
immunocompetent
• Often associated history of atopy with
allergic rhinitis or asthma
• Chronic headaches, nasal congestion, and
chronic sinusitis for years
Allergic Fungal Sinusitis - Imaging
• Usually bilateral with multiple sinuses involved if
not pansinus involement
• Often has a nasal component
• Noncontrast CT – high attenuation allergic mucin
within lumen of sinuses – can mimic a mucocele
with expansion of the sinus
• MRI – variable T1 appearance, low T2 signal
(attributed to high concentration of iron,
magnesium, and manganese concentrated by
fungal organisms and also due to a high protein,
low free water content of allergic mucin
Allergic Fungal Sinusitis - Imaging
Allergic Fungal Sinusitis - Imaging
• Moderately high T1 signal, low T2 signal with
expanded sinus can be seen in allergic fungal
sinusitis, mucocele, or sinonasal polyposis
Allergic Fungal Sinusitis Treatment
• Surgical removal of allergic mucin with
restoration of normal sinus drainage is goal
• Longterm use of topical nasal steroids helps
suppress the immune response and
minimize recurrence
• Topical or systemic antifungals are not
indicated
Fungus Ball
• Older individuals, female>male
• Immunocompetent
• Asymptomatic or minimal symptoms with
chronic pressure or nasal discharge
• Cacosmia (perception of foul odor when no
such odor exists)
Fungus Ball
• Mass within the lumen of paranasal sinus and is
usually limited to one sinus
• Frontal sinus most common followed by sphenoid
sinus
• Noncontrast CT – hyperattenuating mass often
with punctate calcifications
• MRI – variable T1 and hypointense T2 due to
absence of free water, calcifications and
paramagnetic metals also generate decreased T2
signal – no central enhancement to differentiate
from neoplasm
Fungus Ball - CT
• High density material with thickened walls of the
maxillary sinus due to chronic inflammation
Fungus Ball Treatment
• Surgical Removal with restoration of
drainage of the sinus
• Antifungal medications usually unnecessary
• Recurrence is rare