Imaging of Noninvasive and Invasive Fungal Sinusitis
Allergic Fungal Sinusitis
Fungus Ball
Acute Invasive Fungal Sinusitis
Chronic Invasive Fungal Sinusitis
Granulamatous Invasive Fungal Sinusitis
Introduction
Summary
References

IMAGES 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20

Acute Invasive Fungal Sinusitis

Overview:
-"Acute invasive rhinocerebral zygomycosis (mucormycosis)" is typically found in poorly controlled diabetics. The causative organism is
usually Rhizopus. Mucor has been only rarely found to cause invasive disease. Therefore, this infection is more correctly termed
zygomycosis.
-" Fulminant invasive fungal sinusitis" is typically found in neutropenic patients
-Both of the above syndromes are essentially similar and are more appropriately and collectively termed "acute invasive fungal sinusitis".
-Inhaled fungal organisms are deposited in the nasal passageways and paranasal sinuses
-Fulminant progression over a few days to several weeks in which fungal organisms invade the mucosa, submucosa, blood vessels, and
bony walls of the paranasal sinuses
-Frequent angioinvasion and hematogenous dissemination
-Associated with a high rate of mortality especially if treatment is delayed
-Common causative fungi include Absidia, Aspergillus, Fusarium, Mucor, Pseudallescheria, Rhizomucor, and Rhizopus

Clinical Presentation:

-With rare exceptions, acute invasive fungal sinusitis is found only in immunocompromised individuals, such as those with AIDS,
leukemia, uncontrolled diabetes mellitus, and those receiving immunosuppressive therapy
-Symptoms include fever, facial pain or numbness, nasal congestion, serosanguinous nasal discharge, and epistaxis
-In cases of zygomycosis, the oral palate, nasal turbinates, and nasal septum may have a musty appearance or a black eschar and may be
anesthetic
-Symptoms also include proptosis, visual disturbances, headache, lethargy, mental status changes, seizures, neurologic deficits, coma,
and maxillofacial soft tissue swelling as intraorbital, intracranial, and maxillofacial extension is common

Imaging:

-Non-contrast CT scan demonstrates minimal circumferential mucosal thickening or complete opacification of the involved paranasal
sinus
-Variable T1 and T2 WI signal intensity of the mucous within the involved sinus
-Inflamed mucosal lining of the involved sinus demonstrates increased T2 WI signal intensity and contrast enhancement
-Predilection for unilateral involvement of the ethmoid and sphenoid sinuses
-Aggressive bone destruction of the sinus walls without bony expansion
-Paranasal sinus walls may remain intact with fungal dissemination along the perivascular channels of the penetrating blood vessels
-Invasion of adjacent structures such as the orbit, anterior cranial fossa, and maxillofacial soft tissues
-Obliteration of the periantral fat planes about the maxillary sinus is an indicator of invasive disease
-Associated findings include vascular invasion and thrombosis, meningitis, epidural abscess, cerebritis or cerebral abscess, cavernous
sinus involvement, mycotic aneurysm, osteomyelitis, intracranial hemorrhage, cerebral infarct, and orbital abscess
-Intracranial granulomas appear hypointense on T1 and T2 WI and show minimal enhancement with contrast

Treatment and Prognosis:

-Biopsy and aggressive surgical debridement of affected tissues
-Prompt systemic antifungal medication is needed
-Reversal of the source of immunocompromise
-Mortality is higher in those with underlying neutropenia and may be as high as 85%

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