Fungal Sinusitis: An Overview

1
Fungal Sinusitis An Overview

• Cade Martin, MD

2
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

3
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

4
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)

5
Acute Invasive Fungal Sinusitis

• Most lethal form of fungal sinusitis mortality
  50-80
• 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

6
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

7
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

8
Acute Invasive Fungal Sinusitis - CT

• Unilateral ethmoid involvement with bone
  destruction, intraorbital spread and proptosis

9
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.
10
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

11
Aspergillus in left maxillary sinus with
extension anterior and posterior to the
retroantral space. There is diffuse involvement
of the muscles of mastication.
12
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

13
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

14
Chronic Invasive Fungal Sinusitis Clinical
Features

• 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

15
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

16
Chronic Invasive Fungal Sinusitis
17
Chronic Invasive Fungal Sinusitis Treatment

• Surgical exenteneratin of affected tissues and
  systemic antifungal
• Needs aggressive treatment

18
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

19
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

20
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

21
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

22
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

23
Allergic Fungal Sinusitis - Imaging
24
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

25
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

26
Fungus Ball

• Older individuals, femalegtmale
• Immunocompetent
• Asymptomatic or minimal symptoms with chronic
  pressure or nasal discharge
• Cacosmia (perception of foul odor when no such
  odor exists)

27
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

28
Fungus Ball - CT

• High density material with thickened walls of the
  maxillary sinus due to chronic inflammation

29
Fungus Ball Treatment

• Surgical Removal with restoration of drainage of
  the sinus
• Antifungal medications usually unnecessary
• Recurrence is rare