Fungal Sinusits

FUNGAL SINUSITIS
NON INVASIVE FUNGAL SINUSITIS
Two forms are described in this category: Allergic Fungal Sinusitis and Sinus Mycetoma/ball.
ALLERGIC FUNGAL SINUSITIS
  • A combination of type 1 and 3 hypersensitivity reaction is thought to be involved in the pathogenesis of Allergic fungal sinusitis. It is thought to involve direct stimulation of eosinophils by a subset of helper T cells (TH2) primed by fungal antigens.
  • It results in vigorous inflammation and polyp formation.
  • Causative organisms includes usually those of the Dematiaceae family, but Aspergillus species are also seen.
  • Patients usually presents with features of chronic sinusitis.
  • The diagnostic criteria for allergic fungal sinusitis (AFS) are the presence of characteristic allergic mucin, type I hypersensitivity (eosinophilic-lymphocytic inflammation), absence of fungal invasion, immuno-compromised individuals and radiological confirmation (areas of high attenuation on CT scan).
  • Patients are treated with systemic steroids, surgery, and nasal irrigations.
  • Topical Steroids are indicated post-surgery.
SINUS MYCETOMA/BALL
  • This condition is usually unilateral and involves the maxillary sinus.
  • Mucopurulent, cheesy, or claylike material is present at the time of surgery.
  • Patients with sinusitis mycetoma are immunocompetent.
  • Allergic conditions and fungus-specific IgE are less common.
INVASIVE FUNGAL SINUSITIS
Invasive fungal sinusitis includes the acute fulminant type, which has a high mortality rate if not recognized early and treated aggressively, and the chronic and granulomatous type
ACUTE INVASIVE FUNGAL SINUSITIS-MUCORMYCOSIS
Caused by - rhizopus, rhizomucor, cunninghamella.
The higher prevalence of mucormycosis in India turned out to be statistically significant in comparison with all other countries
  • Predisposing factors:
  • Organ transplant recipients
  • Long term desferroxamine therapy
  • Immunosuppression due to steroids or cytotoxic drugs
  • Hematological malignancy
  • Diabetis Mellitus
  • Chronic renal failure
Five forms of mucormycosis are:
  • Rhinocerebral (most common site)
  • Pulmonary mucormycosis (2nd most common)
  • Cutaneous
  • Gastrointestinal
  • Disseminated
  • Miscellaneous
Clinical Presentation
  • Intitially, the disease runs a subtle course with only fever and rhinorrhea. Later on, it invades the orbit and intracranial cavity with rapid loss of vision, meningitis, 
  • cavernous sinus thrombosis and multiple cranial nerve palsies.
  • It has marked predilection for vascular invasion leading to widespread thrombosis, tissue necrosis, and gangrene.
  • Characteristic nasal finding is a dark necrotic turbinate surrounded by pale mucosa blackish discharge and crusts.
  • M/C site is middle turbinate followed by middle meatus and septum.
  • Investigation of choice is MRI, while biopsy is confirmatory.
Diagnosis: Biopsy with histopathologic examination is the most sensitive and specific modality for definitive diagnosis. Biopsy shows wide, thick walled, ribbon like, aseptate hyphal elements that branch at acute angles.
Histologic examination of affected tissue reveals either infarction, with invasion of blood vessels by many fungal hyphae, or acute necrosis, with limited inflammation and hyphae.
Treatment: Includes IV amphotericin-B, heparin, hyperbaric oxygen, and surgical debridement.
CHRONIC INVASIVE FUNGAL SINUSITIS
  • It is a slowly progressive fungal infection with a low-grade invasive process and usually occurs in patients with diabetes.
  • Orbital apex syndrome, which is characterized by a decrease in vision and ocular immobility due to a mass in the superior portion of the orbit, is usually associated with this condition.
  • Aspergillus fumigatus is the only fungus associated with chronic invasive fungal sinusitis.
  • On microscopy,shows hyaline, narrow, septate and irregular branching hyphae with invasion of the blood vessels ..
GRANULOMATOUS INVASIVE FUNGAL SINUSITIS
  • This condition has been reported almost exclusively in immunocompetent individuals from North Africa.
  • Generally, proptosis is associated with granulomatous invasive fungal sinusitis.
  • Aspergillus flavus exclusively has been associated with granulomatous invasive fungal sinusitis.
Exam Question
  • The diagnostic criteria for allergic fungal sinusitis (AFS) are the presence of characteristic allergic mucin, type I hypersensitivity (eosinophilic-lymphocytic inflammation), absence of fungal invasion, immuno-compromised individuals and radiological confirmation (areas of high attenuation on CT scan).
  • Type 1 and Type 3 Allergic reaction is seen in patients with Allergic fungal sinusitis.
  • Causative organism in a diabetic with orbital cellulitis and maxillary sinusitis showing hyaline, narrow, septate and irregular branching hyphae with invasion of the blood vessels on microscopy would be Aspergillus.
  • Mucormycosis has a predilection for vascular invasion.
  • Orbital mucormycosis may occur as a complication of Diabetic Ketoacidosis.
  • Amphoterecin B IV is used for invasive fungal sinusitis.

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