Fungal Sinusits

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.
  • TreatmentIncludes 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.
Don’t Forget to Solve all the previous Year Question asked on Fungal Sinusits

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