Fungal Sinusitis: Current Trends in Diagnosis and Treatment

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Acute or Fulminant Fungal Sinusitis

Acute or fulminant fungal sinusitis usually affects diabetics and immunocompromised hosts. Patients at highest risk for acute invasive fungal sinusitis are poorly controlled diabetics and those with conditions that predispose to metabolic acidosis such as chronic renal failure or diarrhea. Immunosuppressive states secondary to chemotherapy, hematologic disorders, transplantation, and AIDS also place their hosts at risk for opportunistic infection. Blitzer and colleagues.[1] studied 179 patients with acute invasive fungal sinusitis and found the prevalence of diabetes to be 70% (n=126); only 4% (n=8) had no identifiable risk factors. The other patients (26%) had underlying diseases such as leukemia, renal disease, infant diarrhea, immunosuppresion after transplant, and pancreatitis.

The offending fungi originate from the classes zygomycetes (Mucor spp) and Ascomycetes (Aspergillus spp). The species of Aspergillus, such as fumigatus, causes aspergillosis, and species of the various genera (such as Mucor and Absidia and Rhizopus) of the order Mucorales cause mucormycosis. Within the Mucoraceae family are the genera Rhizopus, Mucor, and Absidia with species of Rhizopus responsible for the more serious infections.[2]Aspergillus species include A fumigatus, A flavus, A niger, and A oryzae.[3] These saprophytic fungi reproduce and grow in soil, decaying food, grain, and plants. They thrive in any environment with an acidic pH and an abundance of glucose.[1] The disease process is usually aggressive and necessitates prompt diagnosis and treatment.

After becoming airborne, Mucor spores settle onto the mucosa of a susceptible host. They penetrate into the tissue, allowing angioinvasion to occur. Mucor has a predilection for the internal elastic lamina of the arteries. The invasion produces thrombosis, with secondary ischemic infarction and hemorrhagic necrosis. The fungus thrives in this environment and spreads along injured vessels. Angioinvasion may also occur with Aspergillus, resulting in a mycotic aneurysm or thrombosis formation. Histologic examination reveals necrosis of the tissue, neutrophilic infiltration, and hyphae. The Mucor hyphae are nonseptate with branching near 90 degrees in contrast to Aspergillus hyphae that are septate with dichotomous branching.[1,4]

Studying the presentation of this mucomycosis, Blitzer and Lawson[5] found that the most common clinical signs included cranial nerve deficit, proptosis, facial swelling, palatal ulcer, coma, and stupor. Physical examination of the nasal cavity reveals pale to red to black necrotic areas involving the turbinates or septum. If acute or fulminant fungal sinusitis suspected, prompt biopsy should be performed and sent to the pathologist for examination. Communication of the presumptive diagnosis helps to ensure proper staining and interpretation.

Radiographic evaluation with CT and MRI are useful in assessing the extent of disease. CT better defines soft tissue invasion, necrosis, and early bone erosion.[6,7] MRI best evaluates early changes in major vessels, including carotid artery thrombosis, cavernous sinus thrombosis, and intracranial extension.[8,9,10] Cavernous sinus thrombosis is well delineated by both MRI and CT.[6,7,8,9,10]

In addition to the prompt and accurate diagnosis, the underlying medical problem needs to be addressed because it confers important prognostic implications. Diabetic patients have an overall survival rate of 60%, compared with 70% in patients with no underlying disease and 20% in patients with other systemic disorders, demonstrating the morbidity and mortality that can be associated with the fungal infectionthe underlying disease[3,4,11,12,13]

Once diagnosed, surgical intervention is the treatment of choice. All devitalized tissues need debridement to prevent the fungus from proliferating in the necrotic tissue. Re-establishing the vitalized and bleeding tissue will allow pharmacologic agents to reach the necessary areas.[5] There is controversy over whether orbital exenteration should be performed, which is cosmetically deforming, improves the survival rate. Blitzer and colleagues[1,4] and Ochi and colleagues[14] demonstrated a 78% survival rate with radical debridement versus 57.5% with only medical therapy. Amphotericin B is the drug of choice, increasing the survival rate in diabetics from 37% to 79%. In those patients without diabetes, survival was also improved; 0% to 47%. The combination of surgery and amphotericin B resulted in an overall survival rate of 81%.[1,4,8,15]

A 14-year-old, insulin-dependent diabetic presented with an upper respiratory infection. Laboratory evaluation revealed a blood glucose greater than 600. Within 24 hours the patient's nose had become dark and necrotic (Figure 1). She underwent debridement of the nose and surrounding areas until viable tissue was encountered (Figure 2). Her diabetes was brought under control medically. Her final appearance without prosthesis is illustrated in Figure 3.

Figure 1.

Photo of patient 24 hours after presentation. Crusting and dusky skin of the philthrum, dorsum, left ala, and tip of the nose are evident.

Figure 2.

Appearance after the debridement of all nonviable tissues. The external nose, anterior septum, philthrum, medial portions and the left and right cheek, left and right medial canthal regions, and glabella required debridement.

Figure 3.

Facial appearance without a prosthesis several weeks after partial closure and healing by secondary intention.

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