Microsporidian sinusitis in patients with the acquired immunodeficiency syndrome.

Sinusitis in patients with human immunodeficiency virus (HIV) infection usually arises from the same organisms that are infective in the nonimmunosuppressed population. The authors of this article report that optimal antimicrobial treatment and functional endoscopic sinus surgery failed to eradicate sinonasal disease in three of five patients with acquired immunodeficiency syndrome (AIDS) and refractory sinusitis. The sinonasal disease was manifested by congested, edematous, and polypoid mucosa, often with a superimposed bacterial infection from ostial obstruction. After tissue was sent for electron microscopy (EM), the patients were eventually diagnosed with microsporidiosis of the sinonasal cavities. Microsporidia are obligate intracellular protozoans that have been seen in AIDS patients with diarrhea. These protozoans have only recently been identified in sinonasal tissue. Microsporidia are often missed on routine histopathology. The authors present case reports on their five AIDS patients with refractory sinusitis. The management of refractory sinusitis in the HIV-infected population, including mandatory EM of sinonasal tissue, is also discussed.