Scedosporium apiospermum of the Orbit

Scedosporium apiospermum is an emerging fungal pathogen commonly found in soil (even in hospital potted plants¹) and polluted water. Ocular infection can occur including keratitis, conjunctival mycetome, endophthalmitis, and panophthalmitis. Reports of orbital involvement have been rare. We describe a 68-year-old man with leukemia who developed an orbital subperiosteal abcess from extension of contiguous fungal pansinusitis. We also review the role of pharmacotherapeutics in the management of this disease. Remarkably, this patient defervesced on antifungal therapy without aggressive surgical debridement.

A 68-year-old man with an 8-month history of acute lymphotogenous leukemia was seen in consultation for the hematology service. He complained of a red, protruding left eye and progressive diplopia over 3 days. He had been admitted to the hospital with neutropenic fevers 5 days earlier.

He had left periorbital edema and erythema (greatest inferomedially). Palpation of the affected area revealed no crepitus or bony abnormality. Sensory divisions of the trigeminal nerve were intact. The left eye was displaced forward 2 mm and laterally 2 mm. Best-corrected visual acuity was 20/20 OD and 20/25 OS. Pupillary responses were brisk with no relative afferent pupillary defect. Slitlamp examination showed no other abnormalities. Intraocular pressures were normal. Left eye abduction was notably diminished and there was a large angle esotropia. Retinal evaluation showed no abnormalities.

White blood cell count was 0.5 ×10⁹/L, demonstrating profound neutropenia. Computed tomographic scan (Figure 1) revealed a pansinusitis with a soft tissue density extending into the left inferomedial aspect of the orbit. Needle drainage of the left aspect of the maxillary sinus produced 30 mL of thick, yellow fluid. Initial smears demonstrated septated hyphae and were negative for bacteria.

Amphotericin B (1 mg/kg per day) was immediately started and itraconazole (400 mg/d) was added the next day. The fungus was identified as S apiospermum (Figure 2) and the infectious disease consultant recommended aggressive treatment due to the relative in vitro insensitivity to antifungal therapy. Surgical debridement of the sinuses and orbit was recommended; however, the patient declined this procedure. By day 2 of medical therapy, the patient's fever cleared and the edema and diplopia resolved. On the seventh day of medical treatment, there were no ocular signs or symptoms. The patient was discharged from the hospital on a regimen of identical doses of amphotericin B and itraconazole. He had no orbital recurrences and died 3 months later from complications of his leukemia.

Scedosporium apiospermum is an opportunistic fungus commonly found in soil and decaying vegetation. In 1944, Emmons demonstrated that S apiospermum is the asexual form of Pseudallescheria boydii. Prior to 1944, P boydii was known as Allescheria boydii.² This organism can, in cases of penetrating injury, infect healthy individuals. Here, it produces an indurated lesion at the site of the injury.³ In immunocompromised patients, aggressive spread is common. Systemic sites of infectious mycoses in the immunosuppressed include the lungs, joints, central nervous system, sinuses, and ears.²

Orbital involvement of this organism has rarely been reported. In 1977, Gluckman et al⁴ reported orbital extension of pansinusitis of S apiospermum in a diabetic host. The patient had both liver and renal failure. He was treated with surgical drainage and systemic amphotericin B but died 3 months later from unrelated complications. In 1984, Anderson et al⁵ described the successful treatment of a 4-year-old boy who had suffered a penetrating orbital injury with orbitocranial involvement of the infection. His therapy included multiple surgical interventions and intravenous amphotercin B and miconazole.

In cases of localized disease, it seems as if local debridement of as much of the fungus as possible, combined with systemic antifungal medication, provides the best chance of cure.^3,5 This organism is known to have relative in vitro insensitivity to amphotercin B; however, recent reports have shown good clinical responses.³ Both itraconazole and miconazole (ie, imidazoles) have shown greater effectivity in vitro and may be used as monotherapy.^3,6 Combined treatment with amphotercin B and an imidazole seems reasonable.

In our patient, needle drainage of the involved maxillary sinus performed for diagnostic purposes also provided some therapeutic decompression. This, combined with amphotericin B and itraconazole, resolved the signs and symptoms of orbital infection. Surgical debridement may still be the treatment of choice in this disease; however, antifungal therapy alone may be reasonable in patients unwilling or unable to undergo aggressive surgery. Ideal dosage and duration of treatment are unknown, although this patient's clinical course may provide helpful information.

Corresponding author: Steven E. Katz, MD, William H. Havener Eye Center, University Hospitals Clinic, 5717 456 W 10th Ave, Columbus, OH 43210.