Unilateral Blastomyces dermatitidis optic neuropathy case report and systematic literature review.

OBJECTIVE

To describe the clinical and histopathologic findings of a unique case of isolated optic nerve Blastomyces dermatitidis infection and to summarize the ophthalmic blastomycosis literature.

DESIGN

Case report and systematic literature review.

METHODS

A 70-year-old healthy man experienced impaired vision in his left eye. Magnetic resonance imaging (MRI) showed an enhancing process of the left optic nerve sheath. Although vision initially improved with oral dexamethasone, visual acuity subsequently decreased from 20/25 to no light perception over 8 weeks. An optic nerve biopsy revealed blastomycosis. Because ophthalmic blastomycosis infections are unusual, the Cochrane Library, PubMed, OVID, and UpToDate databases were searched using the term blastomycosis with the limits English and humans. Articles that predated the databases were gathered from current references.

MAIN OUTCOME MEASURES

Visual acuity of the left eye and MRI of the orbits and brain.

RESULTS

Histopathologic examination of the nerve specimen showed B. dermatitidis infection. Needle biopsy and culture results of a suspicious lung scar were positive for Blastomyces. The patient was treated with intravenous amphotericin B followed by oral itraconazole for 6 months. The left eye remained blind 23 months after the biopsy. Approximately 40 articles describing ophthalmic infection were found in the literature search.

CONCLUSIONS

Ophthalmic blastomycosis infections can cause rapid, complete vision loss. Prompt treatment is required, but infections are uncommon and usually are misdiagnosed, often because of lack of biopsy results. Tissue must be biopsied, cultured, or both for a definitive diagnosis. Because virtually all blastomycosis cases begin in the lungs, a chest radiograph or computed tomographic scan should be obtained. Any questionable lung lesion should be biopsied to corroborate possible ophthalmic disease.