Lyme-associated orbital inflammation presenting as painless subacute unilateral ptosis.

A 90-year-old woman presented with subacute painless left ptosis. Examination of the left eye revealed ptosis with loss of the superior eyelid sulcus, 2 mm of proptosis, mild tenderness with retropulsion, and optic disc edema. Levator function and extraocular movements were normal, and there was no relative afferent pupillary defect. MRI demonstrated thickening of the extraocular muscles in the left orbit with lacrimal gland enlargement and mild enhancement of the optic nerve sheath. Serology revealed a positive enzyme-linked immunosorbent assay for Lyme antibodies and a positive Western blot of Lyme IgG titer. The patient recalled a tick bite 6 months earlier, at which time Lyme serologies were negative. After 3 weeks of intravenous ceftriaxone, she had a significant improvement and a full recovery by 3 months. Lyme disease should be included in the differential diagnosis of orbital inflammation, especially in Lyme-endemic areas.