NOV 22, 2011
The authors describe a novel case of Lyme-associated orbital inflammatory disease presenting as painless unilateral ptosis. The patient, a 90-year-old woman from a Lyme-endemic area, reported a tick bite six months earlier without erythema migrans and was treated presumptively with oral doxycycline even though her Lyme titers at that time were negative. Serology later revealed a positive enzyme-linked immunosorbent assay for Lyme antibodies and a positive Western blot of Lyme IgG titer. These findings suggest that the list of known presenting symptoms for Lyme-associated orbital inflammation should be expanded to include ptosis, and Lyme disease should be included in the differential diagnosis of orbital inflammation, especially in Lyme-endemic areas.
The authors report in this article, published electronically in September in the Journal of Neuro-Ophthalmology, that the patient presented with unilateral subacute left eyelid ptosis (margin reflex distance1.5 mm OD versus 2 mm OS) and 2 mm of relative left proptosis that had developed over one month. She had associated unintentional weight loss and malaise. Visual acuity was 20/25 OD and 20/50 OS.
Examination did not show an afferent pupil defect, and both eye movements and confrontation visual fields were full. The left optic nerve had mild edema and peripapillary hemorrhages. There was no resistance but some tenderness to retropulsion. MRI showed diffuse enlargement of the extraocular muscles and lacrimal gland, as well as enhancement of the optic nerve sheath consistent with optic perineuritis. The authors note that Lyme seroconversion can take six weeks from infection, which may explain the patient's initial negative Lyme titer and subsequent seroconversion.
The patient received a three-week course of 1,500 mg of intravenous ceftriaxone daily since oral doxycycline had not been effective. Visual acuity improved to 20/25 OS in three weeks; the ptosis and optic disc edema resolved in three months.
The authors say that their patient's presentation with the primary complaint of unilateral painless ptosis without diplopia is unusual since the most common presentation of orbital myositis is acute and unilateral, with symptoms of orbital and periorbital pain worsening with ocular movement (85 to 100 percent of cases), diplopia (50 to 100 percent of cases), mild proptosis of 1 to 2 mm (30 to 56 percent of cases), swollen eyelids and conjunctival hyperemia. The diffuse thickening of extraocular muscles seen on MRI has been previously reported in other orbital Lyme myositis cases.
They say that although 2 g of intravenous ceftriaxone daily or 20 to 24 million units of penicillin G daily are typically recommended as first-line agents for ophthalmic or neurologic disease, there are no clear recommendations for treating orbital disease without ocular or neurologic involvement. However, successful treatment of Lyme orbital inflammation with either three to four weeks of oral doxycycline or two to three weeks of intravenous ceftriaxone has been reported.