Two days later, he returned after experiencing a sudden onset of binocular diplopia and ptosis of the right eye. Partial ptosis was noted, with restricted adduction and elevation. Pupils were reactive and equal bilaterally. Hutchinson sign, which would indicate an impaired nasociliary nerve and increased risk for corneal and ocular sequelae,6 was absent. Relative afferent pupillary defect also was absent. All other CN functions were intact, with no systemic neurologic deficit. Contrast CT of the brain and orbit showed no radiologic evidence of meningitis, space-occupying lesion, or cerebral aneurysm.
Given the unremarkable imaging findings and lack of symptoms of meningism (eg, headache, vomiting, neck stiffness, or fever), we diagnosed right eye pupil-sparing partial TNP secondary to HZO. The patient continued taking oral acyclovir, which was tapered over 6 weeks. After 4 weeks of antiviral treatment, he recovered full extraocular movement and the ptosis subsided.
CASE 2
Posterior communicating artery aneurysm
A 71-year-old woman with hypercholesterolemia, hypertension, and ischemic heart disease presented to the ED with a 4-day history of headache, vomiting, and neck pain and a 2-day history of a drooping left eyelid. When asked if she had double vision, she said “No.” She had no other neurologic symptoms. Her blood pressure (BP) was 199/88 mm Hg. An initial plain CT of the brain ruled out ischemia, intracranial hemorrhage, and space-occupying lesion.
Once her BP was stabilized, she was referred to us for detailed eye assessment. Her best corrected visual acuity was 6/12 bilaterally. In contrast to her right eye pupil, which was 4 mm in diameter and reactive, her left eye pupil was 7 mm and poorly reactive to light. Optic nerve functions were preserved. There was complete ptosis of the left eye, with exotropia and total limitation of elevation, depression, and abduction (FIGURE 2). There was no proptosis; intraocular pressure was normal. Fundus examination of the left eye was unremarkable. All other CN and neurologic examinations were normal. We diagnosed left eye pupil-involving TNP.
Further assessment of the brain with magnetic resonance imaging (MRI) revealed a left posterior communicating artery aneurysm. We performed cerebral angiography (FIGURE 3) with coiling. Postoperatively, her ptosis resolved at 2 months but with residual left eye exotropia.
CASE 3
Viral infection
A 20-year-old male student presented to the ED for evaluation of acute-onset diplopia that was present upon awakening from sleep 4 days earlier. There was no ptosis or other neurologic symptoms. He had no history of trauma or viral illness. Examination revealed limited adduction, depression, levo-elevation, levo-depression, and dextro-depression in the right eye (FIGURE 4). Both pupils were reactive. There was no sign of aberrant third nerve regeneration. The optic nerve and other CN functions were intact. A systemic neurologic examination was unremarkable, and the fundus was normal, with no optic disc swelling. All blood work was negative for diabetes, hypercoagulability, and hyperlipidemia.
CT angiography (CTA) and MR angiography (MRA) did not reveal any vascular abnormalities such as intracranial aneurysms, arteriovenous malformations, or berry aneurysm. We treated the patient for right eye partial TNP secondary to presumed prior viral infection that led to an immune-mediated palsy of the third nerve. He was given a short course of low-dose oral prednisolone (30 mg/d for 5 days). He achieved full recovery of his ocular motility after 2 weeks.
Continue to: CASE 4