Clinical Reasoning: Woman With Acute Bilateral Ophthalmoplegia

Discussion

GCA, also referred to as temporal arteritis, is a systemic vasculitis affecting large and medium sized arteries, with predilection for the cranial branches of carotid arteries. Based on the American College of Rheumatology 1990 criteria, GCA is diagnosed in patients who have 3 or more of the following: age ≥50 years, new onset of localized headache, temporal artery tenderness or decreased temporal artery pulse, elevated ESR ≥50 mm/h, and artery biopsy showing necrotizing arteritis, characterized by a predominance of mononuclear cell infiltrates or granulomatous process with multinuclear giant cells.¹ Our patient met 5 of 5 for these criteria, confirming the diagnosis of GCA.

Various neuro-ophthalmologic complications of GCA have been recognized. Arteritic anterior ischemic optic neuropathy is the most common ocular manifestation resulting in monocular vision loss, although central, branch, and cilio-retinal artery occlusions have also been described. In addition, transient ischemic phenomena, pupillary autonomic dysfunction, postchiasmal field defects and cortical blindness from occipital lobe infarction, visual hallucinations, and ophthalmoparesis have been reported.^2,3 Concomitant optic nerve head and retinal ischemia in an elderly patient, as seen in our case, is very specific to GCA.³ In a 2018 review article describing visual complications of GCA, 1%–19% of cases presented with diplopia and ophthalmoplegia.³ Since then, there have been a handful of other case reports of bilateral ophthalmoplegia related to GCA.^4,-,8 Only 1 of the 5 cases involved bilateral cranial nerves III and VI.⁵ One case presented with bilateral oculomotor nerve plegia,⁴ and all other cases involved bilateral internuclear ophthalmoplegia.^6,-,8 The mechanism of ophthalmoplegia in GCA is from ophthalmic artery and vasa nervorum ischemia, which supply the extraocular muscles and the oculomotor nerves, respectively.³

This case represents an atypical presentation of GCA. It is important to consider GCA in the differential diagnosis of ophthalmoplegia to initiate timely treatment. This case was challenging owing to a broad differential for multiple cranial neuropathies, which was prematurely narrowed by a false-positive MRV suggestive of CVST. The sensitivity and specificity of MRV vary by technique, ranging between 71.4%/55.6%, respectively, for 2-dimensional time-of-flight MR venography (MRV) imaging to 85.7%/97.2%, respectively, for elliptic centric ordered 3-dimensional MRV.⁹ False-positive diagnoses can occur because of congenital hypoplasia of veins, slow flow because of downstream compression of the brachiocephalic or internal jugular veins, direction of venous flow, and idiopathic intracranial hypertension.¹⁰ In comparison, CTV is not affected by flow-related artifacts.¹¹ A CVST could explain the patient's initial presentation of headache and cranial nerve VI palsy. Left eye ptosis is more commonly caused by left-sided Horner syndrome in cases of CVST, although cranial nerve III palsies due to increased intracranial pressure are also possible.¹² It is also possible that the patient initially had a CVST which resolved on repeat imaging with treatment; however, the patient continued to have progression despite therapeutic anticoagulation, and her opening pressure was normal. In addition, the degree to which the patient's ESR and CRP were elevated should prompt early consideration of vasculitis. ESR and CRP can be mildly elevated in CVST¹³; however, this may be less prominent than seen in GCA where the median ESR and CRP was elevated at 62.0 and 52.0, respectively, in a group of 177 patients.¹⁴

In all previously reported cases, patients had good response to prednisone therapy with complete resolution of ophthalmoplegia after 2–3 weeks of treatment^6,7 or only mild residual deficits.^4,8 In our case, the patient's headaches resolved with IV methylprednisolone, and she had mild improvement in ophthalmoplegia. On follow-up examination 1 month later, the patient's visual acuity in her left eye had improved to 20/40. Her extra ocular movements were still restricted for the first several months but had significantly improved on follow-up examination 5 months later (Figure 1).