Sixth Nerve Palsy and Myocarditis as the Only Presenting Manifestation of Giant Cell Arteritis

Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Caroline Froment, MD, PhD An-Gour Wang, MD Sixth Nerve Palsy and Myocarditis as the Only Presenting Manifestation of Giant Cell Arteritis Edward Margolin, MD, Trishal Jeeva-Patel, MD W Address correspondence to Edward Margolin, MDDepartment of Ophthalmology and Visual Sciences, University of Toronto, 801 Eglinton Avenue West, Suite 301, Toronto, ON M5N 1E3, Canada; E-mail: [e-mail] and the decision to start treatment with prednisone 60 mg daily was made. Two days after the treatment commenced, there was a complete resolution of a left abduction deficit. Cardiac rhythm returned to normal. Temporal artery biopsy revealed intimal proliferation resulting in a markedly narrowed lumen and focal widespread destruction of the internal elastic lamina, consistent with the diagnosis of GCA. A month later while undergoing slow prednisone taper, inflammatory markers and troponin-T levels both normalized. Follow-up echocardiography performed 1 month later demonstrated improvement in ejection fraction with a resolution of ventricular bigeminy on electrocardiogram. It is well known that diplopia, especially transient diplopia, can occur in 2%–15% of patients with GCA (1). Several large studies described sixth nerve palsy as the most common cause for diplopia in patients with GCA, but third nerve palsy has also been described (1–4). Among several cohorts of patients with GCA who had transient or permanent diplopia at presentation, most patients had prominent systemic symptoms of GCA accompanying diplopia (1,3). There is only one study that mentioned 3 patients with GCA who had sixth nerve palsy without accompanying symptoms, but it not provided details of their presentation (2). One study described 4 patients with third nerve palsies as the initial manifestation of GCA and 2 of the patients had no systemic symptoms, except for severe periocular pain (4). In our case, diplopia was the only presenting symptom. The patient otherwise felt well without any systemic symptoms of GCA, and the ophthalmologist who initially evaluated the patient assumed that the abduction deficit was secondary to microvascular sixth nerve palsy because she had many cardiovascular risk factors. This case makes one rethink whether all elderly patients with sixth nerve palsies should be screened for GCA and have inflammatory markers checked. One recent prospective study reported that in patients with GCA who complained of diplopia at presentation, 56% had involvement of extracranial vessels by GCA as determined on ultrasonography of the arterial regions. Interestingly, our patient also had involvement of the extracranial vasculature by GCA, thus raising the question of whether all patients with GCA who have diplopia should have CT angiography of the chest performed as part of their workup. In most of the articles describing cranial nerve palsies as the initial manifestation of GCA, extraocular motility Margolin and Jeeva-Patel: J Neuro-Ophthalmol 2021; 41: e335-e336 e335 e present a rare case of giant cell arteritis (GCA) presenting with isolated sixth nerve palsy and no other systemic symptoms. The patient was also incidentally found to have myocarditis secondary to GCA. A 74-year-old Caucasian woman of Italian heritage developed double vision when looking to the left. She had a history of hypertension, hypothyroidism, and hyperlipidemia and was taking bisoprolol, atorvastatin, and Synthroid. She was a lifetime nonsmoker. The patient denied all symptoms of GCA and was otherwise feeling well. An ophthalmological consultation 3 days after the onset of symptoms revealed a left abduction deficit, and an outpatient brain MRI was ordered. Five days later, the patient decided to go to the emergency department (ED) because she wanted to expedite the MRI examination. There, the diagnosis of left sixth cranial nerve palsy was confirmed. Incidentally, the patient was noticed to have an irregular heart rate when her blood pressure was measured in the ED; electrocardiogram was thus performed, and the diagnosis of ventricular bigeminy was made. Because of the new diagnosis of bigeminy, a transthoracic echocardiography was performed and revealed left ventricular hypertrophy and hypokinesis of its inferior wall and decreased ejection fraction of 35%. The troponin-T level was 18 ng/L (normal , 14). Computed tomography (CT) angiography of the brain and neck was performed, as mild enlargement of the aorta was noticed on chest X-ray and revealed proximal right vertebral artery occlusion, 40% stenosis of the distal basilar artery, and almost complete occlusion of the left posterior cerebral artery. CT of the chest revealed soft-tissue thickening around great arteries. These findings were believed to be secondary to atherosclerosis, but vasculitis was a possibility; thus, inflammatory markers were obtained. The erythrocyte sedimentation rate was 86 mm/hr (normal , 42) and C-reactive protein 12 mg/L (normal , 10). Neuro-ophthalmology was consulted, Department of Ophthalmology and Vision Sciences (EM, TJ-P), University of Toronto Faculty of Medicine, Toronto, Canada; and Department of Medicine (EM), Division of Neurology, University of Toronto Faculty of Medicine, Toronto, Canada. The authors report no conflicts of interest. Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence normalized within days after the therapy with high dose of steroids commenced, differentiating it from microvascular ischemia of cranial nerves where the resolution of motility deficits usually takes 2–3 months. This was also the case in our patient whose complete sixth nerve palsy has completely resolved within 48 hours after the first high dose of steroids. The etiology of diplopia in patients with GCA is believed to be either secondary to vasculitis involving vasa nervosum supplying the cranial nerves or the vessels supplying the extraocular muscles themselves (1,5). Another rare mechanism is vasculitic involvement of the small vessels supplying the brainstem and causing dysfunction of nuclei or fascicles of the third, fourth, or sixth cranial nerves. Vasculitis of the small brainstem vessels can also affect the vestibule–ocular pathway, causing skew deviation, or the medial longitudinal fasciculus, causing internuclear ophthalmoplegia (5). Myocarditis associated with GCA has been described in only 7 other cases (6). Resolution of bigeminy and normalization of troponin-T levels after the initiation of treatment in our case support the conclusion that myocarditis had developed secondary to the involvement of the coronary vasculature by vasculitis. Interestingly, ejection fraction has also improved to 40% on follow-up echocardiogram, supporting the theory that cardiac dysfunction was secondary to the coronary vasculature involvement by GCA. Although it is difficult to definitively opine whether vascular occlusions seen on imaging were secondary to GCA or atherosclerosis, it is possible that both etiologies played a role. Our case serves as a reminder for practicing ophthalmologists that patients older than 55 years presenting with isolated cranial nerve palsy, especially sixth nerve palsy, which is the most common motility deficit associated with GCA, should have inflammatory markers drawn because they could harbor this vision-threatening disease. In our patient, there was severe narrowing of the arterial lumen on biopsy heralding impending most feared complication of GCA, severe visual loss, which was prevented by timely administration of high-dose steroid therapy. e336 Margolin and Jeeva-Patel: J Neuro-Ophthalmol 2021; 41: e335-e336 STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: E. Margolin and T. JeevaPatel; b. Acquisition of data: E. Margolin and T. Jeeva-Patel; c. Analysis and interpretation of data: E. Margolin and TJP. Category 2: a. Drafting the manuscript: E. Margolin and T. Jeeva-Patel; b. Revising it for intellectual content: E. Margolin and T. Jeeva-Patel. Category 3: a. Final approval of the completed manuscript: E. Margolin and T. Jeeva-Patel. REFERENCES 1. 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