Abduction Variant One and a Half Syndrome Due to a Massive Right Hemispheric Stroke With Uncal Herniation and Rapid Intracranial Hypertension

Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Caroline Froment, MD, PhD An-Gour Wang, MD Abduction Variant One-and-a-Half Syndrome Due to a Massive Right Hemispheric Stroke With Uncal Herniation and Rapid Intracranial Hypertension Maureen B. O’Marro, DO, Sarkis M. Nazarian, MD C onjugate horizontal gaze palsy combined with an ipsilateral internuclear ophthalmoplegia (INO) results in one-and-a-half syndrome. It is usually due to a brainstem lesion that affects the medial longitudinal fasciculus, along with the ipsilateral paramedian pontine reticular formation and abducens nucleus. The name refers to the loss of 3 of the horizontal half movements (abduction and adduction) of the 2 eyes, leaving abduction of the contralateral eye as the only remaining movement. There is no name for the variant one-and-a-half syndrome where the only remaining movement is adduction of the contralateral eye. This variant, described in this case report, is not due to brainstem disease but rather to dysfunction in 3 of the paired oculomotor and abducens nerves. A 61-year-old left-handed woman with a past medical history of hypertension and hyperlipidemia was transferred to our hospital 24 hours after suffering a massive right middle cerebral artery stroke. Her initial NIH score was 17 for left gaze palsy, complete left hemianopia, left lower facial palsy, flaccid paralysis of the left upper and lower extremities, moderate left sensory disturbance, moderate dysarthria, and left sensory extinction. She also had right eye deviation to the right, almost complete lid ptosis, and pupil dilation with a sluggish response to light. Her left eye was midline, and her left pupil was normal. Initial computed tomography of head revealed a large acute infarct involving nearly the entire right middle cerebral artery territory, with effacement of the Sylvian fissure and approximately 1 mm right-to-left midline shift at the level of the septum pellucidum. A small area of hypoattenuation was seen within the left occipital lobe and mesial temporal lobes, likely representing a Department of Neurology (MOM), Advocate BroMenn Medical Center, Normal, Illinois; and Departments of Neurology and Ophthalmology (SMN), University of Arkansas for Medical Sciences, Little Rock, Arkansas. The authors report no conflicts of interest. Address correspondence to Sarkis M. Nazarian, MD, Neurology and Ophthalmology, Department of Neurology, University of Arkansas for Medical Sciences, Slot 500, 4301 W. Markham Street, Little Rock, AR 72205; E-mail: [e-mail] e348 subacute infarct. Remote lacunar infarcts in the left caudate nucleus head and a small acute to subacute infarct within the left inferior cerebellar hemisphere were also noted. On Day 1 of admission, she gradually became comatose and developed right lateral rectus palsy and right upper extremity paresis to painful stimuli, suggesting worsening right-to-left shift and increased intracranial pressure (ICP) in addition to the right uncal herniation inferred by neuro examination at admission. She underwent decompressive right hemicraniectomy, and the right abduction deficit improved after this procedure. Her right oculomotor palsy, especially the ptosis, also improved, although she still had 2–4 mm of anisocoria and sluggish right pupil. She responded to verbal and tactile stimuli, although she did not speak. She continued to have left hemiplegia, left upper and lower extremity sensory loss, and prominent left Babinski sign but was able to move her right upper extremity on request. The left gaze palsy gradually improved over the next few days. MRI brain without contrast on Day 4 showed a large right hemispheric infarct involving nearly the entirety of the right middle cerebral artery territory, with a small area of sparing within the medial right occipital and temporal lobes (Fig. 1). There was approximately 4–5 mm of right-to-left midline shift. A few foci of punctate acute to subacute infarct within the left posterior parieto-occipital lobes and multiple patchy acute to subacute infarcts along the left cerebellar hemisphere and cerebellar vermis were seen. A T1 hyperlucency within the right basal ganglia was believed to represent a small area of hemorrhagic conversion. Occlusion of the right internal carotid and right middle cerebral arteries was noted on MRA. The suspected etiology of her acute stroke was paroxysmal atrial fibrillation, with multiterritorial infarctions of varying ages. Between Days 4 and 6, her neurologic examination declined, with development of bilateral Babinski signs and loss of response to verbal and tactile stimuli. She had continued anisocoria with a minimally responsive 7-mm right pupil and a reactive 4-mm left pupil. Partial ptosis was present in the right eye. She was found to have bilateral abduction palsies and a right adduction palsy on O’Marro and Nazarian: J Neuro-Ophthalmol 2021; 41: e348-e350 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence FIG. 1. MRI FLAIR images, 4 days after stroke onset. A, B, C. Axial sections at levels of pons, midbrain, and head of caudate; (D) coronal section at the level of the head of caudate. FLAIR, fluid-attenuated inversion recovery. horizontal oculocephalic maneuvers. Her only movement was adduction of the left eye. She underwent emergency debridement of necrotic cerebral tissue on Day 6. Her examination did not change except for temporary improvement, which waned over the following several days, in left eye abduction. Oculocephalic maneuvers on Day 11 revealed no ocular movement except for partial adduction of the left eye with head turn to the left. Right hypotropia was noted, unchanged in all positions of gaze. Hospice care was elected by family, and she died on Day 15. No autopsy was obtained. This case is unique in combining pupil-involving right oculomotor palsy, due to compression related to uncal herniation, with bilateral and sequential abducens palsies due to rapid increase in intracranial hypertension. These deficits temporarily improved after surgeries to relieve brain herniation and elevated ICP but then recurred. We do not have an explanation for the right eye hypotropia O’Marro and Nazarian: J Neuro-Ophthalmol 2021; 41: e348-e350 seen late in her course. We could not test for skew deviation vs. trochlear nerve palsy. Combined ocular motor nerve palsies in connection with stroke and malignant cerebral edema are uncommon. When ocular motor cranial nerve palsies are seen, they typically occur in isolation and as a result of infarctions within the brainstem or cerebellum. Of 915 poststroke patients reported by Rowe and colleagues in 2011, 498 (54%) had ocular motor disturbances (1). Of 89 patients with ocular motor cranial nerve palsies, 58% had isolated sixth nerve palsies, 26% isolated third nerve palsies, and 16% fourth nerve palsies. Myasthenia gravis can lead to pseudo–one-and-a-half syndrome (2). Traumatic INO with ipsilateral abducens paresis (“half and half” syndrome) has been reported (3). Probable skew deviation due to brainstem injury in patients with uncal herniation has been described in one of 25 patients, 13 of whom had INO, in a 1986 article (4). Reversible vertical ocular deviations associated with e349 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence increased ICP, characterized as skew deviations, were described in 5 patients reported in 1985 and 6 more noted in the authors’ literature search (5). In this case, the patient’s right uncal herniation and rapid onset of intracranial hypertension due to massive right hemisphere edema resulted in the previously undescribed abduction variant one-and-a-half syndrome, which could be called a “pseudo-inverse” one-and-a-half syndrome. STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: M. O’Marro and S. M. Nazarian; b. Acquisition of data: M. O’Marro and S. M. Nazarian; c. Analysis and interpretation of data: M. O’Marro and S. M. Nazarian. Category 2: a. Drafting the manuscript: M. O’Marro and S. M. Nazarian; b. Revising it for intellectual content: S. M. Nazarian. Category 3: a. Final approval of the completed manuscript: M. O’Marro and S. M. Nazarian. e350 ACKNOWLEDGMENTS The authors acknowledge valuable input from Amit R. Vyas, MD, Bloomington Radiology, Bloomington, IL, in reviewing and selecting radiographic images for this publication. REFERENCES 1. Rowe F; VIS Group UK. Prevalence of ocular motor cranial nerve palsy and associations following stroke. Eye. 2011;25:881– 887. 2. Davis TL, Lavin PJM. Pseudo one-and-a-half syndrome with ocular myasthenia. Neurology. 1989;39:1553. 3. Randhawa S, Shah VA, Kardon RH, Lee AG. An internuclear ophthalmoplegia with ipsilateral abduction deficit: half and half syndrome. J Neurol Neurosurg Psychiatry. 2007;78:309. 4. Keane JR. Bilateral ocular motor signs after tentorial herniation in 25 patients. Arch Neurol. 1986;43:806–807. 5. Frohman LP, Kupersmith MJ. Reversible vertical ocular deviations associated with raised intracranial pressure. J Clin Neuroophthalmol. 1985;5:158–163. O’Marro and Nazarian: J Neuro-Ophthalmol 2021; 41: e348-e350 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.