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Show Jminial of Neiim- Oplilhaliiiology 18( 2): 114- 116, 1998. © 1998 Lippincott- Ravcn Publishers, Philadelphia Eight- and- a- Half Syndrome: One- and- a- Half Syndrome Plus Cranial Nerve VII Palsy Eric Eggenberger, D. O. Three cases of isolated one- and- a- half syndrome with facial nerve palsy related to infarction are presented. Magnetic resonance imaging in cases 1 and 2 was unremarkable, whereas magnetic resonance angiography demonstrated pathophysiological ly significant vertebral basilar disease. Case 3 is unique due to its association with giant cell arteritis. Ipsilateral adduction improved to a greater extent than abduction in each case, perhaps providing insight into the exact localization of these lesions or selective vulnerability of the ocular motor structures within the pons. This combination of clinical findings, termed the 8- 1/ 2 syndrome ( cranial nerve 7 + 1- 1/ 2), allows precise localization, and magnetic resonance angiography appears to be the imaging study of choice. Key Words: Facial palsy- giant- cell arteritis- Internuclear ophthalmoplegia- One- and- a- half syndrome. The one- and- a- half syndrome is a term originally coined by C. Miller Fisher to describe the combination of horizontal- gaze palsy and internuclear ophthalmoplegia, indicative of a pontine tegmentum lesion involving the paramedian pontine reticular formation ( PPRF) and medial longitudinal fasciculus ( MLF) ( 1). These structures are intimately related to the nucleus and intraaxial fasciculus of the facial nerve. Accordingly, ipsilateral lower motor neuron facial palsy may accompany this syndrome. In Wall's and Wray's review of 20 cases of the one- and- a- half syndrome, the seventh nerve was the most common associated cranial neuropathy ( 4 cases, 20%) ( 2). We have recently seen three cases of isolated one- and- a- half syndrome combined with lower motor neuron cranial nerve VII palsy resulting from cerebrovascular disease. We refer to this constellation as the " eight- and- a- half syndrome" ( the one- and- a- half syndrome plus cranial nerve VII). Manuscript received May 21, 1997; accepted February 20, 1998. From the Unit for Neuro- Visual Disorders and the Department of Physical Medicine and Rehabilitation, Michigan State University College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, U. S. A. Address correspondence and reprint requests to Eric Eggenberger, D. O., Center for Clinical Neuroscicncc and Opthalmology, Michigan Stale University College of Osteopathic Medicine, A217 Clinical Center, 138 Service, Michigan Stale University, East Lansing, Michigan 48824- 1313, U. S. A. CASE REPORTS Case 1 Diplopia and right facial palsy developed in a 56- year-old man who had a history of hyperlipidemia. Neuro-ophthalmologic examination was notable for right horizontal- gaze palsy, right internuclear ophthalmoplegia ( right one- and- a- half syndrome) and right lower motor neuron facial palsy ( Fig. 1). Gaze paresis did not improve with the vestibular- ocular reflex. Upbeat nystagmus was noted in primary position; visual fixation was consistent with a central vestibular pathophysiology. Findings in the remainder of the neurologic examination were normal. Magnetic resonance angiography ( MRA) produced findings consistent with an occluded right vertebral artery with approximately 60% stenosis of the carotid arteries. The patient was given 250 mg ticlopidine twice daily. Reevaluation during the next several months revealed only intermittent episodes of diplopia with marked improvement in ocular motility and facial weakness. Adduction in the right eye recovered more quickly than abduction, and residual esotropia in the right gaze remained. Case 2 A 77- year- old man with diabetes, coronary artery disease, and hyperlipidemia experienced sudden onset of diaphoresis, diplopia, vertigo, cephalalgia, nausea, and vomiting. Neuro- ophthalmologic examination showed left- gaze palsy, left internuclear ophthalmoplegia, vertical- gaze- evoked nystagmus, and lower motor neuron facial palsy. Vestibular- ocular reflex failed to improve eye movement excursion. Magnetic resonance images showed high- signal lesions on T2- weighted images in the deep white matter bilaterally, and MRA images demonstrated nonvisualization of the left vertebral artery consistent with slow flow or occlusion ( Fig. 2). No abnormal signal or enhancement was noted in the pons. Anticoagulation was initiated with heparin and subsequently was converted to warfarin. Re- examination during the ensuing several weeks showed improved ocular motility; adduction in the left eye improved faster than abduction. Six weeks after the infarction, the patient noted only intermittent diplopia in the extreme left gaze 114 EIGHT- AND- A- HALF SYNDROME 115 FIG. 1. Patient 1 exhibits right internuclear ophthalmoplegia and lower motor neuron facial palsy ( note forehead wrinkle asymmetry and slightly widened palpebral fissure on the right). Right- gaze palsy was also present. ( associated with small- angle esotropia), and minimal left facial asymmetry was present. Case 3 Diplopia and right facial palsy developed in a 72- year-old man with the recent diagnosis of hypertension. Neuro- ophthalmologic examination was notable for right- gaze palsy unimproved by vestibular- ocular reflex, right internuclear ophthalmoplegia, and right lower facial nerve palsy. Magnetic resonance imaging revealed high-signal abnormalities in the right pontine tegmentum more so than in the left, consistent with ischemia. Treatment was initiated with 250 mg ticlopidine twice daily. During the next 2 months, the facial palsy and diplopia resolved. Adduction in the right eye recovered more quickly than abduction; however, fatigue, anorexia, and episodic fevers developed. The erythrocyte sedimentation rate was 94 mm/ h, and examination of a temporal artery biopsy specimen showed inflammatory and giant cells consistent with giant- cell arteritis. High- dose prednisone resolved the symptoms and normalized the erythrocyte sedimentation rate. Small- angle esotropia in the right gaze was still present at I- year follow- up. DISCUSSION The one- and- a- half syndrome consists of internuclear ophthalmoplegia in addition to ipsilateral horizontal-gaze palsy. It most often results from vascular or demy-elinating pathophysiologies. The horizontal- gaze palsy in one- and- a- half syndrome may result from lesions in the abducens nucleus ( motor neurons with fibers to the lateral rectus and internuclear neurons with axons to the medial rectus oculomotor subnucleus through the MLF), abducens nerve plus medial longitudinal fasciculus, or PPRF. The PPRF is a supranuclear structure, and accordingly, isolated PPRF lesions are associated with retained vestibular- ocular reflex- induced abduction; in clinical practice, however, this is rarely encountered ( 3). More rapid resolution of ipsilateral adduction compared with abduction may imply involvement of abducens nerve fascicle and MLF, rather than abducens nucleus, or may reflect relative vulnerability of abducens motor neurons innervating the lateral rectus. Case 3 is unique because of the association with giant-cell arteritis. Although the pathophysiologic link between the arteritis and brain stem infarction in this case remains speculative, it serves to re- emphasize the well-described but rare association between giant- cell arteritis and cerebrovascular disease, which appears to involve the posterior circulation preferentially ( 4). The current cases illustrate the isolated combination of one- and- a- half syndrome with ipsilateral lower motor facial nerve palsy that we have termed the eight- and- a- half syndrome. This finding provides precise clinical localization to the dorsal tegmentum of the caudal pons. Clinical localization remains vital because high- quality MRI in cases 1 and 2 was unremarkable, highlighting the di- FlG. 2. Magnetic resonance angiography from patient 2 demonstrates nonvisualization of the left vertebral artery. J Neiiro- Oplulmlinol, Vol. IX, No. 2, IWH 116 E. EGGENBERGER minutive size of the lesion. However, MRA showed the presumptive vascular pathophysiology of the process. High- quality MRA concentrating on the vertebrobasilar circulation with fluid attenuation inversion recovery ( FLAIR) images through the brain has become our diagnostic method of choice in suspected brain stem infarctions. In these cases, not only can MRA often illustrate the lesion, but it can also demonstrate the vascular pathophysiology, which assists in therapeutic decision making. The prognosis for resolution of diplopia and facial palsy in cases of isolated eight- and- a- half syndrome appears excellent; abduction paresis persisted longer than adduction weakness in our patients. REFERENCES 1. Fisher CM. Some neuro- ophthalmological observations. J Neurol Neurosurg Psychiatry 1967; 30: 383- 92. 2. Wall M, Wray SH. The one- and- a- half syndrome- a unilateral disorder of the pontine tegmentum: a study of 20 cases and review of the literature. Neurology 1983; 33: 971- 80. 3. Leigh RJ, Zee DS. The Neurology of Eye Movements. Philadelphia: F. A. Davis, 1991. 4. Caselli RJ. Giant cell ( temporal) arteritis: a treatable cause of multi- infarct dementia. Neurology 1990; 40: 753- 5. J Neuro- Ophtlmlmol, Vol. 18, No. 2, 1998 |
