Cerebral Cavernomas: A Cause of One-and-a-Half Syndrome
June 13, 2016
Chief complaint: Double vision
History of present illness (HPI)
An alert and oriented 72-year-old female presented to the emergency department with complaint of binocular horizontal diplopia, nausea, vomiting, and vertigo that has gradually evolved over several hours. She denies any numbness, tingling, muscle weakness, or trouble with speech. She experienced a similar episode when she was 15 years old. A brain MRI obtained at an outside facility showed stable diffuse cavernomas (diagnosed seven years prior). She was transferred to the University of Iowa Hospitals and Clinics for further evaluation.
Past ocular history
According to the patient, her episode of diplopia at age 15 was attributed to an influenza infection. Her vision returned to baseline after 1 month. No chronic eye conditions or previous eye surgery noted.
Past medical history:
- Diffuse cavernomas of the cerebrum and brainstem (first noted seven years ago, presented with vertigo)
- Type II diabetes mellitus (diet-controlled).
Past surgical history
- No known allergies
- No tobacco or illicit drug use
- Rare alcohol use
Review of systems
- Negative unless detailed in the HPI
Distance visual acuity (with correction)
- Right eye (OD): 20/100 pinhole to 20/70
- Left eye (OS): 20/125 pinhole no improvement
Near visual acuity (with correction)
- OD: 1.6M (20/80)
- OS: 1.25M (20/63)
Intraocular pressure (tonometry)
- OD: 11 mmHg
- OS: 11 mmHg
- OS: 4mm (dark) to 3mm (light), no RAPD
- OS: 4mm (dark) to 3mm (light), no RAPD
Confrontation visual fields (red targets)
- OD: partial superior temporal and superior nasal loss
- OS: partial superior nasal loss
Color vision testing (Ishihara)
- OD: 6/14
- OS: 13/14
Slit lamp exam
- Eyelids/lashes: ptosis both eyes (OU); meibomian gland disease OU
- Conjunctiva/sclera: white and quiet OU
- Cornea: punctate epithelial erosions inferiorly OS
- Anterior chamber: deep and quiet OU
- Iris: normal architecture OU
- Lens: 1+ nuclear sclerosis OU
Dilated fundus examination (DFE)
- Vitreous:clear OU
- Disc: normal OU
- Cup-to-disc ratio: 0.2 OU
- Macula: drusen OD, normal OS
- Vessels: normal OU
- Peripheral Fundus: normal OU
Optical coherence tomography (OCT)
OCT of the macula and disk were performed and were within normal limits.
Color fundus photography
Magnetic Resonance Imaging (MRI)
One-and-a-half syndrome secondary to vascular malformation (cavernomas)
The patient was diagnosed with one-and-a-half syndrome, with cerebral cavernomas being the most likely etiology. Upon discharge, she was given a patch to wear for comfort and advised not to drive. At her six-week follow-up appointment, her diplopia had nearly resolved. Her visual acuity was 20/20 in both eyes, suggesting her initial decrease in acuity was ocular surface disease and/or difficulty with vision testing in the acute setting. Extra-ocular motility was full with normal convergence, but a residual left intermittent exotropia was noted during right gaze. She returned to clinic four months later with complete resolution of signs and symptoms.
PathophysiologyOne-and-a-half syndrome, first described by Fisher in 1967, is a horizontal motility disorder that requires two major components caused by a lesion (or lesions) in the dorsal pontine tegmentum:
1. Ipsilateral complete conjugate horizontal gaze palsy due to a lesion at
a. the ipsilateral paramedian pontine reticular formation (PPRF), or
b. the ipsilateral abducens (VI) nucleus
The eye ipsilateral to the lesion has limited horizontal motility, and the contralateral eye has only one-half of its horizontal motility intact (abduction). Hence the name "one-and-a-half" syndrome. The only horizontal movement that remains is abduction of the contralateral eye, which is usually accompanied by nystagmus. (Figure 5) 1-3
Well known causes include infarction (usually due to occlusion of paramedian perforating branches of the basilar artery)4, demyelinating disease [e.g. multiple sclerosis (MS), acute demyelinating encephalomyelitis (ADEM)], tumor (including metastasis), hemorrhage, aneurysms, vascular malformations, hindbrain anomalies (e.g. Chiari malformation), and infectious mass lesions (e.g. tuberculoma). In the elderly, infarction tends to be the most common etiology, while tumors and MS should be considered in younger patients.2
More on cavernomas
While our patient's benign brain lesions appeared stable on imaging, it is possible that systemic hemodynamic changes (potentially from vomiting, unreported diarrhea, or decreased fluid intake) could have caused transient changes via a steal mechanism. Microaneurysms undetected on imaging and minute growth leading to compression are other potential mechanisms of her one-and-a-half syndrome.
The most common symptom of one-and-a-half syndrome is diplopia. Further questioning will likely yield a description of binocular, horizontal diplopia that is worse with contralateral gaze. Other complaints include blurred vision, oscillopsia, difficulty looking to the affected side, and a 'quivering' eye.2
Depending on the etiology, size, and location of the lesion, other neurological findings may be noted on physical exam. Inclusion of cranial nerves II, V, VII, VIII, IX, and XII were detected in Wall and Wray's 1983 case and literature review.2 Other findings included Horner Syndrome, weakness or spasticity, sensory deficits, abnormally brisk or asymmetric reflexes, extensor plantar responses, and incoordination. 2 Additionally, when the facial motor nucleus is simultaneously affected, a central facial palsy can be seen, and such cases have been deemed "eight-and-a-half syndrome."8 Other interesting associations with one-and-a-half syndrome include oculopalatal myoclonus9 and Cheirooral Syndrome.10
A full ocular motility exam, including convergence, should be performed. In one-and-a-half syndrome, the apparent adduction deficits can be overcome with convergence. Forced ductions may be helpful to rule out a restrictive palsy. A neurological exam with attention to the cranial nerves may help you further localize a lesion. Consider thyroid function testing, MG antibody testing, or in-office endrophonium testing if thyroid eye disease or MG are a clinical concern. Adduction deficits due to MG cannot be overcome by convergence. Neuro-imaging is indicated, with MRI being the modality of choice.
Treatment, management, and prognosis depend on the underlying etiology of the lesion. Collaboration with neurology or neurosurgery may be necessary.
- Pontine hemorrhage
- Infective mess lesions (e.g. tuberculomas)
- Multiple Sclerosis and other demyelinating conditions
- Thyroid-related Ophthalmopathy
- Myasthenia Gravis (MG)
- Chronic progressive external ophthalmoplegia
- Orbital inflammatory pseudotumor
- Extraocular muscle entrapment
Most common cause of INO
Epidemiological statistics are dependent on the individual etiologies and their presence within specific patient populations. One-and-a-half syndrome is not known to be limited by age, sex, or race.
"Popcorn" lesions on MRI
Dependent on the underlying etiology of the lesion.
- Fisher CM. Some neuro-ophthalmological observations. Journal of Neurology, Neurosurgery, and Psychiatry. 1967;30(5):383-392.
- 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(8):971-980.
- Bae YJ, Kim JH, Choi BS, Jung C, Kim E. Brainstem Pathways for Horizontal Eye Movement: Pathologic Correlation with MR Imaging. RadioGraphics. 2013;33(1):47-59.
- de Seze J, Lucas C, Leclerc X, Sahli A, Vermersch P, Leys D. One-and-a-half syndrome in pontine infarcts: MRI correlates. Neuroradiology. 1999;41(9):666-669.
- Trentadue M, Mucelli RP, Piovan E, Pizzini FB. Incidental optochiasmatic cavernoma: Case report of an unusual finding on 3 Tesla MRI. Neuroradiol J. May 2016:1-6.
- Rotondo M, Natale M, D'Avanzo R, Pascale M, Scuotto A. Cavernous malformations isolated from cranial nerves: Unexpected diagnosis? Clinical Neurology and Neurosurgery. 2014;126:162-168.
- James K Liu, Yuan Lu, Ahmed M Raslan, S Humayun Gultekin, Johnny B Delashaw Jr. Cavernous malformations of the optic pathway and hypothalamus: analysis of 65 cases in the literature. Neurosurg Focus. 2010;29(3):E17.
- Eggenberger E. Eight-and-a-Half Syndrome: One-and-a-Half Syndrome Plus Cranial Nerve VII Palsy. Journal of Neuro-ophthalmology. 1998;18(2):114-116.
- Wolin MJ, Trent RG, Lavin PJ, Cornblath WT. Oculopalatal myoclonus after the one-and-a-half syndrome with facial nerve palsy. Ophthalmology. 1996;103(1):177-180.
- Shintani S, Tsuruoka S, Shiigai T. Radiologic-clinical correlation. One-and-a-half syndrome associated with cheirooral syndrome. AJNR Am J Neuroradiol. 1996;17(8):1482-1484.
Suggested Citation format:
Kramer BA, Myers (Provencher) LA, Kardon RH, Wall M. Cerebral Cavernomas: A Cause of One-and-a-Half Syndrome. EyeRounds.org. June 13, 2016; Available from: http://EyeRounds.org/cases/236-Cerebral-Cavernoma.htm