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Show NEURO- OPHTHALMOLOGY AT LARGE 54th Annual Meeting of the American Academy of Neurology, Denver, Colorado, April 13- 20, 2002 This review includes highlights of posters and platform presentations presented at the 54th Annual Meeting of the American Academy of Neurology ( AAN), held in Denver, Colorado, April 13- 20, 2002. Abstracts, published in Neurology 2002; 58( suppl 3) Al- 515, are referenced here by number, and are presented according to topic. MULTIPLE SCLEROSIS Analysis of placebo- treated patients from the Controlled High- Risk Avonex Multiple Sclerosis Prevention Study ( CHAMPS) demonstrated that, in patients with a first demyelinating event ( including acute optic neuritis) and a high- risk magnetic resonance imaging ( MRI) scan (> 2 white matter lesions), the strongest single predictor of clinically definite multiple sclerosis ( MS) at 18 months was the presence of enhancing MRI lesions. Clinically definite MS, which requires a second clinical attack, developed in 43% of patients with enhancing lesions at baseline, compared with 23% of those without enhancing MRI lesions ( Simon J, Denver, CO, S67.001). NEUROMYELITIS OPTICA Neuromyelitis optica, a demyelinating disorder affecting the optic nerves and spinal cord, has a more favorable prognosis for neurologic recovery in children than in adults. Whereas complete recovery of optic nerve and spinal cord function was observed in 77% of 32 children, only 18% of 45 adults experienced complete recovery following a first demyelinating event ( Chaves- Carballo E, Riyadh, Saudi Arabia, P01.025). In a study that compared 30 patients with neuromyelitis optica and 50 consecutive patients with MS whose first demyelinating event was optic neuritis or acute myelitis, clinical outcomes were significantly more severe in the neuromyelitis optica group, based on Expanded Disability Status Scale ( EDSS) scores ( P < 0.001). Clinical features were distinct enough to suggest consideration of neuromyelitis optica as a disease separate from MS ( de Seze J, Lille, France, P03.027). MYASTHENIA GRAVIS The co- occurrence of MS and myasthenia gravis ( MG) in a population- based University of British Columbia MS center was 10- fold higher than expected based on random association of these two disorders. Nine patients with both MS and MG were identified at this center. The authors hypothesize that antibody mediation may represent a common underlying mechanism of pathogenesis ( Isbister C, Vancouver, BC, Canada, P03.019). Antistriational antibodies ( StrAb), which are antibodies to contractile elements of skeletal muscle, were elevated in 4% of MG patients who were seronegative for antiacetylcholine receptor antibodies ( AChR- Ab). StrAb may therefore be useful for confirming the diagnosis of MG in some patients ( Sanders D, Durham, NC, P03.137). A single course of high- dose cyclophosphamide ( HiCy), administered to three patients, provided an effective treatment of MG where disease manifestations were disabling and refractory to plasmapheresis and other immunosuppressive therapies. HiCy treatment may serve to " reboot" the immune system by inducing immune tolerance to the acetylcholine receptor ( Drachman D, Baltimore, MD, S44.001). As demonstrated in a pilot study of 15 MG patients and 5 normal control subjects, repetitive nerve stimulation of the masseteric branch of the trigeminal nerve is a well tolerated, reliable, and easily performed technique for the evaluation of patients with suspected MG ( Rubin D, Rochester, MN, S49.008). MITOCHONDRIAL DISEASES Familial progressive external ophthalmoplegia ( PEO) is characterized by multiple mitochondrial DNA deletions. Mutations of genes encoding the main subunit of mitochondrial DNA polymerase gamma ( POLG) are a frequent cause of familial PEO ( Zeviani M, Milan, Italy, S44.004). Proton magnetic resonance spectroscopy ^ Fl- MRS) techniques were successfully used in vivo ( 4 normal subjects and 1 patient with optic neuropathy) to demonstrate lactate in the vitreous. Quantitation of vitreous lactate concentrations may represent a useful method in the future for evaluation of mitochondrial retinal and optic nerve disease ( Rucker J, Atlanta, GA, P06.028). The production of reactive oxygen species ( ROS) was found to be increased in cybrids carrying the Leber hereditary optic neuropathy ( LHON) mutations 11778, 14484, and 3460. Although ROS were increased, there was also a modified pattern of antioxidant activity, which might Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. JNeuro- Ophthalmol, Vol. 23, No. 1, 2003 87 JNeuro- Ophthalmol, Vol. 23, No. 1, 2003 NEURO- OPHTHALMOLOGY AT LARGE relate to an attempt to limit the ROS damage ( Carelli V, Bologna, Italy S69.001). A likely animal model for LHON utilized ribozymes against mitochondrial genes involved in complex 1 activity in mice. Similar pathologic changes to those of optic nerves in LHON patients were produced, including thinning of the inner retina and demyelination and axonal loss of the optic nerve. ( Qi X, Gainesville, FL, S69.002). Gene therapy with an ND4 subunit of mitochondrial DNA was introduced into cybrid cell lines from patients with LHON and the 11778 mutation. With this treatment, ATP synthesis was restored from 60% reduction to normal, raising the possibility of future gene- based treatment of LHON ( Guy J, Gainesville, FL, S69.003) NEUROGENETIC DISORDERS Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy ( CADASIL) is associated with neurologic dysfunction and retinal vascular abnormalities. These authors reported the first known case of genetically confirmed CADASIL in which anterior ischemic optic neuropathy was the initial presenting feature ( Rufa A, Siena, Italy, P06.025). A description of the clinical spectrum and correlation between genotype and phenotype in episodic ataxia- type 2 ( EA2) was presented. Many types of mutations can cause EA2, and there is no simple correlation between genotype and phenotype. There is overlap with congenital myasthenia, seizures, and familial hemiplegic migraine. Nystagmus may be gaze- evoked, downbeat, or rebound. Episodic symptoms may last from hours to days ( Jen J, Los Angeles, CA, S69.004). EA2 and SCA6 patients were found to have atrophy of the cerebellar vermis and hemispheres. These findings correlated with the known distribution of the subunit of a particular type of calcium channel encoded by the CACNA1A gene ( Ying S, Los Angeles, CA, S69.005). Two families with congenital horizontal gaze palsy and progressive scoliosis had the disease locus mapped to a 30- cm interval. Patients had no horizontal gaze from birth, which included pursuit, saccades, and the vestibulo- ocular reflex. Vertical gaze was normal. Four patients had low amplitude horizontal pendular nystagmus. The disease gene likely encodes a protein important in neuronal development ( Bosley T, Riyadh, Saudi Arabia S69.006). HEADACHE Spontaneous intracranial hypotension, a condition resulting from a cerebrospinal fluid leak in the absence of trauma, may present with acute " thunderclap" headaches that mimic subarachnoid hemorrhage. Clinical features among four patients reported in this series included sudden-onset postural headache, nausea, and neck stiffness ( Eross E, Scottsdale, AZ, P02.067). Visual aura is a common feature of migraine headache. Prosopanomia, selective anomia for peoples' names, a very rare manifestation of migraine aura, was reported in a 52- year- old man with a 30- year history of migraine with an aphasic aura ( Nisipeanu P, Hadera, Israel, P02.068). VENOUS SINUS THROMBOSIS Cerebral venous thrombosis may present with a wide spectrum of clinical manifestations, as demonstrated in a prospective follow- up study of 50 patients in Brazil. Papilledema was the most common neurologic sign at diagnosis ( 70% of patients), while headache was the most common presenting symptom ( 92%). Favorable clinical outcomes, with modified Rankin Scores of 0 or 1, occurred in 76% of patients, while 5 patients died despite aggressive treatment in the acute phase of illness ( Camargo E, Sao Paulo, Brazil, S68.005). IDIOPATHIC INTRACRANIAL HYPERTENSION A description of four patients and a review of the literature related to idiopathic intracranial hypertension concluded that anemia may play a role in the occurrence of raised intracranial pressure. It suggested that hemograms be obtained in patients presenting with this disorder, especially when there are no clear risk factors, such as obesity or causative medications ( Rucker J, Atlanta, GA, S71.002). CAROTID ARTERY DISSECTION Three patients with cervical vertebral or carotid artery dissections presented with headache symptoms that fulfilled International Headache Society diagnostic criteria for specific primary headache syndromes, including greater occipital nerve neuralgia, cluster headache, and cervico-genic headache. ( Zanferrari C, Parma, Italy, P02.069). Carotid dissection is an uncommon but definite risk in patients who undergo intracarotid amobarbital testing ( IAT), a standard test used to lateralize language and memory function in patients prior to epilepsy surgery. In a retrospective review of 435 patients who underwent IAT, 3 ( 0.7%) were diagnosed with carotid artery dissection. In one of these three patients, the dissection was accompanied by Horner syndrome ( Loddenkemper T, Cleveland, OH, P01.091). TRIGEMINAL NEURALGIA A recent clinical trial and meta- analysis demonstrated that oxcarbazepine, a keto- analogue of carbamaze-pine, has efficacy comparable to carbamazepine in symptomatic treatment of pain associated with trigeminal neuralgia. Adverse events, including dizziness, vertigo, Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 88 © 2003 Lippincott Williams & Wilkins NEURO- OPHTHALMOLOGY AT LARGE JNeuro- Ophthalmol, Vol. 23, No. 1, 2003 fatigue, nausea, and ataxia, were reported less frequently in the oxcarbazepine than in the carbamazepine treatment group, suggesting that this medication offers a safe and effective alternative for trigeminal neuralgia therapy ( Bey-doun A, Ann Arbor, MI, P02.083, P06.116). PARANEOPLASTIC SYNDROMES The diagnosis of underlying malignancies in patients with paraneoplastic neurologic syndromes is frequently difficult. A recent study of 13 patients with paraneoplastic syndromes and circulating specific antibodies ( 10 anti- Hu, 1 anti- CV2, 1 anti- Yo, 1 anti- amphiphysin) demonstrated that fluorodeoxyglucose positron emission tomography ( 18- FDG PET) is a useful method for detecting occult cancer. In this series, 18- FDG PET body scans detected abnormal uptake in all patients, and led to tumor diagnosis in 10 patients, 6 of whom had normal conventional radiologic studies ( Honnorat J, Lyons, France, P01.071). Of the 10 patients for whom PET scanning led to tumor diagnosis, 8 had lung cancer, 1 had ovarian carcinoma metastatic to lymph nodes, and 1 had breast cancer. In the other three patients, 18- FDG- PET demonstrated mediastinal uptake of 18- FDG, but surgery could not be performed. Paraneoplastic opsoclonus is commonly associated with small cell lung carcinoma. A heterogeneous autoantibody response, including " atypical" antibodies distinct from anti- Hu and anti- Ri, was noted in three recently reported patients with this syndrome ( Dropcho E, Indianapolis, IN, POL 072). EPILEPSY Acute myopia with secondary increased intraocular pressure was reported in 30 epilepsy patients treated with topiramate. Symptoms were commonly bilateral ( in contrast to primary narrow- angle glaucoma), and consisted of visual blurring and ocular pain, and occurred generally within the first month of topiramate therapy. Fortunately, elevations in intraocular pressure resolved rapidly following discontinuation of the drug and medical management. Surgical treatment of angle closure was not usually necessary ( Keates E, Philadelphia, PA, S57.005). Vigabatrin therapy has been associated with marked retinal electrophysiological changes and visual field constriction. Tiagabine, a related anticonvulsant, does not produce retinal dysfunction, as demonstrated by a cross-sectional study comparing visual function parameters in patients being treated with vigabatrin, tiagabine, and other anticonvulsants ( Krauss, G, Baltimore, MD, S57.007). Pregabalin, another 7- aminobutyric acid- mediated ( GABAergic) anticonvulsant medication, was also examined for potential vigabatrin- like retinal toxicity. A review of 3,600 pregabalin- treated patients from clinical studies revealed no evidence of retinal or optic nerve toxicity ( Brigell M, Ann Arbor, MI, P06.026). CAT- SCRATCH DISEASE Cat- scratch disease, which most frequently manifests as neuroretinitis, has other neurologic manifestations and neuroimaging features that are less well defined. Examination of a single case and review of the literature revealed that seizures, memory difficulty, and focal neurologic deficits are common manifestations of cat- scratch encephalopathy. MRI or computed tomography ( CT) abnormalities have been reported in 36% of cases, and may involve cerebral gray matter as well as white matter tracts ( Seah A, Atlanta, GA, P06.029). PROGRESSIVE SUPRANUCLEAR PALSY Sleep disorders, including excessive daytime sleepiness and sleep- disordered breathing, were prevalent in a cohort of 15 patients severely disabled by progressive supranuclear palsy ( PSP). While these findings may represent lesions within brainstem structures that control rapid eye movement sleep, the importance of medications and other contributing factors remains unknown ( Arnulf I, Paris, France, S21.004). PARKINSON DISEASE Visual hallucinations occur in approximately one-third of patients with Parkinson disease ( PD) who are treated chronically with dopaminergic agents. A recent functional MRI study of six patients with PD and chronic visual hallucinations suggests that a shifting of activated circuitry in the visual cortex may play a role in the pathophysiology of PD- associated visual hallucinations ( Goetz C, Chicago, IL, P03.061). Hypometabolism within the occipital lobes may also explain the recent finding that visual hallucinations in PD are significantly associated with visuospatial construction deficits ( Buck B, Vancouver, BC, Canada, P06.022). VISUAL PROCESSING Category- specific visual agnosia, associated with prosopagnosia, was reported in a 50- year- old man who was able to recognize man- made objects with significantly greater accuracy than living things. His deficits occurred postoperatively; the responsible lesion being located in the anteromedial aspect of the right occipital lobe ( Wolk D, Philadelphia, PA, P04.014). The line bisection task is commonly used for the evaluation of visuospatial neglect. Performance bias, however, may occur in normal subjects on the basis of eye dominance and monocular viewing of test lines (" pseudone-glect"). Among 22 normal adult volunteers, leftward bias Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 89 JNeuro- Ophthalmol, Vol. 23, No. 1, 2003 NEURO- OPHTHALMOLOGY AT LARGE on horizontal line bisections was frequently noted in right eye- dominant subjects, and was increased with monocular viewing of the test lines using the dominant OD. This study emphasized that these factors should be considered when interpreting results of the line bisection task ( Roth H, Gainesville, FL, P05.055). Gordon Holmes' contributions to mapping of the visual cortex during World War I were landmarks. The authors of this abstract assert that while Holmes correctly mapped essential features of the visual cortex, particularly the retinotopic organization, his reports substantially underestimated the area of cortex subserving central vision ( Lan-ska D, Heerlen, Netherlands, S51.008). Two patients with bilateral peristriate lesions had impaired thresholds for discriminating fine differences in shades of gray. The simultaneous brightness contrast illusion, in which the local contrast of black and white backgrounds influences lightness judgments, was exaggerated in two subjects with right occipital lesions who had normal thresholds. On the other hand, two subjects with left occipital lesions had normal thresholds and normal simultaneous brightness contrast, but an exaggerated White effect. In White effect, a set of occluding stripes of opposite polarity to the background are placed on top of the simultaneous brightness contrast display. The illusion follows the effect of the perceived background, not the stripes, even though the stripes have more contact with the gray target, against predictions based on local opponency. Investigations of lightness constancy suggest that left occipital lesions may impair the matching of local ratios of lightness, which compensates for variations in lighting and shadow, whereas right occipital lesions may impair global anchoring, which is needed to ignore irrelevant differences in background color ( Barton J, Boston, MA, S71.004). VERTIGO Isolated vertigo may represent a manifestation of acute stroke, particularly among patients with cerebrovascular risk factors. Among 31 patients in Singapore who were hospitalized and evaluated with MRI for acute isolated vertigo, 4 ( 13%) demonstrated acute infarcts on diffusion- weighted scans. Three infarcts involved the cerebellum; one involved the cerebral cortex, although the exact location was not specified. One or more cerebrovascular risk factors were present in all patients with infarcts ( Chan Y, Singapore, P04.055). LABYRINTHINE DYSFUNCTION Sensitivity and specificity for the head thrust test ( HTT) in the diagnosis of vestibular hypo function may be increased by pitching the head downward 20 degrees and by moving the head at unpredictable intervals. Overall sensitivity and specificity of the HTT to detect a peripheral vestibular lesion were 79% and 81%, respectively, in a cohort of 176 patients with unilateral or bilateral vestibular hypo-function ( Schubert M, Atlanta, GA, P06.031). NYSTAGMUS A study of six patients with nystagmus treated with contact lenses suggests that the benefit is likely due to improvement in refractive correction and the placebo effect. The nystagmus was not dampened by the contact lenses ( Biousse V, Atlanta, GA, S71.001). CRANIAL NEUROPATHIES In 40 patients aged between 19 and 44 years who had an isolated fourth cranial nerve palsy, the most common cause was decompensation of a long- standing phoria ( 65%). Other etiologies were trauma ( 18%), neurosurgical injury ( 5%), undetermined ( 5%), pituitary adenoma ( 2.5%), ventricular enlargement after a shunt for hydrocephalus ( 2.5%), and multiple sclerosis ( 2.5%). The recommendation is that patients with signs of long- standing phoria with decompensation require no further evaluation; in others, the history is often suggestive of the diagnosis ( Jacobson D, Marshfield, WI, S71.003). Laura J. Baker, MD, MSCE Philadelphia, Pennsylvania Mark L. Moster, MD Philadelphia, Pennsylvania Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 90 © 2003 Lippincott Williams & Wilkins |
