1/349. carbon monoxide poisoning causes optic neuropathy.PURPOSE: To describe the electrophysiological and psychophysical effects of carbon monoxide (CO) poisoning on visual function. methods: Three patients are presented who suffered CO poisoning, two due to suicide attempts and one in the course of a road traffic accident. After a full ocular examination, Goldmann visual fields, flash and pattern visual evoked potentials (VEPs) and flash and pattern electroretinograms (ERGs) were tested. RESULTS: electrophysiology showed reduced or absent N95 components of the pattern ERG and delayed, reduced VEPs. A positive-negative-positive (PNP) VEP waveform was seen in two cases. In one case, where presentation occurred at an early stage, visual and electrophysiological function was improved with hydroxycobalamine. CONCLUSIONS: The combination of ERG and VEP findings suggest that CO poisoning can cause a toxic optic neuropathy that may have a similar aetiological mechanism to that in tobacco amblyopia. Early treatment with hydroxycobalamine may be of some benefit.- - - - - - - - - - ranking = 1keywords = neuropathy (Clic here for more details about this article) |
2/349. Acquired convergence-evoked pendular nystagmus in multiple sclerosis.Nystagmus seen only with convergence is unusual. We describe four cases of acquired convergence-evoked pendular nystagmus in patients with multiple sclerosis. The nystagmus was horizontal and asymmetric in all patients. eye movement recordings in one subject showed a conjugate rather than a convergent-divergent relationship of the phase of movement between the two eyes. All patients had evidence of optic neuropathy and cerebellar dysfunction. Occlusion of either eye during fixation of near targets led to divergent drift of the covered eye and a decrease in nystagmus. Intravenous scopolamine reduced nystagmus in one patient. Base-in prisms alleviated symptoms of oscillopsia at near and improving reading visual acuity. Convergence-evoked pendular nystagmus may be more common than currently appreciated, particularly among patients with multiple sclerosis.- - - - - - - - - - ranking = 0.2keywords = neuropathy (Clic here for more details about this article) |
3/349. Inefficiency of the anticoagulant therapy in the regression of the radiation-induced optic neuropathy in Cushing's disease.radiation-induced optic neuropathy is a rare complication (prevalence less than 1%) following radiotherapy of the sellar region. However, the vasculopathy in Cushing's disease predisposes to radiation-induced injury. We report the case of a 24-year-old man with Cushing's disease since he was 16. The hormonal study including bilateral inferior petrosal sinus catheterization diagnosed a pituitary right lesion, but imagiology was always negative. He underwent a transsphenoidal microadenomectomy and the pathological study showed the presence of corticotrophic hyperplasia but no adenoma. Secondary hypothyroidism and hypogonadism as well as permanent diabetes insipidus were diagnosed and because the patient was not cured he underwent a second transsphenoidal total hypophysectomy. After that and because he was still hypercortisolemic, pituitary external irradiation was given in a total dose of 6000 rad. Six months later he developed progressive bilateral visual loss. Cerebral MR revealed focal enhancement of the enlarged optic nerves and chiasm, associated with demyelination areas of the posterior visual pathways. Treatment was tried first with high doses of corticosteroids and later with anticoagulants-heparin EV. 1000 U/h during 7 days followed by warfarin, but unsuccessfully, probably because the patient was already amaurotic at the beginning of the last treatment.- - - - - - - - - - ranking = 1keywords = neuropathy (Clic here for more details about this article) |
4/349. Optic neuropathy in systemic lupus erythematosus and antiphospholipid syndrome (APS): clinical features, pathogenesis, review of the literature and proposed ophthalmological criteria for APS diagnosis.Optic neuropathy is a well-known ocular manifestation occurring in patients with systemic lupus erythematosus (SLE), and it remains one of the major causes of blindness in these patients. We report data from six SLE patients with optic neuropathy, one of whom was considered to have antiphospholipid syndrome (APS). This patient had monolateral optic neuropathy, whereas the other five SLE patients had bilateral optic nerve disease. We believe that the monolateral occurrence of optic neuropathy in our patient can be considered as a 'focal' neurological disease due to a thrombotic event involving the ciliary vasculature. Conversely, bilateral optic nerve damage in SLE could be considered to be a 'general' neurological disease due to different immunological mechanisms, such as vasculitis. Additionally, the literature on SLE patients affected by optic neuropathy is reviewed to evaluate the major clinical features, particularly neurological features. In reviewing the literature, it appears that bilateral optic neuropathy in SLE occurs more frequently than monolateral optic neuropathy, and the main neurological manifestation seen in these patients is transverse myelitis, particularly in SLE patients with bilateral optic nerve disease. Finally, we propose a clinico-ophthalmological spectrum of APS and outline the ocular clinical manifestations that can be considered as diagnostic for the syndrome.- - - - - - - - - - ranking = 2.2keywords = neuropathy (Clic here for more details about this article) |
5/349. Acquired mitochondrial impairment as a cause of optic nerve disease.BACKGROUND: blindness from an optic neuropathy recently occurred as an epidemic affecting 50,000 patients in cuba (CEON) and had clinical features reminiscent of both tobacco-alcohol amblyopia (TAA) and Leber's hereditary optic neuropathy (Leber's; LHON). Selective damage to the papillomacular bundle was characteristic, and many patients also developed a peripheral neuropathy. Identified risk factors included vitamin deficiencies as well as exposure to methanol and cyanide. In all 3 syndromes, there is evidence that singular or combined insults to mitochondrial oxidative phosphorylation are associated with a clinically characteristic optic neuropathy. PURPOSE: First, to test the hypothesis that a common pathophysiologic mechanism involving impairment of mitochondria function and, consequently, axonal transport underlies both genetic optic nerve diseases such as Leber's and acquired toxic and nutritional deficiency optic neuropathies. According to this hypothesis, ATP depletion below a certain threshold leads to a blockage of orthograde axonal transport of mitochondria, which, in turn, leads to total ATP depletion and subsequent cell death. Second, to address several related questions, including (1) How does impaired energy production lead to optic neuropathy, particularly since it seems to relatively spare other metabolically active tissues, such as liver and heart? (2) Within the nervous system, why is the optic nerve, and most particularly the papillomacular bundle, so highly sensitive? Although there have been previous publications on the clinical features of the Cuban epidemic of blindness, the present hypothesis and the subsequent questions have not been previously addressed. methods: patients in cuba with epidemic optic neuropathy were personally evaluated through a comprehensive neuro-ophthalmologic examination. In addition, serum, lymphocytes for dna analysis, cerebrospinal fluid (CSF), sural nerves, and eyes with attached optic nerves were obtained from Cuban patients, as well as from Leber's patients, for study. Finally, we developed an animal model to match the low serum folic acid and high serum formate levels found in the CEON patients, by administering to rats low doses of methanol after several months of a folic acid-deficient diet. Optic nerves and other tissues obtained from these rats were analyzed and compared with those from the Cuban patients. RESULTS: patients from the Cuban epidemic of optic neuropathy with clinical evidence of a selective loss of the papillomacular bundle did much better once their nutritional status was corrected and exposure to toxins ceased. patients with CEON often demonstrated low levels of folic acid and high levels of formate in their blood. Histopathologic studies demonstrated losses of the longest fibers (in the sural nerve) and those of smallest caliber (papillomacular bundle) in the optic nerve, with intra-axonal accumulations just anterior to the lamina cribrosa. Our animal model duplicated the serologic changes (low folic acid, high formate) as well as these histopathologic changes. Furthermore, ultrastructural examination of rat tissues demonstrated mitochondrial changes that further matched those seen on ultrastructural examination of tissues from patients with Leber's. CONCLUSION: mitochondria can be impaired either genetically (as in Leber's) or through acquired insults (such as nutritional or toxic factors). Either may challenge energy production in all cells of the body. While this challenge may be met through certain compensatory mechanisms (such as in the size, shape, or number of the mitochondria), there exists in neurons a threshold which, once passed, leads to catastrophic changes. This threshold may be that point at which mitochondrial derangement leads to such ATP depletion that axonal transport is compromised, and decreased mitochondrial transport results in even further ATP depletion. neurons are singularly dependent on the axonal transport of mitochondria. (- - - - - - - - - - ranking = 1.4keywords = neuropathy (Clic here for more details about this article) |
6/349. Anterior ischaemic optic neuropathy in a patient with optic disc drusen.BACKGROUND: Although visual field defects are well-known complications of optic disc drusen, reduction in visual acuity with this condition is rare. METHOD/RESULTS: We report on a 68-year-old male with bilateral optic disc drusen who presented with monocular loss of vision in the right eye associated with an inferior altitudinal visual field defect and signs consistent with acute anterior ischaemic optic neuropathy, confirmed on fluorescein angiography. He also had a left inferior nasal step, but no evidence of glaucomatous cupping. The disc drusen were documented clinically and on B scan ultrasound and computed tomography. CONCLUSIONS: The diagnosis of acute anterior ischaemic optic neuropathy should be considered in patients with optic disc drusen who present with reduced visual acuity, particularly when the visual loss has been acute and non-progressive and is associated with altitudinal field loss and characteristic fluorescein angiography signs.- - - - - - - - - - ranking = 1.2keywords = neuropathy (Clic here for more details about this article) |
7/349. cimetidine-associated optic neuropathy.Two cases of optic neuropathy associated with cimetidine therapy are reported. Recovery occurred in both after drug withdrawal. Rechallenge with the same agent totally reproduced the condition in the first case. cimetidine exerts an unequivocal toxicity on the central and peripheral nervous systems. Since its introduction in 1976, it has been used in over 100 million patients, but only 3 cases of optic neuropathy have been reported as far as we know. Although the mechanism of toxicity is still unclear, cimetidine is a well-recognized zinc chelator, and zinc deficiency has been implicated in causing optic neuropathy. Hence, it can be concluded that cimetidine produced this toxicity through its mechanism of zinc chelation. However, close ophthalmic follow-up of such patients is unnecessary, but an unexplained visual deterioration should prompt immediate drug withdrawal.- - - - - - - - - - ranking = 1.4keywords = neuropathy (Clic here for more details about this article) |
8/349. New technologies for diagnosing and monitoring glaucomatous optic neuropathy.BACKGROUND: Recently, instruments have been developed to provide real-time, quantitative measurements of the optic disc and retinal nerve fiber layer (RNFL) for use in glaucoma management. Our objective is to (1) provide an overview of two of these instruments, the confocal scanning laser ophthalmoscope (Heidelberg retina Tomograph, HRT) and scanning laser polarimeter (Nerve Fiber Analyzer, NFA) and (2) compare measurements obtained with these instruments to clinical features used in the diagnosis of glaucoma. methods: Twenty glaucoma patients, 4 normal subjects and 20 glaucoma subjects were included. All subjects had images obtained with the HRT and NFA, and RNFL and optic disc photography completed within 5 weeks of each other. The HRT results were compared with qualitative evaluation of stereophotographs of the optic disc, and NFA results were compared against a semi-quantitative RNFL photograph severity score. RESULTS: Twenty-five (57%) subjects had thinning of the neuroretinal rim identified by evaluation of stereoscopic optic disc photographs. Despite overlap, HRT measurements of rim volume, rim area, and rim/disc ratio were significantly smaller in eyes with evidence of rim thinning than in eyes with no evidence of rim thinning. Moderate to severe RNFL damage was detected by evaluation of photographs in 25 (57%) of subjects. NFA RNFL thickness measures were smaller in eyes with moderate to severe RNFL damage than in relatively healthy eyes. CONCLUSIONS: Previous studies have documented the reproducibility of these instruments and suggested analytic techniques for improving their ability to differentiate between normal and glaucoma eyes. Our results indicate that despite overlap in values, these instruments provide measurements that reflect clinically relevant features of the optic disc and RNFL. Whether these technologies can improve our ability to detect glaucomatous progression over time needs to be determined with well-designed longitudinal studies and comparison with established diagnostic techniques for evaluating glaucomatous optic neuropathy.- - - - - - - - - - ranking = 1keywords = neuropathy (Clic here for more details about this article) |
9/349. Optic neuropathy in Behcet's disease. Report of two cases.Orbital magnetic resonance imaging demonstrated increased signal of the optic nerve in short time inversion recovery (STIR) images of two young women with unilateral visual blurring. In both, recurrent oral and genital ulcerations and papulopustular lesions appeared within the next 14-15 months, respectively, allowing a diagnosis of Behcet's disease. Optic neuropathy may be an early manifestation of Behct's disease and clinical follow-up is crucial for its diagnosis.- - - - - - - - - - ranking = 1keywords = neuropathy (Clic here for more details about this article) |
10/349. Results of transmedial-canthal ethmoidal decompression for severe dysthyroid optic neuropathy.PURPOSE: To study the effects of ethmoidal wall (one-wall) decompression using a transmedial-canthal approach (transmedial-canthal ethmoidectomy) for the treatment of dysthyroid optic neuropathy. methods: The ethmoidal wall and air cells were completely removed using a transmedial-canthal approach in 6 eyes of 4 patients (mean age = 55 years; age range, 46-69 years) with dysthyroid optic neuropathy. Similar surgery was performed on 2 contralateral eyes in 2 of the patients for cosmetic reasons. The preoperative corrected visual acuity in the 6 eyes ranged from hand motion to 20/100. Centrocecal scotomas were detected using automatic static threshold perimetry in the 6 eyes. RESULTS: After transmedial-canthal ethmoidectomy, the corrected visual acuity improved to better than 20/20 in the 6 eyes, and the centrocecal scotomas had almost completely resolved. There were no major complications, such as cerebrospinal fluid leakage or diplopia associated with the surgery. There were no relapses during an average follow-up period of 29 months. CONCLUSIONS: These findings suggest that transmedial-canthal ethmoidectomy is an effective and safe therapy for dysthyroid optic neuropathy.- - - - - - - - - - ranking = 1.4keywords = neuropathy (Clic here for more details about this article) |
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