1/88. 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 = 1keywords = nervous system (Clic here for more details about this article) |
2/88. 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 = 1keywords = nervous system (Clic here for more details about this article) |
3/88. Dysgenesis of the internal carotid artery associated with transsphenoidal encephalocele: a neural crest syndrome?We describe two original cases of internal carotid artery dysgenesis associated with a malformative spectrum, which includes transsphenoidal encephalocele, optic nerve coloboma, hypopituitarism, and hypertelorism. Cephalic neural crest cells migrate to various regions in the head and neck where they contribute to the development of structures as diverse as the anterior skull base, the walls of the craniofacial arteries, the forebrain, and the face. Data suggest that the link between these rare malformations is abnormal neural crest development.- - - - - - - - - - ranking = 0.38887688129989keywords = brain (Clic here for more details about this article) |
4/88. A bad eye and a sore lip.A 48-year-old woman developed painful visual loss in the left eye, meningismus, and painful oral ulcers. magnetic resonance imaging of the brain with gadolinium demonstrated enhancement of the left optic nerve. Lumbar puncture showed a lymphocytic pleocytosis, and a biopsy specimen of one of the oral ulcerations was consistent with Behcet's disease. epidemiologic factors and diagnostic criteria for Behcet's disease are discussed.- - - - - - - - - - ranking = 0.38887688129989keywords = brain (Clic here for more details about this article) |
5/88. Visual-evoked potential evidence of chiasmal hypoplasia.PURPOSE: To show that chiasmal hypoplasia or aplasia need not be an isolated developmental anomaly and to examine the spectrum of associated clinical findings to explore the possibility that these patients may represent a phenotypic manifestation of a developmental gene anomaly. DESIGN: An observational case series. PARTICIPANTS: Five infants, between several weeks and 7 months of age, in whom the electrophysiologic characteristic of chiasmal hypoplasia had been noted were included. methods: Flash electroretinography and flash and pattern visual-evoked potentials (VEPs) were elicited from all patients. Clinical ophthalmologic examinations, including funduscopy, were performed, and all patients had magnetic resonance imaging (MRI) brain scans. MAIN OUTCOME MEASURES: The occipital distribution of monocular VEP response peaks was studied. The symmetry of lateral channel responses was compared for monocular stimulation. RESULTS: All five patients had a crossed asymmetry in the monocular VEP occipital distribution, which is consistent with a paucity of fibers crossing at the chiasm. The MRI findings supported this electrophysiologic observation, illustrating degrees of chiasmal hypoplasia and variable coincidence of other midline abnormalities of the brain. Optic disc appearances varied from normal to hypoplastic and colobomatous. CONCLUSIONS: The ophthalmologic and MRI findings of five patients who showed a crossed asymmetry in monocular flash VEPs are consistent with a paucity of axons crossing at the chiasm. The similarities between achiasmia in humans and mice due to a Pax2 gene anomaly are discussed.- - - - - - - - - - ranking = 0.77775376259979keywords = brain (Clic here for more details about this article) |
6/88. Visual function and brain organization in non-decussating retinal-fugal fibre syndrome.functional neuroimaging, psychophysical and electrophysiological investigations were performed in a patient with non-decussating retinal-fugal fibre syndrome, an inborn achiasmatic state in which the retinal projections of each eye map entirely to the ipsilateral primary visual cortex. Functional magnetic resonance imaging (fMRI) studies showed that for monocularly presented simple visual stimuli, only the ipsilateral striate cortex was activated. Within each hemisphere's striate cortex, the representation of the two hemifields overlapped extensively. Despite this gross miswiring, visual functions that require precise geometrical information (such as vernier acuity) were normal, and there was no evidence for the confounding of visual information between the overlapping ipsi-lateral and contralateral representations. contrast sensitivity and velocity judgments were abnormal, but their dependence on the orientation and velocity of the targets suggests that this deficit was due to ocular instabilities, rather than the miswiring per se. There were no asymmetries in performance observed in visual search, visual naming or illusory contour perception. fMRI analysis of the latter two tasks under monocular viewing conditions indicated extensive bilateral activation of striate and prestriate areas. Thus, the remarkably normal visual behavior achieved by this patient is a result of both the plasticity of visual pathways, and efficient transfer of information between the hemispheres.- - - - - - - - - - ranking = 1.5555075251996keywords = brain (Clic here for more details about this article) |
7/88. Optic nerve aspergillosis: report of a case diagnosed by fine-needle aspiration biopsy.The aim of this study was to describe the fine-needle aspiration biopsy (FNAB) procedure in patient with a optic nerve lesion. A case of optic nerve and brain aspergillosis, an infrequent condition that can mimic tumor or tumor-like lesions, is reported. The patient was studied by CT and MRI and definite diagnosis was established by means of an ultrasound-guided FNAB. Specimen preparation revealed the presence of multiple hyphae of aspergillus fumigatus in the optic nerve lesion. The FNAB procedure is a safe and reliable diagnostic method for suspected intraorbitary tumors and tumor-like conditions especially when other less-invasive modalities have failed to establish the diagnosis and when cytologic confirmation is needed to implement aggressive therapy.- - - - - - - - - - ranking = 0.38887688129989keywords = brain (Clic here for more details about this article) |
8/88. Ophthalmic manifestations of neonatal onset multisystem inflammatory disease.PURPOSE: To report the ophthalmic manifestations of neonatal onset multisystem inflammatory disease, a recently recognized, rare systemic disorder characterized by the triad of arthropathy, rash, and abnormal central nervous system development. METHOD: Case report. RESULTS: A 2-year-old female with neonatal onset multisystem inflammatory disease presented with visual acuity of fix and follow with each eye, bilateral optic nerve head pallor and gliosis, as well as marked sheathing of the peripapillary vessels. No vitreous inflammation or macular edema was found. visual acuity was stable from the neonatal period through the 3 months of follow-up after the changes involving the optic nerve heads and peripapillary vessels were observed (a total of 33 months). CONCLUSIONS: This report provides a description of the ocular manifestations of neonatal onset multisystem inflammatory disease and supports earlier suggestions that swelling of the optic nerve heads can occur. In this case, optic nerve head pallor may have been a sequela of such swelling. The pathogenesis of neonatal onset multisystem inflammatory disease is unknown.- - - - - - - - - - ranking = 3.9746590348671keywords = central nervous system, nervous system (Clic here for more details about this article) |
9/88. Superficial siderosis of the central nervous system: a 70-year-old man with ataxia, depression and visual deficits.BACKGROUND: Superficial siderosis of the central nervous system (SSNS) is caused by cerebral, cerebellar and spinal cord tissue deposition of hemosiderin, often related to repeated episodes of subarachnoid hemorrhage. Typical symptoms include ataxia, sensorineural deafness and dementia. methods AND RESULTS: An elderly patient with SSNS presenting with ataxia, depression and severe visual impairment was admitted to the Unit of geriatrics of the University Hospital of Perugia, italy. Late diagnosis and the association of symptoms with SSNS prevented the possible surgical treatment of the disease. CONCLUSIONS: Recognition of uncommon clinical variants may facilitate early diagnosis of SSNS and improve therapeutic results.- - - - - - - - - - ranking = 19.873295174335keywords = central nervous system, nervous system (Clic here for more details about this article) |
10/88. Laser in situ keratomileusis-induced optic neuropathy.OBJECTIVE: To report a case of bilateral optic neuropathy after bilateral laser-assisted in situ keratomileusis (LASIK) surgery. DESIGN: Observational case report. methods: Complete eye examination with detailed evaluation of the optic nerve, detailed medical history, stereo disc photographs, GDx Nerve Fiber Analyzer testing, Humphrey 24-2 SITA visual field testing, diurnal intraocular pressure measurement, serologic evaluation, and magnetic resonance imaging of the brain and orbits. MAIN OUTCOME MEASURES: Optic nerve status, visual field status, and visual acuity. RESULTS: A subject with previously healthy optic nerves had bilateral optic neuropathy develop after LASIK surgery. This neuropathy manifested with a subjective decrease in visual field, normal visual acuity, normal color vision, relative afferent pupillary defect, increased cupping of the optic nerve with focal neuroretinal rim defects, decreased nerve fiber layer thickness, and nerve fiber bundle-type visual field defects. The subject had no other risk factors for optic neuropathy. No other cause of neuropathy was identified. CONCLUSIONS: Optic neuropathy is a potential vision-threatening complication of LASIK surgery. This complication may be due to barotrauma or ischemia related to extreme elevation of intraocular pressure by the suction ring. Careful examination of the optic nerve before and after LASIK surgery is warranted.- - - - - - - - - - ranking = 0.38887688129989keywords = brain (Clic here for more details about this article) |
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