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Biomedical subjects

A C Arnold

Publications and source records attributed to A C Arnold.

At least 19 recordsLinked to original sources
PubMed2001

Horner's syndrome and dissection of the internal carotid artery after chiropractic manipulation of the neck.

PURPOSE: To report a case of Horner's syndrome and dissection of the internal carotid artery after chiropractic manipulation of the neck. METHODS: Case report. A 44-year-old woman with no prior ocular or vascular history presented with severe right-sided head and neck pain, ptosis, and miosis following chiropractic treatment for a strained right shoulder muscle. RESULTS: Magnetic resonance angiography of the neck and brain revealed a dissection of the right internal carotid artery as well as a suggestion of subtle dissection in the right vertebral artery. No significant brain abnormalities were noted on magnetic resonance imaging. Pharmacological testing was consistent with preganglionic oculosympathetic damage. CONCLUSION: Acute, painful Horner's syndrome as a manifestation of vascular dissection may be associated with chiropractic manipulation of the neck.

Adult↗
PubMed2001

Ischemic optic neuropathies.

Ischemia of the optic nerve may occur in several forms, usually associated with vasculopathic risk factors or vasculitis, and may present with various patterns of optic disc appearance and dysfunction. Though a proven therapy is not available for the most common syndromes, correct identification may present severe visual loss or systemic complications in some cases.

Diagnostic Techniques, Ophthalmological↗
PubMed2000

Bilateral blindness and lumbosacral myelopathy associated with high-dose carmustine and cisplatin therapy.

PURPOSE: To report the early ocular pathologic findings associated with high-dose carmustine and cisplatin therapy. METHODS: A patient with metastatic breast carcinoma developed an acute onset of branch retinal artery occlusion, bilateral blindness, and a myelopathy involving the lower extremities after high-dose chemotherapy and bone marrow transplant. RESULTS: Histopathologic examination of the eye and optic nerves at autopsy disclosed nerve fiber layer infarction secondary to right inferior temporal retinal artery thrombosis. Patchy necrosis of both optic nerves, medulla oblongata, and spinal cord was associated with focal small-vessel thrombosis. CONCLUSIONS: The syndrome of retinal vascular occlusion, optic neuropathy, and myelopathy is associated with the high-dose chemotherapeutic agents carmustine and cisplatin. The distribution of necrosis suggests an ischemic event rather than direct neurotoxic effects.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Control of visual symptoms in two men with birdshot retinochoroidopathy using low-dose oral corticosteroid therapy.

PURPOSE: To describe two men with birdshot retinochoroidopathy whose severe subjective visual symptoms were controlled by long-term use of low-dose oral corticosteroid therapy. METHOD: Chart review. RESULTS: Vision improved subjectively in both men after initial treatment with oral prednisone (1 mg/kg/day) and remained stable while taking 5 mg daily or less of prednisone for periods of 54 and 81 months. CONCLUSION: Some patients with birdshot retinochoroidopathy do well with no long-term therapy or only low-dose oral corticosteroids as long-term therapy.

Administration, Oral↗
PubMed1998

Deep transorbital approach to the apex and cavernous sinus.

Tumors of the orbital apex are difficult to approach through a standard lateral orbitotomy exposure. The transcranial approach has been described, but it requires an open craniotomy as well as dissection through the annulus of Zinn in its tight superior segment to reach intraconal and inferior lateral tumors. It is well recognized that the transcranial approach is optimal only for tumors of the superomedial orbital apex. Our study demonstrates that by enlarging the bony incision of a classic lateral orbitotomy to include a generous marginotomy and removing the deep sphenoid wing up to the superior orbital fissure, good exposure of the lateral orbital apex can be obtained. Tumors of the apex, including those that extend slightly into the cavernous sinus, can be removed from the cranial nerves and extraocular muscle origins in en face fashion, providing optimal ability to identify the delicate neurovascular structures of the orbital apex and avoid damage to them. The operating microscope is extremely useful for bony and soft tissue dissection. We report four benign tumors of the orbital apex removed using this approach. Two tumors encroached slightly into the cavernous sinus. Three of four patients were told that they had inoperable tumors. By use of the deep orbital apex approach described, all four tumors were successfully exposed and removed. Visual and motor function was unchanged or improved in all four patients, with the exception of one tumor that incorporated the inferior division of the third cranial nerve; in that patient, the transected nerve was anastomosed microscopically, and partial return of function was noted. The transorbital ophthalmic approach to tumors of the inferolateral orbital apex has significant potential advantages in comparison with a frontal craniotomy approach.

Adult↗
PubMed1997

Frequency-selective fat suppression MR imaging. Localized asymmetric failure of fat suppression mimicking orbital disease.

Our objectives were to further characterize an artifact related to the localized failure of the frequency-selective (FATSAT) fat suppression magnetic resonance (MR) imaging technique. We constructed two phantoms simulating human orbital anatomy and imaged them on a 1.5-T MR scanner using (FATSAT) and short T1 inversion recovery (STIR) techniques of fat suppression. The first phantom resembled orbit structural configurations; it was imaged in coronal and axial planes and in varying orientations with respect to the main magnetic field (Z axis) to study the features of the artifact and to reproduce the asymmetry seen in clinical cases. We designed the second phantom to enable quantification of the change in artifact size with change in orientation. We imaged the orbits of a normal human volunteer in similar planes and orientations, and compared the results to clinical cases demonstrating the artifact and true orbital disease. The artifact identified with localized failure of FATSAT fat suppression manifested as regions of hyperintensity maximal at fat-air interfaces, with gradual fading of the increased signal with distance from the interfaces. The artifact was most prominent when the interfaces were perpendicular to the axis of the main magnetic field (Z axis). The regions of increased brightness obscured normal orbital structures but were not associated with alterations in the geometry of these structures. Changes in orientation of the interfaces with respect to the Z axis, both in the phantoms and normal volunteer, reproduced the asymmetry of fat suppression failure seen in clinical cases. The relationship of size of the artifact to change in orientation was non-linear. The artifact was not seen on STIR images. We concluded that failure of FATSAT fat suppression may mimic orbital disease, particularly if asymmetric. As predicted by the Maxwell electromagnetism equation, slight variations in orientation of the fat-air interface to the Z axis may produce large asymmetries in fat suppression failure in the orbit. Confirmation may require either comparison with additional pulse sequences [T1-weighted spin echo (T1W SE) or STIR] or repositioning the patient's head to check for persistence of the finding with varying orientations.

Adipose Tissue↗
PubMed1996

Fluorescein angiography in nonischemic optic disc edema.

OBJECTIVE: To determine whether nonischemic optic disc edema is associated with significant delay in fluorescein angiographic optic disc filling. METHODS: Fluorescein angiograms from 16 patients with acute papillitis, five with papilledema, and one with optic disc edema from orbital cavernous hemangioma were compared with those of age-matched controls. Early views of the optic disc were evaluated for onset of central retinal artery dye filling and both onset and completion of choroidal and prelaminar optic disc dye filling. Data were compared with our previously published figures for patients with nonarteritic anterior ischemic optic neuropathy (NAION) and a new group of patients aged 46 years and younger with NAION (NAIONy). Subgroup analysis was performed on data from patients with papillitis. RESULTS: Mean onset or completion of filling was not significantly delayed compared with controls for the central retinal artery, choroid, or prelaminar optic disc in patients with nonischemic optic disc edema, including the subgroup of patients with papillitis. In comparison, significant delay had been detected for onset and filling of prelaminar disc in typical NAION; similar significant delay was noted in this study for patients with NAIONy. No patients with nonischemic optic disc edema (including those with papillitis) demonstrated delay of disc filling by at least 5 seconds, while this feature was detected in 76% of patients with typical NAION and 62% of those with NAIONy. CONCLUSIONS: Optic disc filling delay is common in typical NAION and NAIONy; it is not a feature of nonischemic optic disc edema. This characteristic may aid in the differentiation of NAION from papillitis.

Acute Disease↗
PubMed1996

The effect of aspirin on the visual outcome of nonarteritic anterior ischemic optic neuropathy.

PURPOSE: To examine the effect of aspirin use on the visual outcome of nonarteritic anterior ischemic optic neuropathy. METHODS: This retrospective case-controlled study included 23 patients who used aspirin regularly before and during the course of nonarteritic anterior ischemic optic neuropathy and 55 control patients with nonarteritic anterior ischemic optic neuropathy. Snellen visual acuity in logMAR and mean deviation on automated perimetry were compiled from the initial and final follow-up examinations. RESULTS: The comparisons of patients who took aspirin with control patients disclosed that neither initial logMAR (P = .36) nor the follow-up logMAR (P = .95) data differed significantly. There was no significant difference between the groups for the initial (P = .60) and the follow-up mean deviation (P = .41). CONCLUSIONS: Aspirin use does not improve the visual outcome of patients with nonarteritic anterior ischemic optic neuropathy. Additional studies are needed to further elucidate this issue.

Aged↗
PubMed1996

Hyperbaric oxygen therapy for nonarteritic anterior ischemic optic neuropathy.

PURPOSE: To evaluate the effectiveness of hyperbaric oxygen therapy in reducing optic nerve damage in acute nonarteritic anterior ischemic optic neuropathy. METHODS: Twenty-two eyes in 20 patients with acute nonarteritic anterior ischemic optic neuropathy were treated with hyperbaric oxygen (100% oxygen, 2.0 absolute atmospheres of pressure) in two 90-minute inhalation sessions per day for ten days. Changes in mean visual acuity and mean sensitivity loss were compared with those of 27 untreated control patients with acute nonarteritic anterior ischemic optic neuropathy, and proportions of patients with a change in acuity or mean sensitivity loss were compared with controls. Similar analysis was performed on subgroups based on time delay from symptom onset to therapy. RESULTS: Mean values for visual acuity were increased at final examination in both groups; although the increase was greater in controls, the difference was not statistically significant. Mean visual field sensitivity loss was minimally increased; although the increase was smaller in controls, the difference between groups was not significant. There was no significant difference between groups in proportions of patients with change in acuity score or mean sensitivity loss. Stratification by time delay to therapy did not suggest that treatment within nine days produced better visual results than that for either controls or those treated later. CONCLUSIONS: Hyperbaric oxygen therapy using 100% oxygen and 2.0 absolute atmospheres of pressure did not produce a significant improvement in visual acuity or visual field for patients with acute nonarteritic anterior ischemic optic neuropathy.

Acute Disease↗
PubMed1996

Bilateral ocular neuromyotonia: oculographic correlations.

We observed bilateral ocular neuromyotonia in a 45-year-old woman previously treated for a pituitary adenoma. She experienced episodic diplopia attributable to dysfunction of muscles innervated by both oculomotor nerves. Oculography demonstrated episodes of tonic adduction with slowing and restriction of saccades in all directions, but no oscillatory component. A combination of impaired phasic firing in agonist muscles and tonic contraction of antagonist muscles explains the paroxysms of eye movement limitation in this disorder.

Female↗
PubMed1995

Metastasis of adenocarcinoma of the lung to optic nerve sheath meningioma.

A 71-year-old woman developed chronic progressive visual loss in the right eye and computed tomographic scan showed enlargement of the intraorbital optic nerve consistent with optic nerve sheath meningioma. Over 12 years, the contralateral optic nerve was not clinically affected, and serial neuroradiologic imaging showed no evidence of intracranial tumor extension. Death occurred from metastatic adenocarcinoma of the lung 14 years after initial visual loss. Examination of the postmortem specimen of optic nerve and chiasm revealed extradural extension of meningioma with spread to the region of the optic chiasm and hypothalamus. A large focus of metastatic adenocarcinoma was present within the intraorbital portion of the meningioma. Carcinoma metastatic to intracranial meningioma is rare; to our knowledge, this is the first reported case in an optic nerve sheath meningioma. Neuroimaging may be inadequate to predict the value of tumor excision in preventing intracranial spread of optic nerve sheath meningioma.

Adenocarcinoma↗
PubMed1995

Fluorescein angiographic characteristics of the optic disc in ischemic and glaucomatous optic neuropathy.

Fluorescein angiography has been utilized to study the microvascular supply of the prelaminar optic disc and the peripapillary choroid. Observation of hypofluorescence of these structures both in patients with anterior ischemic optic neuropathy (AION) and with chronic open-angle glaucoma (COAG) has led to speculation as to the pathogenetic mechanism in each disorder. In AION, studies consistently show defective filling of the disc without atrophy, suggesting hypoperfusion as a primary mechanism. In COAG, defective filling is common, but typically occurs in regions of atrophy or increased cupping, which may show hypofluorescence as a nonspecific sequela of disc tissue loss. The hypofluorescence seen in some ocular hypertensive patients supports but does not confirm a primary vascular role in the pathogenesis of COAG. Peripapillary choroidal filling delay outside the range of normal is consistently seen in arteritic AION, but not in either nonarteritic AION or COAG. This finding suggests that any vasculopathy present in these disorders is distal within the branches of the posterior ciliary artery system.

Chronic Disease↗
PubMed1995

Anterior ischemic optic neuropathy.

AION is the most common acute optic neuropathy in patients over 50 and, although the diagnosis is often straightforward, our methods for managing the associated visual loss are inadequate. Analysis of the wealth of information gained from recent clinical studies may move us closer to an effective therapy.

Acute Disease↗
PubMed1995

Magnetic resonance imaging of the brain in nonarteritic ischemic optic neuropathy.

We wished to determine whether the number of central nervous system (CNS) white matter lesions on magnetic resonance imaging (MRI) is increased in patients with nonarteritic ischemic optic neuropathy (NAION). T2-Weighted axial images of the brain in 13 patients with acute NAION and 16 age-matched controls were used to tabulate the number of subcortical and periventricular white matter lesions. Groups were compared by t test for means, the Wilcoxon-Mann-Whitney rank-sum test, and chi-square test for proportions with at least one lesion. The mean number of CNS white matter ischemic lesions in the NAION group was 4.0 (range 0-20) as compared to 1.4 (range 0-7) in the control group. The difference in these samples suggested a significant increase in NAION (p = 0.069, rank-sum test). The proportions of patients with at least one lesion were not significantly different (53.8% NAION vs. 56.3% controls). The data suggest an increased number of CNS white matter lesions in patients with NAION.

Acute Disease↗
PubMed1994

Progression of retinal nerve fiber myelination in childhood.

Myelination of the visual pathway has been demonstrated to occur by as early as 32 weeks of gestation and continues for several years into early childhood. In most cases, the process of myelination does not extend beyond the lamina cribrosa. We studied a boy with progressive myelination that extended beyond the lamina cribrosa to the retinal nerve fibers. Ocular examination at 15 months of age disclosed myelinated optic nerve fibers of the right eye. We repeated examination every two to six months and found progression of the extent and density of the myelinated nerve fibers. Despite the marked myelination, the patient did not experience a decrease in visual acuity.

Follow-Up Studies↗
PubMed1994

Fluorescein angiography in acute nonarteritic anterior ischemic optic neuropathy.

Fundus fluorescein angiograms from 41 patients with nonarteritic anterior ischemic optic neuropathy of less than three weeks' duration were compared with those from 43 age-matched control subjects. Patients with disease showed statistically significant delay in both the onset and the time to completion of prelaminar optic disk filling. Neither onset nor completion of peripapillary choroidal filling were markedly delayed when compared with control subjects. Frequency of occurrence of delayed filling within peripapillary choroidal watershed zones was not increased in patients with disease. There was no consistent correlation by quadrant between optic disk filling delay, choroidal filling delay, optic disk swelling or hyperfluorescence, and visual field deficit. No trend for change in characteristics was found with increasing time interval from onset of symptoms to performance of angiography. Fluorescein angiography in nonarteritic anterior ischemic optic neuropathy demonstrates delayed optic disk filling without consistent relation to adjacent peripapillary choroidal filling delay or other disease findings.

Acute Disease↗