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Biomedical subjects

Neil R Miller

Publications and source records attributed to Neil R Miller.

At least 37 records · Page 2Linked to original sources
PubMed2004

Clinical features associated with lesions other than pituitary adenoma in patients with an optic chiasmal syndrome.

PURPOSE: Pituitary adenomas are the most common cause of an optic chiasmal syndrome, and treatment of these lesions is considerably different from the treatment of most of the other lesions in this region. Although the diagnosis of a pituitary adenoma is usually inferred from the results of neuroimaging, lesions other than pituitary adenomas can have an appearance that suggests an adenoma. The objective of our study was to determine whether there are clinical findings that suggest a lesion producing a chiasmal syndrome is something other than a pituitary adenoma. DESIGN: Retrospective, case-controlled, analysis of medical record data. METHODS: The records of the Neuro-Ophthalmology Unit of the Wilmer Eye Institute were searched for patients with a chiasmal syndrome who had been evaluated before treatment and for whom pathologic or laboratory confirmation of the etiology was available. Presenting clinical features of these patients were recorded, and analyses with both a single variable and multiple variables were performed to determine whether there were any features that could identify with a high degree of probability the etiology of the lesion producing the syndrome. RESULTS: The search revealed 149 patients who met the inclusion criteria, including 90 patients with pituitary adenomas and 59 patients with other lesions. Variables that were highly suggestive of an etiology other than pituitary adenoma included symptomatic visual loss, younger age, unilateral optic disk pallor, a relative afferent pupillary defect, and an absolute or a complete visual field defect or one was greater inferiorly than superiorly. CONCLUSION: Although no single clinical feature can be used to determine the specific nature of a lesion that produces an optic chiasmal syndrome, certain features are highly suggestive of an etiology other than pituitary adenoma. When these features are present, the likelihood that a suprasellar lesion is a pituitary adenoma is much lower, regardless of the appearance on neuroimaging.

Adenoma↗
PubMed2004

Plasma ghrelin levels are normal in obese patients with idiopathic intracranial hypertension (pseudotumor cerebri).

PURPOSE: Idiopathic intracranial hypertension (IIH) occurs predominantly in young, obese women. Weight loss may alleviate symptoms of IIH yet may be difficult to achieve. Ghrelin, a gastric hormone, is involved in normal body weight and appetite regulation. Its levels are elevated in syndromes of overeating and decline in simple obesity. We postulated that fasting plasma ghrelin levels are elevated in IIH patients and that the typical postprandial decline in plasma ghrelin may not occur. DESIGN: Prospective, observational case-control study. METHODS: Prospective study. SETTING: University hospital and clinic. STUDY POPULATION: Sixty-five patients with a diagnosis of IIH and 25 obese control patients (screened for IIH symptoms). Patients with intracranial abnormalities or a history of gastric surgery were excluded. OBSERVATION PROCEDURE: Fasting plasma ghrelin, leptin, and insulin levels were assessed between 8 am and 10 am. Subjects were fed a standard breakfast, and postprandial ghrelin levels were measured 30 minutes later. RESULTS: Fasting plasma ghrelin levels negatively correlated with body mass index in both IIH subjects (r = -.48) and controls; leptin showed a positive correlation with body mass index in both IIH (r =.59) and controls. Levels were not significantly different between the groups. Postprandial ghrelin declined by 71 +/- 31 (95% CI) pg/ml in the IIH group and 71 +/- 35 (95% CI) pg/ml in the control group. CONCLUSION: Plasma ghrelin levels, both fasting and postprandial, do not differ between IIH patients and obese controls. Obese IIH patients should be encouraged to lose weight and referred for medical weight loss management to maximize their chances of alleviating their symptoms.

Adult↗
PubMed2004

A randomized, placebo-controlled, crossover clinical trial of super blue-green algae in patients with essential blepharospasm or Meige syndrome.

PURPOSE: To evaluate the effectiveness of super blue-green algae (SBGA) supplements on the severity of essential blepharospasm treated with botulinum toxin A injections. DESIGN: Double-masked, placebo-controlled, two-period, crossover randomized trial. PATIENTS AND METHODS: The study was carried out in patients with essential blepharospasm or Meige syndrome undergoing routine treatment with botulinum toxin A injections. INTERVENTION: Patients were randomly assigned to either SBGA capsules or placebo. After 6 months of treatment, patients underwent a 6-month washout period with no treatment, then were administered the alternate treatment for an additional 6 months, thus serving as their own controls. MAIN OUTCOME MEASURES: Video documentation of blink rate and involuntary facial movements, time between botulinum toxin A injections, and patients' subjective assessment of the impact of blepharospasm on functioning were obtained at the beginning and end of the first and second (crossover) treatment periods. RESULTS: A total of 24 patients (10 men, 14 women; aged 42 to 83 years) completed both treatment periods. Mean within-patient difference in blink rate between SBGA and placebo periods was -2.1 blinks per 2 minutes (95% confidence interval [CI]: -20.8-+31.9), not statistically different from zero (P =.83). Mean within-patient difference in time between injections between SBGA and placebo periods was 4.6 days (95% CI: -13.3-+22.5), not statistically different from zero (P =.62). The lack of statistical significance may have been because of small sample size. There were no significant differences in severity of involuntary movement between SBGA and placebo treatment periods. However, patients were more likely to report limitation in function during the period they took SBGA than during the period they took placebo (odds ratio, 0.2; P =.03). CONCLUSION: Overall, we found no evidence of a beneficial effect of SBGA as an adjunct to botulinum toxin A injections; however, a few patients, all younger than 60 years, did appear to benefit from SBGA.

Adult↗
PubMed2004

Incidence of and risk factors for perioperative optic neuropathy after cardiac surgery.

BACKGROUND: Visual loss from optic neuropathy rarely occurs in the perioperative period in patients who have undergone nonocular surgery. We performed a retrospective, matched, case-control study to determine the incidence of perioperative optic neuropathy (PON) after cardiac surgery with the use of cardiopulmonary bypass (CPB) and to determine risk factors that may lead to this potentially devastating complication. METHODS: Medical records of all patients undergoing cardiac surgery during a 9-year period were reviewed retrospectively to identify visual loss from acute unilateral and bilateral optic neuropathy during the perioperative period that had developed in patients. Data were collected from these patients and compared with data from control subjects matched for age, gender, risk factors for vascular disease, and type of surgery to determine the incidence of and potential risk factors for PON. RESULTS: Of 9701 surgical patients requiring CPB, 11 patients (0.113%) with PON were identified. Although both the absolute and relative drop in hemoglobin during the perioperative period approached statistical significance, no other putative risk factors were identified. CONCLUSIONS: The risk of PON associated with cardiac surgery in which CPB is used is low but substantial. The factors that lead to the condition remain unknown, although the presence of systemic vascular disease and both the absolute and relative drop in hemoglobin during the perioperative period seem to be important. Because PON often causes profound permanent visual loss, we recommend that patients, particularly those with systemic vascular disease, for whom cardiac surgery with CPB is planned, be made aware of this potential complication.

Acute Disease↗
PubMed2004

Traumatic optic neuropathy in children and adolescents.

PURPOSE: Retrospective review to describe the features and visual outcome of traumatic optic neuropathy (TON) in children and adolescents. METHODS: Interventional and observational case series of children <18 years with TON. RESULTS: Forty children, 24 boys and 16 girls, were identified with 43 affected eyes. The mean age was 11.6 years (range, 2 to 18). The most common causes were motor vehicle accidents (62%) and sports injuries (22%). The trauma was blunt in 78% of cases and penetrating in 22%. Visual acuity at presentation for 27 patients whose visual acuity could be assessed ranged from no light perception to 20/80. Interventions included corticosteroids (n = 18), decompression of the optic canal (n = 3), and optic sheath nerve fenestration (n = 1). Visual outcome for 22 children with at least 1 month of follow-up was no light perception in 10 (45%), < 20/200 in 7(32%), 20/200 to < 20/80 in 1(4%), and > or = 20/80 in 4 (18%). There was no difference in the rate or degree of improvement between treated and untreated patients. CONCLUSION: TON in children is caused by mechanisms similar to those that cause TON in adults. The severity of visual loss as well as the rate and degree of improvement are also similar. Our data do not indicate that treatment improves visual outcome.

Accidents, Traffic↗
PubMed2004

Radiation retinopathy after fractionated stereotactic radiotherapy for optic nerve sheath meningioma.

PURPOSE: To report a patient with radiation retinopathy after fractionated stereotactic radiotherapy for treatment of optic nerve sheath meningioma (ONSM). DESIGN: Interventional case report. METHODS: The clinical presentation, radiation treatment, and subsequent visual complications of a patient with ONSM are described. MAIN OUTCOME MEASURES: Development of radiation retinopathy and Snellen visual acuity. RESULTS: A 36-year-old man presented with a left optic neuropathy. Magnetic resonance imaging studies showed abnormalities consistent with ONSM. Because of progressive vision loss, the patient underwent fractionated stereotactic radiotherapy for the lesion. Vision initially improved after treatment, but 22 months later, retinal abnormalities consistent with radiation retinopathy were noted in the left eye. Visual acuity worsened over the next 24 months in association with the development of retinal hemorrhages, lipid, and retinal edema predominantly within the nasal portion of the posterior pole. Fluorescein angiography showed edema associated with microaneurysms, retinal telangiectasia, and capillary nonperfusion. Laser photocoagulation was performed on several occasions in areas of microaneurysms and retinal telangiectasia; however, the retinal edema and lipid remained, associated with persistent decreased vision. CONCLUSIONS: Radiation retinopathy and vision loss may occur after fractionated stereotactic radiotherapy for ONSM and should be discussed as a potential complication.

Adult↗
PubMed2004

Adult-onset acquired oculomotor nerve paresis with cyclic spasms: relationship to ocular neuromyotonia.

PURPOSE: To describe the characteristics and significance of acquired oculomotor nerve paresis with cyclic spasm. METHOD: Retrospective case series of two patients with a history of previous skull base irradiation for intracranial tumor who developed double vision and were found to have oculomotor nerve paresis with cyclic spasm. Both patients underwent a complete neuroophthalmologic assessment, including testing of eyelid position, pupillary size and reactivity, and ocular motility and alignment during both the paretic and spastic phases of the condition. RESULTS: Both patients developed unilateral lid retraction and ipsilateral esotropia with limitation of abduction during the spastic phase of the cycle, with ipsilateral ptosis, exotropia, and variable limitation of adduction during the paretic phase. The cycles were continuous and were not induced or altered by eccentric gaze. CONCLUSIONS: Cyclic oculomotor nerve paresis with spasms may occur years after irradiation of the skull base. This condition is different from the more common ocular motor disturbance that occurs in this setting-ocular neuromyotonia. However, in view of the similarity between these two disorders, it seems likely that they are caused by a similar peripheral mechanism.

Adenoma↗
PubMed2004

Visual function more than 10 years after optic neuritis: experience of the optic neuritis treatment trial.

PURPOSE: To assess visual function more than 10 years after an episode of optic neuritis in patients enrolled in the Optic Neuritis Treatment Trial. DESIGN: Longitudinal follow-up of a randomized clinical trial. METHODS: Vision testing included measures of visual acuity, contrast sensitivity, and visual field. Quality of life was assessed with the National Eye Institute Visual Function Questionnaire. RESULTS: Examinations were completed on 319 patients. In most patients, visual function test results in the eyes that experienced optic neuritis at study entry ("affected eyes") were normal or only slightly abnormal after 9.9 to 13.7 years. Visual acuity in the affected eyes was >or=20/20 in 74%, 20/25 to 20/40 in 18%, <20/40 to 20/200 in 5%, and <20/200 in 3%. On average, visual function was worse in patients with multiple sclerosis (MS) than in those without MS. Recurrent optic neuritis in either eye occurred in 35% of patients. Such attacks were more frequent in patients with MS (P <.001). The National Eye Institute Visual Function Questionnaire scores were lower when visual acuity was abnormal and when MS was present. CONCLUSIONS: Most patients retained good to excellent vision more than 10 years after an attack of optic neuritis. Recurrences were more frequent in patients with MS.

Adolescent↗
PubMed2004

Noninvasive neuroimaging of basilar artery dolichoectasia in a patient with an isolated abducens nerve paresis.

PURPOSE: To describe the neuroimaging findings in a patient with an isolated abducens nerve palsy caused by a dolichoectatic basilar artery. DESIGN: Retrospective case report. METHODS: A 65-year-old man presented with a 3-year history of gradually worsening horizontal double vision. He subsequently underwent magnetic resonance imaging, magnetic resonance angiography, and computed tomographic angiography. RESULTS: Neuroimaging revealed dolichoectasia of the basilar artery. The enlarged, tortuous vessel appeared to be compressing the subarachnoid portion of the nerve at its exit from the brainstem. CONCLUSION: Noninvasive neuroimaging studies are sufficient to establish a diagnosis of basilar artery dolichoectasia in patients with isolated cranial neuropathies.

Abducens Nerve Diseases↗
PubMed2004

Chronic myokymia limited to the eyelid is a benign condition.

BACKGROUND: Eyelid myokymia, unlike myokymia of the other facial muscles, is assumed to be a benign, self-limited disorder. However, no systematic follow-up study has been performed on patients with chronic, isolated eyelid myokymia to verify its benign nature. METHODS: Retrospective single-institution chart review of 15 patients examined between 1983 and 2002 with a diagnosis of isolated eyelid myokymia who have had at least 12 months of follow-up. RESULTS: In all patients, symptoms began as unilateral, weekly or biweekly, intermittent eyelid spasms, and progressed to daily spasms over several months. The mean duration of symptoms at first examination was 91 months (range 2.5 months to 20 years). In no patient was the myokymia the first manifestation of a neurologic disease, although one patient progressed to ipsilateral hemifacial spasm. Thirteen patients (86.7%) underwent neuroimaging that gave negative results. The myokymia resolved spontaneously in four patients. Of the remaining 11 patients, eight were treated with botulinum toxin injection at regular intervals, with most reporting an improvement in symptoms. CONCLUSION: Chronic isolated eyelid myokymia is a benign condition. It tends not to progress to other facial movement disorders or to be associated with other neurologic disease. It responds well to treatment with botulinum toxin.

Adolescent↗
PubMed2003

Pathophysiology of the optic neuropathy associated with Friedreich ataxia.

OBJECTIVES: To describe the optic neuropathy associated with the genetic defect in Friedreich ataxia and suggest a pathophysiologic mechanism. METHODS: An experimental model of retinal ganglion cell death in the presence of metal chelation was used to test a hypothetical mechanism for the optic neuropathy of Friedreich ataxia. RESULTS: Study of cultured rat retinal ganglion cells suggests that abnormal regulation of intracellular iron levels could increase sensitivity to reactive oxygen species and lead to cell death in these metabolically active tissues. CONCLUSION: We hypothesize that decreased expression of frataxin, the mutated gene in Friedreich ataxia, could cause an optic neuropathy by increasing the sensitivity of retinal ganglion cells to oxidative stress.

Animals↗
PubMed2003

High- and low-risk profiles for the development of multiple sclerosis within 10 years after optic neuritis: experience of the optic neuritis treatment trial.

OBJECTIVE: To identify factors associated with a high and low risk of developing multiple sclerosis after an initial episode of optic neuritis. METHODS: Three hundred eighty-eight patients who experienced acute optic neuritis between July 1, 1988, and June 30, 1991, were followed up prospectively for the development of multiple sclerosis. Consenting patients were reassessed after 10 to 13 years. RESULTS: The 10-year risk of multiple sclerosis was 38% (95% confidence interval, 33%-43%). Patients (160) who had 1 or more typical lesions on the baseline magnetic resonance imaging (MRI) scan of the brain had a 56% risk; those with no lesions (191) had a 22% risk (P<.001, log rank test). Among the patients who had no lesions on MRI, male gender and optic disc swelling were associated with a lower risk of multiple sclerosis, as was the presence of the following atypical features for optic neuritis: no light perception vision; absence of pain; and ophthalmoscopic findings of severe optic disc edema, peripapillary hemorrhages, or retinal exudates. CONCLUSIONS: The 10-year risk of multiple sclerosis following an initial episode of acute optic neuritis is significantly higher if there is a single brain MRI lesion; higher numbers of lesions do not appreciably increase that risk. However, even when brain lesions are seen on MRI, more than 40% of the patients will not develop clinical multiple sclerosis after 10 years. In the absence of MRI lesions, certain demographic and clinical features seem to predict a very low likelihood of developing multiple sclerosis. This natural history information is a critical input for estimating a patient's 10-year multiple sclerosis risk and for weighing the benefit of initiating prophylactic treatment at the time of optic neuritis or other initial demyelinating events in the central nervous system.

Acute Disease↗
PubMed2003

Long-term outcome in children with gliomas of the anterior visual pathway.

We performed a retrospective assessment of the long-term visual, neurologic, and systemic outcomes of 47 patients with anterior visual pathway gliomas seen at the Johns Hopkins Hospital. All of the patients had follow-up of at least 10 years or died during the follow-up period. Two patients died before 10 years of follow-up were achieved. The remaining 45 patients (including three patients who subsequently died) had follow-up of 10-28 years (mean, 15.3 years; median, 15 years). Sixteen of the patients in this study, most of whom had neurofibromatosis type 1 (NF1), received no treatment. None of these patients died or developed neurologic morbidity as a result of their tumor. Thirty-one of the patients, most of whom did not have evidence of NF1, received treatment. Many of these patients subsequently developed neurologic, endocrine, or visual morbidity. However, although patients with anterior visual pathway gliomas who were not treated fared better visually, neurologically, and systemically than patients who were treated, patients who required treatment for progression generally had a good overall prognosis, particularly patients with tumors that did not involve the hypothalamus. Most of these patients survived and maintained useful vision in at least one eye. We believe that patients with anterior visual pathway gliomas, particularly those with NF1, should not be treated unless there is clear clinical or neuroimaging evidence of progression.

Adolescent↗