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Biomedical subjects

S Lessell

Publications and source records attributed to S Lessell.

At least 19 recordsLinked to original sources
PubMed1992

Spontaneous visual improvement in chiasmal gliomas.

Three untreated patients with presumed chiasmal gliomas had spontaneous visual improvement, although serial magnetic resonance imaging in two of the patients showed the lesions to be unchanged. Two patients had evidence of neurofibromatosis. Three other patients with similar disease courses have been documented in the medical literature. These cases demonstrate that conservative management of optic chiasmal gliomas may sometimes be associated with favorable outcomes.

Adolescent↗
PubMed1992

Retinocalcarine function in Alzheimer's disease. A clinical and electrophysiological study.

Impaired visual function in Alzheimer's disease (AD) could result from either precortical or cortical lesions, or both. In a parallel psychophysical study of visual function in AD, we found that contrast sensitivity function, color vision, stereoacuity, and backward masking were impaired relative to the performance of age-matched control subjects, whereas performance on a critical flicker fusion test was normal. The intent of the present study was to determine whether abnormalities of the retinocalcarine pathway contribute to visual dysfunction. We performed neuro-ophthalmological examinations on 38 patients with AD; from this group, 25 received additional psychophysical testing and 13 underwent electrophysiological testing. Clinical neuro-ophthalmological examinations, full-field electroretinograms, focal electroretinograms, and pattern visual evoked potentials were normal in all patients tested. There was no evidence of retinocalcarine abnormality specific to AD. We conclude that the visual impairment experienced by some patients with AD primarily results from involvement of the visual association cortices rather than from precortical damage, at least before the end stage of the disease.

Aged↗
PubMed1992

Bilateral optic neuropathies with remission in two HIV-positive men.

Two patients seropositive for the human immunodeficiency virus (HIV) developed bilateral optic neuropathies. Evaluations failed to identify an infectious or neoplastic etiology. Both patients improved, one in temporal relation to treatment with azidothymidine (AZT), the other during oral steroid therapy. Optic neuropathy in HIV-positive patients does not necessarily carry a poor prognosis even when a treatable cause is not found. A role for primary HIV infection in the pathogenesis remains speculative.

Adult↗
PubMed1991

Recurrent idiopathic lateral rectus muscle palsy in adults.

Recurrent, unilateral, isolated, idiopathic lateral rectus muscle palsy is an uncommon but well-recognized disorder in children that has not been recognized as well in other age groups. We studied five cases of this uncommon entity that we encountered in adults and adolescents. Ages at onset ranged from 15 to 72 years and there were three to eight episodes per patient. Most of the patients shared the following features with the previously reported pediatric cases: ipsilateral recurrence, lack of pain, spontaneous recovery within six months, and no clear cause. Unlike the children, females or left-eye involvement was not preponderant in adults.

Adolescent↗
PubMed1991

Horner's syndrome from hypothalamic infarction.

We report a case of Horner's syndrome due to ipsilateral posterior hypothalamic infarction, occurring in the absence of other signs of hypothalamic dysfunction. Associated symptoms of contralateral faciobrachial weakness and dysarthria correlated with the extension of the infarct into the posterior limb of the internal capsule seen by magnetic resonance imaging. The likely vascular anatomy of this lesion is discussed.

Cerebral Infarction↗
PubMed1991

Optic neuritis and ischemic optic neuropathy. Overlapping clinical profiles.

A retrospective analysis of the clinical features of 81 patients with acute idiopathic optic neuritis and 58 patients with nonarteritic anterior ischemic optic neuropathy revealed a surprising overlap of manifestations. The rate of visual decline and the range of visual acuities were the same for both. Central scotomas and improvement in acuity were more common in optic neuritis, but occurred often enough in nonarteritic anterior ischemic optic neuropathy to limit their value as single diagnostic criteria. The similarities observed in this study suggest that it may be difficult to differentiate between optic neuritis and nonarteritic anterior ischemic optic neuropathy solely on nosologic grounds in some instances of acute, unilateral optic neuropathy.

Adult↗
PubMed1991

Mitogenic effects of excitatory amino acids in the adult rat retina.

We studied the retinas of adult rats after the intravitreal injection of excitatory amino acids and ouabain. Kainic acid, domoic acid, N-methyl D-asparate and ouabain produced swelling and vacuolization of the outer plexiform, inner nuclear and inner plexiform layers and pyknosis. Mitoses were present in retinas treated with all agents other than N-methyl D-asparate. Rompun ketamine anesthesia blocked the mitogenic effects. Immunohistochemical labeling of both glial fibrillary acidic protein and S100 protein would indicate that the mitoses are occurring in glial cells. We suggest that the mitogenic effects are mediated through action on glial cationic channels, and might account for the reactive gliosis observed in some retinal lesions.

Animals↗
PubMed1991

Optic chiasmal neuritis.

In four of six patients with clinical optic chiasmal neuritis, MRI demonstrated abnormalities of the chiasm. Optic chiasmal neuritis may be the initial manifestation of multiple sclerosis, a reflection of established CNS demyelination, or an isolated clinical finding.

Adolescent↗
PubMed1991

Steroid-induced visual recovery in fibrous dysplasia.

Fibrous dysplasia is a rare disorder of bone that may be associated with acute loss of vision. Surgical intervention is generally advocated and sometimes restores vision in these patients. We report a case of a patient with unilateral optic neuropathy from fibrous dysplasia who suffered two acute episodes of visual impairment. The first episode of vision loss was reversed by surgery and the second by corticosteroid treatment. A trial of corticosteroid therapy may be beneficial in cases of acute vision loss due to fibrous dysplasia.

Adult↗
PubMed1979

Amyloid tumor of the orbit.

A patient with an amyloid tumor of the orbit was studied by computed tomographic scanning. The tumor density was 10 delta units unenhanced and 72 units enhanced.

Adult↗
PubMed1979

Chiasmal syndrome due to metastasis.

We examined three patients with a chiasmal syndrome due to metastasis and were able to find only two additional cases in the literature. The characteristic presentation consisted of progressive impairment of vision without headache or abnormal plain skull x-ray films in patients with weight loss or diabetes insipidus. In three of the five patients, the primary malignant neoplasm was occult when symptoms and signs of chiasmal dysfunction were seen. Four patients responded well to irradiation. The chiasm may be compromised by suprasellar extension of pituitary metastasis, by infiltration from an infundicular or hypothalamic metastasis, or by hematogenous spread of tumor.

Adult↗
PubMed1979

Phosphenes induced by sound.

Three adults with acquired unilateral visual impairment noticed phosphenes when they heard noises. They witnessed them only when resting in a dark or dimly illuminated room. The hallucinations persisted for days in a postkeratoplasty patient, for weeks in a patient with optic neuritis, and for months in a patient with compression of the optic nerve. The sound-induced phosphenes in these cases seemed to be a pathologic variety of hypnagogic hallucination. We theorize that under conditions of altered excitability and visual deafferentation of the brain, cells capable of responding to both visual and auditory stimuli become hyperresponsive to sounds.

Acoustic Stimulation↗
PubMed1979

A prospective study of the risk of developing multiple sclerosis in uncomplicated optic neuritis.

We prospectively studied 60 patients with uncomplicated optic neuritis (ON) to determine the risk of subsequent multiple sclerosis (MS). All patients were followed for at least 5 years (mean, 7.1 years). Seventeen patients (28 percent) developed definite MS and four (7 percent) developed probable or possible MS. Six of the 17 patients who developed definite MS did so within the first year. Forty-five percent of the women but only 11 percent of the men developed MS. Both sexes were at highest risk if the ON occurred between the ages of 21 and 40. Fifty-one percent of patients in this age group progressed to MS, whereas the risk for others was 12 percent. There was an overall increased risk of MS with recurrent ON. The course of the MS appeared to be benign during the period of observation.

Adolescent↗
PubMed1979

Retraction of the lower eyelid.

Retraction of the lower eyelid is a useful sign of disease. It is an early manifestation of weakness of the facial muscles, occurring with myopathies, myasthenia, and upper and lower motor neuron facial paresis. Rarely, lower and upper lid retraction occur without proptosis in patients with Graves disease. Lower lid retraction occurs in proptosis and varies directly with the degree of proptosis. It is also seen with senile entropion or ectropion, after eye muscle or orbital surgery, and with contraction of lid tissues. Apparent retraction results when the contralateral lower lid is pathologically elevated, as in Horner syndrome, in enophthalmos, or with vertical deviations of the eye.

Exophthalmos↗