Primary aberrant regeneration of the oculomotor nerve. Occurrence in a patient with abetalipoproteinemia.
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Abetalipoproteinemia↗
Biomedical subjects
T M Bosley
Publications and source records attributed to T M Bosley.
Optic nerve involvement in the acute retinal necrosis syndrome.
Two patients with acute retinal necrosis syndrome demonstrated enlarged computed tomographic images of the optic nerves, a previously undescribed manifestation of this disorder to the best of our knowledge. One patient, with the bilateral variety of this syndrome, demonstrated bilateral optic nerve enlargement and, in one eye, appeared to achieve visual improvement following an optic nerve sheath decompression. The second patient, with the unilateral variety of the syndrome, demonstrated only unilateral optic nerve enlargement. These observations suggest that the intraorbital optic nerve may be primarily or secondarily involved in the acute retinal necrosis syndrome.
Acute Disease↗
Hemifacial spasm treated with botulinum A toxin injection.
Fifteen patients with hemifacial spasm were treated with botulinum A toxin injections. All patients experienced relief from spasm, with the effect lasting an average of 12.2 weeks. Complications were tearing in four patients, inability to close the involved eye in three patients, corneal exposure in one patient, and ectropion in one patient. All complications were transient and deemed minor by the patients.
Adult↗
Visual function in prolactinoma patients treated with bromocriptine.
Ten patients with prolactin-secreting pituitary adenomas (prolactinoma) and visual dysfunction were treated primarily with bromocriptine. Nine patients had improvement of visual field or acuity associated with computed tomography (CT) evidence of a decrease in tumor size and reduction of serum prolactin level (SPL). Visual improvement usually began within days of commencing bromocriptine therapy. One patient with initial improvement had a worsening of visual fields at 11 months despite a normal SPL and a stable CT appearance of tumor size. This patient and the single patient without visual improvement underwent trans-sphenoidal hypophysectomy (TSH), but neither patient had postoperative visual improvement. Two other patients underwent TSH for nonvisual reasons. The remaining six patients have maintained excellent visual function at last follow-up (average of 18 months on bromocriptine therapy). This study shows that bromocriptine is an effective short- and long-term therapy for most patients with visual dysfunction due to prolactinoma.
Adult↗
Ischemic lesions of the occipital cortex and optic radiations: positron emission tomography.
We used 18-F-fluoro-2-deoxyglucose positron emission tomography (PET) and computed tomography (CT) to study eight patients with homonymous hemianopias or quadrantanopias due to ischemic lesions of the visual pathways. Four patients with ischemic damage to all or part of the occipital lobe had decreased glucose metabolism in the affected region. Three patients with ischemic damage limited to the optic radiations had decreased glucose metabolism in the portion of striate cortex appropriate for the visual field defect. Changes in glucose metabolism frequently occurred in the undamaged ipsilateral thalamus and visual association areas.
Adult↗
Comparison of metrizamide computed tomography and magnetic resonance imaging in the evaluation of lesions at the cervicomedullary junction.
We compared intrathecal metrizamide-enhanced CT (metrizamide-CT) and magnetic resonance imaging (MRI) in the evaluation of 17 patients with clinical suspicion of lesions at the cervicomedullary junction. MRI was superior in imaging the position of the cerebellar tonsils and the size and extent of mass lesions. MRI and metrizamide-CT were equal in detecting syringomyelia. CT with and without IV contrast enhancement was necessary to detect calcium or defects in the blood-brain barrier within neoplasms.
Adolescent↗
Isolated sixth-nerve palsies in younger adults.
Acquired sixth-nerve palsies are relatively rare in younger adults. We reexamined 49 patients, aged from 15 to 50 years, with isolated sixth-nerve palsies who were seen between 1972 and 1982 at the Wills Eye Hospital in Philadelphia. In this group, the following etiologies were encountered: vasculopathy (14 patients [29%]), tumors (eight patients [16%]), multiple sclerosis (six patients [12%]), presumed inflammation (four patients [8%]), trauma (three patients [6%]), postlumbar puncture (two patients [4%]), and orbital amyloidosis (one patient [2%]). Eleven patients (22%) had no determined cause of their sixth-nerve palsy. The implications for the clinical management of isolated sixth-nerve palsies in younger adults are discussed.
Abducens Nerve↗
Effects of anoxia on the stimulated release of amino acid neurotransmitters in the cerebellum in vitro.
The effect of anoxia and ischemia on the release of amino acid transmitters from cerebellar slices induced by veratridine or high [K+] was studied. Synaptic specificity was tested by examining the tetradotoxin (TTX)-sensitive and the Ca2+-dependent components of stimulated release. Evoked release of endogenous amino acids was investigated in addition to more detailed studies on the stimulated efflux of preloaded [14C]GABA and D-[3H]aspartate (a metabolically more stable anologue of acidic amino acids). [14C]GABA release evoked by either method of stimulation was unaffected by periods of up to 35 min of anoxia and declined moderately by 45 min. In contrast, induced release of D-[3H]Asp increased markedly during anoxia to a peak at about 25 min, followed by a decline when anoxia was prolonged to 45 min. Evidence was obtained that the increased evoked efflux of D'[3H]Asp from anoxic slices was not due to impaired reuptake of the released amino acid and that it was completely reversible by reoxygenation of the slices. Results of experiments examining the evoked release of endogenous amino acids in anoxia were consistent with those obtained with the exogenous amino acids. Only 4 of the 10 endogenous amino acids studied exhibited TTX-sensitive veratridine-induced release under aerobic conditions (glutamate, aspartate, GABA, and glycine). Anoxia for 25 min did not affect the stimulated efflux of these amino acids with the exception of glutamate, which showed a significant increase. Compared with anoxia, effects of ischemia on synaptic function appeared to be more severe. Veratridine-evoked release of [14C]GABA was already depressed by 10 min and that of D-[3H[Asp showed a modest elevation only a 5 min. Stimulated release of D-Asp and labelled GABA declined progressively after 5 min. These findings were compared with changes in tissue ATP concentrations and histology. The latter studies indicated that in anoxia the earliest alterations are detectable in glia and that nerve terminals were the structures by far the most resistant to anoxic damage. The results thus indicated that evoked release of amino acid transmitters in the cerebellum is compromised only by prolonged anoxia in vitro. In addition, it would appear that the stimulated release of glutamate is selectively accentuated during anoxia. This effect may have a bearing on some hypoxic behavioral changes and, perhaps, also on the well-known selective vulnerability of certain neurons during hypoxia.
Amino Acids↗
Clinical diagnosis of cavernous sinus syndromes.
A general approach to the complex topic of cavernous sinus syndromes is developed that attempts to make the best use of information available from the history and physical evaluation. Emphasis is on the observations and decisions that occur in the physician's office.
Arteriovenous Fistula↗
Electrophysiologic evidence of subclinical injury to the posterior columns of the human spinal cord after therapeutic radiation.
Spinal somatosensory conduction velocity (SSCV) was indirectly estimated from cerebral evoked potentials in 15 adults who had received therapeutic radiation (RT) (2000-4380 rad) to the thoracic spinal cord during treatment for lung cancer, and in 15 age-matched normal controls. Thirteen of the patients had also received 4400-5500 rad to the supraclavicular fossae. One-way impulse conduction time in the arm, estimated from F-wave latency, was prolonged in the patients as compared to controls (12.0 +/- 1.2 versus 10.4 +/- 1.0 msec; P less than 0.001) but conduction time in the leg was similar in the two groups (22.4 +/- 2.4 versus 22.0 +/- 2.5 msec; P less than 0.1). SSCV was significantly slower in the patient group (37.9 +/- 13.9 versus 54.5 +/- 12.9 m/sec; P less than 0.001) whereas supraspinal latency (cervical cord to cortex) was identical (5.5 +/- 0.9 versus 5.5 +/- 0.8 msec; P less than 0.1). SSCV in the patient group was not related to total RT dose (r = 0.15; P = 0.2), but was correlated with both treatment time and number of fractions (r = 0.49 and 0.43; P = 0.003 and 0.007, respectively). These findings suggest that RT may produce subclinical spinal cord dysfunction even at conventional dosage schedules, and that it may be possible physiologically to monitor the myelopathic effects of RT in individual patients.
Aged↗
Use of cerebral evoked potentials to evaluate spinal somatosensory function in patients with traumatic and surgical myelopathies.
Cerebral somatosensory evoked potentials (SEP's) were elicited by electrical stimulation of the median nerve in the arm (SEPA) and of the posterior tibial nerve in the leg (SEPL) in 23 patients with incomplete localized lesions (including traumatic injuries, neoplasms, vascular malformations and infarcts) of the low cervical, thoracic, or lumbar spinal cord. In eight of 46 attempts (left and right sides), SEPL could not be recorded. Of the remaining 38 sides, spinal somatosensory conduction velocity (SSCV, indirectly estimated) was abnormally slow (less than 35 m/sec) in 20, and the amplitude of SEPL relative to SEPA (L:A ratio) was abnormally low (less than 0.5) in 20 (p less than 0.001 in each case, compared to normal controls). All three criteria yielded a combined 72% incidence of abnormality, correlating best with impairment of joint position sense. Serial postoperative studies in four cases documented an increase in the SSCV and L:A ratio following spinal decompression. These results demonstrate that the latency and amplitude characteristics of the cerebral SEP's from arm and leg permit quantitative evaluation of the functional status of the spinal somatosensory system.
Adult↗
Age-related changes in peripheral and central nerve conduction in man.
Somatosensory evoked potential (SEP) latencies, motor and sensory nerve conduction velocities (CVs), and F-wave latenies were measured in 15 elderly normal subjects (mean age 74.1 years), and the results were used to derive indirect estimates of spinal cord CVs. These measurements were compared to those from 15 younger normal adults (mean age 31.6 years), and the nerve conduction characteristics of all 30 subjects were analyzed with respect to age. Peripheral motor and sensory CVs slowed progressively, and the onset latencies of F-waves and SEPs increased gradually with advancing age. Spinal cord CVs showed little change until approximately age 60, and declined sharply thereafter. In addition, the latencies of F-waves and SEPs were positively associated with height. Human clinical and experimental studies utilizing SEP and F-wave measurements must allow for morphologic differences between individuals, and for the systematic changes which accompany normal aging.
Adult↗
Electrophysiological localization of central somatosensory lesions in patients with multiple sclerosis.
Somatosensory evoked potentials (SEPs) and selected indices of peripheral nerve function were compared in 30 multiple sclerosis (MS) patients and 15 normal controls. A high incidence of delayed SEP onset was observed in the MS patients, correlating with sensory loss--particularly of joint position and vibration sense. Using a method for deriving an indirect estimate of spinal cord conduction velocity, the longitudinal level of the sensory disturbance could in many cases be localized either to the spinal or to the supraspinal segment (or both) of the somatosensory pathway. Abnormally low spinal conduction velocity correlated with clinical judgements of spinal cord malfunction, but abnormalities were encountered also in some cases with no clinical evidence of myelopathy. Electrophysiological studies can contribute to the assessment of patients with suspected MS by demonstrating conduction abnormalities in specific segments of the somatosensory pathway.
Adolescent↗
Ictal blindness and status epilepticus amauroticus.
Five cases of ictal blindness are presented. All are documented to be ictal by simultaneous EEG monitoring during the period of blindness. In three cases, the blindness was complete; in two, it manifested as a homonymous hemianopia. Three cases (including the two with hemianopia) were secondary to vascular lesions; one case was due to a metastatic lesion; and there was one case of idiopathic epilepsy. Age ranged from 13 to 74 years. In all cases, the blindness was reversible with anticonvulsant therapy. All cases but one lasted from hours to days, meeting a criterion of "status epilepticus amauroticus." In the literature, ictal blindness is seldom reported and even less often documented. Unexplained cortical blindness might represent unrecognized seizure activity more often than is appreciated.
Adolescent↗
MR imaging of Tolosa-Hunt syndrome.
The Tolosa-Hunt syndrome consists of painful ophthalmoplegia caused by cavernous sinus inflammation, which is responsive to steroid therapy. The MR features of 11 patients with the clinical diagnosis of Tolosa-Hunt syndrome were studied. Two patients had normal MR studies of the orbit and cavernous sinuses. In nine patients, abnormal signal and/or mass lesions were seen in the cavernous sinuses; in eight cases, the abnormality was hypointense relative to fat and isointense with muscle on short TR/TE images and isointense with fat on long TR/TE scans. Extension into the orbital apex was seen in eight cases. In six of nine cases the affected cavernous sinus was enlarged; in five of nine it had a convex outer margin. One patient had a thrombosed cavernous sinus and superior ophthalmic vein in addition to a cavernous sinus soft-tissue mass. The signal intensity of Tolosa-Hunt syndrome in this limited series was similar to that of orbital pseudotumor and is confined to a limited differential diagnosis, which includes meningioma, lymphoma, and sarcoidosis.
Adolescent↗
Internuclear ophthalmoplegia: MR-anatomic correlation.
Internuclear ophthalmoplegia is a gaze disorder characterized by impaired adduction on the side of a lesion involving the medial longitudinal fasciculus with dissociated nystagmus of the abducting eye. Eleven patients with internuclear ophthalmoplegia (nine with clinical multiple sclerosis, two with clinical infarction) underwent MR imaging with spin-echo techniques on a 1.5-T system. Nine patients also had CT. MR showed focal or nodular areas of high signal intensity on T2-weighted images in the region of the medial longitudinal fasciculus in 10 of 11 patients. In one of four patients with internuclear ophthalmoplegia who had MR after intravenous gadolinium-DTPA, an enhancing ring lesion was seen in the region of the medial longitudinal fasciculus on short TR/TE images, indicating active blood-brain-barrier disruption, which correlated with this patient's recent-onset internuclear ophthalmoplegia. CT failed to show the lesions in all nine patients examined. This report demonstrates the superiority of MR in evaluating gaze disorders attributable to brainstem dysfunction, such as internuclear ophthalmoplegia, and correlates MR findings with the relevant neuroanatomy of the medial longitudinal fasciculus.
Adolescent↗
Dural malformations with ophthalmic manifestations: results of particulate embolization in seven patients.
Seven patients with proptosis, chemosis, diplopia, and elevated intraocular pressure were found to have dural arteriovenous malformations with drainage into the cavernous sinus and superior ophthalmic vein. These patients had sufficient symptoms to justify therapeutic embolization with polyvinyl alcohol. Five of seven patients had complete resolution of their ophthalmic symptoms after embolization; the other two had transient improvement. Follow-up was 9-29 months. When 50% or more of the vessels supplying a malformation were embolized, complete relief of symptoms was obtained. Particulate embolization is an effective therapeutic approach in patients with significant ophthalmologic symptoms from dural malformations.
Adult↗