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Biomedical subjects

B R Younge

Publications and source records attributed to B R Younge.

12 recordsLinked to original sources

Acquired oculomotor, trochlear, and abducent cranial nerve palsies in pediatric patients.

Between January 1966 and December 1988, 160 pediatric patients (age range, 0 to 17 years) were seen at the Mayo Clinic with an acquired oculomotor (35 patients), trochlear (19 patients), abducent (88 patients), or multiple (18 patients) cranial nerve palsy. The clinical findings in the 160 pediatric patients were compared with the results obtained in other reviews of cranial nerve palsies in the pediatric age group and with the adult Mayo Clinic patients with acquired cranial nerve palsies. Trauma was the most common reason for an acquired cranial nerve palsy in our pediatric group. The percentage of patients with an acquired cranial nerve palsy resulting from trauma was significantly greater in the pediatric group (42.5%) than in adults (15.4%) (P < .01). The difference between the percentage of adults (15.2%) and pediatric patients (16.9%) with a cranial nerve palsy secondary to a neoplasm was not statistically significant (P = .28).

Abducens Nerve

Causes and prognosis in 4,278 cases of paralysis of the oculomotor, trochlear, and abducens cranial nerves.

We collected data from a large series of patients with ocular palsies and compared them with data in previous series from the Mayo Clinic. The largest group of patients among 4,278 cases was that in which the cause was undetermined for a long period of follow-up. The abducens nerve was most commonly affected. The probability of establishing a diagnosis was higher in patients younger than 50 years and among those with associated neurologic findings or multiple ocular palsies. The prognosis for recovery was best in the vascular group but was better than 50% for all groups except those with tumors. Investigation may be tailored to each patient according to clinical findings and probabilities of finding a cause, and judicious clinical judgement should be exercised.

Abducens Nerve

The four-meter confrontation visual field test.

The 4-m confrontation visual field test has been successfully used at the Mayo Clinic for many years in addition to the standard 0.5-m confrontation visual field test. The 4-m confrontation visual field test is a test of macular function and can identify small central or paracentral scotomas that the examiner may not find when the patient is tested only at 0.5 m. Also, macular sparing in homonymous hemianopias and quadrantanopias may be identified with the 4-m confrontation visual field test. We recommend use of this confrontation visual field test, in addition to the standard 0.5-m confrontation visual field test, on appropriately selected patients to obtain the most information possible by confrontation visual field tests.

Hemianopsia

Late juvenile-onset Krabbe's disease.

Krabbe's disease is an autosomal recessive leukodystrophy characterized by a lack of galactocerebroside beta-galactosidase activity. In contrast to the classic early infantile-onset form of Krabbe's disease, less recognized, late-onset variants exist. The authors present a case of late juvenile-onset Krabbe's disease, including the associated magnetic resonance imaging (MRI) findings. Most patients with late-onset Krabbe's disease present with visual loss due to optic atrophy. Associated gait abnormalities and parental consanguinity should increase the clinician's suspicion that a child may have late-onset Krabbe's disease. Because of the prolonged survival in late-onset Krabbe's disease, the recent development of bone marrow transplantation for these patient makes diagnosis of this disorder particularly important.

Adolescent

The significance of retinal emboli.

This review contrasts two of the more common forms of retinal emboli, i.e., cholesterol emboli and calcific emboli. These two forms vary in ophthalmoscopic appearance and in regard to significance.

Calcium

Treatment of acute central retinal artery occlusion.

Central retinal artery occlusion very often leads to irreversible visual loss and seldom responds to treatment. Retrograde cannulation of the supraorbital artery followed by irrigation with anticoagulants and vasodilators may be of value in the early management of this problem. A case in point is described.

Adult

Analysis of trochlear nerve palsies. Diagnosis, etiology, and treatment.

At the McGill University neuro-ophthalmology unit, 52 patients with superior oblique palsy were seen during the 2-year period October 1973 to August 1975; these included patients with congenital, traumatic, vascular, and other more rare causes of trochlear paralysis. Half of the patients with congenital palsy had diplopia, requiring treatment, although surgery was rarely necessary. Patients with palsy due to trauma, the major cause in our series, included four with bilateral involvement. With the exception of recovery in a single muscle of one patient in this group with traumatic palsy, no spontaneous recoveries have been observed. Treatment modalities have been tried, including observation alone, occlusion for symptomatic relief of diplopia, use of prisms, and recession of the ipsilateral inferior oblique muscle. Four patients with palsy of presumed vascular cause recovered spontaneously within a 4-month period. All patients who were surgically treated improved.

Adolescent

Fluorescein angiography and retinal venous sheathing in multiple sclerosis.

Venous sheathing found in 11% of a series of patients with multiple sclerosis was studied with routine color fundus photography, and fluorescein angiography. In the early phases of the disease, sheathing is seldom found. Its detection is facilitated by fluorescein angiography and ophthalmoscopy with a cobalt filter. Fluorescein leakage may disappear despite persistence of the sheathing.

Adult

Electronystagmographic findings in cerebellar dysfunction.

Ocular dysmetria is seldom mentioned in the neurootologic literature as an electronystagmographic (ENG) abnormality. For the last two years, we found ocular dysmetria on 38 cases out of 1,879 ENG recordings. Cerebellar dysfunction was the most apparent cause in 13 out of 21 cases examined by us. The group of unilateral hypermetria showed some other ENG abnormalities like positional nystagmus, post-caloric directional preponderance, failure of fixation suppression of post-caloric nystagmus (FFS), more scattered distribution of quick phase amplitudes of post-caloric and optokinetic nystagmus on the side of hypermetria. We wonder whether this symptomatology, or at least part of it, is due to dysfunction of the flocculo-nodular lobe of the cerrebellum.

Aged

Midline tilting between seeing and nonseeing areas in hemianopia.

The line separating the seeing from the nonseeing parts of the visual field was found to be tilted away from the expected vertical position in 24 of 200 patients diagnosed as having various types of hemianopia, including homonymous hemianopia, homonymous quadrant hemianopia, homonymous scotomata, and bitemporal hemianopia. The causes of these defects include vascular accidents, trauma, tumor, and neurosurgery for convulsive disorders. Once discovered by standard monocular field testing methods, the existence of the tilting phenomenon was distinguished from testing artifact by employing binocular fixation and red-green glasses along with red and green test objects. A difference in the overlapping fields of the two eyes was found to exist only in areas where corresponding lines between seeing and nonseeing fields were separated by a tilting away from the vertical in one or both eyes. This can occur superiorly or inferiorly with homonymous scotomata, and in bitemporal hemianopia as well as in homonymous hemianopia or quadrant hemianopia. This incongruity of fields is possibly explained by a variation in anatomic determination of crossing from noncrossing fibers at the level of the retina.

Adult

Tonic pupil: a simple screening test.

The tonic pupil has a typical appearance and characteristic reactions to both light and the near reflex. Testing with Mecholyl (methacholine) is not possible since the drug is no longer manufactured. The reactions of a group of 25 patients with tonic pupil were studied using dilute pilocarpine, and compared with the pupil responses of a separate control group. We found that concentrations of 0.2% pilocarpine produced too many false-positive reactions in the control group and that 0.05% pilocarpine produced an insufficient response. The 0.1% concentration seemed suitable for ordinary clinical examinations and is recommended for pharmacologic confirmation of the diagnosis of tonic (Adie's) pupil.

Adie Syndrome