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Biomedical subjects

J J Corbett

Publications and source records attributed to J J Corbett.

At least 37 records · Page 2Linked to original sources
PubMed1990

The search for causes of idiopathic intracranial hypertension. A preliminary case-control study.

Idiopathic intracranial hypertension (pseudotumor cerebri) is a condition that occurs predominantly in obese women. It consists of elevated spinal fluid pressure, normal spinal fluid contents, papilledema, and headaches with normal imaging studies. Long lists of putative causes and associations have arisen, many consisting of individual case reports. We did a retrospective case-control study on 40 patients and 39 age- and sex-matched control subjects to examine the incidence of these associated conditions. Our results are only suggestive due to the small sample size; however, obesity and recent weight gain occurred more commonly in patients with idiopathic intracranial hypertension than in control subjects. All forms of menstrual abnormalities, incidence of pregnancy, antibiotic use, and oral contraceptive use were equal in both groups. A larger multicenter study will be needed to more completely characterize the risk factors for this condition.

Adolescent↗
PubMed1990

Transient monocular visual loss patterns and associated vascular abnormalities.

To determine if certain transient monocular visual loss patterns predict the associated vascular abnormalities, we prospectively evaluated 100 consecutive patients. Each patient had hematologic tests, a carotid artery study (arteriography in 74, duplex ultrasonography in the remaining 26), and an ophthalmologic examination. Patients with altitudinal or lateralized transient monocular visual loss were more likely to have carotid artery stenosis, carotid artery ulceration, cardiac sources of emboli, or visible retinal emboli than patients with other visual loss patterns. Our findings suggest that altitudinal or lateralized transient monocular visual loss is primarily caused by embolism but that other visual loss patterns are usually caused by nonembolic mechanisms.

Adult↗
PubMed1990

Retinal infarction during sleep and wakefulness.

Brain and retinal infarctions during sleep have been attributed to focal hypoperfusion caused by systemic hypotension combined with underlying arterial stenosis, rather than to embolism. Because some retinal emboli may be visualized on ophthalmoscopy, we studied 24 consecutive patients (18 men and six women) aged 26-78 (mean 58) years with recent retinal infarction and determined whether the infarction had occurred during sleep or wakefulness. All patients underwent dilated ophthalmoscopy and a carotid artery study (arteriography in 20, duplex ultrasound in the remaining four), and 12 had echocardiography. Retinal infarction occurred during sleep at an unexpectedly rate (14 of 24 observed compared with eight of 24 expected, p = 0.02). Retinal cholesterol emboli were seen in one half of the patients regardless of whether the retinal infarction had occurred during sleep or wakefulness. Carotid artery disease was found in seven of the 14 patients in whom infarction had occurred during sleep and in eight of the 10 patients in whom infarction had occurred during wakefulness (p = 0.21). Cerebrovascular occlusive disease was not found in the five patients aged less than 50 years. Our findings suggest that embolism is a common mechanism of retinal infarction during sleep or wakefulness, that in patients aged greater than 50 years extracranial carotid artery disease is a common source of retinal emboli, and that the retina may be especially susceptible to infarction during sleep.

Cerebral Infarction↗
PubMed1990

Seizure-induced miosis and ptosis: association with temporal lobe magnetic resonance imaging abnormalities.

Two patients with seizure-associated miosis and ptosis are described. In both there are magnetic resonance imaging abnormalities of the temporal lobe. In one patient, increased magnetic resonance imaging signal intensity is present in the temporal lobe contralateral to ptosis and miosis. In the other, there is temporal lobe asymmetry with the smaller temporal lobe ipsilateral to the miotic pupil and ptotic lid. The relevant human and experimental literature related to cortical control of pupil size and lid movement is reviewed. Based on the available literature and the findings in these two patients, it is proposed that the increased signal intensity in the temporal lobe of one patient represents an irritative stimulus causing contralateral miosis and ptosis, whereas the temporal lobe hypoplasia in the second patient permitted impulses from the contralateral normal temporal lobe to predominate, resulting in miosis and ptosis homolateral to the hypoplastic temporal lobe.

Adolescent↗
PubMed1990

Treatment of visual loss in pseudotumor cerebri associated with uremia.

Ten patients with pseudotumor cerebri associated with renal insufficiency had papilledema and elevated intracranial pressure, but neurologic examinations and CT were normal. The 40% frequency of severe visual loss, 20/100 or worse, was higher than expected for pseudotumor cerebri. While furosemide was effective in 3 patients with renal transplants, administration of corticosteroids to 2 other patients did not halt progressive loss of vision. The visual function of 2 patients deteriorated even after lumboperitoneal shunting. Five patients underwent fenestration of the optic nerve sheath. This procedure improved the visual acuity of 3 patients and stabilized vision in the others. While the pathogenesis of pseudotumor cerebri in renal insufficiency is unknown, optic nerve sheath fenestration is the surgical treatment of choice for visual loss unresponsive to medical therapy.

Adolescent↗
PubMed1989

Downbeat nystagmus associated with dolichoectasia of the vertebrobasilar artery.

We reviewed the case records and radiographic studies of 41 patients with primary position downbeat nystagmus seen during a 5-year period to investigate whether a relationship existed between dolichoectasia of the vertebrobasilar artery and cases of unknown cause. The cause of downbeat nystagmus could not be determined in 12 cases (29%). Two of these cases had dolichoectasia of the vertebrobasilar artery as the only identifiable abnormality. One other case had a dolichoectatic vertebrobasilar artery, but other potential etiologic factors for the development of downbeat nystagmus were present. Compression of the caudal brain stem by an enlarged and tortuous vertebrobasilar arterial system may be the cause of downbeat nystagmus in some cases unassociated with more commonly recognized causes.

Adolescent↗
PubMed1989

The rational management of idiopathic intracranial hypertension.

Idiopathic intracranial hypertension is a diagnosis most frequently made in young, overweight women. The chief hazard to the patient is permanent visual loss due to chronic papilledema. After the diagnosis has been clearly established using lumbar puncture and imaging techniques, the neurologist is involved in helping to lower the intracranial pressure, control the headaches, and encourage weight loss. Careful vision monitoring is essential and should be done in collaboration with an ophthalmologist. Visual fields, fundus photographs, intraocular pressure measurement, and visual acuity should be performed at each follow-up visit. The use of visual evoked response and repeated measurement of intracranial pressure by lumbar puncture do not provide data that help to guide therapeutic decisions. Indications for surgery are loss of visual field or decline in visual acuity in the fact of medical therapy, persistent headache, or the inability to perform visual-function studies. Optic nerve sheath fenestration and lumbar peritoneal shunt both appear to be effective surgical means to reduce the pressure on the optic disc. A neurologist and an ophthalmologist working together provide the evidence on which to base rational decisions in the care of the patient with idiopathic intracranial hypertension.

Female↗
PubMed1989

Amaurosis fugax and ocular infarction in adolescents and young adults.

Because the cause and natural history of amaurosis fugax and ocular infarction are unknown in most younger patients, we reviewed the records of 83 patients who had become symptomatic before the age of 45. Cerebral transient ischemic attacks had occurred in 9 of these patients but no case of stroke was found. A striking feature of these patients was that 41% had headache or orbital pain accompanying their amaurotic spells and an additional 25.3% had severe headaches independent of the visual loss. Results of laboratory studies were rarely abnormal and echocardiography disclosed that only 1 patient had previously unknown heart disease. Mitral valve prolapse was detected in 6.5%, a figure similar to that expected for the general population. Of the original 83 patients, 42 were reexamined after a mean period of 5.8 years. None of the patients in this group had had a stroke, and the clinical status at follow-up was not found to correlate with the duration of the visual loss (amaurosis fugax versus ocular infarction), frequency (single versus recurrent episodes), sex, presence of headache or heart disease, cigarette smoking, use of oral contraceptives, or abnormal findings on echocardiograms or laboratory studies. We conclude that amaurosis fugax and ocular infarction occurring in the younger patient are probably associated with a more benign clinical course than that seen in older persons and that migraine is a likely cause for the episodes of visual loss in a majority of this group. Because of this, we believe that a conservative approach to the evaluation of such patients seems warranted.

Adolescent↗
PubMed1989

Downbeating nystagmus and other ocular motor defects caused by lithium toxicity.

We report the clinical and neuropathologic findings of a 63-year-old woman who died following an accidental lithium overdose that produced coma, respiratory depression, horizontal gaze palsy, and downbeating nystagmus. She also had mild hypomagnesemia. The pathology was cytotoxicity, predominantly in the regions of the nuclei prepositus hypoglossi and medial vestibular nucleus. Damage to this area with kainate and ibotenate in rhesus monkeys has produced horizontal gaze palsy and downbeating nystagmus. In addition, we report our clinical experience during the past 6 years with other examples of downbeating nystagmus in patients receiving lithium.

Cranial Nerve Diseases↗
PubMed1988

Enlargement of the blind spot caused by papilledema.

Blind spot enlargement in papilledema has been attributed to either mechanical disruption of the integrity of the peripapillary percipient elements by the swollen optic disk or to the Stiles-Crawford effect. We investigated the possibility that blind spot enlargement in papilledema is caused, at least in part, by a refractive scotoma due to peripapillary hyperopia. We reduced the enlarged blind spot in a patient with focal peripapillary hyperopia, without papilledema, to near normal size by using progressively stronger plus lenses. Similarly, with the addition of plus sphere, we reduced the size of the blind spot in five of six patients with papilledema, but in none of our normal subjects.

Adult↗
PubMed1988

Pseudotumor cerebri in men.

We describe 29 men with pseudotumor cerebri (PTC) and compare them with aged-matched women with PTC and male control subjects. Pseudotumor cerebri occurs less frequently in men but in a similar age distribution. Although signs and symptoms of PTC are similar in men and women, men may require surgical treatment for impending visual loss. Black men appear to be at greater risk to loss of vision. Even though men with PTC are less likely to be obese than women, they tend to be more obese than control subjects and should be counseled on weight-reduction diets.

Acetazolamide↗
PubMed1988

The incidence of pseudotumor cerebri. Population studies in Iowa and Louisiana.

We surveyed all neurologists, ophthalmologists, and neurosurgeons in Iowa, eastern Nebraska, and Louisiana over one year to determine the annual incidence of pseudotumor cerebri in residents of Iowa and Louisiana. The results were similar for both states. In Iowa, the annual incidence in the general population was 0.9 per 100,000 persons. When obesity was considered, this increased the incidence to 13/100,000 persons in Iowa and 14.85/100,000 persons in Louisiana for women 20 to 44 years of age who were 10% or more over ideal weight. Furthermore, the incidence became 19.3/100,000 for women in the same age range when they were 20% or more over ideal weight. The female-to-male ratio was 8:1, and the mean weight was 38% above ideal weight for height. Pseudotumor cerebri is a relatively common neurologic illness and may be an important preventable cause of blindness in obese young women.

Adult↗
PubMed1988

Results of optic nerve sheath fenestration for pseudotumor cerebri. The lateral orbitotomy approach.

Twenty-eight patients with pseudotumor cerebri underwent 40 optic nerve sheath fenestrations for relief of visual loss or to preserve vision. Twenty women and eight men underwent 16 unilateral fenestrations and 12 bilateral operations. Papilledema disappeared or was strikingly reduced in 24 of 28 patients. The other four patients had gliotic discs (two patients) or were followed up for only a short time. Visual acuity improved in 12 of 40 eyes and remained the same in 22 of 40 eyes. Seventeen eyes had preoperative visual acuity of 20/30 or better. In six eyes visual acuity decreased. Of eight eyes operated on that had visual acuity of 20/200 or worse, only three showed improvement. Visual fields improved in 21 of 40 eyes and remained the same in ten eyes. Five of the ten eyes that did not change had poor vision before surgery. Eight eyes in five patients continued to lose acuity postoperatively. Each of these eight eyes had a concomitant loss of visual field. An additional two eyes developed visual field loss with preserved visual acuity. The indications for surgery are early evidence of progressive loss of visual field or acuity in a patient with pseudotumor cerebri. Severe vision loss presents little opportunity for improvement but fenestration may be used in a last effort to preserve or restore vision.

Adult↗
PubMed1988

Optic nerve sheath fenestration in pseudotumor cerebri. A lateral orbitotomy approach.

In patients with pseudotumor cerebri accompanied by loss of vision, optic nerve sheath fenestration is an effective route to prompt recovery of vision. A lateral orbitotomy approach to decompression of the optic nerve is appropriate for the ophthalmologist with adequate orbital experience. A rectangular window of dura and arachnoid, measuring approximately 3 X 5 mm, is excised from the bulbous portion of the optic nerve. It is important that the arachnoid within the window is excised because an intact arachnoid is an effective barrier to cerebrospinal fluid egress. The use of operating microscope, microsurgical instrument, and microdissecting techniques are emphasized. Twenty-eight patients (40 eyes) with progressive visual loss were treated by surgical nerve sheath fenestration. A study of the indications, results, and complications of this procedure is presented in a companion article.

Arachnoid↗
PubMed1988

Optic neuritis in the elderly: prognosis for visual recovery and long-term follow-up.

We evaluated 14 patients with idiopathic optic neuritis, 50 years of age or older, within 1 month of symptomatic onset from 1980 through 1985. We obtained follow-up information from case records an average of 13 months after initial examination and from telephone interviews an average of 57 months after initial evaluation. Four patients were men and ten were women. Visual loss was monocular in ten cases and binocular in four. Only one of 18 affected eyes initially had an acuity of 20/30 or better. Eleven eyes recovered acuities of 20/30 or better. There was no apparent benefit to those patients treated with corticosteroid agents. Six patients (43%) developed other neurologic sequelae an average of 16 months later; four (28%) had a second bout of optic neuritis and three (21%) developed clinically definite MS. Optic neuritis in the elderly behaves similarly to that disorder in younger age groups.

Aged↗
PubMed1988

CT and hemifacial spasm.

Forty-six patients with typical hemifacial spasm had CT. Thirty-eight (83%) were abnormal, including two with surgically documented tumors. Thirty-six had a characteristic dolichoectatic vertebrobasilar artery, with the convexity pointing to the side of the spasm in 92% of the scans. This study suggests that CT is worthwhile procedure in the evaluation of hemifacial spasm and that dolichoectatic vertebrobasilar arteries are very frequently associated with hemifacial spasm.

Adult↗
PubMed1988

Experience of a Wyoming county streptococcal control project.

Figures from Natrona County, Wyoming, during the period 1957-1959 and from the Papago Indian Health Service in Arizona during the years 1970-1982 indicate that a vigorous control program targeted to school children that used throat culturing to detect group A streptococci and to recommend adequate treatment effectively lowered the incidence of first attacks of rheumatic fever. Statistics from the Wyoming Department of Public Health for the years 1972-1983 recorded a consistently lower rate of rheumatic fever in Natrona County, where such a control program was maintained, than for the rest of the state, although the national decline in rheumatic fever incidence makes these figures more difficult to assess. Experience gained in these programs may be valuable for third world countries where rheumatic heart disease is still a major cause of death and disability.

Child↗