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Biomedical subjects

J J Corbett

Publications and source records attributed to J J Corbett.

At least 19 recordsLinked to original sources
PubMed1995

Optic nerve compression from a basal encephalocele.

A woman developed headaches, transient visual obscurations, anosmia, and decreased visual acuity. Ocular examination showed bilateral pulsatile proptosis and disc edema with choroidal folds. Standardized ophthalmic echography showed absence of bony orbital roofs, prominent dural pulsations, direct apposition of brain parenchyma and orbital tissues, and echographic signs suggesting bilateral optic nerve compression. CT and MRI showed a large defect in the floor of the anterior cranial fossa. The cribriform plate, both orbital roofs, and sphenoid bones were displaced by a large basal encephalocele. Clinical improvement followed reconstruction of the anterior cranial fossa and decompression of both optic nerves.

Adult↗
PubMed1993

The forgotten lumbar puncture.

Lumbar puncture is crucial in two distinct clinical situations in the diagnosis of the headache patient. The first is the patient who is suspected of having a symptomatic headache; the second is the patient with a chronic intractable or atypical headache disorder. This review discusses the usefulness of the lumbar puncture in the diagnosis of headache secondary to subarachnoid hemorrhage, meningitis, and intracranial hypotension and hypertension. The value of lumbar puncture in the presence of a normal CT/MRI scan is discussed.

Headache↗
PubMed1993

Cerebrospinal fluid diversion procedures in pseudotumor cerebri.

We reviewed the efficacy of CSF diversion for pseudotumor cerebri (PTC) in patients from six different institutions. Thirty-seven patients underwent a total of 73 lumboperitoneal shunts and nine ventricular shunts. Only 14 patients remained "cured" after a single surgical procedure. The average time between shunt insertion and shunt replacement was 9 months, although 64% of shunts lasted less than 6 months. Shunt failure (55%) and low-pressure headaches (21%) were the most common causes for reoperation. The vision of most patients improved (13) or stabilized (13) postoperatively. However, three who had initially improved subsequently lost vision. Six had a postoperative decrease in vision. Two patients improved in one eye but worsened postoperatively in the other. Four lost vision despite apparently adequate shunt function. Shunt failure with relapse of PTC occurred as late as 7 years after insertion. CSF diversion procedures have a significant failure rate as well as a high frequency of side effects.

Cerebrospinal Fluid Shunts↗
PubMed1993

Neuro-ophthalmic complications of intracranial catheters.

We report four patients who sustained direct injury to the brain after insertion of intraventricular shunts and pressure monitoring lines, which resulted in permanent neuro-ophthalmic deficits. These included hemianopsia from an optic tract lesion, esotropia and residual bilateral facial paresis from dorsal pontine injury, unilateral blindness from damage to the optic nerve, and dorsal midbrain syndrome from catheter compression in the region of the posterior commissure. Although presumably rare, such injuries should be considered in diagnosing patients with neuro-ophthalmic complaints after insertion of such devices.

Adult↗
PubMed1992

A randomized, controlled trial of corticosteroids in the treatment of acute optic neuritis. The Optic Neuritis Study Group.

BACKGROUND AND METHODS: The use of corticosteroids to treat optic neuritis is controversial. At 15 clinical centers, we randomly assigned 457 patients with acute optic neuritis to receive oral prednisone (1 mg per kilogram of body weight per day) for 14 days; intravenous methylprednisolone (1 g per day) for 3 days, followed by oral prednisone (1 mg per kilogram per day) for 11 days; or oral placebo for 14 days. Visual function was assessed over a six-month follow-up period. RESULTS: Visual function recovered faster in the group receiving intravenous methylprednisolone than in the placebo group; this was particularly true for the reversal of visual-field defects (P = 0.0001). Although the differences between the groups decreased with time, at six months the group that received intravenous methylprednisolone still had slightly better visual fields (P = 0.054), contrast sensitivity (P = 0.026), and color vision (P = 0.033) but not better visual acuity (P = 0.66). The outcome in the oral-prednisone group did not differ from that in the placebo group. In addition, the rate of new episodes of optic neuritis in either eye was higher in the group receiving oral prednisone, but not the group receiving intravenous methylprednisolone, than in the placebo group (relative risk for oral prednisone vs. placebo, 1.79; 95 percent confidence interval, 1.08 to 2.95). CONCLUSIONS: Intravenous methylprednisolone followed by oral prednisone speeds the recovery of visual loss due to optic neuritis and results in slightly better vision at six months. Oral prednisone alone, as prescribed in this study, is an ineffective treatment and increases the risk of new episodes of optic neuritis.

Acute Disease↗
PubMed1992

Neurologic conditions presenting as psychiatric disorders.

Neurologic disease can present as a psychiatric disorder. Understanding underlying neuroanatomic function helps physicians to localize defects and search for treatable neurologic conditions. Neurologic conditions such as Huntington's chorea, Wilson's disease, Gille de la Tourette syndrome, brain tumors, encephalitis and meningitis, neurodegenerative conditions and metabolic or toxic conditions can have psychiatric manifestations.

Adolescent↗
PubMed1991

Cerebrospinal fluid protein and opening pressure in idiopathic intracranial hypertension (pseudotumor cerebri).

We studied the relationship between the CSF protein concentration and the degree of elevation of the CSF opening pressure in 177 patients with idiopathic intracranial hypertension (pseudotumor cerebri). There was no linear correlation between the CSF protein and opening pressure. In addition, low CSF protein (less than 20 mg/dl) was present in only 26% of the patients. Our findings fail to confirm previous reports of an inverse relationship between the CSF opening pressure and CSF protein as well as low CSF protein in these patients.

Cerebrospinal Fluid Proteins↗
PubMed1991

Neuro-ophthalmologic vascular emergencies in the elderly.

The significance, management and prognosis of several disorders affecting either vision or ocular motility are discussed. Transient and persistent visual loss are common problems in the elderly. Anterior ischemic optic neuropathy is extensively reviewed because of the importance of recognizing forms due to giant cell arteritis, which require urgent treatment with steroids to prevent further visual loss. The various pathologic conditions that can affect the ocular motor nerves in the cavernous sinus are mentioned. The problem of differentiating benign ischemic lesions causing a third nerve palsy from ominous compressive palsies due to aneurysms is addressed, with emphasis on the clues provided by the pupil.

Aged↗
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↗