Simmons Lessell

Pediatric pseudotumor cerebri (idiopathic intracranial hypertension).

This review focuses on the features of pseudotumor cerebri in the pediatric age group. There is no sex predilection in children, and obesity does not appear to be an important factor. Infants and young children may present with irritability, apathy, or somnolence, rather than headache. Dizziness and ataxia may also occur. Papilledema is infrequently noted in pediatric patients if the fontanelles are open or the sutures are split. Pre-adolescents appear more likely than adults or adolescents to have manifestations of their pseudotumor cerebri other than headache and papilledema, including lateral rectus pareses, vertical strabismus, facial paresis, back and neck pain. Among the etiologies that are particularly pertinent to children are tetracycline therapy, malnutrition or renutrition, and the correction of hypothyroidism. Children with pseudotumor cerebri are at risk for visual loss and their visual function must be closely monitored. Surgical intervention is imperative when vision is threatened.

Paraneoplastic Night Blindness With Malignant Melanoma

A 69-year-old hyperopic man developed acute night blindness and hallucinations of shimmering lights three years after resection of a cutaneous malignant melanoma. There were no metastatic ocular lesions and he had received no medications. His electroretinogram showed abnormalities comparable to those of patients with congenital stationary night blindness with myopia. Metastatic melanoma was recognized several months later. His electroretinographic responses were also identical to those ascribed to vincristine therapy in a previously described patient with malignant melanoma. Our findings showed that acquired night blindness, apparently resulting from interruption of intraretinal rod signal transmission, can be a paraneoplastic effect of a malignant melanoma.

Posterior ischemic optic neuropathy during general surgery.

We examined two patients who awoke with profound bilateral visual loss after operations under general anesthesia. Their fundi, initially normal, later showed bilateral optic atrophy. Neither patient showed other neurologic deficits, although one demonstrated radiologic evidence of a small cerebral infarction in the deep white matter. These patients probably suffered intraoperative infarction of the retrobulbar segments of both optic nerves, producing posterior ischemic optic neuropathy. Profound systemic hypotension may have been a contributing factor in one patient, the use of the pump-oxygenator in the other, and anemia in both.

Optic Canal Decompression in Indirect Optic Nerve Trauma

BACKGROUNDnThe proper management of neurogenic visual loss after blunt head trauma is controversial. Non-treatment, corticosteroids, and surgical decompression of the optic canal are all currently considered to be reasonable alternatives. The goal of this study was to identify factors affecting improvement in patients treated with canal decompression.nnnMETHODSnA retrospective analysis of 31 cases in which transethmoidal decompression of the optic canal had been performed for neurogenic visual loss after closed head trauma was conducted. Each patient was alert and free of injury to the globe when evaluated before surgery. Surgery was performed within 6 days of injury, and all were given perioperative steroids.nnnRESULTSnVisual acuity improved in 22 (71%) patients, with 6 (19%) regaining visual acuity of 20/40 or better. The mean improvement from preoperative visual deficit was 42.0% +/- 6.6%, with a median improvement of 45.2%. Both univariate and multivariate analysis suggested that vision improved more in patients who were younger than 40 years of age than in patients who were 40 years of age or older. Interval between injury and surgery, preoperative visual acuity, and the presence of optic canal fracture did not affect outcome.nnnCONCLUSIONnAny future randomized trials of therapy should stratify patients based on age. Enrollment of patients with no light perception or who experienced delay between injury and treatment may be reasonably considered.

Quandtadve Analysis of Optic Disc Cupping in Compressive Optic Neuropathy

PURPOSEnCupping of the optic disc, a characteristic sign of glaucoma, has been anecdotally described in association with compressive optic neuropathy. The aim of this study is to perform a masked, controlled, and quantitative measurement of the optic disc cup to determine if compressive lesions of the afferent visual pathway were associated with increased cupping.nnnMETHODSnThe ratio of cup area:disc area of 29 patients with intracranial lesions impinging on the optic nerves and the chiasm (14 with pituitary adenomas, 7 with meningiomas, 6 with craniopharyngiomas, and 2 with aneurysms) was compared with those of 20 age-matched control subjects. The areal ratios were derived planimetrically from hand-drawn images of magnified stereophotographs. Patients were divided into three groups based on the degree of laterality of visual compromise. Uninvolved eyes served as an internal control for patients with unilateral disease.nnnRESULTSnThe median ratio of cup area:disc area was 0.37 for all eyes with visual compromise (n = 51) and 0.10 for control eyes, which was statistically significant (P = 0.0001). The median intereye difference in the ratio of cup area:disc area was 0.13 for patients with unilateral lesions and 0.04 for control subjects. This difference also was statistically significant (P = 0.0001).nnnCONCLUSIONSnThe finding of intereye asymmetry in patients with unilateral optic nerve compression is convincing evidence that the enlarged cup is an acquired feature. Several types of compressive lesions of the anterior visual pathway can be associated with increased cupping of the optic disc in the absence of increased intraocular pressure.

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.

Ocular neuromyotonia after radiation therapy

Ocular neuromyotonia is a paroxysmal monocular deviation that results from spasm of eye muscles secondary to spontaneous discharges from third, fourth, or sixth nerve axons. We observed this rare disorder in four patients who had been treated with radiation for tumors in the region of the sella turcica and cavernous sinus. Based on these cases and four others identified in the literature it would appear that radiation predisposes to a cranial neuropathy in which ocular neuromyotonia may be the major manifestation. Radiation appears to be the most common cause of ocular neuromyotonia.

Endothelial cell loss in irradiated optic nerves.

OBJECTIVEnRadiation optic neuropathy usually occurs months to years after exposure of the anterior visual pathways to ionizing radiation. It is characterized by high signal on gadolinium-enhanced T1-weighted magnetic resonance imaging. Radiation-induced endothelial cell damage resulting in blood-nerve barrier breakdown is hypothesized to produce this pattern, but histologic evidence of this in the optic nerve is lacking. We attempted to evaluate the effect of radiation on endothelial cells in the optic nerve.nnnDESIGNnCase-controlled histologic study.nnnMETHODSnWe studied the optic nerves of 16 enucleated eyes from patients with uveal melanoma treated with proton beam irradiation, 6 from normal eyes and 5 from eyes with unirradiated uveal melanomas. Binding of Ulex europaeus agglutinin I (UEA-I) lectin was used to identify endothelial cells in single paraffin sections. Transverse and longitudinal sections of vessels were counted in masked fashion.nnnRESULTSnThere were 49.4+/-6.9 transversely sectioned endothelial cells per millimeter of nerve in 6 optic nerves exposed to 0 to 1000 cGyE (low-dose) compared with 17.3+/-5.3 in 10 nerves exposed to 5500 to 7000 cGyE (high-dose) (P = 0.002). Longitudinally sectioned vessels stained with UEA-I were separately identified, with 11.5+/-2.1 in the low-dose group and 5.6+/-1.6 in the high-dose group (P = 0.044). The thickness and staining of the endothelial cell layer appeared greater in the high-dose group. Endothelial cell counts did not correlate with age, gender, acuity, or interval after irradiation.nnnCONCLUSIONSnIncreased radiation dosage to the optic nerve correlates with smaller numbers of endothelial cells.

Visual Outcome and Tumor Control After Conformal Radiotherapy for Patients With Optic Nerve Sheath Meningioma

PURPOSEnOptic nerve sheath meningioma (ONSM) is a rare tumor that almost uniformly leads to visual dysfunction and even blindness without intervention. Because surgical extirpation carries a high risk of postoperative blindness, vision-sparing treatment strategies are desirable.nnnMETHODS AND MATERIALSnWe retrospectively reviewed the outcomes of 25 patients (25 optic nerves) with ONSM, treated at a single institution with conformal fractionated radiotherapy by either stereotactic photon or proton radiation. Primary endpoints were local control and visual acuity.nnnRESULTSnThe patients presented with symptoms of visual loss (21) or orbital pain (3) or were incidentally diagnosed by imaging (3). The mean age was 44 years, and 64% were female patients. The indication for treatment was the development or progression of symptoms. Of the patients, 13 were treated with photons, 9 were treated with protons, and 3 received a combination of photons and protons. The median dose delivered was 50.4 gray equivalents (range, 45-59.4 gray equivalents). Median follow-up after radiotherapy was 30 months (range, 3-168 months), with 3 patients lost to follow-up. At most recent follow-up, 21 of 22 patients (95%) had improved (14) or stable (7) visual acuity. One patient had worsened visual acuity after initial postirradiation improvement. Of the 22 patients, 20 (95%) had no radiographic progression. Three patients had evidence of asymptomatic, limited retinopathy on ophthalmologic examination, and one had recurrent ONSM 11 years after treatment.nnnCONCLUSIONSnHighly conformal, fractionated radiation therapy for symptomatic primary ONSM provides tumor control and improvement in visual function in most cases, with minimal treatment-induced morbidity. Longer follow-up is needed to assess the durability of tumor control and treatment-related late effects.

Progressive and Recurrent Nonarteritic Anterior Ischemic Optic Neuropathy

We examined ten patients with nonarteritic anterior ischemic optic neuropathy in whom the visual deficit progressed over a number of weeks or who suffered a recurrence in the same eye. The visual deficits progressed over a month or more in five patients, four patients suffered a recurrence in the same eye after a long interval, and one patient had bilateral progression and a recurrence.