Light-induced amaurosis fugax.

PURPOSE: To describe an important symptom of bilateral amaurosis precipitated by exposure to bright light. METHODS: Case report. Clinical analysis of transient, painless, asymmetrical visual loss occurring in bright light in a 54-year-old man. RESULTS: Carotid ultrasound showed bilateral carotid disease. Carotid angiography demonstrated occlusion of the left internal carotid artery and severe stenosis of the right internal carotid artery and both external carotid arteries. Visual symptoms and an abnormal photostress test completely remitted after a right carotid endarterectomy. CONCLUSION: Light-induced amaurosis is an unfamiliar manifestation of ocular ischemic syndrome occurring with severe, often bilateral, carotid artery disease. Its recognition is important because the complaint is associated with severe carotid occlusive disease and recognition is necessary for timely surgical intervention because of the major risk for stroke.

Acute multifocal placoid pigment epitheliopathy and central nervous system involvement: nine new cases and a review of the literature.

OBJECTIVE: The authors describe nine new cases of acute multifocal placoid pigment epitheliopathy (AMPPE) with associated central nervous system (CNS) involvement and permanent visual sequelae. The study includes a review of the literature and discussion of evaluation, management, and treatment options. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Nine patients were identified with AMPPE and CNS involvement in addition to 22 patients reviewed in the literature. MAIN OUTCOME MEASURES: A review of nine patients with AMPPE and CNS involvement was performed. Charts were reviewed for age, gender, preceding viral prodromes, visual acuity, ophthalmologic examination findings, CNS findings, and treatment. RESULTS: Thirty-one patients (nine new patients) were diagnosed with AMPPE and various degrees of CNS involvement. Ages ranged from 8 to 54 years, with an average of 27 years. Twenty-one males (68%) and 10 females (32%) were identified. Eleven patients (35%) had antecedent viral illnesses. Visual acuity was variable and ranged from 20/20 to count fingers. The spectrum of CNS findings ranged from headaches to sagittal sinus thrombosis. CONCLUSIONS: Acute multifocal placoid pigment epitheliopathy can be associated with CNS abnormalities and permanent visual deficits. Neuroimaging, lumbar puncture, and cerebral angiography analysis provide useful diagnostic tools when CNS involvement is suspected. Intravenous corticosteroids and collaboration with neurovascular colleagues should be considered in these situations. In cases complicated by CNS arteritis, immunosuppressive agents can be a beneficial adjunct to corticosteroids.

Retinol-binding protein in idiopathic intracranial hypertension (IIH).

OBJECTIVE: We postulated that an alteration in endogenous vitamin A (retinol) metabolism plays a causal role in the pathogenesis of idiopathic intracranial hypertension (IIH). MATERIALS AND METHODS: Serum retinol was determined by a fluorometric method from 40 control subjects and 58 patients with idiopathic intracranial hypertension (IIH). Retinol binding protein (RBP) was also assayed by quantitative radial immunodiffusion in 17 control subjects and 30 patients with IIH. RESULTS: Mean retinol values were higher in the IIH group compared with the control group, but did not reach a significant level. However, seven of 30 patients with IIH had high RBP levels, but none of the control subjects did. CONCLUSION: This data suggests that IIH is associated with an abnormality in vitamin A metabolism that is linked to its transport system.

MRI in Lhermitte-Duclos disease.

Lhermitte-Duclos disease (LDD) is a disorder sometimes referred to as a dysplastic gangliocytoma of the cerebellum. This is a focally indolent growth of the cerebellar cortex in which the folia enlarge due to a profusion of dysplastic cortical neurons and a thickening of the molecular layer. Loss of Purkinje cells and thinning of medullary white matter results. The enlarged folia lose their secondary foldings and asymmetrically expand the cerebellar hemisphere. These morphologic features produce a characteristic pattern on some CTs and all MRIs, affording an opportunity for a preoperative diagnosis. MRI of a pathologic specimen suggested that the abnormal T1 and T2 signals corresponded to the atrophic folial white matter, thickened granule cell layer, and outer molecular layer. Because of inherent Hounsfield artifact in posterior fossa with CT, MRI is the imaging modality of choice, with better visualized striated pattern. The uniqueness of these imaging features obviates the need for an obligatory biopsy for asymptomatic patients and either permits more definitive planning for surgical decompression or, in restricted lesions, guides more assuredly complete excision of the cerebellar mass.

Optic neuropathy, headache, and diplopia with MRI suggestive of cerebral arteritis in relapsing polychondritis.

The pathogenesis of central nervous system disease in relapsing polychondritis (RPC) is unknown but may be related to cerebral arteritis. Previous reports have described clinical and histopathologic evidence of cerebral vasculitis in RPC; however, a neuroimaging correlate has not been reported. We present a 36-year-old man with neuro-ophthalmic features of RPC whose magnetic resonance imaging revealed multifocal gray- and white-matter high intensities. This pattern is consistent with cerebral arteritis as described in other systemic vasculitides.

Uhthoff and his symptom.

At the turn of the last century, Wilhelm Uhthoff was a renowned clinical neuro-ophthalmologist, and probably the first clinician whose entire career was devoted to this discipline. His achievements are among those that mark the commencement of contemporary neuro-ophthalmology. Uhthoff's symptom of visual loss with exercise is most frequently associated with optic neuritis. The symptom carries a major risk for recurrence of optic neuritis and development of multiple sclerosis. This study and its companion in the publication show that, independently, a metabolic byproduct of exercise or increases in body temperature cause a reversible conduction block in demyelinated optic nerves and result in temporary loss of vision [corrected].

Visual evoked potentials during hyperthermia.

OBJECTIVES: We sought to evaluate the effect of hyperthermia (HT) on central conduction pathways by alterations in pattern visual evoked potentials (PVEPs) in normal and demyelinated optic nerves. MATERIALS AND METHODS: We studied PVEP peak latency and amplitudes in 10 normal subjects and six patients with demyelinating optic neuropathy before and during HT. RESULTS: In normal subjects, a mean rise in temperature of 2.5 degrees C resulted in a decrease in the second positive peak (P2) latency of 6.1 ms (p < 0.0001) and a slight decline in P2 amplitude of 1.16 muV (p < 0.009). These results were compared to those obtained from six patients with multiple sclerosis. These patients had a history of monocular optic neuritis; two patients had had bilateral optic neuritis, and one patient had not had involvement of the optic nerve. Average temperature elevations during PVEPs were 1.60 degrees C. PVEPs among these patients showed decrease in mean P2 latencies, except in patients with multiple sclerosis, who showed an increase in latency with 60 min check size in the left eyes. There was a consistent decline in P2 amplitudes. Loss of amplitude was greater among the six optic nerves of those patients having transient, mild losses in visual acuity during HT. Reductions in P2 amplitude were best explained by partial or complete conduction block. CONCLUSIONS: These changes in conduction time and amplitude during HT provide a neurophysiologic correlation to the well-known sensitivity of demyelinated optic nerves to elevated temperatures. They are also relevant to the monitoring of central pathways in the operative or intensive care setting. The demonstrated reversible loss of amplitudes also gives promise to therapeutic manipulation of impaired pathways by impeding the loss of current from denuded nerve fibers.

Magnetic resonance evidence of perineural metastasis.

Contiguous spread along perineural and endoneural spaces, that is, perineural tumor extension, in cutaneous squamous cell carcinoma is fairly common. Infrequently, these tumors spread and involve intracranial structures. One consequence of this complication is meningeal carcinomatosis which is underrecognized. Herein described is a patient with recurrent cutaneous squamous cell carcinoma with perineural invasion along the maxillary nerve that was subsequently shown by magnetic resonance imaging to the trigeminal root. The patient initially presented with a cavernous sinus syndrome but despite aggressive treatment, extensive meningeal carcinomatosis and cauda equina dysfunction developed. Awareness of perineural invasion and proper evaluation are crucial. Perineural spread intracranially worsens the prognosis and limits treatment options to palliation.

Hyperdense basilar artery. An early computed tomography sign of thrombosis.

Noncontrast computed tomographic scans (CT scans) may show a hyperdense basilar artery before a brainstem infarct is visualized. This early sign should assist clinicians in confirming the diagnosis of basilar artery thrombosis. In a review of admission records of 750 patients with acute cerebrovascular disease from July 1991 to June 1993, at Saint Louis University Hospital, 20 patients were identified with clinical signs of nonlacunar, vertebrobasilar distribution infarction. Eight of these had pontomesencephalic ischemia. Their neuroimaging studies and medical records were evaluated. Four patients with acute clinical signs of pontomesencephalic infarction were found to have a hyperdense basilar artery on CT scans. The scans of 2 patients were excluded because of dolichoectasia; in the other 2 patients, the basilar artery appeared normal on the CT scan. The hyperdense basilar artery was detected within the early hours of neurological symptoms and often was the only detectable abnormality on the scan. In 3 patients extensive brainstem infarcts subsequently developed and they died. Basilar artery thrombosis was confirmed by pathological study in all these patients. In the fourth patient basilar artery occlusion and a large pontine infarct were evident by magnetic resonance imaging and angiography. A hyperdense basilar artery is a common feature on CT scans of patients presenting with an early clinical diagnosis of thrombosis. Untreated, the hyperintense basilar artery often portends a poor prognosis. Its ready recognition should guide further interventional studies and treatment.

Delayed sequelae of vertebral artery dissection and occult cervical fractures.

We report three patients who developed delayed (ie, more than a week after the injury) symptoms of vertebrobasilar ischemia following motor vehicle accidents. The patients all had angiographic evidence of vertebral artery dissection and, upon further evaluation, occult fractures of the second cervical vertebra that were not detected by simple cervical spine radiography and required polytomography or CT for diagnosis. Vertebral artery dissection can result from occult cervical spine fractures and may present with delayed symptoms of brain ischemia.

Epidermoid-induced pulsating eye.

An otherwise asymptomatic 62-year-old woman had a pulsating but not proptotic eye. Computed tomography showed a low-density mass lesion in the temporal lobe that extended through a defective greater wing of the sphenoid, indented the lateral rectus muscle, and displaced the optic nerve. Magnetic resonance imaging confirmed these findings and showed no enhancement of the lesion by gadolinium. An epidermoid cyst was diagnosed on the basis of its location in the cleavage lines of the temporal lobe, irregular margins, low density by imaging scans, lack of enhancement, and invasion of the orbit. Epidermoid tumors are, therefore, another cause for a pulsating eye.

Early computed tomography demonstration of cerebral infarction does not correlate with clinical outcome.

The results of unenhanced computed tomography (CT) obtained in 105 consecutive patients admitted with cerebral infarction were compared with the patients' clinical outcome and their Glasgow Outcome Scores upon discharge. Specific analysis of the findings in patients with early admission CT (within 12 h of onset) was carried out. The size of the infarction was calculated from delayed CT images (small if less than 50 mm(3); moderate if 50-250 mm(3); large if greater than 250 mm(3)). Initial CT demonstration of the cerebral infarction was accomplished in 57 (54.3%) patients. Forty patients were studied early (<12h) and, of these, 20 (50%) showed abnormal admission CT. The size of the infarction correlated with its demonstration by admission CT. This correlation was found in all patients (p < 0.0001), as well as in those who had early CT (p = 0.015). Also, the size of the infarction correlated with the outcome of the patient (p < 0.001). The demonstration of the lesion by early CT, however, failed to correlate with the outcome of the patients. This finding, although at first surprising, is analogous to reports addressing the predictive value of other CT parameters.

Meso-diencephalic infarction: a not so rare form of stroke.

26 patients admitted with clinical pictures consistent with meso-diencephalic infarction were studied using computerized axial tomography, magnetic resonance imaging and angiography. All of the patients presented symptoms in two of three major categories which comprise the "top of the basilar" syndrome. Lesions in the territory of the basilar-communicating artery were demonstrated in 22 of them. The remaining patients died before adequate neuroimaging documentation was obtained. Overall prognosis appeared relatively good since 80% of the patients recovered completely or incompletely from the ictus. Meso-diencephalic infarction is a very important and not uncommon subtype of cerebrovascular disorder.

Bilateral altitudinal visual fields.

We describe two patients with absolute, complete, binocular inferior altitudinal hemianopias. These altitudinal visual-field defects (AVFDs) involved both nasal and adjacent temporal quadrants and respected the horizontal meridian. The reported conditions and locations in the visual system that cause "conventional" AVFDs and their bilateral occurrence are reviewed. Division of the visual system into altitudinal halves results from the topographic arrangement of nerve fibers and their blood supply in the retina, optic nerves, and visual cortex. Lesions at these locations resulting in AVFDs are usually due to vascular occlusion or may result from a penetrating missile injury to the superior occipital lobes. It is important to emphasize that the nerve fiber layer of the retina respects the horizontal meridian only in the nasal field, not in the temporal field; therefore incomplete AVFD is more common. Because of the anastomotic blood supply of the occipital pole, only AVFDs due to occipital infarcts spare fixation. Diagnosis of retinal branch artery occlusion or anterior ischemic optic neuropathy is aided by the presence of a unilateral AVFD along with ipsilateral funduscopic abnormalities and, in most bilateral examples, by its sequential temporal development. Bilateral occipital infarcts, as in our two cases, are characterized by sudden, simultaneous onset of AVFDs, an absence of retinal, retinovascular, or optic nerve abnormality and confirmation by computed tomographic scanning.

Post-traumatic midbrain tremors.

We report 3 patients with post-traumatic tremor and describe the characteristics of the tremor and accompanying neurologic signs. Radiographic and pathologic examination indicated a contralateral midbrain localization of the lesion. The tremor responded to anticholinergic or dopaminergic therapy.

Acute thalamic esotropia.

Three men developed acute esotropia, stupor, and impaired upward gaze. Vestibulo-ocular stimulation showed that the adducted eye remained immobile while the fellow eye responded normally. The alteration of consciousness, the long-tract neurologic signs, and the esotropia quickly resolved. Upgaze paresis and brief bursts of convergence-retraction nystagmus were the major residual signs. Imaging techniques demonstrated lesions of the contralateral posterior thalamus in each patient. Several mechanisms are proposed to explain the acute esotropia. Impairment of monocular projections in the contralateral posterior thalamus could disinhibit neurons in the oculomotor complex, or ischemia of inputs to neurons involved with vergence control in the midbrain could result in tonic activation of the medial rectus. The clinical and radiographic findings are consistent with infarction in the territory of penetrating branches of the basilar-communicating (mesencephalic) artery. Embolism to the top of the basilar artery is presumed to be the precipitating event.