Downbeat nystagmus with magnesium depletion.

Two patients with neurological signs of magnesium depletion complained of oscillopsia and manifested downbeat nystagmus. Serum magnesium levels measured less than 1.0 mg/dL. Hypomagnesemia resulted from debilitating intestinal disease in both patients and apparently was aggravated in one case by failure to add magnesium sulfate to the patient's regimen for total parenteral nutrition. Neither patient had any of the neurological conditions reported with downbeat nystagmus. Thus, downbeat nystagmus in the primary position occurs with the metabolic derangement of severe magnesium depletion. Another apparent metabolic cause of downbeat nystagmus is thiamine deficiency. Downbeat nystagmus also may occur from a partial deficiency of the metabolic cofactors, magnesium and thiamine.

Midbrain corectopia.

Intermittent corectopia was recently observed in a patient with bilateral, rostral midbrain infarction. Results from neuropathologic examination disclosed isolated but intact Edinger-Westphal nuclei. An explanation of midbrain corectopia centered on segmental innervation of the pupil by the Edinger-Westphal nucleus. In the presence of a paralyzed dilator muscle, select, central inhibition of sphincter tone resulted in an oval and eccentric pupil.

Parainfectious optic neuritis. Report and review following varicella.

Severe loss of vision and bilateral optic disc edema occurred in a 10-year-old girl 38 days after the rash of varicella first appeared and subsequent encephalitis developed. Recovery of visual function was nearly complete, but optic atrophy persisted. Parainfectious optic neuritis following other viral infections, with the exception of herpes zoster, has a similar clinical profile: delayed onset, severe visual loss, optic disc edema, bilaterality, good recovery, and residual optic atrophy. Conduction delays in our patient's patterned visual evoked potentials implicated demyelination within the optic nerves. The often favorable recovery, frequency of delayed onset, and bilateral involvement of the optic nerves support an autoimmune process in the pathogenesis of parainfectious optic neuritis.

Amaurosis fugax from disease of the external carotid artery.

Three patients with proved internal carotid artery occlusion and diseased external carotid artery or common carotid artery had amaurosis fugax. Evidence for retinal embolization through external carotid collaterals is retinal emboli and infarction after carotid artery manipulation, amaurosis during external carotid angiography, and relief of amaurosis by endarterectomy of this vessel. The abundance of external carotid collaterals, their size, and natural incidence are discussed. Reports clinically support embolization to the central retinal artery and ophthalmic artery through these collaterals.

Micromethod for detection of oligoclonal IgG in unconcentrated CSF by polyacrylamide gel electrophoresis.

A micromethod to detect oligoclonal IgG from 50 microL of unconcentrated CSF was developed by using polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE). Of 17 patients with multiple sclerosis, oligoclonal bands were demonstrated in 16 instances (94%) by micro-SDS-PAGE and in 13 (76%) by agarose gel electrophoresis. The corresponding figures among 30 patients with optic neuritis were 16 (54%) and five (17%), respectively, and among ten patients with other neurological disease the figures were two (20%) and none, respectively. Thus, micro-SDS-PAGE is more sensitive than agarose gel electrophoresis for detection of oligoclonal IgG. The small volume of unconcentrated CSF that is required enhances the usefulness of this test.

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.

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.

Ventriculostomy for hydrocephalus in cerebellar hemorrhage.

In a matter of hours the neurologic status of two hypertensive patients deteriorated to coma. Cranial computed tomography (CT) showed mild to moderate cerebellar hemorrhage and secondary hydrocephalus. Ventriculostomy resulted in clinical improvement within 20 minutes and obviated the need for suboccipital craniectomy. Both patients made a very satisfactory recovery. Similar patients have occasionally been observed by others. Ventriculostomy should be considered for patients with cerebellar hemorrhage who have hydrocephalus by CT scan and undergo progressive neurologic deterioration. Because the frequency of improvement and the risk of upward cerebellar herniation following ventriculostomy is unknown, immediate surgical evacuation of the hemorrhage should be anticipated.

Microangiopathy of the brain and retina.

Two women (26 and 40 years old) developed an unusual microangiopathy that affected the brain and retina. Psychiatric symptoms initially overshadowed the subacute features of the progressive neurologic disorder. Ophthalmoscopic findings of multifocal branch retinal artery occlusions provided clinical evidence of vasculopathy. Laboratory data did not reveal evidence of the known vasculitides, including systemic lupus erythematosus (SLE) and syphilis. Cerebral angiography suggested vasculitis in the younger patient. Brain biopsy in the older patient (after 3 months of steroid therapy) revealed a sclerosis of the small pial and cortical vessels that was consistent with a "healed" angitis. Both patients seemed to respond to steroid 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.

Psuedotumor cerebri and insecticide intoxication.

Three patients with headache and increased intracranial pressure had elevated blood, serum, and adipose levels of the organochlorine insecticide chlordecone (Kepone). These patients were among 23 employees who suffered from chronic chlordecone intoxication resulting from industrial exposure. In our three patients, investigations eliminated an intracranial mass or other known causes of psuedotumor cerebri. In all three patients, the capacity for cerebrospinal fluid (CSF) absorption was assessed by graded infusions into the subarachnoid space, and was found to be impaired even when papilledema was minimal.

Chlordecone intoxication in man. I. Clinical observations.

Industrial overexposure to chlordecone, an organochlorine insecticide, caused tremor in 76 of 148 exposed workers. Chlordecone was absorbed through oral, respiratory, and dermal routes, the last possibly the most significant. Epidemiology of this incident disclosed low-level, widespread environmental exposure of man to chlordecone. In 23 workers with chronic chlordecone intoxication, tremor was associated with opsoclonus, pleuritic pain and arthralgia. No seizures were reported. The site of action of chlordecone on the central nervous system is unknown. It concentrates in human adipose and hepatic tissue but is not biodegradable, either in humans or elsewhere in nature.

Sarcoid optic neuropathy.

Three patients presented with unilateral progressive optic neuropathy. None of these patients had signs of symptoms referable to the chiasm or eye, thus confining their decline in vision to the optic nerve. Clinical and neuroradiographic evidence suggested a meningioma involving the optic nerve at the orbital-canalicular junction in one patient and the intracranial optic nerve in another patient. Surgical exploration in both patients, however, revealed a noncaseating granuloma. Decline in vision from granulomatous invasion of the retrobulbar optic nerve is an uncommon manifestation of sarcoidosis. Review of our patients' findings suggests that a nonsurgical diagnosis of sarcoid optic neuropathy may have been tenable.

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.

Ischemic optic neuropathy: a complication of cardiopulmonary bypass surgery.

Ischemic optic neuropathy followed cardiopulmonary bypass surgery in the postoperative period in 7 of 7685 consecutive procedures. Th visual loss was unilateral in four patients and bilateral in three and there was little improvement. This ischemic infarction of the optic nerve disk was attributed to hypotension, hypothermia, and activation of certain complement factors by the bypass procedure.

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.

Anterior ischemic optic neuropathy with internal carotid artery occlusion.

We examined three patients who had anterior ischemic optic neuropathy and ipsilateral internal carotid artery occlusion. Each patient had transient cerebral ischemic attacks associated with the occluded carotid artery. In two patients there attacks were in temporal proximity to the anterior ischemic optic neuropathy. Carotid angiography showed retrograde filling of the ophthalmic artery through the external carotid artery demonstrating altered perfusion and, perhaps, hypoperfusion of the distal optic nerve head.

Retinopathy after tilorone hydrochloride.

Two patients, a 34-year-old woman and a 50-year-old woman, received tilorone HCl, an experimental antitumor drug. After taking the drug orally (total dose, 152 g), the first patient developed corneal subepithelial infiltrates and toxic retinopathy characterized by fine pigment mottling of the peripheral fundus and macula with mild arteriolar narrowing. Although visual acuity was 6/6 (20/20) throughout treatment, Goldmann perimetry showed marked peripheral constriction of the visual fields and results of an electroretinogram and an electro-oculogram were abnormal. After taking the drug orally (total dose, 189 g), the second patient developed corneal subepithelial infiltrates, severe bilateral arteriolar narrowing, and mild pigment mottling of the macula. ERG and EOG were moderately attenuated. Visual fields by Goldman perimetry were within normal limits. Tilorone HCl, like chloroquine, may be an antioxidant that affects the free radical scavenging mechanism of the retinal pigment epithelium. Extensive testing should be done on all patients taking tilorone HCl in order to detect the initial manifestations of retinopathy.

Blindness caused by photoreceptor degeneration as a remote effect of cancer.

Three postmenopausal women developed photoreceptor degeneration one to four months preceding or following discovery of an anaplastic tumor. Two patients had transitory visual obscurations and bizarre visual sensations. Ring scotomas progressed to severe visual field loss. Retinal arteries were markedly narrowed. Electroretinograms revealed almost total absence of response in one patient, and another complained of the recent onset of night blindness. In all three patients severe degeneration of the photoreceptor cells associated with melanophagic activity was shown histologically. In two patients neuropathologic examination from the retinal bipolar cells to the occipital cortex revealed no significant alterations.

Flaccidity after head injury: diagnosis, management, and outcome.

Upon admission, 17 of 223 (8%) consecutive patients with severe head injury exhibited a flaccid, wholly unresponsive motor examination. In this study alcoholic intoxication neither caused depressed motor responsiveness in head-injured patients with high serum ethanol levels nor accounted for the motor examination in those exhibiting the flaccid state. Flaccidity was attributed principally to impaired ventilation in 4 patients, a major intracranial mass in 12, and a spinal cord injury in 1. Compared to the larger group of head-injured patients, the flaccid patients had a significantly greater incidence of hypercapnia (P less than 0.001), acidosis (P less than 0.01), and both elevated and uncontrollable intracranial pressure (ICP) (P less than 0.001). These findings and the high mortality rate (76%) in this study suggest that the magnitude of respiratory complications and the severity of mechanical brain injury are greater in flaccid patients. The flaccid patients undergoing surgical decompression for major intracranial mass lesions (11 cases) have all died and, although still small in number, this group may represent an important subset with a poor prognosis. Nonetheless, a protocol that encourages rapid radiological and electrophysiological assessment and vigorous surgical and ICP management until the probable cause of flaccidity is identified and treated has benefit. The flaccid state was reversed and a good recovery was attained after the restoration of blood pressure and/or ventilation in 2 patients who appeared to have sustained a very grave head injury. In another patient, absent somatosensory evoked potentials greatly facilitated the diagnosis of a spinal subdural hematoma. This program of prompt diagnosis and intense therapy did not result in a protracted course or undue numbers of severely brain-damaged survivors.