Clinical review: the surgical treatment of idiopathic pseudotumour cerebri (idiopathic intracranial hypertension).

To review the literature on the surgical treatment of idiopathic pseudotumour cerebri (PTC) [idiopathic intracranial hypertension (IIH)]. When medical therapy fails or when visual dysfunction deteriorates, surgical therapies for PTC should be considered. The main procedures performed include lumboperitoneal shunt (LPS), ventriculoperitoneal shunt (VPS) and optic nerve sheath fenestration (ONSF). Recently, venous sinus stenting procedures have been performed on selected patients with PTC, especially those with venous sinus occlusive disease. The literature is summarized and appraised in the form of a narrative review. It is evident that ONSF, LPS, VPS and, in selected cases, venous sinus stenting may improve vision and prevent deterioration of vision in patients with PTC. All of the procedures have their advantages and disadvantages and may fail with time no matter what procedure is used. Various authorities have vehemently advocated one or the other of these procedures. Until a prospective, randomized study comparing ONSF with LPS or VPS for PTC is performed, and until the role of venous sinus obstruction as the aetiology of PTC is better defined, the question of which surgical procedure is best for the treatment of PTC remains unanswered.

Recurrent idiopathic familial facial nerve palsy and ophthalmoplegia.

INTRODUCTION: Idiopathic facial nerve palsy is a common neurologic condition but episodes of ophthalmoplegia in these patients are uncommon. MATERIALS AND METHODS: Retrospective case series. RESULTS: Three patients with facial nerve palsy with unusual features, including ophthalmoplegia, are described. CONCLUSION: Recurrent episodes, familial tendency, and associated ophthalmoplegia are uncommon in patients with idiopathic facial nerve palsy.

Homonymous visual field defects in patients without corresponding structural lesions on neuroimaging.

Homonymous visual field defects usually occur with structural processes affecting retrochiasmal visual pathways. The responsible lesion is usually evident on magnetic resonance imaging or on other neuroimaging studies. When results of neuroimaging are normal, functional illness is often suspected. The authors report four patients with homonymous visual field defects who presented with no evident corresponding lesion on magnetic resonance or computed tomography imaging. Etiologies for the visual field defects included the Heidenhain variant of Creutzfeldt-Jacob disease, degenerative dementia, subtle occipital ischemia demonstrated only on positron-emission tomography scanning, and nonketotic hyperglycemia. Clinicians should be aware of the alternative etiologies of organic homonymous visual field loss in patients with normal neuroimaging.

Magnetic resonance venography in idiopathic pseudotumor cerebri.

OBJECTIVE: To inform clinicians about the use of magnetic resonance (MR) venography in idiopathic pseudotumor cerebri. MATERIALS AND METHODS: A prospective study to evaluate for the presence or absence of dural sinus thrombosis using MR imaging and MR venography of the brain in 22 consecutive young, female, overweight patients with typical pseudotumor cerebri. RESULTS: None of the 22 MR imaging and MR venography studies showed venous sinus thrombosis. CONCLUSION: Magnetic resonance venography might not add significantly to the evaluation of typical idiopathic pseudotumor cerebri but may be indicated in atypical cases (e.g., male, thin, or elderly patients).

Hemangioma of the mandibular branch of the trigeminal nerve in the Meckel cave presenting with facial pain and sixth nerve palsy.

In a 25-year-old woman with episodic periorbital-temporal pain who eventually developed a sixth nerve palsy, magnetic resonance imaging revealed a lesion predominantly in the Meckel cave that was found to be a capillary hemangioma arising from the mandibular division of the trigeminal nerve. Hemangiomas of the Meckel cave must be considered in cases of facial pain with a sixth nerve palsy. even if there are no clinical findings of trigeminal neuropathy.

A case of bilateral optic neuropathy in a patient on tacrolimus (FK506) therapy after liver transplantation.

PURPOSE: To report a case of bilateral optic neuropathy in a patient receiving tacrolimus (FK 506, Prograf; Fujisawa USA, Inc, Deerfield, Illinois) for immunosuppression after orthotropic liver transplantation. METHOD: Case report. In a 58-year-old man receiving tacrolimus after orthotropic liver transplantation, serial neuro-ophthalmologic examinations and laboratory studies were performed. RESULTS: The patient had episodic deterioration of vision in both eyes, with clinical features resembling ischemic optic neuropathies. Deterioration of vision occurred despite discontinuation of the tacrolimus. CONCLUSION: Tacrolimus and other immunosuppressive agents may be associated with optic nerve toxicity.

Temporal arteritis: a clinical approach.

OBJECTIVE: To develop a clinical guide to the evaluation of temporal arteritis. DESIGN: A Medline English-language search of the literature from 1966 to 1998, including more than 300 articles about temporal arteritis, was performed to develop a guide to the evaluation of temporal arteritis. RESULTS: A user-friendly guide to the evaluation of temporal arteritis was developed based on the following criteria: (1) clinical suspicion, (2) laboratory testing, and (3) temporal artery biopsy. CONCLUSION: A clinical guide to the evaluation of temporal arteritis may assist clinicians in the care of patients with this condition.

An imaging guide to the evaluation of third cranial nerve palsies.

PURPOSE: To devise a cost-effective imaging guide for the evaluation of third nerve palsies (TNP), based on an extensive review of the literature. METHODS: A review of the pertinent English language literature was performed to devise a guideline for the evaluation and neuroimaging of TNP. The authors also report a retrospective review of the cost of imaging studies performed on 91 patients with TNP. RESULTS: On the basis of the available literature, an imaging guide was developed and applied to a retrospective chart review of 91 patients from a single tertiary care center (Baylor College of Medicine). The cost effectiveness as well as the efficacy of the imaging guide was analyzed. CONCLUSIONS: The evaluation of TNP can be difficult; however, using such guides may allow for more appropriate and cost-effective evaluation of these patients.

Acquired binocular horizontal diplopia.

Binocular horizontal diplopia is an important symptom that may foretell or help localize and characterize various neurologic and neuromuscular disorders. An appropriate evaluation requires a careful and complete neuro-ophthalmic history and examination. This review focuses on the differential diagnosis of binocular horizontal diplopia.

Ishihara color plates as a test for simultanagnosia.

PURPOSE: To alert ophthalmologists to the use of Ishihara color plates in the detection of simultanagnosia. METHODS: We examined seven patients referred for impaired vision. Evaluation included color plate testing with Ishihara color plates. RESULTS: All seven patients had simultanagnosia, with marked difficulty in identifying the numbers in Ishihara color plates despite adequate visual acuity and the ability to name all of the colors in the plates correctly. One of these patients was referred with the diagnosis of a cone dystrophy because of her poor performance on the Ishihara test. All of the patients had bilateral occipitoparietal damage or atrophy on magnetic resonance imaging. CONCLUSIONS: Ophthalmologists must be aware that a poor performance with Ishihara plates may not be attributable to an impairment of color vision but rather to occipitoparietal brain damage associated with simultanagnosia.

Binocular vertical diplopia.

The assessment of a patient with binocular vertical diplopia begins with a thorough history and neuro-ophthalmologic examination. The neuro-ophthalmologic examination includes observation for a compensatory head, face, or chin position; ocular ductions and versions in the nine cardinal positions of gaze; the three-step test; the double Maddox rod test; indirect ophthalmoscopy to observe the location of the fovea in relationship to the optic nerve head to determine cyclodeviation; and the forced ductions test. Binocular vertical diplopia may be due to supranuclear processes, ocular motor nerve dysfunction, neuromuscular junction disease, diseases of eye muscle, mechanical processes causing vertical eye misalignment, and even retinal disease. In this article, the differential diagnosis of these processes is outlined.

Elevated intracranial pressure and pseudotumor cerebri.

The development of papilledema requires high cerebrospinal fluid (CSF) pressure in the distal optic nerve sheath, elevation of the pressure in the central retinal vein, and impaired perfusion of the neurons as they traverse the lamina cribrosa. Pseudotumor cerebri (PTC) is a syndrome defined by four criteria: 1) Increased intracranial pressure, 2) normal or small ventricles on neuroimaging, 3) no evidence of an intracranial mass, and 4) normal CSF composition. Elevated intracranial venous pressure is thought by some authors to be the "universal mechanism" of PTC of varying etiologies. The reason obesity predisposes to idiopathic PTC is unclear, but one mechanism proposed is that central obesity raises intra-abdominal pressure, which increases pleural pressure and cardiac filling pressures, which impede venous return from the brain, leading to increased intracranial venous pressure and increased intracranial pressure. Both optic nerve sheath fenestration (ONSF) and lumboperitoneal shunting (LPS) may improve vision and prevent deterioration of vision in patients with PTC. Both procedures have their advantages and disadvantages, but until a prospective, randomized study comparing ONSF with LPS for PTC is performed, the question of which surgical procedure is best for the treatment of PTC remains unanswered.

Enhanced ptosis in Lambert-Eaton myasthenic syndrome.

A patient with Lambert-Eaton myasthenic syndrome (LEMS) presented with a bilateral ptosis that improved transiently after sustained upgaze. The contralateral ptosis became aggravated on manually lifting either eyelid with and without fixation (enhanced ptosis). Enhanced ptosis is a common finding in many patients with ptosis resulting from myasthenia gravis; however, to our knowledge, this is the first description of this sign in a patient with LEMS. The phenomenon of enhanced ptosis should be sought in all patients with ptosis. Improvement of the ptosis after sustained upward gaze suggests the diagnosis of LEMS.

Tropicamide eyedrops cannot be used for reliable diagnosis of Alzheimer's disease.

OBJECTIVE: To evaluate the mydriatic effect of tropicamide eyedrops as a diagnostic test for Alzheimer's disease. MATERIAL AND METHODS: In a double-blind, placebo-controlled study, we assessed pupillary responses in 22 normal control subjects, 23 patients with probable Alzheimer's disease, 4 patients with isolated memory difficulty, and 6 patients with non-Alzheimer's dementia. Three separate studies were performed, the second and third on a subset of the original group. With use of infrared binocular pupillography, after 5 minutes of dark adaptation, we averaged pupil size during a 1-minute interval for baseline determinations. We then instilled 0.01% tropicamide into one eye. In the first two studies, we averaged pupil size for a 1-minute period at 5-minute intervals for 30 minutes, followed by a pupil light reflex test. In the third study, we measured pupil size every 5 minutes for 45 minutes and omitted the light reflex test. RESULTS: No significant difference was noted in pupil dilatation between normal subjects and patients with Alzheimer's disease and between patients with non-Alzheimer's dementias and the Alzheimer's disease group in all three studies. Furthermore, on reperformance of the test in the same patients, more than 50% changed from a group above or below 13% pupil dilatation (a cutoff reported to distinguish Alzheimer's disease from normal control subjects) to the opposite group. CONCLUSION: Results of this study indicate that pupil measurement after instillation of tropicamide cannot be used as a reliable diagnostic test for Alzheimer's disease. Moreover, test-retest reliability with use of dilute tropicamide eyedrops is questionable.

Idiopathic intracranial hypertension and seventh nerve palsy.

Patients with idiopathic intracranial hypertension may occasionally present with coexisting lower motor neuron facial weakness. This study reviews a 6-year experience at Mayo Clinic. The aim of this study was to determine the possible association of idiopathic intracranial hypertension and facial paresis. Two cases were identified. Both fulfilled the modified Dandy's diagnostic criteria for idiopathic intracranial hypertension. Treatment consisted of steroids in one, and emergent optic nerve sheath fenestration in the other. The cranial nerve palsies resolved in both cases.

Complete ophthalmoplegia after zoster ophthalmicus.

Complete ophthalmoplegia following herpes zoster ophthalmicus (HZO) is rare. We report three cases of HZO-associated complete ophthalmoplegia and review thirteen additional cases reported in the English language medical literature over the past 30 years. HZO-associated complete ophthalmoplegia occurs mostly in individuals over the age of 50 years and usually occurs within one to two weeks of the development of cutaneous HZO. The prognosis for recovery is good, with-significant improvement typically seen within 2 months and complete or near resolution within 18 months time.

Optic disk edema with a macular star.

Optic disk edema with a macular star is a descriptive term encompassing a heterogeneous group of disorders. The clinical features include sudden visual loss, swelling of the optic disk, peripapillary and macular exudates that may occur in a star pattern, and cells in the vitreous. Herein we describe the clinical features, potential etiologic factors, differential diagnosis, work-up, and natural history of this entity. Although optic disk edema with a macular star is usually idiopathic, infectious causes, especially syphilis, Lyme disease, cat-scratch disease, and toxoplasmosis, should be considered. The macular exudate likely results from primary optic nerve disease, not from inflammation of the retina; therefore, we prefer the term "idiopathic optic disk edema with a macular star" for idiopathic cases rather than "neuroretinitis." When optic disk swelling and macular star are associated with focal or multifocal inflammatory lesions in the retina (retinitis), especially if an infectious cause is documented, the term "neuroretinitis" is appropriate. The prognosis for visual recovery is usually good, but residual visual loss may be severe in a few cases. Patients with a recurrent type of the disease may not experience pronounced improvement in optic nerve function. The macular exudate may not develop in cases of disk edema until 2 weeks after the patient's initial assessment; thus, patients who have acute papillitis with a normal macula should be reexamined within 2 weeks for development of a macular star. The presence of a macular star militates strongly against subsequent development of multiple sclerosis.

Posterior ischemic optic neuropathy associated with migraine.

Anterior ischemic optic neuropathy is a well-recognized clinical syndrome that has been described in patients after an episode of migraine with visual aura (classic migraine) and, less commonly, after an episode of visual aura without headache (acephalgic migraine). Little emphasis, however, has been placed on migraine-associated retrobulbar or posterior ischemic optic neuropathy. We report two cases of visual loss presumed to be due to posterior ischemic optic neuropathy that occurred in the setting of otherwise typical migraine episodes. We review the English language literature on ischemic optic neuropathy associated with migraine. Although most cases of ischemic optic neuropathy associated with migraine are of the anterior variety, posterior ischemic optic neuropathy should be considered in the differential diagnosis of any patient with acute loss of vision and evidence for a retrobulbar optic neuropathy, during or after an attack of migraine headache or following an otherwise typical episode of visual aura without headache (acephalgic migraine).