Michael S. Vaphiades

Magnetic resonance imaging in pseudotumor cerebri

OBJECTIVE To determine whether magnetic resonance (MR) imaging can be used to predict the presence of elevated intracranial pressure. DESIGN Retrospective case series. PARTICIPANTS Twenty patients with pseudotumor cerebri and 20 control subjects. INTERVENTION Magnetic resonance imaging. MAIN OUTCOME MEASURES The presence or absence of the following six neuroimaging signs was measured: (1) flattening of the posterior sclera; (2) enhancement of the prelaminar optic nerve; (3) distension of the perioptic subarachnoid space; (4) intraocular protrusion of the prelaminar optic nerve; (5) vertical tortuosity of the orbital optic nerve; and (6) empty sella. RESULTS The MR imaging disclosed flattening of the posterior sclera in 80% of patients with pseudotumor cerebri, empty sella in 70%, distension of the perioptic subarachnoid space in 45%, enhancement of the prelaminar optic nerve in 50%, vertical tortuosity of the orbital optic nerve in 40%, and intraocular protrusion of the prelaminar optic nerve in 30%. Each neuroimaging sign was detected in 5% of control subjects, except for enhancement of the prelaminar optic nerve, which was not detected in control subjects. Based on these MR imaging signs, the examiner was able to predict the presence of elevated intracranial pressure in 90% of cases with pseudotumor cerebri and the absence of elevated intracranial pressure in all control subjects. CONCLUSIONS Elevated intracranial pressure produces a constellation of MR imaging signs that can assist in establishing the diagnosis of pseudotumor cerebri.

Non-arteritic anterior ischaemic optic neuropathy and presumed sleep apnoea syndrome screened by the Sleep Apnea scale of the Sleep Disorders Questionnaire (SA-SDQ)

Background: Two recent studies reported over 70% of the patients with non-arteritic anterior ischaemic optic neuropathy (NAION) had sleep apnoea syndrome (SAS) diagnosed by overnight polysomnography. The current study used the Sleep Apnea scale of the Sleep Disorders Questionnaire (SA-SDQ) to evaluate this association. Methods: A matched case-control study was conducted among 73 cases of NAION matched on age and gender to 73 controls without a history of NAION. Information regarding demographics, medical conditions, health behaviours and SAS was obtained via a telephone questionnaire that included the SA-SDQ. Conditional logistic regression was used to calculate odds ratios (OR) and the 95% confidence intervals (CI) for the association between NAION and the SA-SDQ. Results: Cases were significantly more likely to report symptoms and characteristics consistent with SAS than controls (OR 2.62; 95% CI 1.03 to 6.60) when adjusted for medical and health behaviour characteristics. Conclusions: The results of this study suggest that patients with SAS are at increased risk of NAION. Additional research in a larger population is needed to confirm the observed results and validate the use of the SA-SDQ in patients with NAION.

Hemianopic and Quadrantanopic Field Loss, Eye and Head Movements, and Driving

PURPOSE To compare eye and head movements, lane keeping, and vehicle control of drivers with hemianopic and quadrantanopic field defects with controls, and to identify differences in these parameters between hemianopic and quadrantanopic drivers rated safe to drive by a clinical driving rehabilitation specialist compared with those rated as unsafe. METHODS Eye and head movements and lane keeping were rated in 22 persons with homonymous hemianopic defects and 8 with quadrantanopic defects (mean age, 53 years) who were ≥6 months post-injury and 30 persons with normal fields (mean age, 53 years). All were licensed to drive and were current drivers or aimed to resume driving. Participants drove a 6.3-mile route along non-interstate city roads under in-traffic conditions. Vehicle control was assessed objectively by vehicle instrumentation for speed, braking, acceleration, and cornering. RESULTS As a group, drivers with hemianopic or quadrantanopic defects drove slower, exhibited less excessive cornering or acceleration, and executed more shoulder movements than the controls. Those drivers with hemianopic or quadrantanopic defects rated as safe also made more head movements into their blind field, received superior ratings regarding eye movement extent and lane position stability, and exhibited less sudden braking and drove faster than those rated unsafe. CONCLUSIONS Persons with hemianopic and quadrantanopic defects rated as safe to drive compensated by making more head movements into their blind field, combined with more stable lane keeping and less sudden braking. Future research should evaluate whether these characteristics could be trained in rehabilitation programs aimed at improving driving safety in this population.

Optic nerve enhancement on orbital magnetic resonance imaging in Leber's hereditary optic neuropathy.

An 18-year-old man with Lebers hereditary optic neuropathy and bilateral visual loss had optic nerve enhancement on T1-weighted orbital fat-suppressed magnetic resonance imaging. To our knowledge, this is the first reported case of optic nerve enhancement on orbital magnetic resonance imaging in Lebers hereditary optic neuropathy.

Sheehan syndrome: a splinter of the mind.

A 40-year-old woman presented with headache and diplopia after hypotension from postpartum hemorrhage. A noncontrasted cranial magnetic resonance imaging (MRI) showed an enlarged pituitary with a rim of slight increased signal. A repeat gadolinium-enhanced cranial MRI showed peripheral enhancement of the pituitary gland surrounding an isointense central area consistent with infarction of the pituitary and the clinical diagnosis of Sheehan syndrome. The patient was treated with intravenous hydrocortisone. Immediately after treatment, her symptoms remitted and the examination normalized. One month later, a gadolinium-enhanced cranial MRI was normal. The characteristic appearance of the post-gadolinium enhanced cranial MRI helped confirm the diagnosis of Sheehan syndrome and facilitate early treatment with corticosteroids.

The Disk Edema Dilemma

A 33-year-old diabetic woman experienced visual loss OS and disk edema OU. Extensive evaluation led to the diagnosis of diabetic papillopathy. Appropriate evaluation and management of diabetic papillopathy is discussed.

Atypical features prompting neuroimaging in acute optic neuropathy in adults

BACKGROUND Acute optic neuropathy due to an intracranial lesion may masquerade as optic neuritis or nonarteritic anterior ischemic optic neuropathy (NAION). We reviewed the records of patients who presented with acute unilateral optic neuropathy that was initially diagnosed as optic neuritis or NAION but who ultimately proved to have an underlying structural lesion. METHODS Retrospective observational case series. We reviewed the records of patients with the initial diagnosis of optic neuritis or NAION in whom the diagnosis was changed to an intracranial etiology at four tertiary care neuro-ophthalmology centres between 1995 and 1998. RESULTS Eight cases were identified in which atypical features prompted further investigation, including neuroimaging, leading to the diagnosis of an intracranial etiology for the optic neuropathy. Five patients were discovered to have neoplasms (a tuberculum sellae meningioma in two cases, an optic nerve sheath meningioma in two cases and a metastatic lesion in one case), and three patients had intracranial sarcoidosis. Atypical features for optic neuritis included a progressive course, absence of pain, optic atrophy at presentation, lack of significant visual improvement and age over 40 years. For NAION, the atypical features included progressive course, optic atrophy on presentation, absence of vasculopathic risk factors and preceding transient visual loss. INTERPRETATION Clinicians should be aware that patients with intracranial lesions may present with acute optic neuropathy mimicking optic neuritis or NAION and that certain atypical features should warrant consideration for neuroimaging.

Optic nerve enhancement in hypotensive ischemic optic neuropathy.

A 57-year-old woman who had hypotension and cardiac arrest during coronary artery bypass grafting developed hypotensive ischemic optic neuropathy with no light perception vision OU. Bilateral mid-orbital optic nerve enhancement was found on magnetic resonance imaging (MRI) eight weeks after surgery. Re-examination 16 weeks after surgery showed no light perception vision, dilated un-reactive pupils, and pale optic discs. Bilateral optic nerve enhancement persisted on MRI. Optic nerve enhancement has been reported commonly in radiation-induced ischemic optic neuropathy, occasionally in arteritic ischemic optic neuropathy, and rarely in nonarteritic ischemic optic neuropathy. It has never been reported in hypotensive ischemic optic neuropathy.

A Shot of Adrenaline

Acute macular neuroretinopathy is a rare disorder characterized by the sudden onset of unilateral or bilateral paracentral scotomas with relative sparing of the central vision that occurs mostly in young women. It is often characterized by wedge-like macular lesions. The cause of acute macular neuroretinopathy is unknown but viral, immunological, and vascular etiologies have been proposed. There is no current treatment and the visual prognosis is variable. We describe a young woman in whom this disorder was associated with the administration of epinephrine.

Ocular myasthenia gravis

Purpose of review To review ocular myasthenia gravis (OMG), a localized form of myasthenia gravis clinically involving only the extraocular, levator palpebrae superioris, and orbicularis oculi muscles. Recent findings Ocular manifestations can masquerade as a variety of ocular motility disorders, including central nervous system disorders and peripheral cranial nerve palsies. While sparing the pupils, the diagnosis and management can be challenging. Summary Because several diagnostic and treatment options are available for OMG, clinicians must decide the sequence and combination based on the level of disease activity and patient disability.