Mr Apolinario is a medical student, Texas A and M Health Science Center College of Medicine, College Station, TX. Dr Vickers and Dr Ponce are Neuro-ophthalmology Fellows at the Blanton Eye Institute, Houston Methodist Hospital, Houston, TX. Dr Lee is Chair, Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, and Professor of Ophthalmology, Neurology, and Neurosurgery, Weill Cornell Medicine; Professor of Ophthalmology, UTMB and UT MD Anderson Cancer Center and Texas A and M College of Medicine (Adjunct); Adjunct Professor, Baylor College of Medicine and the Center for Space Medicine, the University of Iowa Hospitals and Clinics, and the University of Buffalo.
Neurologists may be first-line clinicians for patients who present with specific neuro-ophthalmologic conditions. Although these conditions may require co-management with an ophthalmologist or neuro-ophthalmologist, the neurologist should be able to triage and recognize the key and differentiating features of these common neuro-ophthalmic conditions:
(1) papilledema and idiopathic intracranial hypertension (IIH)
(2) anterior ischemic optic neuropathy(AION)
(3) optic neuritis
(4) ocular motor cranial neuropathy
(5) Horner syndrome. Early diagnosis and treatment of these conditions may be potentially life or vision saving.
Idiopathic intracranial hypertension
Idiopathic intracranial hypertension (IIH), also known as primary pseudotumor cerebri, refers to symptoms and signs of increased intracranial pressure (ICP) in the absence of a true tumor (space-occupying lesion) or other potential causes, such as venous sinus thrombosis,meningeal lesions, hydrocephalus/aqueductal stenosis, and others.1 Most commonly affecting younger, obese women, IIH is not completely benign and approximately 1% to 2% of patients suffer vision loss. The pathogenesis of IIH is unknown, although altered cerebrospinal fluid (CSF) production or absorption, abnormal vitamin A metabolism, endocrine dysfunction, and sleep apnea are proposed mechanisms.
Presentation and symptoms. Most patients with IIH initially present with a headache that may mimic migraine. The headache may be unilateral, bilateral, or diffuse; throbbing or non-throbbing in quality; and may be associated with nausea, vomiting, and photophobia. Differentiating features that separate IIH from migraine include pulsatile tinnitus, which is more specific for IIH, transient visual obscurations (lasting seconds at a time) rather than the typical fortification, scintillation scotoma of migraine, and diplopia due to sixth nerve palsies (a non-localizing sign of increased intracranial ICP). The key and differentiating sign of IIH is papilledema (Figure 1)—although it is not required to make the diagnosis. The most common visual field abnormality is enlargement of the blind spot, but any nerve fiber layer type optic nerve defect may occur (eg, arcuate, altitudinal, constriction, nasal step). Visual acuity is generally unaffected until late in the course of IIH but fulminant IIH may produce acute loss of central vision and should be treated more aggressively and urgently. Fulminant IIH may require surgical intervention.
Diagnosis and treatment considerations. IIH is a diagnosis of exclusion and therefore other causes of increased ICP should be excluded, including a mass lesion, venous sinus thrombosis, or malignant hypertension. The diagnosis of IIH is made based on the modified Dandy criteria (Table). Treatment of IIH is multidisciplinary and involves weight reduction, plus medical management including first line treatment with acetazolamide. Agents such as furosemide or topiramate have also been used with anecdotal success, but acetazolamide has been shown in a recent clinical trial to be an effective first-line treatment.2,3 Surgical interventions, such as optic nerve sheath fenestration, venous sinus stenting, or lumboperitoneal or ventriculoperitoneal shunting, may be necessary if maximum medical management fails or in the setting of fulminant IIH.
Anterior ischemic optic neuropathy
Anterior ischemic optic neuropathy (AION) is the most common cause of acute, unilateral optic neuropathy in adults.4 It is classified as arteritic (A-AION) or non-arteritic AION (NAION).
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