A Review of Neuro-ophthalmologic Emergencies Type of Article: Review Bassey Fiebai Department of Ophthalmology, University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria The emphasis of this review are the emergencies where ABSTRACT failure to recognize the early stages of these diseases result Background 2,3,4 in adverse prognosis . These emergencies can be grouped Neuro-ophthalmic emergencies are relatively uncommon, 1 into four major categories for ease of diagnosis (Table 1) . however their outcome cause severe morbidity and even The first 3 groups are based on initial symptoms and the last mortality. The ocular manifestations of these disorders are group accommodates other disease conditions that pointers to a more dangerous central nervous system or constitute a neuro-ophthalmic emergency but do not systemic pathology. The review aims to highlight the major strictly fall under the other 3 groups. The review aims to ocular disorders that constitute neuro-ophthalmologic highlight the major ocular disorders that constitute neuro- emergencies with a view to increasing the index of ophthalmologic emergencies with a view to increasing the suspicion of these visual/life threatening disorders among index of suspicion of these visual/life threatening primary care physicians, neurologists and disorders among primary care physicians, neurologists and ophthalmologists. ophthalmologists by providing relevant information on the clinical presentation and management of these Method emergencies. The available literature on neuro-ophthalmologic emergencies was reviewed, using available journals and Table 1.Categories of Neuro-ophthalmologic internet based search engines and resources. Keywords employed were Neuro-ophthalmology Emergency and emergencies based on initial symptom Ocular Morbidity. INITIAL SYMP TOM OCULAR D ISORDER Visual Lo ss Giant cell arteritis, transient monocular visual Results loss, occipital infarcts,methanol optic n europathy The incidence of this group of emergencies is lower than Ophthalmopleg ia Carvenous sinus thrombosis, intracranial that of other ophthalmic emergencies such as ruptured globe and retinal detachment; however they are associated aneurysms Wernickes encepha lopathy with higher morbidity and even mortality. These Visual Loss and Ophthalmop legia Pituitary apoplexy,mucor mycosis emergencies can be grouped into four major categories for Others Sixth cranial nerve palsy,traumatic optic ease of diagnosis. Nigerian literature on neuro- neuropathy,carotid arterial d issection ophthalmologic emergencies was unavailable. Giant Cell Arteritis (GCA) Conclusion This condition is also known as temporal arteritis, The key to prevention of morbidity and mortality from granulomatous arteritis and cranial arteritis5. Patients with neuro-ophthalmologic disorders is to have a good this condition are at an increased risk of developing knowledge of the manifestations of these disorders and a irreversible visual loss in one or both eyes, hence maintaining high index of suspicion. a high index of suspicion is crucial in preventing visual loss2. Visual manifestations of GCA are the common mode of Keywords: Neuro-ophthalmology; Emergency; Ocular presentation making the ophthalmologists critically Morbidity responsible for early diagnosis and treatment6. Correspondence: Dr B. Fiebai, The disease has a slight predilection for women over men (2-4 times higher). Caucasians are affected much more often than E: Mail: Address [email protected] African- Americans and Hispanics1,5. GCA is a systemic inflammatory vasculitis of unknown aeitiology that affects INTRODUCTION medium and large caliber arteries. Most patients with GCA Neuro-ophthalmologic emergencies are those ocular are over 60 years of age. Sudden loss of vision is the most disorders of neurologic origin which are vision threatening common manifestation of GCA, occurring in approximately and/or life threatening if not promptly diagnosed and 50% of patients7. The most common cause of visual loss in 1,2 treated. In some of these conditions delay of even a few GCA is arteritic anterior ischaemic optic neuropathy1,2,5. hours have dire consequences. Other ophthalmic vascular presentations are central retinal artery occlusion, branch retinal artery occlusion, choroidal The incidence of this group of emergencies is lower than that ischaemia and the ocular ischaemic syndrome. The of other ophthalmic emergencies such as ruptured globe and neuroopthalmic manifestations of GCA include diplopia, retinal detachment; however they are associated with higher ptosis and pupillary abnormalities2, 5. morbidity and even mortality1. The Nigerian Health Journal, Vol. 10, No 1 -2, January - June 2010 Page 01 Fiebai B - Neuro-Opthalmologic emergencies Systemic manifestations of the disease include, new onset having an intraocular or functional problem2. In this headache which is localized ,scalp tenderness, jaw condition the fundus, ocular motility and pupillary light claudication, myalgia and constitutional symptoms like fever, reaction are normal, however there is visual loss2. An isolated malaise, weight loss and anorexia1,2,5,8. homonymous visual field defect (homonymous hemianopia) of sudden onset is the hallmark of occipital stroke3,14. Diagnosis of GCA is based on clinical signs and symptoms. Embolism of the posterior cerebral artery often with a cardiac Positive findings in three or more systems in the elderly source is a common cause3. Occasionally an occipital stroke should raise a high level of suspicion. Features predictive of may be the first sign of a myocardial infarction or atrial permanent visual loss include, jaw claudication and temporal fibrillation3. Headaches are not usually reported by these artery abnormality on physical examination8. Laboratory patients. findings are helpful. Elevated erythrocyte sedimentation rate (ESR), C-reactive protein level and thrombocytosis are An emergent electrocardiogram is pertinent in ruling out a commonly present. For a more definitive diagnosis a cardiac etiology. Neuroimaging would be useful in making a superficial temporal artery biopsy should be done. diagnosis; however a hyper acute infarcts (occurring within the first 6months) may be difficult to detect2. The universally accepted treatment of GCA is high dose corticosteroid1-3,5,9. Initial intravenous steroid therapy is Early recognition of these infarcts will aid early referral to a advocated followed by oral therapy. However there are no stroke specialist. prospective trials that show that intravenous therapy is superior to oral therapy. The recommended dosage is 1- Methanol Optic Neuropathy 2mg/kg/day and reach about 20mg/day at 6months and Methanol(methyl alchohol,wood alchohol) is a colourless 10mg/day at 1year2, 5. flammable liquid with close resemblance and taste to conventional alchohol(ethanol,ethyl alchohol)2,15. Toxicity Other classes of drugs used in the treatment of GCA include, occurs from accidental ingestion or intentional overdose2,15. It antiplatelets, tumour necrosis factor(TNF)-inhibitors, is mainly consumed by those in the lower socioeconomic 10,11 cyclosporine and methotrexate. class in developing counties due to its low cost15. Methanol is metabolized to formic acid by alchohol dehydrogenase which Transient monocular visual loss (TMVL) causes metabolic acidosis leading to blindness, 2,15,16 TMVL and amaurosis fugax are used interchangeably to cardiovascular instability and death . describe painless vision loss in one eye, resulting from ischaemia or vascular insufficiency and lasting for several Presentation is initially with nausea and vomiting. Patients seconds to a few minutes2,12. Compromised perfusion of the then develop abdominal cramps. In the later stages occipital lobe, visual pathway or the eyes may be secondary to drowsiness may progress to obtundation and coma. thromboembolism, hypoperfusion, or angiospasm12,13. Embolic occlusions of the arteries supplying the eye are a Visual loss is believed to result from interruption of common cause of transient visual loss in adults. Emboli mitrochondrial function in the retrolaminar optic nerve. This causing circulatory disturbances may originate in the heart or causes hyperemia, oedema and optic nerve atrophy. the carotid arteries. Hypoperfusion may be due to Scotomas which are seen maybe central or centrocecal. hypotension, cardiac arrhythmias, anemia, heart failure, or atherosclerotic and arteritic cerebrovascular disease. Arteritic Traditionally ethanol is used as an antidote therapy. and nonarteritic anterior ischemic optic neuropathy may also Fomepizole however, inhibits alchohol dehydrogenase and present with transient visual loss13. Angiospasm may cause a prevents the formation of formic acid. Correction of temporary reduction in blood flow to the visual system and metabolic acidosis and hemodialysis may be necessary. transient visual disturbance13. Carvenous Sinus Thrombosis(CST) Septic thrombosis of the carvenous sinus is another TMVL usually presents in people over 50years of age who potentially life threatening condition which may present with have risk factors such as diabetes mellitus, hypertension and diplopia and orbital signs1,3. CST is usually a late hyperlipidemia2,12. Patients usually give a history of similar complication of a facial infections, sinusitis, dental infections previous episodes, other cerebral transient ischaemic attacks. otitis media and orbital infection1,3,16. Midfacial Ocular presentation includes temporary loss of vision, infections(most commonly a