Anterior ischemic optic neuropathy in patients younger than 50 years

PURPOSE

To characterize anterior ischemic optic neuropathy (AION) in patients younger than 50 years.

DESIGN

Retrospective study.

METHODS

Records of all AION patients seen between 1989 and 2006 were reviewed. Patients younger than 50 years when initial visual loss occurred were included.

RESULTS

Of 727 consecutive patients with AION, 169 (23%) were younger than 50 years (median, 43 years; range, 13 to 49 years; 58% men; 93% White). Involvement was unilateral in 59% of patients and bilateral in 41%. At least one cardiovascular risk factor was found in 74% of patients. Hypercoagulable states and vasculitis were found in 8%. An underlying small or anomalous optic disk was found in 92% of eyes (210/230). Isolated disk anomalies (without systemic risk factors) were present in 26% of eyes. Final visual acuities were 20/40 or better in 64% of eyes and 20/200 or worse in 22%. Among patients with bilateral involvement, final visual acuity was similar in the two eyes in 70% of patients. Anemia and type I diabetes were associated significantly with fellow eye involvement. Recurrent AION in the same eye occurred in 6% of patients.

CONCLUSIONS

AION in younger patients is not uncommon and represents 23% of AION patients in a tertiary neuro-ophthalmic service. Except for giant cell arteritis, ocular and systemic risk factors and associated disorders are similar to those described in older AION patients. Younger AION patients have better visual acuity outcomes but a higher risk of fellow eye involvement than older AION patients.

Thrombolysis for Central Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) frequently causes severe and irreversible visual loss. For many years, various conservative treatments have been proposed for acute CRAO, but their efficacy remains unproven. Over the past 20 years, CRAO has also been treated with thrombolytic agents administered intravenously or intra-arterially. However, all thrombolytic studies are retrospective and uncontrolled, so that the benefit of this treatment remains uncertain. A prospective controlled clinical trial is ongoing in Europe and should provide more reliable information. Even if this trial demonstrates a benefit, thrombolytic treatment is unlikely to become widespread in the management of CRAO unless it can be deployed quickly after the event.

Vision loss: overview

Visual loss is a common complaint to the neurologist. The visual pathways represent one third of the supratentorial brain mass and are frequently affected by structural lesions and a wide range of neurological disorders. By performing a basic ocular examination and asking the right questions, the neurologist should be able to evaluate a patient with visual loss. However, a detailed ocular examination is always necessary before obtaining further neurological workup.

Heritable features of the optic disc: a novel twin method for determining genetic significance

PURPOSE

Numerous genetic diseases and environmental stimuli affect optic nerve morphology. The purpose of this study was to identify the principal heritable components of visible optic nerve head structures in a population-based sample of twins.

METHODS

Fifteen optic nerve specialists viewed stereoscopic optic nerve head photographs (Stereo Viewer-II; Pentax Corp., Tokyo, Japan) from 50 randomly selected monozygotic or dizygotic twin pairs. Before viewing, each expert was questioned about which optic nerve head traits they believed were inherited. After viewing a standardized teaching set, the experts indicated which twin pairs they thought were monozygotic. Participants were then questioned about how their decisions were reached. A rank-ordered Rasch analysis was used to determine the relative weighting and value applied to specific optic nerve head traits.

RESULTS

The proportion of twin pairs for which zygosity was correctly identified ranged from 74% to 90% (median, 82%) across the panel. Experts who correctly identified the zygosity in more than 85% of cases placed most weighting on shape and size of the optic disc and cup, whereas experts with the lowest scores placed greater weighting on the optic nerve head vasculature in reaching their decisions.

CONCLUSIONS

In determining the genetic components of the optic nerve head, the results of this study suggest that the shape and size of the optic disc and cup are more heritable and should receive a greater priority for quantification than should vascular features.

Third Nerve Palsies

The diagnosis and management of third nerve dysfunction vary according to the age of the patient, the characteristics of the third nerve palsy, and the presence of associated symptoms and signs. Third nerve palsies can result from lesions located anywhere from the oculomotor nucleus to the termination of the third nerve in the extraocular muscles within the orbit, and may be the herald manifestation of underlying neurological emergencies such as intracranial aneurysm, pituitary apoplexy, and giant cell arteritis. Recent advances in noninvasive neuroimaging facilitate early diagnosis, but the management of a patient presenting with isolated third nerve palsy remains a challenge.

Optic Neuritis

Optic neuritis is a common cause of visual loss in young patients. Visual function generally spontaneously improves over weeks, and 95% of patients return to visual acuity of at least 20/40 within 12 months. The initial magnetic resonance imaging (MRI) helps stratify the risk of multiple sclerosis in patients with acute isolated optic neuritis. High-dose steroids hasten the rate, but not the final extent, of visual recovery in optic neuritis, and the decision to use this therapy is individualized. Interferon therapy should be considered in selected high-risk patients.

Congruency in homonymous hemianopia

PURPOSE

To evaluate the value of congruency in the localization of brain lesions in patients with homonymous hemianopia (HH).

DESIGN

Retrospective observational study.

METHODS

Charts of all patients with HH seen over 15 years were reviewed. Only patients with incomplete HH documented on formal visual field testing and neuroimaging were included. HH was said to be congruent when the fields of both eyes were identical in shape, depth, and size. Patients were divided into two groups based on congruency of HH; demographic, clinical, and radiological characteristics were compared.

RESULTS

Five hundred and thirty patients with 548 incomplete HH were included (373 congruent HH and 175 incongruent HH). Demographic variables were similar in both groups. Stroke caused 75% of congruent HH and 55.8% of incongruent HH; trauma and tumors caused 20.5% of congruent HH and 34.5% of incongruent HH (P < .001). The lesion locations in congruent HH vs incongruent HH included occipital lobe in 47.9% vs 21.3%, occipital lobe and optic radiations in 8.3% vs 5.6%, optic radiations in 32.4% vs 50.6%, optic tract in 7.2% vs 16.3%, and other locations in 4.2% vs 6.3% (P < .0001). Although there was a trend toward more congruent HH for lesions of the posterior visual pathways (P < .001), 50% of optic tract lesions and 59% of optic radiation lesions produced congruent HH.

CONCLUSION

Although lesions involving the occipital lobe characteristically produce congruent HH, at least 50% of lesions in other locations also produce congruent HH, especially if these lesions are stroke-related. The rule of congruency should be used cautiously and may not apply to optic tract lesions.

Profiles of obesity, weight gain, and quality of life in idiopathic intracranial hypertension (pseudotumor cerebri)

PURPOSE

Obesity and weight gain are known risk factors for idiopathic intracranial hypertension (IIH; or pseudotumor cerebri). The authors examined profiles of body mass index (BMI) and patterns of weight gain associated with IIH. They also examined vision-specific health-related quality of life (HRQOL) in newly diagnosed IIH patients and explored the relative contribution of obesity and weight gain to overall HRQOL in this disorder.

DESIGN

Matched case-control study.

METHODS

Female patients with newly diagnosed IIH (n = 34) and other neuro-ophthalmologic disorders (n = 41) were enrolled in a case-control study to assess patterns of self-reported weight gain. The HRQOL was examined using the 25-Item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and the SF-36 Health Survey (Physical Components Summary and Mental Components Summary [MCS]).

RESULTS

Higher BMIs were associated with greater risk of IIH (P = .003, logistic regression analysis adjusting for case-control matching), as were higher percentages of weight gain during the year before symptom onset (P = .004). Moderate weight gain (5% to 15%) was associated with a greater risk of IIH among both obese and nonobese patients. Obesity and weight gain influenced the relation between HRQOL and IIH only for subscale scores reflecting mental health (SF-36 MCS). The NEI-VFQ-25 and SF-36 subscale scores were lower in IIH compared with other neuro-ophthalmologic disorders and published norms.

CONCLUSIONS

Higher levels of weight gain and BMI are associated with greater risk of IIH. Even nonobese patients (BMI <30) are at greater risk for IIH in the setting of moderate weight gain. Vision-specific and overall HRQOL are affected to a greater extent in IIH than in other neuro-ophthalmologic disorders.

Most Cases Labeled as “Retinal Migraine” Are Not Migraine

BACKGROUND

Monocular visual loss has often been labeled "retinal migraine." Yet there is reason to believe that many such cases do not meet the criteria set out by the International Headache Society (IHS), which defines "retinal migraine" as attacks of fully reversible monocular visual disturbance associated with migraine headache and a normal neuro-ophthalmic examination between attacks.

METHODS

We performed a literature search of articles mentioning "retinal migraine," "anterior visual pathway migraine," "monocular migraine," "ocular migraine," "retinal vasospasm," "transient monocular visual loss," and "retinal spreading depression" using Medline and older textbooks. We applied the IHS criteria for retinal migraine to all cases so labeled. To be included as definite retinal migraine, patients were required to have had at least two episodes of transient monocular visual loss associated with, or followed by, a headache with migrainous features.

RESULTS

Only 16 patients with transient monocular visual loss had clinical manifestations consistent with retinal migraine. Only 5 of these patients met the IHS criteria for definite retinal migraine. No patient with permanent visual loss met the IHS criteria for retinal migraine.

CONCLUSIONS

Definite retinal migraine, as defined by the IHS criteria, is an exceedingly rare cause of transient monocular visual loss. There are no convincing reports of permanent monocular visual loss associated with migraine. Most cases of transient monocular visual loss diagnosed as retinal migraine would more properly be diagnosed as "presumed retinal vasospasm."

Fulminant idiopathic intracranial hypertension

OBJECTIVE

To describe the incidence and characteristics of acute and rapidly progressive visual loss in idiopathic intracranial hypertension (IIH).

METHODS

We reviewed the medical records of all patients with IIH seen at two institutions. "Fulminant IIH" was defined as the acute onset of symptoms and signs of intracranial hypertension (less than 4 weeks between onset of initial symptoms and severe visual loss), rapid worsening of visual loss over a few days, and normal brain MRI and MR venography (or CT venogram).

RESULTS

Sixteen cases with "fulminant IIH" were included (16 women, mean age 23.8 years [range 14 to 39 years]). All were obese. One patient had iron-deficiency anemia, four had systemic hypertension, and none had known sleep apnea syndrome. Acute or subacute headache, nausea and vomiting, and visual loss were present in all patients. The first lumbar puncture performed for the diagnosis showed a mean CSF opening pressure of 54.1 cm H(2)O (range 29 to 60 cm H(2)O). In addition to the initial lumbar puncture, medical treatment included acetazolamide (1 to 2 g/day) in all patients, and IV methylprednisolone in four patients. Repeat lumbar punctures were performed in 11 of the 16 patients. Surgical treatment (optic nerve sheath fenestration in five cases, lumboperitoneal CSF shunting procedure in nine cases, and ventriculoperitoneal shunting procedure in two cases) was performed because of ongoing visual loss in all cases. The median delay between evaluation in neuro-ophthalmology and surgery was 3 days (range a few hours to 37 days). All patients reported dramatic improvement of headaches and vomiting following surgery. Visual function improved in 14 cases, although 8 patients (50%) remained legally blind. Visual fields remained severely altered in all cases.

CONCLUSION

Severe and rapidly progressive visual loss suggests "fulminant idiopathic intracranial hypertension" and should prompt aggressive management. Urgent surgery may be required in these patients, and temporizing measures such as repeat lumbar punctures, lumbar drainage, and IV steroids considered.

Advances in neuro-ophthalmology

Highlights from the 33rd Annual Meeting of the North American Neuro-Ophthalmology Society, Snowbird, UT, February 10-15, 2007.

The diagnosis of giant cell arteritis

Giant cell arteritis (GCA) is the most common primary vasculitis in adults older than 50 years. The potential of GCA to cause bilateral, sequential vision loss makes it often a true neuro-ophthalmic emergency. Approximately one fifth of patients with GCA will present with ophthalmic complaints alone. The diagnosis of GCA requires a high index of suspicion and a systematic approach to diagnostic testing. The combination of abnormal laboratory markers of systemic inflammation and unilateral temporal artery biopsy is usually diagnostic. Additional testing with other diagnostic modalities may be required in cases in which clinical suspicion remains high despite a negative initial workup. We systematically review the diagnostic modalities used in suspected GCA patients who present with neuro-ophthalmic symptoms and signs.

MRI findings in isolated spontaneous thrombosis of the superior ophthalmic vein

We report the case of a 40-year-old woman with systemic lupus erythematosus who presented with spontaneous thrombosis of the superior ophthalmic vein resulting in permanent vision loss. The diagnosis was established by noncontrast CT scanning, gadolinium-enhanced MRI, and conventional catheter angiography.

The American Society of Anesthesiologists Postoperative Visual Loss Registry: analysis of 93 spine surgery cases with postoperative visual loss

BACKGROUND

Postoperative visual loss after prone spine surgery is increasingly reported in association with ischemic optic neuropathy, but its etiology is unknown.

METHODS

To describe the clinical characteristics of these patients, the authors analyzed a retrospectively collected series of 93 spine surgery cases voluntarily submitted to the American Society of Anesthesiologists Postoperative Visual Loss Registry on standardized data forms.

RESULTS

Ischemic optic neuropathy was associated with 83 of 93 spine surgery cases. The mean age of the patients was 50 +/- 14 yr, and most patients were relatively healthy. Mayfield pins supported the head in 16 of 83 cases. The mean anesthetic duration was 9.8 +/- 3.1 h, and the median estimated blood loss was 2.0 l (range, 0.1-25 l). Bilateral disease was present in 55 patients, with complete visual loss in the affected eye(s) in 47. Ischemic optic neuropathy cases had significantly higher anesthetic duration, blood loss, percentage of patients in Mayfield pins, and percentage of patients with bilateral disease compared with the remaining 10 cases of visual loss diagnosed with central retinal artery occlusion (P < 0.05), suggesting they are of different etiology.

CONCLUSIONS

Ischemic optic neuropathy was the most common cause of visual loss after spine surgery in the Registry, and most patients were relatively healthy. Blood loss of 1,000 ml or greater or anesthetic duration of 6 h or longer was present in 96% of these cases. For patients undergoing lengthy spine surgery in the prone position, the risk of visual loss should be considered in the preoperative discussion with patients.

Ophthalmoparesis in idiopathic intracranial hypertension

PURPOSE

To report unusual ocular motility disturbances in the setting of idiopathic intracranial hypertension (IIH).

DESIGN

Interventional case series.

METHODS

Two cases with IIH and unusual ophthalmopareses are reported.

RESULTS

Two patients with confirmed IIH presented with headache, diplopia, and papilledema. The first patient had bilateral sixth nerve palsies and a partial right third nerve palsy, which resolved rapidly after a cerebro spinal fluid (CSF) shunting procedure; the second patient had alternating skew deviation and upbeat nystagmus. Both cases had normal brain magnetic resonance imaging (MRI) and magnetic resonance venography (MRV) and normal CSF contents, ruling out a secondary cause of intracranial hypertension.

CONCLUSIONS

These exceptional vertical and horizontal ophthalmopareses in the setting of IIH may be related directly to very elevated CSF pressures and may be secondary to altered CSF flow in the posterior fossa.

Intracranial vascular anomalies in patients with morning glory disk anomaly

PURPOSE

An association between morning glory disk anomaly (MGDA) and intracranial vascular anomalies including Moyamoya disease has been recognized. We evaluated a series of patients with MGDA to ascertain the frequency of cerebrovascular anomalies.

DESIGN

Retrospective observational case series.

METHODS

We reviewed the neurologic histories and neuroimaging studies of twenty patients with MGDA at two institutions between 1982 and 2004. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) of the brain was performed on all patients who had not undergone neuroimaging. MRI/MRA studies done for 40 pediatric patients without MGDA were also evaluated for cerebrovascular anomalies. The prevalence of anomalies in the two groups was compared by Fisher exact test.

RESULTS

Nine of 20 patients (45%) with MGDA had cerebrovascular anomalies. Anomalies ranged from agenesis of the A1 segment of the anterior cerebral artery to bilateral stenosis of the internal carotid arteries with moyamoya disease. Three patients underwent revascularization procedures. Ten of 40 patients (25%) in the control group had any intracranial vascular anomaly, whereas only two of 40 (5%) had an abnormality of the anterior circulation, the most common finding in the MGDA group.

CONCLUSION

We recommend that all patients with MGDA undergo MRI/MRA or computerized tomographic angiography to detect vascular and structural brain anomalies. It may be unclear whether cerebrovascular anomalies represent isolated congenital anomalies or findings of progressive occlusive cerebrovascular disease. Follow-up imaging should be considered in patients with cerebrovascular anomalies and is clearly indicated if neurologic signs or symptoms are present.

Subretinal Hemorrhage From a Peripapillary Choroidal Neovascular Membrane in Papilledema Caused by Idiopathic Intracranial Hypertension

A 42-year-old man with idiopathic intracranial hypertension and chronic papilledema had severe visual loss in his left eye caused by subretinal bleeding from a peripapillary choroidal neovascular membrane (CNVM). After optic nerve sheath fenestration in his left eye, the papilledema improved, allowing improved visualization of the CNVM. Visual function did not improve after the surgery. CNVM can complicate chronic papilledema and account for sudden worsening of vision. The appropriate management of this type of CNVM is unresolved.

The neuro-ophthalmology of pituitary tumors

The management of pituitary tumors requires a multidisciplinary approach involving neurosurgeons, endocrinologists, and ophthalmologists. Patients symptomatic from a pituitary tumor often are first evaluated by an ophthalmologist. This review discusses key issues regarding both the topographic diagnosis as well as the neuro-ophthalmologic manifestations of pituitary disease. Knowledge of the medical, surgical, and radiation treatment options for pituitary tumors is also important in coordinating patient care. The goals of such treatment include the control of tumor growth, normalization of pituitary function, and preservation or restoration of visual function.