This article includes discussion of ulnar neuropathies, Guyon canal neuropathy, ulnar neuropathy at the wrist, and flexor carpi ulnaris exit compression.
Jun. 07, 2021
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Papilledema refers to swelling of the optic disc caused by raised intracranial pressure. It is typically associated with symptoms of elevated intracranial pressure, such as headaches, pulsatile tinnitus, and transient visual obscurations. The visual hallmarks are relatively spared visual acuity in the setting of bilateral optic disc edema with enlarged blind spots, nasal visual field loss, or constriction of the visual fields. The causes of papilledema can be categorized into intracranial mass lesions or fistulas, venous sinus thrombosis, meningitic processes, subarachnoid hemorrhage, traumatic brain injury, and idiopathic intracranial hypertension. A multicenter, randomized clinical trial evaluated the efficacy of acetazolamide in addition to dietary changes for treatment of idiopathic intracranial hypertension. In addition, there have been advances in technologies, such as optical coherence tomography (OCT), nonmydriatic fundus photography, and automated image analysis in the detection and assessment of papilledema. The author addresses these issues in this updated review of papilledema.
• Papilledema is optic disc swelling due to axoplasmic stasis caused by raised intracranial pressure.
• Papilledema is typically bilateral, but it can be asymmetric, or even unilateral, due to anatomic differences in the meningeal covering of the intracranial optic nerves leading to differences in transmitted pressure.
• Papilledema must be distinguished from other acquired causes of optic disc edema and congenitally dysplastic optic disc elevation. This distinction is aided by the features of the clinical examination and by ancillary studies, including ocular ultrasound, CT, optical coherence tomography, and fluorescein angiography.
• The differential diagnosis for raised intracranial pressure includes intracranial mass lesions or fistulas, venous sinus thrombosis, meningitis, subarachnoid hemorrhage, traumatic brain injury, and idiopathic intracranial hypertension.
• Formal visual field assessment is essential to the proper management of patients with papilledema.
The term “papilledema” was first used in 1908 by J Herbert Parsons to describe disc edema due to elevated intracranial pressure (72). Disagreement regarding terminology quickly followed; for example, prominent physicians including Harvey Cushing preferred the term “choked disc,” coined by Albrecht von Graefe in 1861, stating “…though at first we were inclined to accept papilledema, this has seemed unwise on further consideration, for the term actually conveys nothing more of the process than does choked disc, and its adoption would only add confusion” (20).
Although the term papilledema has now been firmly adopted, Cushing was correct that confusion persists in application of the term. Clinicians should be careful to use the term papilledema to describe optic disc edema that is secondary to proven or suspected elevated intracranial pressure. It is best to avoid using the term papilledema to describe causes of optic disc edema in which the intracranial pressure is believed to be normal, as occurs with conditions such as anterior ischemic optic neuropathy or infiltrative diseases affecting the optic nerve head.
Because papilledema is a manifestation of elevated intracranial pressure, its presence requires immediate diagnostic evaluation for potential neurologic emergencies.
Symptoms. Symptoms of elevated intracranial pressure that accompany papilledema include headache, pulsatile tinnitus, nausea, vomiting, and diplopia. Although headache is 1 of the most common symptoms of raised intracranial pressure, many features of headache do not reliably identify the presence or absence of elevated intracranial pressure (37; 66). Worrisome features include an increase in headache severity with Valsalva maneuvers or headaches that awaken the patient from sleep. Pulsatile tinnitus may be unilateral or bilateral, constant or intermittent, and occasionally pronounced enough to be audible to others (07). Binocular horizontal diplopia may occur as a symptom of impaired abduction secondary to unilateral or bilateral sixth nerve palsies. Focal neurologic symptoms such as weakness or numbness may accompany papilledema due to a focal intracranial lesion.
Patients with papilledema may complain of visual loss, may have evidence of visual dysfunction but be unaware of it, or may have no visual complaints and normal visual function. A common visual phenomenon in the setting of papilledema is transient visual obscurations. These consist of monocular or binocular fleeting, painless blackouts of vision that resolve spontaneously and completely. They are frequently induced by postural changes. The pathophysiologic mechanism of these visual obscurations is undetermined, but may be due to transient optic nerve ischemia resulting from hypoperfusion in the small low-pressure vasculature of the optic nerve head as a consequence of increased intraneural tissue pressure (39; 79).
Ophthalmoscopic appearance. The different stages of papilledema have characteristic features that can be observed during an ophthalmoscopic examination. It is important to note the degree of disc edema, color of the optic disc, presence or absence of venous engorgement, obscuration of the vasculature, hemorrhage, nerve fiber layer infarction, choroidal folds, and spontaneous venous pulsations. However, these optic disc signs are not unique to papilledema and often also apply to causes of acquired optic disc edema where the intracranial pressure is normal, including inflammatory and ischemic processes (74).
The earliest sign of papilledema is obscuration of the optic disc margins. As optic disc edema evolves, it progresses in a predictable manner, affecting first the inferior and superior poles of the nerve, then the nasal portion of the nerve, and lastly the temporal nerve (41; 35). In order to identify mild disc edema, the inferior and superior portions of the optic nerve must be carefully examined. In contrast, the entire disc margin is swollen in moderate and severe papilledema.
The following features of papilledema are helpful in distinguishing it from congenital abnormalities that produce optic disc elevation, or so-called “pseudopapilledema.” In the setting of papilledema, the disc is typically hyperemic, possessing a deep reddish color due to hypervascularity and capillary engorgement. In addition to obscuration of the optic disc margin from swelling, hyperemia is often present in mild or early papilledema. As papilledema progresses, decreased venous outflow causes engorgement of the veins. An important observation concerns the appearance of retinal vessels as they traverse the optic disc. In true papilledema, these vessels often become partially obscured by the swollen, edematous nerve fiber layer.
Hemorrhage around the optic nerve head is common, particularly in the form of radially oriented, small, flame-shaped splinter hemorrhages that track between the nerve fibers. Focal peripapillary congestion may result in ischemia of the nerve fiber layer and retinal infarction, visible as white cotton wool spots near the optic nerve head.
In severe papilledema, hard exudates in the perimacular retina may lead to the formation of a macular star or hemi-star figure.
Choroidal folds, known as Paton lines, resulting from pressure-related choroidal distortion may appear as parallel or circumferential striae in the retina surrounding the optic nerve (38; 73).
Papilledema can be mimicked by congenitally anomalous elevated optic nerves, nerves with myelination of the nerve fiber layer, small crowded optic nerves, and optic nerve head drusen.
Measurement of visual acuity does not serve to distinguish these conditions from papilledema because it is expected to be normal in either case. Ophthalmoscopic features of congenitally anomalous elevated optic discs include: (1) normal (rather than hyperemic) disc color; (2) absence of engorgement of the vascular structures; (3) absence of obscuration of the vasculature despite moderate obscuration of the optic disc margins; and (4) absence of hemorrhage, cotton wool spots, or choroidal folds around the optic nerve. Anomalous optic discs are frequently accompanied by tortuous, anomalous vasculature.
Optic nerve head drusen are important to recognize as a unique cause of optic disc elevation with characteristic features on ophthalmoscopic examination. Optic nerve head drusen are calcifications that appear as refractile masses on the surface of the optic nerve head.
Drusen may also be buried beneath the surface of the nerve and cause an elevated nerve appearance, but remain invisible on ophthalmoscopic examination.
The presence or absence of spontaneous venous pulsations can help to determine whether an abnormal-appearing optic disc represents papilledema. Spontaneous retinal venous pulsations refer to rhythmic movements of the vessel wall that can be a useful indicator of the intracranial pressure (47). The best location to observe them is in the venous segment that traverses the optic nerve head. One explanation for spontaneous retinal venous pulsation is that increased venous outflow during systole leads to transient collapse of the proximal intraocular retinal veins. At this location, there is a pressure gradient between the intraocular venous system and the retrolaminar central retinal vein, and that gradient depends upon the intracranial pressure (62; 59). Normal spontaneous venous pulsations may arise because changes in intraocular venous pressure during the cardiac cycle exceed the variation of the CSF pulse pressure transmitted to the retrolaminar central retinal vein. When the intracranial pressure is elevated, however, the CSF pulse pressure is increased, thus matching the intraocular retinal venous pulse pressure and causing cessation of the spontaneous retinal venous pulsations.
Although the presence of venous pulsations provides good evidence that intracranial pressure is normal at that moment (61), absence of venous pulsations does not necessarily indicate increased intracranial pressure, as venous pulsations are absent in approximately 10% of the normal population (65). Furthermore, spontaneous venous pulsations may be absent in the setting of optic disc edema, drusen, a small optic cup, or other disc anomalies without elevated intracranial pressure (67; 42; 59). A final caveat is that the detection of spontaneous venous pulsations is a subjective judgment and interobserver reliability is not high. Some studies show that spontaneous venous pulsations can be detected even in patients with elevated intracranial pressure (94). Overreliance on this examination finding could therefore lead to important diagnostic errors.
When the distinction between acquired and congenital optic disc elevation cannot be made clinically, additional diagnostic tests can be helpful. Fluorescein angiography will demonstrate dye leakage at the optic nerve head in acquired disc elevation, but not in congenital optic disc elevation (15). CT or ultrasound may identify drusen either at or beneath the optic nerve head. With ocular ultrasound, a “30° test” is performed by obtaining measurements of the optic nerve diameter in primary gaze and in eccentric gaze; a reduction in diameter during this maneuver indicates fluid in the optic nerve sheath, as occurs with true papilledema.
Optical coherence tomography can provide ultra-high resolution measurements of the elevation of peripapillary retinal nerve fiber layer thickness and optic nerve head volume. This quantitative imaging method has been suggested as another potential technique for differentiating optic nerve head drusen from acquired optic disc elevation (49; 43; 58). Investigations suggest that an inward angulation of the peripapillary Bruch’s membrane and retinal pigment epithelium layers is relatively specific for papilledema compared to other causes of acquired optic nerve head elevation (58). However, this method does not allow reliable distinction between papilledema and congenital optic disc elevation (56; 76).
It is important to be aware that the appearance of the optic nerve head changes as papilledema becomes chronic. Hyperemia, peripapillary hemorrhages, and cotton wool spots typically resolve and the disc becomes a gliotic gray dotted with yellow, refractile flecks called pseudodrusen. If papilledema gives rise to secondary optic atrophy, the nerve flattens out and assumes a white color.
At this point, it may be difficult to tell that papilledema had been present, as optic disc pallor is a nonspecific sign of axon loss, but surrounding “high water marks” in the peripapillary retina may delineate the extent of prior elevation and swelling.
Although papilledema is typically bilateral, in rare instances unilateral cases also occur (46; 05).
Unilateral papilledema is attributed to anatomic differences in the optic nerve sheath or lamina cribrosa, leading to asymmetric transmission of the elevated intracranial pressure to the optic nerve heads (92; 46; 05). Evidence supports the hypothesis that sequestration of cerebrospinal fluid in the optic nerve subarachnoid space may be responsible for papilledema and, in particular, for unilateral and asymmetric papilledema (51; 52; 48). Unilateral optic disc swelling together with symptoms of elevated intracranial pressure and examination features of papilledema, such as spared visual acuity and enlargement of the blind spot, should alert the examiner to the possibility of unilateral papilledema.
Ophthalmic examination. In addition to a fundus examination, the evaluation of a patient with suspected papilledema should include an assessment of visual acuity, pupillary examination, ocular motility and alignment, and visual fields. Visual acuity is usually normal in the presence of papilledema, unless it is extremely severe or atrophic. In mild to moderate papilledema, preservation of visual acuity is a critical feature that distinguishes it from other causes of acquired optic disc elevation. Visual acuity is retained because visual loss from papilledema develops first in the visual field remote from the point of fixation. Therefore, visual acuity, which represents visual function at the point of fixation (the fovea), is retained unless optic nerve damage is severe or peripapillary retinal swelling has extended to the macula itself (45). Color vision may also be relatively preserved. Another feature of papilledema is that pupillary reactivity is often normal (without a relative afferent pupillary defect). Patients may complain of diplopia owing to ocular misalignment caused by increased intracranial pressure. Unilateral or bilateral impaired abduction of the eyes may occur secondary to traction on the sixth cranial nerves within Dorello’s canal from the increased intracranial pressure. In other cases, the eye movements may be full, yet the patient has double vision owing to esotropia from loss of fusional ability. Patients with raised intracranial pressure may have skew deviation or rarely have palsies of the third, fourth, or seventh cranial nerves (75).
Precise visual field assessment is essential to management. The visual field appearance provides support for a suspected impression of papilledema and is often the most important parameter on which decisions regarding treatment of the papilledema depend. Although confrontation visual fields should be carefully performed, such visual field examinations are insensitive to the early visual field loss in patients with papilledema (50). Formal quantitative visual field analysis is absolutely necessary.
Visual field defects in the setting of papilledema have been most extensively studied in idiopathic intracranial hypertension (90). Enlargement of the blind spots is typical and may be caused by elevation of the retinal elements around the swollen optic nerve (17).
Visual field loss often occurs in the peripheral nasal visual field first, eventually encroaching on the center of the visual field in severe cases (23; 18; 78).
Although papilledema may occur without visual field loss, severe disc edema is correlated with more extensive visual field deficits (92).
Portable digital fundus cameras are becoming increasingly available and can assist in the early detection of papilledema by nonspecialists in settings such as primary care clinics and emergency departments (11; 55). In fact, there have been advances in automated analysis of these digital images, classifying the presence and severity of papilledema based on features such as optic disc blurring, discontinuity of major vessels, and textural properties of the peripapillary nerve fiber layer (25).
Visual prognosis is difficult to predict in the setting of papilledema. Severe visual acuity loss is often due to rapid and severe intracranial pressure elevation and carries a poor prognosis. In fulminant idiopathic intracranial hypertension with acute vision loss, severe visual field loss is often permanent despite aggressive intervention (87). African American and morbidly obese patients appear to be at greater risk of severe vision loss (Rowe et al 1999; 12). Men are more likely than women to have severe vision loss from idiopathic intracranial hypertension, possibly due to variable symptom expression or reporting. Patients of either gender with normal body mass index and aged 50 years or more are likely to have relatively good visual outcomes (Bruce et al 2009; 10). In idiopathic intracranial hypertension, recurrences of papilledema and raised intracranial pressure may occur after a long period of stability and are associated with recurrent weight gain (81; 54).
A 13-year-old non-obese girl presented with headaches and bilateral blurred vision. The headaches were severe, throbbing, and worse with lying down. She reported pulsatile tinnitus in the right ear and transient visual obscurations. Initial visual acuity was 20/40 in each eye. Color vision was normal. Fundus exam revealed severe bilateral disc edema with peripapillary hemorrhages, cotton wool spots, and bilateral macular star figures.
Automated Humphrey visual fields showed extensive bilateral blind spot enlargement.
The symptoms and signs were highly suggestive of elevated intracranial pressure.
MRI with gadolinium and MR venogram were normal. Lumbar puncture showed an elevated opening pressure (54 cm H20) and normal CSF contents. She had been prescribed minocycline for acne. As minocycline is a known cause of elevated intracranial pressure, it was discontinued immediately and acetazolamide was initiated. Within 2 weeks, vision and papilledema improved significantly. At a 3-month follow-up visit, visual acuity was normal, the papilledema had completely resolved, and visual fields showed a minor residual enlargement of the blind spots.
Impaired axoplasmic transport is believed to be the central pathogenetic mechanism of papilledema (40). Increased pressure within the subarachnoid space results in increased pressure in the optic nerve sheaths. This subsequently leads to increased tissue pressure within optic nerve axons, impairment of axoplasmic transport, and axonal swelling (68; 40). Impaired axoplasmic transport may also be the result of compromised perfusion of retrobulbar optic nerve axons due to the perturbed pressure gradient (88). Although obscuration of the optic disc margin may be observed within 24 hours of an experimental elevation in intracranial pressure, it may take days to develop clinically (41; 84).
Once papilledema is suspected, an expeditious evaluation to identify the cause is necessary. Although the differential diagnosis is extensive, it is simplified by considering categories of disease that may elevate intracranial pressure: (1) an intracranial or intraspinal mass lesion or vascular malformation; (2) cerebral venous thrombosis; (3) meningitis; (4) subarachnoid hemorrhage, (5) traumatic brain injury, (6) intracranial hypertension secondary to medication or systemic medical conditions; and (7) idiopathic intracranial hypertension.
Intracranial or intraspinal mass lesion or vascular malformation. Common intracranial mass lesions include primary or metastatic brain tumors, intracranial hemorrhage, and intracranial abscesses. An under-recognized cause is an arteriovenous malformation that produces increased dural sinus venous pressure (01; 16). Intracranial mass lesions may occur with or without obstructive hydrocephalus and ventriculomegaly. Identification of papilledema in a patient with chronic ventriculomegaly is an important indicator of ongoing intracranial pressure elevation (69).
Cerebral venous thrombosis. This condition can mimic idiopathic intracranial hypertension and present with isolated raised intracranial pressure (06). Isolated raised intracranial pressure is the presenting manifestation of cerebral venous thrombosis in one quarter of patients (21).
Meningitis. Acute or chronic bacterial, viral, or fungal meningitis, autoimmune inflammatory meningitis (such as sarcoidosis, lupus erythematosus, or Behçet disease), neoplastic meningitis, and chemical meningitis are potential etiologies of elevated intracranial pressure.
Subarachnoid hemorrhage. Papilledema is present in almost one half of patients with subarachnoid hemorrhage (27). However, papilledema is a delayed sign of subarachnoid hemorrhage, so its absence is expected during an initial examination following the acute presentation.
Traumatic brain injury. Swelling associated with traumatic brain injury may cause massive elevation in intracranial pressure that is closely correlated with poor neurologic outcome. In addition to surgical therapies, including evacuation of an intracranial space-occupying lesion or hemicraniectomy, medical therapy with hyperosmolar agents, including mannitol and hypertonic saline, is often used to reduce intracranial pressure (77).
Medication-induced. The following medications are strongly associated with elevated intracranial pressure: tetracyclines (including doxycycline and minocycline), high doses of vitamin A or vitamin A derivatives (such as retinoids), corticosteroids (typically when being withdrawn), and lithium (33). Although many other medications have been associated with elevated intracranial pressure, the data are weak and prospective controlled trials are lacking.
Idiopathic intracranial hypertension. The diagnosis of idiopathic intracranial hypertension (pseudotumor cerebri) is established following a complete diagnostic evaluation, including normal neuroimaging and spinal fluid formula, that yields no other explanation for elevated intracranial pressure (22; 83; 34).
Papilledema may occur in any age group without gender or racial predilection. The most common causative condition, idiopathic intracranial hypertension, is largely a disease of obese women in the childbearing age range, with an incidence of approximately 19 per 100,000 in women 20% over ideal body weight (24). With increasing rates of obesity across the Unites States, it is likely that the incidence of idiopathic intracranial hypertension will rise (31).
Maintenance of a moderate weight is likely to reduce the likelihood of developing idiopathic intracranial hypertension. Age-appropriate cancer screening may reduce the likelihood of metastatic disease as a cause of elevated intracranial pressure. The other causes of papilledema do not have obvious preventative strategies.
The principal diagnostic challenge is to distinguish papilledema from congenital optic disc elevation and from other acquired causes of optic disc elevation (see Ophthalmoscopic appearance section for discussion of congenital optic disc elevation). On the basis of ophthalmoscopy alone, papilledema cannot be distinguished from other causes of acquired optic disc elevation. However, these other conditions can be distinguished from papilledema by their tendency to cause decreased visual acuity and by their non-ophthalmic manifestations.
Bilateral disc elevation may occur with diffuse infiltration of the meninges by carcinomatosis or lymphomatosis, anterior ischemic optic neuropathy, some forms of toxic optic neuropathy, and inflammatory optic neuropathy. Anterior ischemic optic neuropathy rarely affects both eyes at the same time. This condition is characterized by sudden visual loss and often altitudinal visual field defects. Among the toxic optic neuropathies, methanol toxicity may present with pronounced disc swelling. Other toxins produce minimal or mild bilateral mild disc edema. Neuroretinitis, an idiopathic inflammatory (possibly bacterial, viral, or postviral) condition, may rarely affect both eyes simultaneously and can easily be mistaken for papilledema. Within days to weeks of onset, a distinctive macular star or hemi-star develops. Cat-scratch disease caused by Bartonella henselae is considered a common cause. Optic nerve inflammation (for example, due to sarcoidosis or lupus) may result in bilateral optic disc edema; depressed visual acuity would distinguish these entities from papilledema. At times, inflammation or infiltration may affect only the peripheral optic nerve, in which case visual acuity will be normal. Under these circumstances, these inflammatory conditions can mimic papilledema. MRI should reveal enhancement of inflamed or infiltrated optic nerves. Discovery of a normal opening pressure on lumbar puncture is another important differentiating feature (except in the case of concurrent meningitis that also produces elevated intracranial pressure).
The first diagnostic step in the evaluation of a patient with papilledema is a neuroimaging study, either by CT or MRI, as well as contrast-enhanced CT venography or MR venography. Contrast-enhanced MR venography is more reliable than the standard flow-related MR venography, which is subject to signal loss unrelated to stenosis or occlusion of venous sinuses (29). Evidence of an intracranial mass lesion or hydrocephalus should be sought. Imaging findings that are supportive (but not diagnostic) of a diagnosis of idiopathic intracranial hypertension include dilation of the optic nerve sheaths, flattening of the posterior globe, and an empty (or partially empty) pituitary sella (09).
Diagnostic confusion with regard to the MR venogram is based on the fact that narrowing of the transverse venous sinuses is frequently found in patients with idiopathic intracranial hypertension. Demonstration of stenosis resolution after acute therapeutic lowering of intracranial pressure suggests that the stenosis may be a consequence of elevated intracranial pressure (53; 04; 44). However, the true relationship between increased intracranial pressure and transverse sinus stenosis remains unclear, as persistent stenosis has been demonstrated in some patients following reduction of intracranial pressure and resolution of symptoms (08). Awareness of this diagnostic confusion with MR venography is essential to avoid unnecessary anticoagulation in idiopathic intracranial hypertension patients.
If MRI and MR venography are unremarkable, lumbar puncture should be performed with 3 goals in mind: (1) complete evaluation of the cerebrospinal fluid content, including cytology and flow cytometry; (2) measurement of the opening pressure in the lateral decubitus position; and (3) determination of headache improvement in the 24 to 48 hours following the lumbar puncture. If imaging and cerebrospinal fluid contents are normal and elevated opening pressure (greater than 20 cm H20 in a thin patient, 25 cm H20 in an obese patient, or 28 cm H2O in a pediatric patient) is confirmed, a diagnosis of isolated elevated intracranial pressure is established (93; 03). If causative medications have been excluded, the patient may be diagnosed with idiopathic intracranial hypertension.
With successful treatment of an underlying disorder, intracranial pressure may return to normal and papilledema may subside. In idiopathic intracranial hypertension, the goals of therapy are to alleviate symptoms and to preserve visual function. An indirect result of these goals is often resolution of papilledema, but such resolution is not a primary objective. Treatment options fall into 3 primary categories: (1) weight loss; (2) medical treatment; and (3) surgical treatment.
Weight loss. Weight loss alone via dietary changes and exercise or surgical intervention may cause resolution of the disorder and reversal of papilledema due to idiopathic intracranial hypertension (57; 82). Among patients with idiopathic intracranial hypertension in whom CSF opening pressure was measured at diagnosis and 3 months later, a significant reduction in intracranial pressure was seen in those patients who had weight loss greater than 3.5% BMI, but was not seen in patients who did not lose weight during that interval (82). A nutritionist or physical trainer may be helpful to support this goal. In select cases, bariatric surgery is an effective treatment for morbid obesity (86). However, because weight loss typically does not occur rapidly enough, additional medical or surgical treatments are frequently necessary in the short term.
Medical treatment. Acetazolamide is a potent carbonic anhydrase inhibitor that decreases cerebrospinal fluid production (89). A typical initial acetazolamide dose is 250 mg to 500 mg twice per day. The maximum dose is 4 grams per day although additional benefit is rarely obtained at doses higher than 2 grams per day. Perioral and extremity paresthesias are a frequent side effect.
The Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) was the first multicenter, double-blind, randomized, placebo-controlled study to assess the clinical efficacy of acetazolamide (70). The IIHTT enrolled 165 participants from 38 sites between 2010 and 2012. The trial showed that acetazolamide plus diet was associated with greater improvement in the visual field than placebo plus diet. Topiramate provides moderate carbonic anhydrase inhibition and may be considered as an adjunct or an alternative to acetazolamide (80). A typical starting dose is 25 mg twice per day, followed by a slow titration to 100 mg to 150 mg twice per day. Potential additive benefits from topiramate include chronic migraine prevention and weight loss. Mild cognitive slowing is a common side effect, however. The diuretic furosemide may provide mild clinical benefit. Intravenous corticosteroids lower intracranial pressure and can be used to emergently lower intracranial pressure in severe cases until a surgical procedure can be performed (63).
In men diagnosed with idiopathic intracranial hypertension, a sleep study should be considered to evaluate for obstructive sleep apnea (91; 32).
Surgical treatment. In cases of progressive visual loss despite medical treatments for papilledema, surgical treatments are often warranted. Options include optic nerve sheath fenestration and cerebrospinal shunting procedures. Clinical experience and many uncontrolled studies support their efficacy, but rigorous studies directly comparing these surgical procedures are lacking, and data regarding visual outcomes are limited.
Analysis of a nationwide database demonstrates a rapid increase in the utilization of cerebrospinal fluid shunting procedures for idiopathic intracranial hypertension between 1988 and 2002 (19). Although several studies show that a shunt can be very effective, many series also suggest that the occurrence of subsequent revisions can be fairly high (26; 14). These retrospective studies, however, may overstate some of the complications associated with shunts because some revision procedures may have been performed without proper indications, such as persistent headache not relating to intracranial pressure or unreliable measurements of decline in vision (36). In addition, studies often show that it is a small minority of patients with shunts that undergo multiple revisions. The risk of shunt infection is low and modern developments have reduced the risk of overshunting.
Optic nerve sheath fenestration can be an effective surgical treatment for patients with progressive visual loss from intracranial hypertension, particularly when significant headaches are not associated. Two proposed mechanisms of action for optic nerve sheath fenestration include decompression of cerebrospinal fluid from the optic nerve sheath and compartmentalization of the subarachnoid space, investing the optic nerve head by fibrous tissue scarring (30).
The management of transverse sinus abnormalities on MR venography is controversial. Compression of the transverse sinus appearing as venous stenosis is frequently found in patients with idiopathic intracranial hypertension (29; 85). If this possibility is unrecognized, the venous abnormality may be misinterpreted as a venous thrombosis and unnecessary anticoagulation may be initiated. Some investigators have performed transverse sinus stenting in patients with idiopathic intracranial hypertension if an increased pressure gradient is measured across the venous sinus stenosis (71; 13; 02; 64). If stenting relieves the pressure gradient, the signs and symptoms of elevated intracranial pressure are reported to reverse (02). At present, however, such treatment remains limited given the high potential morbidity of the treatment and the low potential morbidity of standard therapies. A prospective clinical trial of venous stenting in patients with visual loss due to medically refractory idiopathic intracranial hypertension, www.clinicaltrial.gov, is underway.
Management of papilledema during pregnancy depends on the underlying cause of the elevation in intracranial pressure. For idiopathic intracranial hypertension, the safest method of management is recurrent lumbar puncture. When this approach is inadequate to treat or prevent visual loss, acetazolamide treatment may be considered as evidence suggests there is no increased risk of adverse pregnancy outcomes (60; 28).
Sashank Prasad MD
Dr. Prasad of Brigham and Women's Hospital in Boston, Massachusetts, has no relevant financial relationships to disclose.See Profile
Jonathan D Trobe MD
Dr. Trobe of the University of Michigan has no relevant financial relationships to disclose.See Profile
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