Papilledema

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Papilledema


Papilledema is swelling of the optic nerve(s) due to increased intracranial pressure.  It most commonly presents bilaterally, but may be asymmetric or unilateral as well.

Disease Entity

Disease

Papilledema refers to swelling of the optic disc from increased intracranial pressure (ICP)]. It must be distinguished from optic disc swelling from other causes which is simply termed "optic disc edema". Papilledema must also be distinguished from pseudo-papilledema such as optic disc drusen. Since the root cause of papilledema is increased intracranial pressure (ICP) this is an alarming sign which may presage such entities as brain tumor, CNS inflammation, or idiopathic intracranial hypertension (IIH).

Etiology

As noted above, papilledema is due to increased intracranial pressure from any cause. Normal ICP is typically less than 250 mm water when measured with a manometer in the recumbinat position. Papilledema results from orthograde axoplasmic flow stasis at the optic nerve head leading to edema of the nerve from the increased intracranial pressure pressing on the nerve behind the eye. Continued pressure can result in loss of axons and eventual optic atrophy secondary to intraneuronal ischemia ultimately causing vision loss.[1] With optic atrophy there is little or no edema seen even with continuing increased intracranial pressure since there are no fibers to swell.  Increased intracranial pressure can be caused by (1) a space occupying lesion such as a tumor or hemorrhage, by (2) decreased CSF drainage due to blockage (obstructive hydrocephalus) or decreased absorption (infection, hemmorhage, venous sinus thrombosis or venous outflow obstruction), by (3) Idiopathic Intracranial Hypertenion (IIH, also called pseudtumor cerebri) , (4) rarely by increased CSF production such as from a choroid plexus tumor, and lastly by decreased skull volume (craniosynostosis).  The time course for development of papilledema may be weeks if there is only a slow and mild rise in intracranial pressure, but severe and rapid changes in pressure can cause papilledema to present within a day.

Risk Factors

Risk factors for papilledema are those that raise intracranial pressure. This includes space occupying lesions such as tumor or subarrachnoid hemoorhage, decrease of absorption of cerebrospinal fluid, change in the dynamics of cerebrospinal flow through the ventricles (for example by obstruction of the 4th ventricle), or rarely by increase of flow of cerebrospinal fluid.

General Pathology

Optic disc edema with neuronal swelling, venous dilation. Axoplasmic flow stasis and edema of the nerve head are noted.

Diagnosis

Fundoscopy noting disc swelling (usually bilateral unless one disc is atrophic) in the presence of increased intracranial pressure is the key to diagnosis. Other diagnostic tools include ultrasonography, fluroescein angiography, CT or MR imaging, When presented with the possibility of papilledema the first approach is imaging to rule out space occupying lesion. This is best done by MRI and an accompanying MRV can help rule out a venous sinus thrombosis. Occasionally severe papilledema is noted on MRI as flattening of the sclera near the optic nerve and even a raised area at the disc head. A lumbar puncture with opening pressure and fluid sent for cytology and culture is done to confirm the diagnosis of increased intracranial pressure.

Disc Appearance

If spontaneous venous pulsations are present this suggests that ICP is probably not high at this time, however the ICP may have been high before simply due to diurnal variations in intracranial pressure.

Early papilledema - disc hyperemia possibly with dilated disc capillaries. Nerve fiber layer (NFL) opacification and swelling. Blurred disc margin(s). Venous pulsations are absent.  More severe developed papilledema will have elevation of the disc and opacified NFL obscuring disc vessels. There may be dilated veins, disc splinter hemorrhages, cotton wool spots, or hard exudates. With severe disc leakage a macular star may be seen, this is more prominent on the disc side of the macula. Later retinochroroidal folds called Paton's lines may be present. With chronicity of papilledema funduscopy reveals all of the above plus the start of disc pallor along with decreasing disc swelling with the loss of axons.  Sometimes optociliary shunts may be noted.  In the wake of papilledema there may be RPE pigmentary changes around the disc, disc gliosis and residual chroidal folds.

Papilledema Grading System (Frisen Scale)[2]
Stage 0 - Normal Optic Disc Blurring of nasal, superior and inferior poles in inverse proportion to disc diameter. Radial nerve fiber layer (NFL) without NFL tortuosity.

Rare obscuration of a major blood vessel, usually on the upper pole.

Stage 1 -Very Early Papilledema  Obscuration of the nasal border of the disc.  No elevation of the disc borders. Disruption of the normal radial NFL arrangement with

grayish opacity accentuating nerve fiber layer bundles. Normal temporal disc margin. Subtle grayish halo with temporal gap (best seen with indirect ophthalmoscopy).

Concentric or radial retrochoroidal folds.

Stage 2 - Early Papilledema Obscuration of all borders. Elevation of the nasal border. Complete peripapillary halo.
Stage 3 - Moderate Papilledema Obscurations of all borders. Increased diameter of optic nerve head. Obscuration of one or more segments of major blood vessels

leaving the disc. Peripapillary halo-irregular outer fringe with finger-like extensions.

Stage 4 - Marked Papilledema  Elevation of the entire nerve head. Obscuration of all borders. Peripapillary halo. Total obscuration on the disc of a segment of a major

blood vessel.

Stage 5 - Severe Papilledema  Dome-shaped protrusions representing anterior expansion of the optic nerve head. Peripapillary halo is narrow and smoothly demarcated.

Total obscuration of a segment of a major blood vessel may or may not be present. Obliteration of the optic cup.

Examples:

Mild papilledema2.jpg

Mild Papilledema

Moderate papilledema.jpg   Moderate Papilledema

Severe papilledema.jpg  Severe Papilledema

Severe papilledema resolved.jpg Resolved Papilledema (post shunt)

History

Headache is typical and is often worse on waking or postural (worse on lying down and better on standing up).

It is useful to ask about medicines that may cause increased intracranial pressure (such as tetracyclines, vitamin A and derivatives, lithium, steroids - especially changes in the amount of steroids taken and withdrawal of steroids).

Physical examination

In addition to the usual ophthalmic exam including visual fields one should check blood pressure to rule out hypertensive emergency (i.e., “malignant hypertension”) which can mimic papilledema.  Ocular motility exam may reveal a unilateral or bilateral 6th nerve palsy as a non-localizing signs of increased intracranial pressure.

A neurological exam may be appropriate to exclude other focal neurologic deficit.


Symptoms and signs of increased intracranial pressure

Headache is common with increased intracranial pressure and often worse in the morning. Nausea and vomiting are noted with increased intracranial pressure, especially with an acute rise in pressure. This is made worse by straining, coughing or bending. Pulse synchronous tinnitus may be present from increased flow in stenotic cerebral venous sinuses.  Visual field loss (usually an increased size of the blind spot initially) can occur acutely (i.e., fulminant) or be slowly progressive. The patient may note short periods lasting seconds of losing vision which are called transient visual obscurations. These are often observed when raising to stand or changing position. A hyperopic shift may occur in the refraction due to axial length shortening. Increased intracranial pressure leads to increased cerebrospinal fluid (CSF) within the dilated optic nerve sheath and flattening the back of the eye. Increased intracranial pressure can lead to hearing vascular noises, whooshing sounds, or pulsatile tinnitus.  Long standing papilledema may result in severe peripheral visual field loss and may progress to involve central vision if untreated. Increased intracranial pressure can also lead to cranial nerve palsies, usually an abducens palsy as a nonlocalizing finding. It is thought that the long course of the 6th cranial nerve is compressed by the increased CSF pressure.

Clinical diagnosis

Diagnostic procedures

  • Fluorescein angiography can detect disc leakage  in true optic disc edema as opposed to disc staining without leakage in pseudopapilledema. In addition, autofluorescence or B scan ultrasound may  show pseudopapilledema (e.g., optic disc drusen).
  • Stereo disc images may be helpful to follow the disc status over time.
  • Formal (typically automated) perimetry commonly shows enlarged blind spots and nerve fiber layer type visual field defects. In severe chronic papilledema worsening peripheral field loss may be seen and can eventually involve central vision. Acute fulminant cases may present with significant visual field or acuity loss and should be treated emergently.
  • CNS imaging study (CT or MRI with contrast) to identify a central nervous system mass lesion.
  • MR venography(MRV) or CTV should also be considered to look for venous sinus thrombosis.
  • Lumbar puncture (to be done after imaging demonstrates no risk for herniation) to document increased ICP and to look for neoplastic, infectious or inflammatory causes. At a minimum, opening pressure along with glucose, protein, cell count and differential, culture are obtained.


Differential diagnosis

Papilledema must be distinguished from optic disc edema and anonymously elevated discs such as buried drusen, tilted disc, hypoplastic disc.

In addition, other etiologies for optic disc swelling include:

  • Intraocular inflammation causing optic disc edema (such as sarcoidosis, toxoplasmosis, VKH, other uveitis)
  • Central Retinal Vein Occlusion
  • Optic neuritis
  • Diabetic papillopathy
  • Hypertensive disc edema
  • Non-arteritic ischemic optic neuropathy
  • Infiltrative optic neuropathy and tumors (lymphoma, leukemia)
  • Compressive optic neuropathy (optic nerve sheath meningioma)
  • Posterior Scleritis
  • Thyroid ophthalmopathy

Management

The primary cause of the increased intracranial pressure must be addressed.  If a mass is present, primary therapy should be directed towards that lesion (e.g., surgery). If  medications (tetracyclines, vitamin A analogues, etc.) are felt to be causative they should be discontinued.  Patients with mild papilledema should be monitored for visual field defects by formal perimetry as the patients may not be able to recognize them.

Medications are used to decrease intracranial pressure by helping increase CSF absorption or decreasing CSF production.  Diuretics used include Acetalzolamide (diamox - a carbonic anhydrase inhibitor) and  furosemide (Lasix).  Topiramate has also shown some benefit when used in IIH.  In general however as steroids (especially with change in dosage or withdrawal) have also been causative of increased ICP we generally do not recommend steroids for IIH. Serial lumbar punctures are not typically recommended as a treatment for IIH but can be used to treat intracranial hypertension if the patient is not suitable for medical therapy or is pregnant or has cryptococcal meningitis related increased ICP.

Recent clinical trials (e.g., Idiopathic Intracranial Hypertension Trial (IIHT)) have provided strong support for safe and effective use of acetazolamide combined with weight reduction in effectively treating IIH and improving papilledema in these patients with mild vision loss.[3]

Medical therapy

Carbonic anhydrase inhibitors (acetazolamide) and weight loss are first line therapy for IIH but can be used in patients with elevated ICP from other etiologies. Furosemide (Lasix) and topiramate are considered second line agents in IIH but may be useful in patients who are intolerant of acetazolamide.

Surgery

Surgery can be performed to address the cause of elevated ICP (e.g., surgical resection of intracranial tumor). CSF diversion procedures (e.g., ventriculoperitoneal (VP) and lumboperitoneal (LP) shunts) may allow CSF fluid to drain and normalized ICP in patients with hydrocephalus or with IIH.  Optic nerve sheath fenestration- either unilateral or bilateral may be considered if vision is threatened. Dural venous sinus stenting may also be considered for patients with increased ICP and a venous sinus pressure gradient.

Complications

Surgical complications include shunt failure, breakage, or infection in CSF shunting or visual loss related to surgical trauma in optic nerve fenestration have been reported.

Prognosis

Chronic papilledema leads to axon loss with constriction of the visual field, loss of disc substance and in the end, loss of central acuity.Patients (especially those with IIH) need to be followed to prevent vision loss.

Additional Resources

Reference

  1. Lee A, Rigi M, Al marzouqi S, Morgan M. Papilledema: epidemiology, etiology, and clinical management 2015;7-47. Available from https://doi.org/10.2147/EB.S69174
  2. Reference: Frisen L. Swelling of the optic nerve head: A staging scheme. J Neurol Neurosurg Psychiatry 1982; 45:13-18
  3. Smith S, Friedman D. The Idiopathic Intracranial Hypertension Treatment Trial: A Review of the Outcomes 2017;1303-1310. Available from https://doi.org/10.1111/head.13144