Papilledema

Papilledema
Fundal photograph showing severe papilledema in the left eye
Specialty	Ophthalmology,optometry,neuro-ophthalmology,neurology,neurosurgery

Papilledemaorpapilloedemaisoptic discswelling that is caused by increasedintracranial pressuredue to any cause.The swelling is usually bilateral and can occur over a period of hours to weeks.Unilateral presentation is extremely rare.

In intracranial hypertension, the optic disc swelling most commonly occurs bilaterally. When papilledema is found onfundoscopy,further evaluation is warranted because vision loss can result if the underlying condition is not treated.Further evaluation with aCT scanorMRIof the brain and/or spine is usually done. Recent research has shown that point-of-careultrasoundcan be used to measureoptic nervesheath diameter for detection of increased intracranial pressure and shows good diagnostic test accuracy compared to CT.Thus, if there is a question of papilledema on fundoscopic examination or if the optic disc cannot be adequately visualized, ultrasound can be used to rapidly assess for increased intracranial pressure and help direct further evaluation and intervention. Unilateral papilledema can suggest a disease in the eye itself, such as anoptic nerve glioma.

Signs and symptoms

Fundal photograph showing severe papilloedema in the right eye.

Despite being classically referred to as a key symptom of rising intracranial pressure, papilledema is often not present in patients seen in an acute setting such as anemergency room.Many urgent cases of increased ICP only have identifiable papilledema after a day or more.

Early on, papilledema may be discovered on examination with an ophthalmoscope without any changes in patient vision. It can progress to enlargement of the blind spot, blurring of vision, a concentric blind spot pattern, ordiplopia(double vision). Ultimately, total loss of vision can occur, as well as other patterns of permanent injury to theoptic nerve.

Papilledema (right) revealed byscanning laser ophthalmoscopy(top) andlaser Doppler imaging(bottom). Healthy contralateral eye (left).

The signs of papilledema that may be seen using anophthalmoscopeinclude:

• venous engorgement (usually the first signs)
• loss of venous pulsation
• hemorrhages over and/or adjacent to theoptic disc
• blurring of optic margins
• elevation of the optic disc
• Paton's lines (radial retinal lines cascading from the optic disc)

Onvisual fieldexamination, the physician may elicit an enlarged blind spot; the visual acuity may remain relatively intact until papilledema is severe or prolonged.

Causes

Raisedintracranial pressureas a result of one or more of the following:

• Brain tumor,idiopathic intracranial hypertension(also known asPseudotumor Cerebri),cerebral venous sinus thrombosisorintracerebral hemorrhage
• Respiratory failure
• Isotretinoin,which is a powerful derivative ofvitamin A,rarely causes papilledema.
• medications liketetracycline
• Hypervitaminosis A,in some people who take megadoses of nutritional supplements and vitamins.
• Hyperammonemia,elevated level of ammonia in blood (including cerebral edema/intracranial pressure)
• Guillain–Barré syndrome,due to elevatedproteinlevels
• POEMS syndrome,aparaneoplasticsyndrome that can cause increased intracranial pressure.
• Foster Kennedy syndrome(FKS)
• Chiari malformation
• Tumorsof thefrontal lobe
• Acute mountain sicknessandhigh-altitude cerebral edema
• Meningitis,leading to increased crainial pressure
• Intracranial aneurysm,or Cerebral aneurysm, which can causeIntracranial hypertension
• Malignant hypertension
• Medulloblastoma
• Obesity
• Orbital
  • Glaucoma:central retinal vein occlusion,cavernous sinus thrombosis
  • Locallesion:optic neuritis,Ischemic optic neuropathy,methanol poisoning,infiltration of thediscbyglioma,sarcoidosisandLymphoma
• Acutelymphocytic leukemia(caused by infiltration of the retinal vessels by immature leukocytes)
• Long periods ofweightlessness(microgravity)(See alsovisual impairment and intracranial pressure)

Pathophysiology

As theoptic nervesheath is continuous with thesubarachnoid spaceof thebrain(and is regarded as an extension of thecentral nervous system), increased pressure is transmitted through to the optic nerve. The brain itself is relatively spared from pathological consequences of high pressure. However, the anterior end of the optic nerve stops abruptly at the eye. Hence the pressure is asymmetrical and this causes a pinching and protrusion of the optic nerve at its head. The fibers of theretinal ganglion cellsof the optic disc become engorged and bulge anteriorly. Persistent and extensive optic nerve head swelling, or optic disc edema, can lead to loss of these fibers and permanent visual impairment.

Diagnosis

Checking theeyesforsignsof papilledema should be carried out whenever there is a clinical suspicion of raisedintracranial pressure,and is recommended in newly onsetheadaches.This may be done byophthalmoscopyorfundus photography,and possiblyslit lampexamination.

It is important to determine whether the observed condition is due tooptic nerve head drusen,which can cause an elevation of the optic nerve head that can be mistaken for papilledema. For this reason, optic nerve head drusen is also called pseudopapilledema.

Treatment

Historically, papilledema was a potentialcontraindicationtolumbar puncture,as it indicates a risk fortentorial herniationand subsequent death viacerebral herniation,however newer imaging techniques have been more useful at determining when and when not to conduct a lumbar puncture.Imaging byCTorMRIis usually done to find out whether there is a structural cause i.e., tumor. Amagnetic resonance angiography(MRA) andmagnetic resonance venography(MRV) may also be ordered to rule out the possibility ofstenosisorthrombosisof thearterialorvenoussystems.

The treatment depends largely on the underlying cause. However, the root cause of papilledema is theincreased intracranial pressure(ICP). This is a dangerous sign, indicative of abrain tumor,CNSinflammation oridiopathic intracranial hypertension(IIH) that may become manifest in the near future.

Thus, abiopsyis routinely performed prior to the treatment in the initial stages of papilledema to detect whether a brain tumor is present. If detected, laser treatment, radiation and surgeries can be used to treat the tumor.

To decrease ICP, medications can be administered by increasing the absorption ofcerebrospinal fluid(CSF), or decreasing its production. Such medicines includediureticslikeacetazolamideandfurosemide.These diuretics, along with surgical interventions, can also treat IIH. In IIH, weight loss (even a loss of 10-15%) can lead to normalization of ICP.

Meanwhile,steroidscan reduce inflammation (if this is a contributing factor to increased ICP), and may help to prevent vision loss. However, steroids have also been known to cause increased ICP, especially with a change in dosage. However, if a severe inflammatory condition exists, such asmultiple sclerosis,steroids with anti-inflammatory effects such asMethylprednisoloneandprednisonecan help.

Other treatments include repeated lumbar punctures to remove excess spinal fluid in the cranium. The removal of potentially causative medicines includingtetracyclinesandvitamin Aanalogues may help decrease ICP; however, this is only necessary if the medication is truly felt to contribute to the ICP increase.