Papilledema

Papilledema (or papilloedema) is optic disc swelling that is caused by increased intracranial pressure. The swelling is usually bilateral and can occur over a period of hours to weeks. Papilledema has many possible causes but is known to occur in approximately 50% of those with a brain tumor.

Signs and symptoms

In its earliest stages papilledema may not cause any symptoms, but more severe papilledema leads to blurriness in vision, visual obscurations (inability to see in a particular part of the visual field for a period of time) and actual loss of vision.

Diagnosis

Checking the signs of papilledema should be carried out whenever there is a clinical suspicion of raised intracranial pressure, and is recommended in newly onset headaches. This may be done by ophthalmoscopy or slit lamp examination. There are 10 hallmarks of papilledema: *blurring of the disc margins *filling in of the optic disc cup *anterior bulging of the nerve head *edema of the nerve fiber layer *retinal or choroidal folds *congestion of retinal veins *peripapillary hemorrhages *hyperemia of the optic nerve head *nerve fiber layer infarcts *hard exudates of the optic disc

Causes

Raised intracranial pressure: brain tumor, [[pseudotumor cerebri]] or [[cerebral venous sinus thrombosis]], Intracerebral hemorrhage * Respiratory failure * Hypotony *Accutane (Isotrentin), which is a powerful derivative of Vitamin A, rarely causes Papilledema. *Guillain-Barre syndrome due to elevated protein levels

Pathophysiology

As the optic nerve sheath is continuous with the subarachnoid space of the brain (and is regarded as an extension of the central 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 the retinal ganglion cells of 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.

Treatment

The treatment depends largely on the underlying cause. For instance, raised intracranial pressure may improve with glucocorticoids, acetazolamide or surgical shunting.