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".
In other words, papilledema is a swelling of the optic nerve, at the point where this nerve joins the eye, that is caused by an increase in fluid pressure within the skull (intracranial pressure).
The optic nerve is the nerve that transmits signals from the eye to the brain. Papilledema is a swelling of this nerve where it meets the eye (the optic disc) caused by an increase in intracranial pressure. Almost all cases of papilledema are bilateral (affect both eyes) although unilateral papilledema is also possible.
The swelling causes inflammation of optic nerve which interferes with eye's ability to transmit retinal information to the brain. In some instances the optic nerve will only be partially inflamed, while in other instances the optic nerve will be inflamed along the full length of the retina.
Symptoms depend on whether the dondition is unilateral or bilateral. If both nerves are inflammed, signs of blindness may be apparent. Other signs include bumping into things, incapable of catching toys, getting lost in normal habitate, a fearful attitude.
If brain is affected, neurological signs will be apparent while in case of systemic condition, weakness, anorexia and lethargy will be noticeable.