Answer
Papilledema is a condition in which swollen optic discs protrude into the vitreous humor of the eyeball..
This condition is usually caused by increased intracranial pressure which can be due to infections,
trauma, tumors or other causes.
In Mrs. James' case the cause is a brain tumor. The growth of the tumor in the brain increases
intracranial pressure. Since the sutures of the cranial bones are fixed in and adult, the cranium cannot expand to accommodate the increased mass and pressure. As the pressure increases it seeks a spot of least resistance . The optic disc is one such spot ; as the pressure pushes on the optic nerve the optic disc bulges into the vitreous humour of the eyeball. This is papilledema.
Work Step by Step
Papilledema is the intrusion of swollen optic discs into the vitreous humor of the eyeball. The cause is usually increased intracranial pressure.
In an adult the sutures of the cranial bones are fixed; therefore, the cranial cavity cannot expand appreciably to increases in intracranial pressure. In Mrs. James case, she had been diagnosed with a brain tumor.. As the tumor grew it would cause an increase of brain matter and raise the hydrostatic pressure in the cranial cavity-- the brain is about 75% water. The increased pressure would seek to expand at the spot of least resistance. The spot in the cranium where the optic nerve enters is such a spot. Consequently, the intracranial pressure would push on the optic nerve as it seeks to expand; this pressure would both accumulate fluid in the optic disc (the point of entry for major blood vessels of the eye) and move the structure (optic disc) to varying degree into the vitreous humor. If the increased pressure was caused by a central tumor and not by a local metastasis, then the ophthalmologist would see two swollen optic discs- a case of bilateral papilledema
