Papilloedema Flashcards
What is papilloedema?
Bilateral optic disc swelling secondary to raised intracranial pressure
What condition should patients with bilateral optic disc swelling be suspected of having until proven otherwise?
Raised ICP due to a space occupying lesion
Why does raised intracranial pressure cause optic disc swelling?
The optic nerve is an extension of the brain, including the meningeal sheaths.
The cerebrospinal fluid filled subarachnoid space in the meninges of the optic nerve is continuous with the subarachnoid space surrounding the brain
When intracranial pressure increases, it is transmitted to the subarachnoid space, and to the optic nerve
This causes interruption of axoplasmic flow and venous congestion - disc swelling
What are the three brain components?
Brain
Blood
Cerebrospinal fluid
What is the Monro-Kellie hypothesis?
An increase in one of the 3 brain components will result in a decrease of one/both of the other variables as the cranium is rigid and cannot expand
What eventually happens as the intracranial volume increase?
Compression of blood vessels Global brain ischaemia Swelling with herniation through the foramen magnum Brain stem compression Death
What should you always check in bilateral disc swelling, and why?
Blood pressure
Disc swelling can be a sign of malignant hypertension
What are the functions of cerebrospinal fluid?
Maintains stable extracellular environment for brain Buoyancy Provides mechanical protection Waste removal Nutrition
Where is cerebrospinal fluid produced?
Choroid plexus
Describe the movement of cerebrospinal fluid from its production to the subarachnoid space
Majority produced in the lateral ventricles
Travels into the 3rd then 4th ventricles, joining the CSF formed there then into the subarachnoid space
What causes intracranial pressure to increase?
Obstruction of CSF circulation
Overproduction of CSF
Inadequate absorption of CSF
What could cause obstruction of CSF circulation?
Congenital malformation
What could cause overproduction of CSF?
Tumour
What could cause inadequate absorption of CSF?
Haemorrhage
What is idiopathic intracranial hypertension?
Bilateral disc swelling caused by obstruction of CSF circulation and impairment of CSF absorption
