6: Papilloedema Flashcards
Does “swollen optic disc” mean papilloedema?
No
Swollen discs have many causes (e.g CRVO, ischaemic optic neuropathy…)
Papilloedema is a swollen optic disc secondary to raised ICP
All patients with bilateral optic disc swelling should be suspected of having what?
Space occupying lesion in brain
How is CN II examined?
Visual acuity
Pupil exam
Visual field assessment
Colour vision
swinging light test
Why does raised ICP affect the optic nerve?
CN II is an extension of the brain and so is found in the subarachnoid space, so it can be compressed by increased ICP
What space does ICF circulate in?
Subarachnoid space
What does the subarachnoid space surround?
Optic nerve
Why do the optic discs become swollen in papilloedema?
Raised ICP causes swelling of subarachnoid space, compressing VEINS
What is the Monro-Kellie hypothesis?
Brain, blood and CSF make up the volume of the brain
If one volume increases, the others DECREASE (and thus pressure INCREASES inversely)
Can the cranial vault change its volume?
No, fixed
Which hole in the cranial floor does the brainstem pass through?
Foramen magnum
Why can an increased ICP cause you to die?
Compression of respiratory centres of brainstem
What type of hypertension can cause optic disc swelling?
Malignant hypertension
What should be investigated in all patients with optic disc swelling?
Head scan for space occupying lesions
Blood pressure for malignant hypertension
Lumbar puncture if suspected inflammation / infection of CNS
Where is CSF produced?
What is its path?
Where does it drain?
Choroid plexus of lateral ventricles
Lateral > 3rd > Cerebral aqueduct > 4th ventricle > Subarachnoid space > Arachnoid granulations
Dural venous sinuses
What aspects of CSF cause raised ICP?
Obstruction of drainage
Overproduction
