6.1.14 Assesses signs and symptoms of neurological significance. Flashcards
What are signs of ONH dysfunction?
- reduced VA in both near and distnace
severe impaired CV - RAPD
- VF defect
- impaired CS
what should a good neuro history have?
- normal h+s
- cheif complaint - degree, sveerity and duration
v3. visual loss - bino/mono / dist /near - dip / mono / binocular
- medical hist (meds, diseases, surgery)
what are the diffrences between macula / onh dysfunction?
ON = rapd macula = no cv = severe
onh = reduced brightness macula = augmented cv = mild for macula
what is optic neuritis?
inflmmation / demyelination of the ON - MS, TB , viral
why do you get rapid vision loss in optic neuritis?
Rapid vision loss : demylination / damage to the erve fibre layers = slowed transmission = loss of vision.
inflamm response : acute inflammatory response to the optic nerve –> signal distruptions
why do people with ms get optic neuritis?
Autoimmune attack –> immune attacks the CNS
why do you get ocular / retrobulbar pain with optic neuritis?
the optic nerve does not have any pain receptors but the shealth / tissues around it does
when inflammed these become more sensitive = pain when moving eyes
when the tissues in the orbit are inflammed = pain behind the eye
PAIN with eye movmeents
why does heat/ exercise increase visual loss in optic neuritis?
heat will temporarly breakdown the nerve signal transmission = conduction block = in a inflammed nerve the symptoms are more pronounce
why do you get RAPD in optic neuritis?
RAPD = asymmetry in the pupillary light reflex between the two eyes
optic neuritis = inflammation / demylination of the optic nerve = impaired tramission of visual signals to the brain
what will happen during RAPD?
when light is shone into the healthy eye, both will constrict as the afferent (incoming) pathway intact and normal efferent (outgoing) pathway.
when light is shone into the effected eye the response in both pupils is weaker+ slower as this optic nerve dose not transmit effectievly
D + C in optic neuritis?
SLOW for direct + consensual when shone into the effected eye
Swinging light test for optic neuritis?
when swinging to the effected eye , both eyes will appear dilated slightly –> reduction in the afferent signal from the affected eye
why do you get central scotoma with optic neurtis?
distruption of the signals from the central retinal region
why do you get severely imparied colour vision with ON?
The optic nerve has fibres which are sensitive to colour contrast .
cones are responsible for colour vision = high threshold response. == very sensitive to distruptions in signal tranmission –> inflmmation - impaired
why do you get blurry margins?
margins blurred as they are inlfmmated / swollen
why do you get swollen veins?
inflmmation around the disc = congestion = swelling of the viens = impedes the ormal venous outflow
what to do with ON?
emergency / urgent / steroids
What is Anterior ischaemic optic neuropathy? ANION
occlusion of the PCA - common in elderly people
ANION : assiocated with giant cell arteritis . Arteritic
NANION : atherosclerosis non- artertic
Why do you get HA with ANION?
Temporal arteries –> they become tender and inflamed. there are inflammed = manifest into a headache
ischemia –> inflmmation leads to narrow arteries -> reducd blood flow to the sclap and temples –> tissues become ischemic and = pain