Optic Neuropathies I Flashcards
CN II is myelinated by:
oligodendrocytes
What are the four anatomical segments of the optic nerve
- intraocular - vascular insults; inflammation and infection
- intraorbital - muscle engorgement/tumors
- intracanalicular - most susceptible to trauma; fractures an sinus inflammation
- intracranial - pituitary and circle of willis
______ blood supply includes the SPCA (peripapillary choroidal vessels). anastamoses between SPCA are scant, making this a _____ area
Prelaminar; watershed
Lamina _____ is supplied by the SPCA and circle of inn haller
cribrosa
_____ branches from the CRA, branches from pial vessels
retrolaminar
Prelaminar region includes the retina and the ____
choroid
what does pallor of the optic nerve mean
you’ve lost your prelaminar vasculature which includes SPCA
what does it mean when you can’t see the cup ?
obliteration of the nerve
round white globular dots within the optic cup =
optic nerve head drusen
optociliary shunt vessels deal with dilation of pre existing _____ beds due to compromised venous return in the _____ region of the optic disc. They develop as a response to congested blood flow.
capillary; prelaminar
what is etiology of optic nerve shunts
- optic nerve sheath meningioma
- CRVO
- Chronic glaucoma
ON dysfunction includes:
- VA loss
- RAPD
- dyschromatopsia
- VF defect
- reduced CS
- +/- normal optic disc appearance
- Abnormal VEP
ON disease can include:
- Glaucoma
- Ischemic
- Inflammatory
- Infectious
- Demylinating
- Hereditary
- Toxic/metabolic
- Compressive
- Traumatic
optic neuritis is inflammation of the optic nerve. There are two types: typical and atypical.
Typical: due to demyelinating lesion; autoimmune disease that causes antibodies to attack the myelin sheath
Atypical: systemic infectious/inflammatory causes
Describe characteristics of typical optic neuritis
- sudden VA loss - progresses for a week and then improves by a month
- Pain on EOMs
- +/- RAPD
- Dyschromatopsia and reduced CS is usually worse than VA
What is a typical presentation of optic neuritis
- unilateral
- retrobulbar
- age: 15-50 but avg age is 30
- mostly female
optic neuritis also presents with _____ deficits
VF
associated symptoms of optic neuritis may include _____ of hands, problems with bladder control, ______ phenomenon, which includes altered perception of moving objects. Lhermitte’s sign as well as Uthoff sign is also prevent.
numbness; pulfrich
what is lehrmittes sign
flexion of head causes unpleasant electric shock like discharge originating from neck and spreading down the spine
what is uthoff sign
worsening of neurologic symptoms with increased body temperature