PATHOPHYS Flashcards
what is the gene mutation in the most common cause of familial ALS w/ or w/o FTD?
C90RF72 on chromosome 9
what is the mutation in AD familial ALS?
SOD gene mutations in chromosome 21
what are the 2 most common causes of radiculopathy?
disk herniation & degeneration
95% of HNPs affect which 2 lumbosacral vertebral segments?
L5 or S1
herniated nucleus pulposus happens at what cervical vertebral levels?
C7»_space; C6
What lumbosacral vertebral levels have herniated nucleus pulposus?
L5 or S1
what is one of the best maneuvers to show that a pt has a cervical radiculopathy?
neck extension
-also: neck rotation, spurling’s maneuver
what is the historical hallmark of radiculopathy?
pain (often radiating)
what is the most frequent cause of radiculopathy in <50 y/o?
disc herniation
what is a frequent cause of radiculopathy in pts > 50 y/o?
spondylosis
what is the most important component to evaluating radiculopathy?
history and exam
what is the conservative treatment for radiculopathy?
avoid prolonged bed rest, do as many routine activities as possible (as long as they don’t make pain worse), physical therapy, meds, nerve blocks
term for weakness symmetrically, distally?
polyneuropathy
term for weakness in nerve distribution (one nerve)?
mononeuritis
term for weakness in nerve distribution (several nerves)?
mononeuritis multiplex
term for sensory deficit in a glove & stocking pattern?
polyneuropathy
term sensory deficit in the distribution of nerves?
mononeuritis multiplex
name the lesion: compression causing numbness in the first 3.5 digits w/ pain
carpal tunnel syndrome
a _______neuropathy affects the thenar muscles only, but not the hypothenar muscles.
median neuropathy
where is the ulnar nerve most frequently compressed causing weakness and atrophy of the hypothenar and interosseous muscles w/ numbness in the 5th and half of the 4th digit?
at the elbow
saturday night palsy causes what?
wrist drop (lesion of radial nerve)
compression at the knee (at the fibular head) causes what?
foot drop (peroneal nerve)
which type of neuropathy has patchy segmental demyelination w/ decreased reflexes, decreased epicritic, slightly reduced protopathic?
demyelinating neuropathy
name the type of neuropathy: mostly distal weakness w/ distal areflexia, glove & stocking sensory deficit to all modalities, trophic changes (could be caused by uremia, toxins)?
axonal neuropathy
what are two examples of causes for wallerian degeneration?
trauma, vasculitis
what kind of neuropathy has Myelin ovoids?
axonal neuropathy
what is the most important treatment for diabetic neuropathies?
control of diabetes and symptomatic pain control
_______ is an acute autoimmune ascending paralysis accompanied by arreflexia and normal or mildly abnormal sensation w/ albuminocytologica disassociation in the spinal fluid
Guillain-Barre syndrome
name the disease: autoimmune inflamm. neuropathy that affects mainly the myelin sheath. Pts have progressive weakness w/ increased spinal fluid protein and signs of demyelination on EMG
chronic inflammatory neuropathy
on which chromosome do you find genes for M and L cones?
chromosome X
M-cones–> green
L-cones–>red
both rods and cones undergo ____________ in response to light
hyperpolarization (only sensory system in which hyperpolarization is the response to the stimulus)
alpha-ganglion cells, predominate in the peripheral retina-most input from rods, have extensive dendritic trees, large axons, and project to what layer of the lateral geniculate nucleus to help with the location of object in space?
magnocellular layer of lateral geniculate nucleus
beta ganglion cells are found primarily in what?
central retina
which type of ganglion cells has small receptive fields, small dendritic arbors, responsive to color stimuli?
beta-ganglion cells
beta-ganglion cells project to what region in the lateral geniculate nucleus to define color and texture of an object?
project to parvocellular region in lateral geniculate nucleus
the fovea has what in its outer segment and the rest of their signaling pathway (bipolar cells, ganglion cells) project radially away from the fovea?
the fovea has cones
what is the one place in the retina where convergence does not occur?
fovea (one cone is connected to one cone bipolar cell and 1 ganglion cell)
what part of the fovea allows humans to have a crisp image representation?
the fact that one cone is connected to one cone bipolar cell and 1 ganglion cell
the left visual field is processed in the ______visual cortex
right
once passing through the optic chiasm, the visual nerve fibers will move into what part of the thalamus and then onto the visual cortes?
lateral geniculate nucleus
does the peripheral (which hits nasal side of retina) or midline (which hits temporal side of retina) visual field cross at the optic chiasm?
the peripheral vision crosses at the optic chiasm
the ___________ pathway originates from magnocellular ganglion cells, projects to lateral geniculate layers 1 and 2, to layer 4C-alpha in the cortex-space info
M pathway
the P pathway originates from parvocellular ganglion cells, projects to lateral geniculate layers 3-6 to layer ____________ in the cortex
layer 4C-beta in the cortex
in older pts a finding of dense homonymous hemianopsia is associated with what?
loss of perfusion to the occipital cortex on the opposite side of the field defect
what are the two MCC of papilledema?
tumor (space occupying mass)
pseudotumor cerebri
what are some signs of papilledema?
both discs elevated and hyperemic disc margins blurred small vessels at margin obscured retinal vessels tortuous, dilated hemorrhages & exudates spontaneous venous pulsations absent
pts with ischemic optic neuropathy must be evaluated for what?
temporal arteritis
ischemic optic neuropathy respects what?
respects the horizontal midline
what does the optic disc look like in ischemic optic neuropathy?
pale swollen
name the disease: usually assoc. w/ increased ICP, optic nerve damaged, enlarged optic cup & atrophy, early vusal field loss (asymptomatic), loss of central vision (LATE)
chronic open angle glaucoma
a pt with a _______ has a deviation of the visual axes only when fusion is disrupted (such as covering one eye)
phoria
if the uncovered eye moves outward then it was turned IN to start. This would be described as an _________ deviation
ESO
binocular dipolopia is the result of misalignment of the ______________
visual axes
what is probably the cause of horizontal diplopia?
weak LR or MR
what is probably the result of vertical diplopia?
weak SO, IO, SR, IR
what are the clinical findings of CN III palsy?
eye is down and out
non-reactive pupil
ptosis (weakness of levator)
weakness of MR, SR, IR, IO
CN III palsy + headache is what until proven otherwise?
aneurysm (image immediately)
a paralysis of CN III with normal pupillary responses usually indicates a ____________ cause
microvascular
- usually middle-aged or elderly
- DM or HTN common
- recovery w/i 3-4 months
name the lesion:
hypertropia on side of weak SO
diplopia and deviation increase on gaze to side opposite weak SO
Diplopia and deviation increase on Forced head tilt to same side as weak SO
cranial nerve IV palsy
what are the two specialized roles that the ciliary body serves?
- secretion of aqueous humor by epithelial bilayer
2. accomodation by the ciliary muscle
what kind of receptors in the eye are also responsible for stimulating lacrimal secretions?
Muscarinic receptors (M2, M3)
sympathetic (alpha-1)
what role do the sympathetic receptors have in the eye?
play important role in stimulating the mydriasis and producing aqueous humor and lacrimal secretions
how do opioids produce pinpoint pupils?
opiates block the effects of the inhibitory neurons (that would normally inhibit Edinger-westphal nucleus) resulting in unregulated & spontaneous cholinergic stimulation hence (miosis)
how can you get systemic drug effects of topical drugs instilled into the conjunctival cul de sac?
can arise following lacrimal drainage and absorption from the GI tract, or some by direct absorption into ocular blood vessels and thence to the general circulation
what are the precautions with topical occular therapy?
compliance, corneal and conjunctival tox., nasal mucosal tox
what are the precautions with subconjunctival injections?
local to., tissue injury, globe perf. optic nerve trauma
what are the adverse effects of intraocular injections?
corneal toxicity, intraocular tox., relatively short duration of action
what are the adverse effects of intravitreal injection or device?
retinal toxicity
what is the name of the prodrug PG thatis used for localized activation of pro-drugs with better corneal penetration?
latanoprost (PGF2)
what are the muscarinic antagonists like atropine, scopolamine used for?
used in treatment of iris/uveal tract inflammatory conditions & eye examination
the muscarinic antagonists are contraindicated in what two conditions?
glaucoma & with sulfite preservative allergy
which class of drugs produces loss of accommodation (cycloplegia) & adaptation (mydriasis)?
muscarinic antagonists
what is the goal of open angle glaucoma treatment?
decrease aqueous humor production or increase aqueous outflow
what is the goal of closed angle glaucoma?
surgical iridectomy
shortterm medical management to decrease intraocular pressure and clear cornea prior to surgery
miotics should be used with caution in what pts?
in pts who have an increased risk of retinal detachment, because they have been implicated in promoting retinal tears
direct miotic agents are preferred over ____________ inhibitors in phakic pts (those pts with their own crystalline lens) because the latter drugs can promote cataract formation
cholinesterase
what are two 1st line drugs for glaucoma?
latanaprost
bimatoprost
what are the beta receptor antagonists used to treat glaucoma?
timolol
carteolol
what is the carbonic anhydrase (isoenzyme II ) inhibitor used to treat glaucoma?
dorzolamide
what are the acute adverse effects of PGF2 analogs?
blurred vision, burning/stinging, itching
what are the chronic adverse effects of PGF2 analogs?
slow and permanent brown pigmentation of iris, eyelid skin, eyelashes, also increasing their growth including length, thickness
how do beta-2 antagonists reduce intraocular pressure?
inhibits the production of aqueous humor
how do carbonic anhydrase inhibitors reduce intraocular pressure?
they reduce bicarb secretion and fluid transport
25% of pts using carbonic anhydrase inhibitors experience what via inhibition of CA in oral cavity?
bitter taste
the carbonic anhydrase inhibitors are sulfonamides that have what adverse effects?
allergic reactions: -agranulocytosis aplastic anemia fulminant hepatic necrosis SJS, TEN, other blood dyscrasias
how do the direct acting miotics (muscarinic agonists) work?
increased aqueous humor flow
when are direct-acting miotics contraindicated?
contraindicated when constriction is undesirable (iritis, uveitis, inflamm. condition, of ant. chamber)
cholinesterase inhibitors are contraindicated with use of what?
contraindicated with carbamate/phosphate insecticides (potential additive toxicity)
-pts should use appropriate PPE
(also contraindicated in closed angle glaucoma)
name the sympathomimetics?
phenylephrine
apraclonidine
brimonidine
tetrahydrozoline
how do the sympathomimetics reduce intraocular pressure?
decrease IOP by increasing the outflow of aqueous humor from the eye
