SAS/Review Flashcards
Which brain tumors are most likely to arise in young children?
- Pliocytic astrocytoma
- Grade I glioma
- Ependymoma
- Grade II, technically a glimoa but not aways classified that way
- Medulloblastoma
- Grade IV neuronal
- Atypical teratoid/rhabdoid tumor
- Grade IV, neuronal
Retinal vein occlusion leads to [hemorrhage/blanching]
Retinal artery occlusion leads to [hemorrhage/blanching]
Retinal vein occlusion leads to hemorrhage
Retinal artery occlusion leads to blanching
What kind of drug is phentolamine?
What is it used for?
Nonselective alpha-blocker
- Drug of choice for MAO I induced hypertensive crisis
- Hypertensive paroxysms in pheochromocytoma
Basically, out of control hypertension
Which parasympathomimetic is used to treat dry mouth in Sjogren’s?
Cevimeline or pilocarpine
- Stimulate parasympathetic salivation
- Cevimeline is the best one - will also treat other Sjogren symptoms
List 4 locations of demyelinating events characteristic of MS
- Optic neuritis
- Blurred vision, decreased vision, pain with eye movement
- Cerebellar lesion
- Difficulty with balance or coordination
- Spinal cord inflammation
- Bilateral weakness, numbness
- Hemispheric lesion
What kind of tumor is this?
What is the cell of origin?
Meningioma - meningothelial cells
- Dural tails
- Noninfiltrative
- Homogenous enhancing
Describe the symptoms of atropine poisioning (5)
Atropine = anticholinergic
- > decreased parasympathetic activity
- > increased sympathetic activity*
-
Dry as a bone
- Decreased secretions, urinary retention
- **Eccrine sweat gland secretion is inhibitied; only sympathetic action that no longer works
-
Hot as a stove
- **Due to decreased sweating
-
Red as a beet
- Compensates for heat
- Also hitamine is released
-
Blind as a bad
- Pupillary dilation
-
Mad as a hatter
- Delerium, hallucinations, eventual coma
Isolated, bilateral impairment in adduction can result from a lesion in the:
- 6th nerve nucleus
- 3rd nerve fascicle
- 3rd nerve nucleus
- Bilateral orbits
- Bilateral medial longitudinal fasciculus
e. Bilateral Medial longitudinal fasciculus
Indicates demylinating disease or brainstem ischemia
- 6th nerve nucleus -> loss of saccade to one side
- Ex: neither eye can look at an object on the right
- 3rd nerve issue -> Eyes look down and out, pupils dilated
A patient is unable to look left of midline with their left eye. All other eye movements are intact
What is the most likely cause?
CN VI palsy
- If the right eye can look to the left, the saccade signal is intact
- This indicates CN VI palsy, not a problem with the CN VI nucleus
- May be associated with CN V and CN VII palsy
A patient is anesthetized with rocuronium for both intubation and surgery.
When surgery is over, what drug can be given to aid recovery?
How does it work?
Sugammadex
- Like a donut that chelates rocuronium and gets it out of the NMJ
- Works more quickly than neostigmine
What are the signs of transtentorial herniation?
The following appear as the herniation gets worse:
(Ipislateral = the side that is herniating)
- Ipsilateral CN III palsy
- Contralateral weakness
- When the ipsilateral peduncle is compressed
- Ipsilatearl weakness
- When the contralateral peduncle is compressed
A stroke in which artery would result in all of the following symptoms?
- Severe right leg weakness
- Mild right shoulder weakness
- Spastic reflexes on the right side
- Paralysis of the right lower face
Left middle cerebral artery
Describe 4 characteristics of organophosphorous poisoning
Organophosphorous agents = irreversible anticholinesterase
-> tons of parasympathetic action
- Salivation
- Lacrimation (eye watering)
- Urinary frequency (micurition)
- Defecation
Which parasympathomimetic is used to treat GI stasis and urinary retention?
Bethanecol
- Enhances muscle wall contraction and sphincter relaxation
A 22 year old obese women presents with grey outs of her vision when she stands up, headaches, and horizontal binocular diplopia when she looks to the right.
Testing reveals enlarged blindspots, normal color vision and no afferent pupil defect.
What is the most likely pathology?
What do you expect the optic disc to look like?
Papiledema
Bilateral optic nerve swelling, cotton wool spots possible
Describe the status of the following during a phase I block by a depolarizing neuromuscular blocker:
- Membrane potential:
- ACh receptor:
- Volatage-gated Na+ channels:
Phase I block = block by depolarization
- Membrane potential: near equilibirum potential
- No gradient to drive ion flow
- ACh receptor: Occupied by the blocker
- Volatage-gated Na+ channels: Inactivated
- Due to the initial depolarization
- ONLY at the end plate region (presynaptic Na+ channels are fine
- Note: these are TTX sensitive Na+ channels
What kind of drug is yohimbine?
What is it used for?
- Selective alpha-2 blocker
- -> CNS stimulation, aphrodisiac
- -> Used to treat impotence in diabetics
What method of central sensitization results in the activation of the NMDA receptor?
Wind up
- Activated by constant, repetitive stimulation from C fibers?
How do the presentations of MS, ALS, and MG differ?
- MS
-
Weakness AND numbness (spinal cord inflammation)
- Sensory AND motor deficit
- Visual complaints common (optic neuritis)
-
Weakness AND numbness (spinal cord inflammation)
- ALS
-
Weakness ONLY
- No numbness or tingling
- NO visual complaints
- May begin with difficulty speaking
-
Weakness ONLY
- MG
- Weakness worse with activity and stress
- Classic: Ptosis that worsens with sustained upward gaze
- Visual complaint = diplopia
Inhibition of the mGluR6 receptor inhibits the function of which cells?
What is the effect?
Rod bipolar cells
Decreased night vision
Which “neurotransmitter” is important for generating an erection?
NO
- Parasympathetic stimulation
- -> Increased NO synthase activity
- -> increased NO
- -> NO diffuses into smooth muscle
- -> Activates guanylyl cyclase
- -> cGMP
- -> PKG
- -> Phosphorylation
- -> Relaxation + erection
Which method of central sensitizaton results from A-beta fibers “acting like C-fibers”?
Phenotype switching
Due to actions of CGRP
Which of the following is most likely to produce these results?
A) Magnesium
B) Botulism
C) Myasthenia gravis
D) Hemicholinium-3
E) Myasthenic (Lambert-Eaton) Syndrome
C) Myasthenia gravis
- In MG, you will see EPP, MEPP, and response to ACh decline in proportion to each other
- Due to destruction of ACh receptors
- In LEMS you would see decresased EPP amplitude, but no change in MEPPs or response to ACh
- Due to decreased number of P/Q type Ca2+ channels in the membrane
Describe the management of a patient with a ruptured globe
Put a shield over the eye
Call opthomology immediately - this is an emergency!
In a person with normal NMJ physiology, what kind of drug would produce these results?
Non-depolarizing blocker
- Same EPP, MEPP, as myasthenia gravis
Which one of the following pairs of agents act non-synergistically at the neuromuscular junction?
A) Pyridostigmine and calcium gluconate
B) Botulinum toxin and TTX
C) Pancuronium and vecuronium
D) Neomycin and tubocurarine
E) Magnesium salts and pancuronium
C) Pancuronium and vecuronium
- Pancuronium and vecuronium act by the same mechanism
- Both are non-depolarizing blockers
- This means they cannot act synergistically