Neuro Flashcards
All preganglionic neurons use what NT? All sympathetic postgang release what NT, what are the 2 exceptions?
Pregang: Ach
Postgang: NE -> adrenergic-R - except
1. sweat glands: Ach
2. adrenal medulla: 80% epi, 20% NE into bloodstream
Resting Membrane Potential generated by?
High K efflux
Some Na influx
Cryptococcal Meningitis Stain & Tx
India Ink: (36624218) Transparent Capsule Tx: Amphotericin B
Acute Neuronal Injury vs. Axonal Reaction Pathology
“Red Neuron:” shrinkage, pyknosis of nucleus; loss of nissl substance (RER); eosinophilic cytoplasm
Axonal reaction: swelling of cell body; dispersion of nissl substance
Acute Mania Treatment
Mood Stabilizer: Lithium, Valproic Acid, Carbamazepine
+ Atypical Antipsychotic: Olanzapine
What diseases are characterized by anticipation?
Anticipation: sx to worsen or occur earlier in subsequent generations
Huntington’s
Friedrich’s Ataxia
Myotonic Dystrophy
Fragile X
Most common cause of aseptic meningitis?
Enterovirus: Coxsackie, Echo, Polio = Fecal-Oral
Poliomyelitis:
fever, malaise
aseptic meningitis (photophobia, nuchal rigidity)
myalgia and asymmetric paralysis
How is tolerance to morphine developed? What can potentially decrease this?
Phosphorylation of opioid-R
Increased NO levels
Glutamate -> NMDA-R -> increased phos, NO levels
Ketamine can decrease tolerance by blocking glutamate.
What does recurrent laryngeal n. innervate vs. superior laryngeal n.?
Recurrent Laryngeal:
ALL muscles of the larynx except cricothyroid
sensory below the vocal cords
Superior Laryngeal:
Ext: cricothyroid
Int: sensory above the vocal cords
What n. is at risk of damage when ligating the superior thyroid artery in a thyroidectomy?
superior laryngeal - ext branch.
How is the motor end plate affected in MG?
AutoAb to Ach-R -> dec. Ach-R -> dec. motor endplate potential -> threshold potential not reached.
Tredenlenburg gait -> what n. is injured, where is it?
Trendelenburg = hip drops as ipsi foot lifted off
Contralateral superior gluteal n. or gluteus medius (superomedial injection may injure this n.)
How does common peroneal n. injury present and what injury is it commonly associated with?
foot drop (unable to dorsiflex) unable to evert foot Injury to fibular neck
“PED = Peroneal Everts and Dorsiflexes; if injured, foot dropPED”
What does tibial n. control, what injury associated?
TIP: “Tibial invert and plantar flexes; if injured, can’t stand on TIP toes”
Injury to knee, Baker cyst
What part of MMSE tests attention and concentration?
Reciting months of the year backwards, downing back from 100 by intervals of 7, spelling “WORLD” backwards.
What are the symptoms of Wernicke’s? And which sx does not reverse with thiamine administration?
Oculomotor palsy
Ataxia
AMS - disoriented, dec. attention, anterograde amnesia
Memory probs may persist as Korsakoff syndrome (anterior and dorsomedial thalamic nuclei).
What are the genes associated with early vs. late alzheimer’s?
Early: Amyloid precursor protein, presenilin 1, presenilin 2-> promote production of beta-amyloid
Late: e4 allele of apolipoprotein e. (apoE4) -> involved in formation of senile plaques
What kind of necrosis results from hypoxic injury to the brain?
Liquefactive Necrosis (release of lysosomal enzymes)
Cross section of brain: Q1687
…
Damage to what muscle results in hyperacusis?
Hyperacusis - increased sensitivity to sound Stapedius Muscle - innervated by CN 7 Q1452
Clues for identifying spinal cord cross-section: Q8635
- More proximal levels have more white matter
- Lower Cervical and Lumbosacral regions have larger ventral horns bc they are innervating extremities.
- Thoracic and early lumbar (T1-L2) contain lateral gray matter horns.
Low frequency vs. High frequency sounds - vibration where?
Along basilar membrane.
Low Frequency = apex of cochlea near helicotrema
High Frequency = base of cochlea
What are charcot-bouchard pseudoaneurysms?
Due to chronic HTN. Causes intracerebral hemorrhage of basal ganglia, thalamus, internal capsule, or pons.
What condition presents as kyphoscoliosis, high plantar arch, and HCOM?
Friedrich Ataxia
Lacunar Infarcts caused by?
HTN arteriolosclerosis of small, penetrating arteries.
Pure motor hemiparesis -> int capsule
Pure sensory -> VPL or VPM of thalamus
Ataxia-Hemiplegia -> base of the pons
Dysarthria-Clumsy Hand -> base of pons or genu of int. capsule.
CNIII can be compressed by aneurysms of what two arteries?
Either Posterior cerebral or Superior cerebellar.
First line agents for the following seizures:
Simple partial Complex partial Generalized Tonic-Clonic Myoclonic Absence
Simple partial - carbamazepine Complex partial - carbamazepine Generalized T-C - phenytoin, carbamazepine, valproic acid Myoclonic - valproic acid Absence - ethosuximide, valproic acid
Carbidopa added to levodopa leads to increase in what adverse effects?
Anxiety, Agitation (CNS effects)
Decreases peripheral effects.
Demyelination causes an _____ length constant______ time constant?
Decrease Length constant (how far signal can travel until diminishes to 37% of amplitude)
Increase Time constant (lower time constants = faster changes in membrane potential)
How would you differentiate Medulloblastoma vs. Pilocytic Astrocytoma?
MRI
Pilocytic Astrocytoma = Solid + Cystic
Medulloblastoma = Solid
What med do you use with absence + tonic clonic
Valproate
What nerves are unmyelinated?
Afferent sensory fibers for hot temp, dull/burning pain, and olfaction. (Autonomic postganglionic fibers)
C-fibers.
What is thiopental? How is its effect terminated?
Thiopental (Barb)- high potency, high lipid solubility - rapid entry into brain.
Used for induction of anesthesia and short surgical procedures.
Effect rapidly terminated by redistribution into skeletal muscle and fat.
What happens histologically after neuronal shrinkage and intense cytoplasmic eosinophilia?
Those are signs of irreversible neuron damage. Glial Hyperplasia will occur after.
Middle Meningeal Artery is a branch of what artery?
Maxillary Artery (from the External Carotid Artery)
What do the following opioid receptors do? MuKappaDeltaNociception Which receptor is primarily blocked with naloxone?
Mu = Resp and Cardiac depression, Dec GI motility, Dependence, Sedation, Euphoria
Kappa = Miosis
Delta = Antidepressant Nociception = Inc. appetite, anxiolysis
What adverse effects of volatile anesthetics?
Increased cerebral blood flow Myocardial depression Resp depression Hypotension Decreased renal function.
In NPH, what causes urinary incontinence?
Hydrocephalus -> Stretching of the descending cortical fibers -> loss of cortical inhibition on the sacral micturition center -> urge incontinence.
Digoxin Toxicity
- Cholinergic - nausea, vomiting, diarrhea
- Blurry color vision**
- Life threatening arrhythmias4. HyperK
How does an anesthetics solubility in the blood (and blood/gas partition coefficient) affect onset time?
High solubility in blood (Increased blood/gas coefficient): ex: halothane - blood is saturated slowly -> delayed rise in partial pressure -> slower brain saturation -> increased onset time
Low solubility in blood (decreased blood/gas coefficient): Ex: N20 - blood saturates fast -> fast rise in partial pressure -> fast brain equilibration -> decreased onset time.
What adverse effect do opioids have on RUQ?
Cause biliary contraction due to contraction of smooth muscle in the sphincter of oddi - increased pressure in bile duct and gallbladder.
Hyperprolactinemia puts patient at risk of developing what?
Osteoporosis.
Prolactin –| GnRH: leading hypogonadism and decreased estrogen -> osteoporosis
Glaucoma - medications?
- Timolol/B-blockers: Decrease aqueous humor production by the ciliary epithelium
- Acetazolamide: Carbonic Anhydrase inhibitor - also decrease aq humor production
- Prostaglandin F2a and Cholinomimetics - decrease intraocular pressure by increasing outflow of aq humor
What part of brain most likely damaged in global cerebral ischemia (systemic hypoperfusion)?
- HIPPOCAMPUS
2. Purkinje cells of the cerebellum
What are factors that cause slow onset of action of anesthetics?
Increased solubility in blood
Increased solubility in peripheral tissue (increased AV gradient)
Think of it as: blood and peripheral tissue holding onto the anesthetic and not letting it into the brain.
Transient focal tingling and numbness that resolved within minutes is what? What med is given to prevent future recurrences?
TIA - Given Aspirin.
What drug increases toxicity of Phenobarb?
Primidone - metabolizes to Phenobarb and PEMA. NOT Gabapentin.
Most common tumor of Pineal Gland? Presentation?
Pineal Gland Germinoma (hormone secreting tumor derived from embryonic germ cells)
- Precocious puberty - bhCG
- Hydrocephalus - aqueduct compression
- Parinaud (paralysis of upward gaze) - compression of lateral area of tectal area of midbrain.
Succinylcholine - mechs, adverse effect
Mech: Depolarizing neuromuscular blockade. AchR agonist!
Phase I - prolonged depol - no antidote
Phase II - repolarized but blocked - neostigmine antidote
Adverse:
Malignant Hyperthermia
HyperK & Arrhythmia in those with burns, myopathies, crush injuries, denervating injuries, etc
Glossopharyngeal n. functions
Motor: Stylopharyngeus
PNS: Parotid gland secretion
Sensation: post 1/3 of the tongue, tonsillar region, inner surface of tympanic membrane, eustachian tube, upper pharynx (afferent portion of gag reflex), carotid body and sinus.
Selegiline
MAO-B inhibitor. Parkinson’s
Amantidine
Dopaminergic activity + anticholinergic. Parkinson’s
How to differentiate Lambert-Eaton Myasthenic syndrome from Myasthenia Gravis?
Lambert-Eaton: Ab against voltage gated presynaptic Ca++ channels (can be paraneoplastic - small cell lung cx)
proximal muscle weakness - hypo/areflexia**
autonomic sx: dry mouth, impotence**
CN involvement (diplopia, ptosis, dysarthria, dysphagia)
incremental increased response to repetitive stimulation**
Gait ataxia, Truncal instability, intention tremor of hands and fingers, and rhythmic postural “Parkinsonian” tremor of the fingers and hands + Chronic alcoholism = degeneration of what structure
Cerebellum = Purkinje cells and vermis
Due to chronic thiamine deficiency = Alcoholic Cerebellar Degeneration
Note: Korsakoff = bilateral temporal lobes = amnesia
Parinaud syndrome
Pineal tumor - mass effect on dorsal midbrain in region of superior colliculus
- upward gaze palsy
- absent pupillary light reflex
- failure of convergence
- wide based gait Damage to oculomotor, trochlear, edinger-westphal nucleus.
What is defect in Amyotrophic lateral sclerosis and how to treat?
Defect in superoxide dismutase
Ant horns and LCST
Tx Riluzole - decreases presynaptic glutamate release
Friedrich Ataxia
Frataxin gene (Fe binding protein) - GAA rpts chr 9 impairment in mitochondrial functioning -> impairs multiple tracts
gait ataxia, dysarthria, nystagus, frequent falling
HCOM (cause of death)
kyphoscolosis, pes cavus, hammer toes
“he’s your fav frat brother; always staggering, falling, but has a big heart”
What do see with cavernous sinus lesion?
opthalmoplegia
decreased corneal and maxillary sensation
normal visual acuity
CN lesions - deviate toward or away? V X XI XII
V = jaw = towards lesion
X = uvula = away from lesion
XI = weakness turning head contralateral side (SCM); shoulder drop on side of lesion
XII = deviate toward “lick lesion”
Conductive vs. Sensorineural using Weber and Rinne
Conductive:
Weber: localized to affected ear
Rinne: BC > AC
Sensorineural:
Weber: localizes to the unaffected ear
Rinne: AC > BC
What syndromes does blockage of the following arteries lead to: PCA Basilar AICA PICA ASA
PCA = contralateral hemianopia with macular sparing, weber syndrome (3, contralat spastic hemiparesis)
Basilar = locked in, medial inf pontine syndrome (VI)
AICA = lateral pontine syndrome (VII)
PICA = lateral medulla/ wallenberg - nucleus accumbens X
ASA = medial medulla (XII)
Vasogenic vs. Cytotoxic Edema
Intracranial mass = vasogenic = increased ICP
Ischemic insult = cytotoxic = usually no increased ICP, but it’s a shift in fluid from extra to intracellular, not more fluid.
