Nervous System Flashcards
Huntington disease mode of inheritence
Autosomal dominant
Huntington disease is caused by an increase in _______ in the gne that codes for the huntingtin protein
CAG trinucleotide repeats
Expansion of the huntingtin protein’s polyglutamine region in huntington disease results in ________ which leads to pathological interaction with other proteins, including various transcription factors
Gain-of-function
in huntington disease, abnormal hintingtin causes increased histone ____ which silenes the genese necessary for neuronal survival
Deacetylation
Occlusion of the PICA results in _____ syndrome
Lateral medullary (Wallenberg)
PICA arises from what artery
Vertebral
What arteries course through the transverse foramina in the neck before entering the skull at the foramen magnum and therefore can be easily injured by cervical spinal trauma
Vertebral
Oclussion of which vessel is characterized by vertigo/nystagmus, ipsilateral cerebellar signs, loss of pain/temperature sensation in the opsilateral face and contralateral body, bulbar weakness and ipsilateral horner syndrome
Posterior inferior cerebellar artery
Blood pressure above ____ increases verebral vascular volume and blood flow, causing a corresponding increase in ICP
150 mmHg
Blood pressure below _____ causes cerebral hypoperfuion and potential ischemia
50 mmHg
A drop in PaCO2 whill have what effect on intercranial blood flow
Causes vasoconstriction –> decreases cerebral blood volume –> decreased ICP
Lowering ____ is one of the measures employed to reduce ICP in mechanically ventilated patients with cerebral edema
PaCO2
Carbon dioxide is a potent ____ of cerebral vasculature
Vasodilator
The anterior pituitary is derived from what embryonic tissue
Surface ectoderm
Bitemporal hemianopsia, amenorrhea, and elargement of the pituitary gland on brain imaging are suggestive of ___________
Prolactin secreting pituitary adenoma
Prolactinomas develop from ____ cells in the anterior pituitary (adenohypophysis)
Lactotroph
What occurs at 3 eks of embryogenesis resulting in 3 germ layers
Gastrulation
During gastrulation, epiblast cells undergo what transition, causing them to lose their cell-to-cell adhesion properties
Epithelial-to-mesenchymal
The anterior pituitary is derived from what structure, which is an evagination of the surface ectderm that lines the fetal oral cavity
Rathke pouch
The posterior pituitary is derived from what embryonic cells
Neuroectoderm
The posterior pituitary is derived from the ______ which is an extension of neuroectoderm from the diencephalon
Infundibulum
What is the condition characterized by a sudden, involuntary contraction of a major muscle group that developes within 4 hours and 4 days of starting an antipsychotiv medication
Acute dystonic reaction
What is the presentation of dystonia as a oculogyric crisis
Forced, sustained elevation of the eyes in an upward position
How does opisthotonus (a dystonic reaction) present
Arching of the back with the head thrown backward
How does spasmodic torticollis (a dystonic reaction) present
Pain and stiffness on one side of the neck
Acute dystonic reactions a theorized to result from the antipsychotic property of D2 antagonism in what pathway
Nigostriatal
Dopamanergic blockade causes excess _____ _activity in the striatum leading to extrapyramidal side effects
Cholinergic (M1)
L5 radiculopathy presents with sensory loss where?
Lateral thigh
Calf
Dorsal foot
L5 radiculopaty often presents with weakness where?
Great toe extension
Foot dorsiflexion, inversion, and eversion
What is pleocytosis in a CSF sample
Elevated leukocyte count
What bacteria has distinctive tumbling motililty at room temperature
Listeria monocytogenes
How is listeriosis most commonly transmitted in adults
Food ingestion (can replicate in cold (refrigerator)
Listeriosis can have what presentation in immunocompromised adults
Meningitis
Migraines are associated with cortical spreading depression and subsequent stimulation of _____ afferents in the meninges causing release of vasoactive neuropeptides
Trigeminal
Trigeminal aferents in the meninges cause release of vasoactive peptides including substance P and __________, resulting in neurogeninc inflammation, vasodilation, and plasma protein extravasation which can casue migranes
Calcitonin gene-related peptide (CGRP)
Triptans, such as sumatriptan, are ________ agonists that directly counter migraine hedaches by binding trigeminal ____ receptors and inhibiting CGRP release from trigeminal neurons
Sertonin 5-hydroxytryptamine 1B/1D
Triptans bind serotonin recepotrs on smooth muscle cells of blood vessels and result in intracranial ____
Vasodilation
Tryptans are commonly prescribed as ______ therapy for acute migraines, particularly in patients who are not responsive to analgesics
Abortive
Significant adverse effects of triptans (used aas migrain therapy) include dizziness, chest tightness, and _____
Hypertension
The extracranial portion of the facial nerve exits the skull via ______ foramen
Stylomastoid
Where does CN VII divide into 5 terminal branches
Within the parotid gland
Parotid gland tumors can compress and disrupt the ipsilateral facial nerve and its branches leading to _____
Facial droop
Parotid gland tumors that cause facial nerve paralysis are often ______
Malignant
Tetanospasmin (potent metalloprotease exotoxin) inhibits release of what neurotransmitters
Glycine and gamma-aminobutyric acid (GABA)
What is the term for lockjaw seen in C.tetani infections
Trismus
What is the term for the contractions of back muscles resulting in backward acing seen in infections with C. Tetani
Opisthotonos
all 3 opiate receptor subtypes are transmemrane receptors that are coupled to ____ G proteins
Inhibitory
Which opiate recepter exerts the strongest analgesic effects
Mu
What effects do opiates have when binding to mu receptors on the primary afferent neurons
Closure of voltage gated calcium channels –> reduced calcium influx –> decreased excitatory neurotransmitter release from presynaptic terminal
What effects do opiates binding on mu rceptors on the postsynaptc membrane have
Opens potassium channels –> potassium eflux –> hyperpolarization
Dopamine agonists in treating Parkinson disease can result in what behavior change
Impulse control disorders
Dopamine agonists, treatment for parkinsons disease, act by binding central dopamine receptors and stimulating dopamine activity in the _____ and substantia nigra
Ventral striatum
Where is the nucleus accumbens located
Ventral striatum
Nucleus accumbens is involved in motivation and the _____ pathways
Reward
Zolpidem is a short-acting nonbenzodiazepine ___ agent
Hypnotic
Mechanism of action for zolpidem
Bind GABAa receptor at benzodiapine receptor site and act as GABAa agonist
What differs nonbenzodiazepines such as zolpidem from benzos
More specific binding –> primarily hypnotics and do not produce anxiolytic, muscle relaxant, o anticonvulsant effects
Campylobacter jejuni causes guillain barre syndrome via immune mediated polyneuropathy due to _________
Cross-reacting antibodies (molecular mimicry
In guillain barre syndrome an antecedent event (typically infection) provokes an immune response that cross reacts with the ______ and ______ of peripheral nerves
Schwann cells and myelin sheath
Underlying etiology of temporomandibular disorder (TMD) is multifactoral but includes tempromandibular joint(TMJ) derangement and hypersensitivity of the _______ nerve
Mandibular
The mandibular nerve is the largest branch of what nerve
Trigeminal nerve (it is CNV3)
The mandibular nerve supplies sensation to the TMJ, floor of mouth, ______ tongue and lower part of the face
Anterior
The mandibular nerve innervates the muscles of mastication, tensor veli palatini, and ________ which is in the middle ear and dampens loud sounds by tensing the tympanic membrane
Tensor tympani
Where does te herpes simplex virus 1 most commonly lay dormany
Neural sensory ganglia of trigeminal nerve
During reactivation HSV particles rely on anterograde axonal transport, carried out by ________, to reach the skin and oral mucosa
Kinesin
What motor protein, moves intracellular cargo via retrograde axonal transport
Dynein
What are two ways that critical illness can cause neuromuscular weakness
Critical illness myopathy (atrophy of myofibers)
Critical illness polyneuropathy (axonal degeneration)
What is the cause of cavernous sinus thrombosis
Contiguous spread of an infection from the medial third of face, siuses, or teeth
Methylmalonic acidemia results from complete or partial deficiency fo the enzyme ________
Methylmalonyl-coA mutase
In methylmalonic acidemia, a methylmalonyl-CoA mutase deficiency, results in a metabolic acidosis and what blood glucose status
Hypoglycemia
Why is there an anion gap metabolic acidosis present in methylmalonic acidemia (a deficiency in methylmalonyl CoA mutase)
Hypoglycemia –> increased FFA metabolism –> ketones –> anion gap
Why is there hyperammonemia in methylmalonic acidemia
There is a build up methylmalonic acid and propioinic acid. Organic acids directly inhibit urea cycle –> hyperammonemia
How is a diagnosis of methylmalonic acidemia confirmed
Elevated urine methylmalonic acid and propionic acid
Propionic acidemia is due to deficiency in what enzyme
Propionyl CoA carboxylase
How do the lab findings in propionic acidemia differ from methylmalonic acidemia
Will not have elevated levels of urine methylmalonic acid
Both have hyperammonemia, hypoglycemia, metabolic acidosis
Axillary nerve originates from the ____ cord of brachial plexus
Posterior
Axillary nerve carries fibers from what spinal nerves
C5, C6
What is the motor inervation of the axillary nerve
Deltoid and teres minor
What is the sensory inveration of the axillary nerve
Skin over lateral shoulder
What nerve injury leads to sensory loss over upper later arm and weakness on shoulder abduction due to denervation and possible atrophy of the deltoid muscle
Axillary nerve
kinesin is a microtubule associated motor protein whose funciton is anterograde transport of intracellularvesicles and organells toward the ____ end of microtrubules
Plus (rapidly growing)
What is the most common cause of cerebellopontineangle (betwen the cerebellum and lateral pons) tumors in adults
Vestibular schwannoma
Spontaneous vestibular schwannomas are usually unilateral, whereas bilateral vestibular schwannomas are associated with ___________
Neurofibromatosis type 2
What 3 nerves are in proximity at the cerebellopontine anlgle and therefore at risk of being compressed by a vestibular schwannoma
VII (facial)
V (trigeminal)
VIII (vestibularcochlear)
What common manifestation of multiple sclerosis is characterized by monocular visual loss with pain on eye movement and an afferent pupillary defect
Optic neuritis
MRI findings in _________ typically include white matter lesions scattered throughout the brain and/or spinal cord with a predilection for the subcortical periventricular regions
Multiple sclerosis
The pathogenesis of MS involves an autoimmue response targeting ________
Oligodendrocytes
Most patients with MS have ______ immunoglobulin bands in the cerebrospinal fluid
Oligoclonal
The auto-immune response in multiple sclerosis is __________ mediated
T cell and antibody
List the abortive medications use in migraine therapy
Triptans (sumatriptan)
NSAIDs, acetaminophen
Antiemetics (metoclopramide, prochlorperazine)
Ergotamine
List the preventative medications used for migraine therapy
Anticonculsants (topiramate or valproate)
Beta blockers (metoprolol, propranolol)
Antidepressents (tricyclic: amitrptyline, or venlafaxine)
What age group is almost exclusived affected by febrile seizures
6 mo - 5 years (seizure threshold is lower during early years of brain development)
What is the treatment for most febrile seizures
Antipyretics (NSAID)
Botulinum toxin prevents the presynaptic release of _____ from the nerve terminal at the neuromuscular junction
Acetylcholine
Clostridium botulinum spore formation occurs at _______ location which allows the bacteria to survive adverse conditions such as heat and high oxygen enironments
Subterminal (between the terminal end and center of the bacteria)
Injection of _____ into the a dystonic muscle results in muscular relaxation and relief of symptoms
Botulinum toxin type B
What is hydrocephalus ex-vacuo
Normal CSF expansion following cerebral volume loss rather than abnormal CSF accumulation as seen in hyrdrocephalus
Infants with hydrocephalus typically develop macrocehaly, poor feeding and what two other musculoskeletal/neural findings
Muscle hypertonicity
Hyperreflexia
In hydrocephalus, Hypertonicicty and hyperreflexia result from upper motor neuron injury caused by stretching of the ________ tracts
Periventricular pyramidal
Treatment of hydrocephalus requires ________
Surgical placement of a shunt
Infants with hydrocephalus will show what on imaging
Enlarged ventricles
What is the characteristic presentation of paralysis in a patient with botulism
Symetric, descending paralysis that first manifests with cranial nerve abnormalities: 3 D’s: diplopia, dysphagia, dysphonia
How does the botulinum toxin prevent the release of Acetylcholine
Destroys SNARE proteins
Transected nerves udergo __________ which involves axonal dissolution while activated schwann cells and macrophages degrade myelin
Wallerian degeneration
In addition to clearing cellular debris, ______ and macrophages stimulate formaiton of a growth cone from te proximal axon stump to facilitate nerve regeneration
Schwann
If regenerating axons cannot find their distal target, regeneration can result in formation of a disroganzed mass of axonal processes, Schwann cells, vascular hyalinization, and fibrosis know as a _______
Neuroma
Chronic axonal injury or inflammation induces increased expression of ___________ chanels
Voltage gated sodium chanels
To supportthe diagnosis of a neuroma, _______, is administered which will often provide immediate relief of pain
Local anesthetic (blocks sodium channels in the neuronal cell membrane –> prevents depolarization of the nerve)
What are the preferred anticonvulsants for focal onset seizures
Carbamazepie
Lamotrigine
Levetiracetam
Phenytoin
What anticonvulsants are prefered for tonic-clonic and myoclonic seizures
Leveltiracetam
Valproic acid
What are the preffered anticonvulsants for absence seizures
Ethosuxamide
Valproic acid
What typically presents in adolscents with brief, involuntary jerking movements involving both upper extremities with preservation of consciousness and symptoms usually occring within the first hour of waking and can be provoked by sleep deprivation
Juvenille myoclonic epilepsy
Individuals who consume more than 10 times the daily value of ______ are prone to developing toxicity and may suffer hepatic injury so severe as to cause cirrhosis
Vitamin A
Signs and symptoms of acute vitamin A toxicity occur after ingestion of a single high dose of vit A and include:
Nausea, vomitting, vertigo and blurred vision
Sings and symptoms of chronic vitamin A toxicity occur after the long-term ingestion of high doses of vit A and include:
Alopecia Dry skin Hyperlipidemia Hepatotoxicity Hepatosplenomegly Visual difficulties
The cerebellar hemispheres are primarily responsible for _______ of the ipsilaeral extremities
Motor planning and coordination
Lesions in the left cerebellar hemisphere typically result in left ________(impaired rapid alternating movements), _______ (overshooting/undershooting during targeted movement), and ________ tremor
dysdiadochokinesia
Limb dysmetria
Intention tremor
The cerebellar vermis modulates _____ via connections with the medial descending motor systems
Axial/truncal posture and coordination
Vertigo and nystagmus may occur due to disruption of what regions of the cerebellum
Inferior vermis and flocculonodular lobe
Mechanism of action: triptans
Serotonin 1B/1D agonist
Mechanism of action: metoclopramide
Dopamine recepor blocker
Dopamine receptor blockers have both antiemetic and anaglesic effects on migraine headaches by antagonizing central dompamine ____ receptors in midbrain and striatum
D2
Dopamne receptor bloackade in teh basal ganglila can cause excess ______ activity that manifests as significant extrapyramidal symptoms such as acute dystonic reaction
Cholinergic
What can be co-administered with metoclopramide or prochlorperazine to prvent extrapyramidal symptoms
Diphenhydramine (anticholinergic)
________ presents with vague lower extremity discomfot and an urge to move the legs that worsens at night
Restless leg syndrome
Causes of restless leg syndrome include idiopathic and 3 others:
Iron deficiency
Uremia
Diabetes (especially with neuropathy)
Pathophysiology of restless leg syndrom is not completely understood by likely involves CNS iron deficiency (even in patients with normal serum iron levels) and abnormalities in _______ transmission
Dopaminergic
Treatment of restless leg syndrome includes avoidance of aggravating medications, iron replacement, and ________
Dopamine agonists (ropinirole, pramipexole)
Characterisc pathologic changes associated with alzheimer disease involve acumulation of intracellulr ______ and extra cellular ______ plaques
Neurofibrillary tangles
Amyloid beta
Neurofibrillary tangles are composed of _____ protein, a primary component of intracellular microtubules
Tau
In alzheimer disease, tau protein is _____ causing microtubule structures to collapse into “tangles” that contribute to global neuronal dysfunction
Hyperphosphorylated
Amyloid beta is an abnormal fragment of ________ protein, which is normally involved in synaptic formation and repair
Amyloid precursor protein
An extra copy of ____ gene, located on chromosome 21, present in trisomy 21, is thought to lead to early onset alzheimers disease
APP (amyloid precursor protein)
______ phenomenon describes what patients with parkinson disease being treated with levodopa experience in terms of periodc flucuations in motor function
“On-off”
As parkinson disease progresses, the therapeutic windo for levodopa narrows, possibly due to natural or levodopa induced ______ degeneration
Nigrostriatal
In advanced PD, motor fluctuations can occur independently of dosing and may become _______
Unpredictable
A patien who developes prolonged muscle weakness after receiving succinylcholine could have _____________ deficiency, an autosomal recessive disorder caused by a genetic polymorphism in the BCHE gene
Pseudocholinesterase deficiency
Psuedocholinesterase deficiency is an autosomal recessive disorder caused by a genetic polymorphism in the _____ gene
BCHE
Succinylcholine is a _______ neuromuscular blocking agentused to induce skeletal muscle relaxation during intubation and surgery
Depolarizing
Succinylcholine acts as a _________ of nicotinic acetylcholine receptors of the motor endplate, where it induces persistent depolarization, leading to desensitization and skeletal muscle paralysis
Competitive agonist
Succinulcholine is rapidly hydrolyzed by plasma ________, only around 10% of the administered dose reaches the neurmuscular junction, where it typically has a duration of action of < 10 min.
Pseudocholinesterase
What is another name for neurofibomatosis type I
Recklinghausen disease
Neurofibromatosis type I is an autosomal dominant neurocutaeous disorder caused by mutations in _______ gene
NF1 (tumor supressor)
In neurofibromatosis type 1, patients typically develop _____ over the trunk
Cage au lait spots (hyperpigmented macules)
Patients with neurofibromatosis type I are at increased risk of developing ______ which can cause elevated intracranial pressure and headache
Central nervous system neoplasms (optic gliomas, pilocytic astrocytomas)
Cutaneous neurofibromas usually manifest during early adolescence as multiple, raised, fleshy tumors that often increase in size and number with age. These are benign sheath neoplasms predominantly comprised of _____ cells which are embryologically derived from _______
Schwann cells
Neural crest
Absence seizures are characteristically provoked by ______
Hyperventillation
Treatment for absence seizures
Ethosuximide (or valproate if first line is not tlerated or inneffective)
Absence seizures show _____ on electroencephalogram
3 Hz spike wave
Mechanism of action of ehosuximide
Inhibits T type calcium channels in thalamic neurons
A patient with sudden-onset confusion, memory loss, and anterograde amnsia that resolves in a couple hours is consistent with what dagnosis
Transient global amnesia
Risk factors for transient global amnesia
History of migraine
Older age
Transient global amnesia is likely due to dysfunction of what area of the brain which is responsible for formation of new memories
Hippocampus
When testing the plantar reflex, what action of the patients foot is a positive babinski sign
Dorsiflexion with or without fanning of the toes
Babinski signs indicates a _______ motor neuron lesion
Upper
Upper motor neuron injury can occur anywhere proximal to _____
The anterior hor
A sign of UMN injury includes _____reflexia, _____ paralysis, and ____ muscle tone
Hyper
Spastic
Increased
Describe clasp- knife rigidity
Increased muscle tension with sudden release on passive flexion
Clasp knife rigidity is present in ____ motor neuron lesions
Upper
In pyramidal weakness, a sign of upper motor neuron injury, weakness is more pronounced in lower extremity ______ and upper extremety ______
Flexors
Extensors
Pronator drift, due to upper extremity supination being weaker than pronation, is a sign of a ________ motor neuron lesion
Upper
Lower motor neuron lesion signs include ____ _paralysis, _______ tonia, and _____ reflexia
Flaccid
Hypo
Hypo (or absent)
Fasciculations are present in ___ motor neuron lesions
Lower
Histology of guillain barre syndrome demonstrates an inflammatory infiltrate located within the ______
Endoneurium (innermost layer of connective tisue that surrounds a nerve axon adn its corresponding blood vessels)
In guillian barre syndrome, macrophages strip the myelin sheath from the axon, and ________ macrophages are seen following the engulfment of myelin
Lipid laden
The speed of conduction down an axon depends on what two constants
Length (space) constant
Time constant
Myelin _____ the length constant by reducing charge dissipation across the membrane
Increases (allows the electrical impulse to propagate further without requiring active regeneration by ion channels)
Myelin ____ the time constant
Reduces (allows membrane potential to change faster)
Unilateral hand pain and numbness, thenar atrophy, and weakness of thumb opposition is characteristic of ________
Carpal tunnel syndrome
The carpal tunnel is an antaomic space in the wrist between the carpal bones and the ______
Transverse carpal ligament (flexor reinaculum)
What structures run through the carpal tunnel
Median nerve
9 tendons: flexor digitorum superficialis and profundus, flexor pollicis longus
If carpal tunnel syndrome is not treatable with wrist splints and glucocorticoid injection, surgical decompression can be performed by making a longitudial incision of the ______
Transvers carpal ligament
What role do the pili on the capsular surface of N meningitidis have?
Attachment to and colonization of the nasopharyngeal epithelium as well as bacterial movement and epithelial penetration
What is the role of Opa-proteins in N. Meningitidis
Aid in endothelial attachment and invasion
What virulence factor aids N. Meningitidis by destroying mucosal antibodies that would otherwise inhbit epithelial colonization
IgA protease
Capsulr polysaccharides provide what benefit to bacterial organisms (including N. Meningitidis)
Prevent phagocytosis and phagolysisime destrution
Why are pili in N. Meningitidis a difficult target for vaccines
Significant antigenic variations
What nerve courses along the pericardium and overlies hte right atrium puting it at high risk during procedures that target structures in or near the right atrum
Right phrenic nerve
How can an injury to the right phrenic nerve be visualized on a chest xray
Elevation of the right (ipsalteral) hemidiaphragm
A patient with history of A fib presenting with isolated left lower extremety motor deficits, most likely had a carioembolic stroke in what artery
Right anterior cerebral artery
Occlusion of the ACA characteristically causes contralateral _____ limb weakness and _____ motor neuron signs
Lower
Upper
Atrial thromemboli traveling to and obstructing the middle cerebral artery characteristically has contralateral _____ extremity weakness and _____ deficits
Upper
Face
Portion of the hypothalamus that mediates satiety, and lesions –> hyperphagia
Ventromedial
Ventromedial injury makes you very massive
Portion of hypothalamus that mediates hunger, lesion –> anorexia
Lateral
Lateral injury makes you lean
Portion of hypothalamus that mediates heat dissipation, lesion –> hyperthermia
Anterior
A/C = Anterior cooling
Portion of hypothalamus that mediates head conservation, lesion –> hypothermia
Posterior
Heating controled by posterior= hot pot
Portion of hypothalamus that secretes dopamine (inhibits prolactin) and GHRH
Arcuate
Portion of hypothalamus that secretes GnRH and regulates sexual behavior
Medial preoptic
Portion of hypothalamus that secretes oxytocin, CRH, TRH, and small amounts of ADH
Paraventricular
POX = paraventricular = oxytocin
Portion of hypothalamus that secretes ADH and small amounts of oxytocin
Supraoptic
SAD= supraoptic = ADH
Portion of the hypothalamus that regulates circadian rhythm and pineal gland function
Suprachiasmatic
SCN is Sun Censing Nucleus
Musculocutaneous nerve roots
C5-C7
Musculocutaneous nerve arises from ____ cord of brachial plexus
Lateral
Motor innervation of the musculocuaneous nerve
Forearm flexors adn corachobrachialis
Sensory innervation of musculocutaneous nerve
Lateral forearm
Brown sequard syndrome (result of a spinal cord hemisection) will produce _____lateral paralysis, _____ lateral loss of vibration, proprioception, and light touch, and ____ lateral loss of pain and temperature sense
Ipsilateral paralysis
Ipsilateral vibration
Contralateral pain/temp
If a patient fails the romberg test with eyes open then they have ____ ataxia
Cerebellar
If a patient is steady during the romberg test with eyes open but fails when eyes are closed they have _____ ataxia
Sensory (loss of proprioception)
Tabes dorsalis causes sensory ataxia due to what infection
Syphilis
Over 95% of glioblastoma cases are associated with the overexpression of _________ on the surface of neoplastic cells
Epidermal growth factor (EGRF)
Mechanism of action: erlotinib
Inhibits EGFR/EGFR-ligand interaction
A biopsy of a tumor with hypercellular white matter with extensiveastrocytic aberration, microvascular proliferation and areas of necrosis lined with tumor cells will have what diagnosis
Glioblastoma
Right arm numbness and paresthesia caused by a focal onset seizure originates in the ____ side ____ central gyrus
Left
Post
(Primary somatosensory cortex)
Wernicke korsakoff syndrome is a complication of ______ defciency and most commonly occurs in patients with history of long standing alcohol abuse or other forms of malnurishment
Thiamine (B1)
Thiamine is a vitamin cofactor involved in ____ metabolism and decifiecy resultsin neuoronal damage and necrosis
Glucose
Iatrogenic wernike korsafoff an be precipitaed by the administration of ________
Glucose containing fluids which depletes the last remianing stores of thiamine
Areas of the brain with high metabolic demand are particularly susceptible to wernicke korsakoff syndrome, focal hemorrhage and atrophy of _______ is characteristic
Mammillary bodies
Neurofibromatosis type 1 gene mutation is located on chromosome ___ while NF2 gene mutation is located on chromosome ____
17
22
NF1 is a tumor supressor gene that codes _____
Neurofibromin
NF2 is a tumor supressor gene that codes protein ____
Merlin
Von Recklinghausen disease is associated with what gene mutation
NF1 (neurofibromatosis type 1)
Central neurofibromatosis is associated wiith what gene mutation
NF2 (neurofibromatosis type 2)
What are the main clinical features of neurofibromatosis type 1
Cafe au lait spots
Multiple neurofibromas
Lisch nodules
What are the main clinical features of neurofibromatosis type 2
Bilateral acoustic neuromas
A brain tumor causing cerebellar symptoms with sheets of primitive cells with many mitotic figures indicates what diagnosis
Medulloblastoma
Primitive neuroetodermal tumors are composed of sheets of small cells with deeply ____ nuclei and ____ cytoplasm
Basophilic
Scant
Primitive neuroectodermal tumors are well or poorly differentiated? And good or bad prognosis?
Poorlydifferentiated
Poor prognosis
Syringomyelia presents with loss of pain and temperature sensation in the arms and hands due to a fluid filled cavity called a _______ that damages the ________ and sometiems the ventral horns
Syrinx
Ventral white commissure
The ventral whitecommissure is the area of decussation for the fibers of the ____ tract
Lateral spinothalamic
Axons of the spinothalamic tract briefly ascend in the zone of ____ before decussating
Lissauer
The anterior 2/3 of the spinal cord is perfused by the ______ which receives blood flow form segmental arteries arising from te ______
Anterior spinal artery
Thoracic aorta
In an anterior cord syndrome how do initial changes in motor fuction progress
Initially: flaccid paralysis from spinal shock
Upper motor neuron signs devlop (spasticity, hyperreflexia) over days to weeks
Neoplastic spinal cord compression most commonly results from local extension of vertebral metastases into the ______ space
Epidural
Characteristic CT findings of ischemic stroke 6-12 hours after onset of inschemic injury include _____ of the tissue and loss of _____ differentiation within affected region
Hypoattenuation
Grey-white matter
Signs of irreversible damage during the first 24 hours after injury in ischemic stroke are ____ (microscopic finding)
Red neurons
Neutrophils move into area of ischemic stroke ____ following injury and microglial cells _____ after onset of injury
1-2 days
3-7 days
_______ is the product of neuron disintegration and microglia phagocytosing their fragments which along w myelin breakdown products accumulate in the microglia cytoplasm
Foamy lipids
In Guillain barre syndrome, ______ demyelination and an _____ inflammatory infilttrate composed of lymphocytes and macrophages are seen on light microscopy
Segmental
Endoneurial
Fragile X syndrome mode of inheritence
X linked
Fragile x syndrome is an x linked disorder caused by ____ mutation in hat gene
Loss of function
Fragile x mental retardation 1 (FMR1)
Which arm of the x chromosome is the FMR1 gene located
Long arm
Presentation of _______ includes long, narrow face, prominent forehead and chin, large testes, hyperlaxity of joints, developmental delay, and neuropsychiatric features
Fragile x syndrome
Anxiety and agnitation are central effects of dopamine and are caused by what parkinson disease treatment
L-dopa
Why might adding carbidopa to L-dopa treatment worsen anxiety and agitation side effects
Carbidopa inhibits peripheral conversion of levodopa, making more of it availible to the brain
How long following an ischemic stroke do red neurons with eosinophiliccytoplasm, pyknotic nuclei and loss of Nissl substance appear
12-24 hours
How long following an ischemic stroke does neutrophilic infiltration occur
24-72 hours
How long after a stroke do macrophage/microglia innfiltratation and phagocyosis begin
3-7days
How long after an ischemic stroke does reactive gliosis and vascular proliferation around he necrotic area occur
1-2 weeks
How long afer an ischemic stroke does a glial scar form
> 2 weeks
How long after an ischemic stroke does liquefactive necrosis occur
1 wk-1 month
How long after an ischemic stroke does a cystic area surrounded by dense glial fibers form
> 1 month
Why might someone exposed to organophosphates experience wheezing
Cholinesterase inhibitor –> cholinergic overstimulation –> bronchospasms
In viral meningitis, CSF will have a WBC count of ______ with ______ cell predominance
<500
Lymphocytic
In viral meningitis, glucose levels are _____ and protein levels are _____
Normal or slightly reduced
<150
In CSF of viral meningitis, CSF gram stain/culture will have what result
No organsism identified
In bacterial meningitis, CSF WBC count is ______ with _____ cell predominece
> 1000
Neutrophilic
In bacterial meningitis, the CSF has glucose levels of ______ and protein is _______
<45
>250
A CSF gram stain in bacterial meningitis will often have what result
Positive for a specific organism
What is the most common viral cause of meninitis
Enterovirus (>90%)
What virus can present with the following clinical signs: fever, headache, rash, meningitis, echphalitis, acute asymmetric flaccid paralysis, parkinson symptoms
West nile virus
West nile virus is a _____ sense _____ stranded RNA virus
Positive
Single
Who is at risk for a west nile virus becoming neuroinvassive
Older
Malignancy
Organ transplant
What may be suspected of a patient with oral thrush and cervial and inguinal lymphadenopathy
HIV
Headache, seizures, multiple ring enhancing central nervous system lesions in a patient with HIV indicates what diagnosis
Toxoplasmic encephalitits
List two modes of transission for tocoplasmic encephalitits
Extensive pet (cat)exposure Contaminated food
Neuroleptic malignant syndrome is a life threatening adverse effect due to block of _____ receptors in the brain
Dopamine
If a patient who recently started using an antipsychotic presents with fever, confusion, muscle rigidty, and autonomic instability (abnormal vital signs, sweating) what might they be experiencing
Neuroleptic malignant syndrome
Mechanism of action: dantrolene
Atnagonizes ryanodine receptors and inhibits calcium release from sarcoplasmic reticulum
____ of inhaled anesthetic is inversly proportional to the minimal alveolar concentration
Potency
The minimal alveolar concentration referes to the percentage of anesthetic in the inspired gas mixture that renders ____ of patients unresponsive to painful stimulil
50%
What nerve innervates all of the extensor muscles of the upper limb below the shoulder and provides sensory inervation to the skin of the posterior arm, forear, and dorsal lateral hand
Radial
Radial nerve receives fibers from what nerve roots
C5-T1
The radial nerve tracks within the radial groove of the humerus, therefore it is vulnerable to tramatic injury at the ______
Humeral midshaft
Patients with proximal radial neuropathy typically have weakness during _______ and variable sensory loss over the posterior arm and forearm
Wrist and finger extension (wrist drop)
Damage to the proximal radial nerve can occur at the _____ or the midshaft of the humerus
Axilla
The blood brain barrier is formed by _____ between nonfenestrated capillary endothelial cells that prevent the paracellular pasage of fluidsand solutes
Tight junctions
L-DOPA has low lipid solubility but is able to enter brain due to _______
Its high affinity for the large neutral amino acid transporter
Liquefactive necrosis is charcteristic of irreversible CNS injury becuase of the brains high cholesterol content and lack of supporting architecture. It also occurs in other body tissues in the setting of severe infection/inflamation because of the release of _______ from reacting inflammatory cells.
Hydrolytic enzymes
How does a nicotinic receptor function
Its 2 acetylcholine binding sites must be filled and the ion channel opens, allowing sodium and calcium influx and sodium outflux —> end plate potential
Nitrous oxide is a ____ soluble gas
Poorly
A gas that is poorly soluble, such as nitrous oxide, partial pressure will rise rapidly and plateua, indicating that the blood quickly becoems _____with the anesthetic
Saturated
Blood solubulity of an anesthetic is indicated by itsblood/gas partition coefficient, anesthetics with a higher blood slubility will have a ______ blood/gas partition coefficent
Larger
A gas with higher solubulity (thus a larger blood/gas partition coefficient) will havea partial pressure in blood that rises more _____ than a low solubilty gas
Slowly
Poorly soluble gases equilibrate with the brain ______ than highly soluble gases
Faster
Poorly soluble gases have a ______ onset than highly soluble gases
More rapide
The first pharyngeal arch is associated with what nerve
Trigeminal (V)
Bony derivatives of first pharyngeal arch
Maxilla Zygoma Mandible Incus Malleus
Muscle derivatives of first pharyngeal arch
Muscles of mastication
Second pharyngeal arcassociated with what nerve
Facial nerve (VII)
Second pharyngeal arch gives rise to what bones
Styloid process of temporal bone, lesser horn of hyoid, and stapes
Muscles derived from 2nd pharyngeal arch
Muscles of facial expression
Treacher collins syndrome is a genetic disorder resulting in abnormal development of _____
1st and 2nd pharyngeal arches
Treacher collins syndrome will preset with craniofacial abnormalities resulting in airway compromise and feeding difficulties as well as what other clinical finding
Profound conductive hearing loss
The most notable manifestaions of vitamin E deficiency are hemolysis and neurologic dysfunciton due to _____
Free radical damage of cell membranes
Neurologic symptoms of vitamin E deficiency closely mimic _______ which include ataxia ue to degeneration of spinocerebellar tracts, loss of position and vibration sense due to degeneration of the dorsal columns and loss of deep tendon reflexes due to peripheral nerve degeneration
Friedreich ataxia
Intraventricular hemorrhage in preterm infants usually originates from ______, a highly cellular and vascularized layer in the subventricular zone (source of neurons and glial cells during brain development)
Germinal mattrix
The germinal matrix contains numerous fragile, thin walled vessels that lack _____ that support other blood vessels throughout the bain, making them more susceptible to hemorrhage
Glial fibers
There is reduced risk of intraventricular hemorrhage in infants born after _____ weeks because the germinal matrix starts to become less prominent and its cellularity and vascularity decreases
32
Neonatal intraventricular hemorrhage occurs in infants born before 32 weeks nd/or birth weight
1,5000 g (3 lb 5o z)
Creutzfeldt-Jakob disease is a ____ disease: transmissible spongiform encephalopathy
Prion
Creutzfeldt-Jakob disease presents in previously healthy patients with ______ dementia associated with ________
Rapidly progressive
Myoclonus
Prion diseases are associated with the hange in structural confirmation of ______
Prion protein (PrPc)
The abnormal prion protein (PrPsc) in prion diseases is resistant to ______ and accumulates within neuronal and glial cells causing neural cell death
Enzymatic degredtion
Histopathology of Creutzfeldt-jakob disease shows widespread neuronal loss with small, uniform ____ in the gray matter of the brain
Vacuoles (spongiform encephalopathy)
What form of vaccine is administered for measles virus
Live attenuated
Measles genome codes for structural proteins including ____ which mediates cell surface adhesion and ____ which is important for virral assembly
Hemagglutinin
Matrix protein
______ is a rare complication of measles that occurs in children or young adults several years after the infection
Subacute sclerosing panencephalitis
Subacute sclerosing panencephailtis is caused by a form of measles virus with a mutated or absent _____ protein, allowing the virus to replicate intracellularly, evading the immune system
Matrix
Accumulation of measles viral ______ within neurons and oligodendrocytes results in the formation of intranuclear inclusions and eventually leads to inflammation, demyelination, and gliosis in manny cerebral areas (subacute sclerosing panencephalitis)
Nucleocapsids
________ of measles virus antibodies are found in the CSF of patients with subacute sclerosing panecephalitis secondary to measles infection
Oligoclonal bands
Cognitive decline and chorea along with a family history of similar symptoms are suggestive of what diagnosis
Huntingon disease
Huntington disease is due to ______ in the huntington gene leading to a gain of function mutation
Excessive number of CAG trinucleotide repeats
In Huntigton disease, the buildup of abnormal/toxic mutant huntingtin protein leads to loss of ____ in what region of the brain
Inhibitory GABA neurons
Caudate nucleus
Imaging in a patient with Huntington disease will reveal atrophy of the ___ leading to enlargement of the _____
Caudate nuclei
Lateral ventricles
The caudate nucleus and the _____ make up the striatum which is critical for movement control and coordination as well as behavior regulation
Putamen
Common manifestations of tabes dorsalis inlude sensory ataxia, absent deep tendon reflexes, and _____
Lancinating pains
Spirochetal damage to the midbrain _____ commonly results in Argyll Robertson pupil
Tectum
Positive VDRL is diagnostic of what infection
Syphilis
Normal aging leads to the following sleep changes: _______ total sleep time, slow wave sleep with _____ nighttime sleep latency
Decreased
Increased
What is the cause of isolated anosmia (leading to lack of taste) due to a head trauma
Acceleration-deacceleration forces lead to avulsion of olfactory nerve rootlets
A spinal cord disection at C7 would effect maximum insipiration or expiration more?
Expiration
Above the splenic flexure, peristalsis is controlled parasympathetic stimulation from what nerve
Vegas
Below the splenic flexure, peristalsis is controlled by parasympathetic innervation from what nerve
S2-S4 nerve roots
The external anal sphincter is controled by voluntary control (skeletal muscle) whic is innerrvated by what nerve
Pudendal nerve (S2-S4)
Decerebrate posture is due to a lesion _____ the red nucleus and results in contraction of the _______ muscles
Below
Extensor
Decorticate posture is due to a lesion ____ the red nucleus and results in contraction of the ___ muscles
Above
Flexor
Intracranial hemorrhage can cause significant mass effect and increase cranial pressure which can manifest with seizures and_________ triad (hypertension, bradycardia, bradypnea)
Cushing
Uncal herniation initially disrupts the ipsilateral occulomotor nerve (CN III) leading to _____
Fixed dilated pupil
The _____ tract regulates upper extremity flexor tone and originates from the red nucleii in the rstral midbrain
Rubrospinal tract
The rubrospinal tract is ______ by descenfing cortical output from the cerebral cortex
Inhibitted
The opthalmic nerve (CN V1) exits the skull through what foramen
Superior Orbital fissure then supraorbital foramen
The maxillary nerve (CN V2) exits the skull through what foramen
Foramen rotundum then infraorbital canal then infraorbital foramen
The mandibular nerve (CN V3) exits the skull through what foramen
Foramen oval
The alveolar nerve branch enters mandibular foramen then exits through mental foramen
what protein has apple green birefringence when stained ith congo red
Amyloid
Amyloidosis and Alzheimer disease both show apple green befringence with congo red staind but how do they differ
Alzheimer disease amyloid deposits are only seen in brain tissue
Spastic cerebral palsy may be caused by periventricular white matter necrosis which leads to loss of descending _____control from the upper motor neurons
Inhibitory
Lack of CNS inhibition leads to hyperactve ______
Stretch reflex
In the stretch reflex, muscle lengthening is sensed by _____
Muscle spindle
Afferent signal of stretch is conveyed to the spinal cord via the ____ nerve fibers
Dorsal
Efferent signals of the stretch reflex are conveyed via the ___ root of the spinal cord
Ventral
In the stretch reflex ____ muscle fibers are stimulated, causing muscle contraction
Extrafusal
The ___ reflex is responsible for deep tendon reflexes and the maintenacne of muscle tone
Stretch
A selective dorsal rhizotomy procedure destroys the ____ arm of the reflex arch, which decreses muscle tone without sacrificing motor innervation of the muscles
Afferent (sensory)
Symmetric, bilateral wedge shaped strips of necrosis over the cerebral convexity are characteristic of _____ cerebral ischemia
Global
Profound systemic hypotension diminishes blood suply to the entire brain, resulting in neuron cell death in areas that are vlnerable to hypoxia such as _____ and _____
Watershed areas and regions with high metabolic demand
______ is a group of hereditary peripheral neuropathies characterized by mutations in genes coding for peripheral nerce axonal or myelin proteins presenting with adolescent lower extremett weakness, muscle atrophy and peripheral neuropathy
Charcot marie tooth disease
The most common type of charcot marie tooth (CMT1) occurs due to autosmal dominant mutation in the ______ gene
PMP22
Sudden upward jerking of the arm at the shoulder can cause injury to the _____ trunk of the brachial plexus
Lower
the lower trunk of the brachial plexus carried nerve fibers from the C8 and T1 spinal levels that ultimately contribute to the ____ and ___ nerves
Median and ulnar
Injury to the intrinsic hand muscles leads to ______ palsy: weakness of the lumbricals –> impaired flexion of metacarpophalangeal joints and impaired extension of the interphalangeal joints: claw like deformity
Klumpke’s palsy
What nerve exits the brain stem at the lateral aspect of the mid-pons at the level of the middle cerebellar peduncles
Trigeminal
What is a key neuroanatomic andmark for locating the trigeminal nerve
Middle cerebellar peduncle
Infarcts to the anterior pons can affect the ____ tracts
Corticospinal (contralateral hemiparesis)
Corticobulbar (contralateral lower facial palsy, dysarthria)
In an isolated CN III palsy, how is the eye oriented
Down and out
What eye muscles are not innervated by CN III
Superior oblique (CN IV) Lateral rectus (CN VI)
Aneurysms causing CN III palsy most often involve the ______ artery
Posterior communicating artery
Hydrocepalus (enlargement of the ventricles) caused by central neuronal volume loss (rather than excessive CSF) is called_______
Hydrocephalus ex-vacuo
In hydrocephalus ex-vacuo, the CSF pressure is____
Normal
In communicating hydrocephalus, CSF flows freely between the ventricles and subarachnoid space but there is decreased CSF absorptionin at the ________
Arachnoid granulations
Normal pressure hydrocephalus is _______ while high pressure hydrocephalus is _______
Chronic
Acute
A patient with unilateral optic neuritis is most likely to demonstrate an _____ pupillary defect due to demyelination of the right optic nerve
Afferent
The optic nerve carries the afferent limb of the puppillary light reflex, transmitting informaiton about light entering the eye to the ______ area in the midbrain
Pretectal
The pretectal area activates the ______ nuclei bilaterally which send paraympathetic efferent motor fibers down the oculomotor nerve to innervate the pupillary sphincter muscle to each iris
Edinger-westphal
Patients with an afferent pupillary defect will have what effect on pupillary constriction when light s shined in the non affected eye
Normal pupillary reflex bilaterally
What is first line therapy for essential tremor
Beta blocker (propranolol)
In patients with __________ exposure to certain anesthetic agents such as succinycholine and inhalation gasses causes unregulated passage of calcium form the sarcoplasmic reticulum into the intraacellular space
Malignant hyperthermia
In malignant hyperthermia, excessive myoplasmic _____ accumulation results in sustained muscle contraction, which is often first noted in the masseter
Calcium
What causes a high temperature in patients with malignant hperthermia
Sustained muscle contractions –> ATP consumption –> excessive heat production
Treatment for malignant hyperthermia
Dantrolene (blocks further release of calcium into the intracellular space)
Blotchy red muscle fibers on Gomori trichrome stain are characteristic of ________
Mitochondrial myopathies
In mitochondrial myopathies, abnormal mitochondria accumulate under the sarcolemma of muscle fibers causing the muscle fibers ro have irregular shape and size on cross section, for this erason mitochondrial myopathies are also known as ______
Red ragged fiber disease
Phenytoin is a ______ of p450
Inducer
_______ malformations are a group of congential disorders caused by unerdevelopment of the posterior fossa
Chiari
Chiari type I is more benign and presents when?
Adolescence/adulthood
Chiari tpe II typically presents when
Neonatal period
How does chiari type I differ from the herniation seen in chiari type II
Chiari type I only has the ccerbellar tonsils below the foramen magnum but chiari type II has downward displacement of the cerebellum and the medulla through the foramen magnum
What complications are common in type two chiari
Non communicating hydrocephalus
Lumbar myelomeningocele
Where does VZV lie dormant
(Migrates via sensory nerves to) cranial nere and dorsal spinal ganglia
What organism is a round/oval yeast surrounded by thick polysaccharide capsule
Cryptococcus neofromans
Cryptococcal diagnosis can be confirmed by cryptococcal antigens in CSF or visualiztion of encapsulated budding yeasts in CSF using what 2 specilized stains
India ink
Methenamine silver
Spinal muscular atrophy is caused by mutation in the ______ gene which encodes a protein involved in the assembly of small nuclear ribonucleoproteins (snRNPs)
Survival motor neuron gene (SMN1)
Defective snRNP assembly, as seen in spinal muscular atrophy, results in impaired _____ function and degeneration of anterior horn cells in the spinal cord
Splicesome
Non-coding RNA differs from other RNA how?
They carry out functions without first being translated into proteins
A collection of snRNPs and other proteins on a pre-RNA is referred to as a ____
A splicesome
Splicesomes remove ____ from preRNA
Introns
Infants with spinal muscular atrophy often have flaccid paralysis due to degeneration of _____ cells in the spinal cord
Anterior horn
Long standing rheumatoid arthritis frequntly involvesthe cervical spine and causes joint destruction with vertebral malalignment which is called _______
Subluxation
What is concerning about endotracheal intubation with a patient who has long standing rhuematoid arthritis
Extension of the neck can worsen subluxation leading to acute compression of the spinal cord and or vertebral arteries
Mechanism of methotrexate
Folic acid analog –> inhbits dihydrofolate reductase –> rapidly dividing cells dodnt have DNA synthesis or repair
An MRI with ventriculomegaly without sulcal enlargemnt is characteristic of ____
Normal pressure hydrocephalus
Normal pressure hydrocephalus causes lateral entrical expansion –> stretching of _______
Descending cortical fibers (corona adiata)
What is the classic triad of normal pressure hydrocephalus symptoms due to stretching of te cortical fibers
Dementia, gait disturbance, and urinary incontinence
The micturition reflex is an autononomic spinal reflex that receives inhibition from ____
Cerebral cortex
Lack of cortical inhibition on the micturition reflex results in _____ hyperactivity
Detrusor (–> urge incontinence)
The stapedius nerve, which innerates the stapes, is a brnch of what nerve
Cranial nerve VII (facial)
Paralysis of the stapedius muscle results in ______ (increased sensitivity to sound)
Hyperacusis
The pudendal nerve oriinates from ____ nerve roots
S2-S4
Pudendal nerve exits the pelvis throught hte ____ foramen
Sciatic
Motor branches of the pudendal nerve innervated the _____ and _____
Pelvic floor muscles
External urethral and anal sphincters
What is the draw back of using atropine rather than pralidoxime in organophosphate poisoning
Atropine is competitive inhibitorat muscarinic receptors only, nicotinic symptoms will persist (muscle paralysis)
How do demyelinating neuropathies differ from axonal neuropathies on a nerve conduction study
Demyelinating: delayed nerve conduction velocity
Axonal: reduced signal amplitude
Ulnar neuropathy is characterized by numbness of the _____ digits, pain, and weakness
4th and 5th
___ is the most common brain tumor in children and appears as a heterogenous, well-circumscribed cerebellar mass
pilocytic astrocytoma
what are the two microscopic findings in a pilocytic astrocytoma
glial fibrillary acidic protein (GFAP) positive hairlike processes rosenthal fibers (eosinophilic intracytoplasmic inclusions)
how can a pilocytic astrocytoma be differentiated from a medulloblastoma
presence of both cystic and solid components on imaging
the neural tube is a structure that is connected to the amniotic cavity by opening at the ends know as ____ and ______
anterior and posterior neuropores
failure of neuropore closure by 4 weeks gestation leads to _____
neural tube defects
anterior nerual tube defects include ____ (absence of forebrain) and _______ (protrusion of neural tissue through the cranial defect)
anecephaly
encephalocele
what is the most mild form of a posterior neural tube defect
spina bifida occulta
a meningocele and meningomyelocele present as cystic masses at the lower spine that are sometimes covered by a tuft of hair, meningomyelocele has what difference from meningocele though
meningocele = meninges protruding meningomyelocele= meninges and spinal cord or cauda equina protruding
prenantal use of what medication, used for bipolar or epilepsy, is associated with a 10 - 20 fold increased risk for NTD
valproate
lamotrigine MOA
blocks voltage gated sodium channels
most concerning side effect associated with lamotrigine use
stevens johnson syndrome, or toxic epidermal necrolysis
what is the difference between stevens-johnson syndrome and toxic epidermal necrolysis
SJS involves <10% of the body and TEN has >30% involvement
presentation of steven johnson syndrome
flu like symptoms followed by widespread mucocutaneous epidermal necrosis
the presence of nonreactive pupils to light stimulation following cardiac arrest carries a por prognosis and indicates anoxic damage to the brainstem at the level of ______
the upper midbrain
cryptococcus neoformans is a llow virulence yeast with a thick polysaccharide capsule/ . It resides in soil contaminated by bird droppings and human exposure primarily occurs due to inhalation into the ____
lungs
first line treatment for trigemnial neuralgia
carbamazepine
carbamazepine MOA
reduces ability of sodium channels to recover from inactivation
fatigable muscle weakness with restoration of strength after rest, affecting voluntary muscles, particularyl those innervated by motor nuclei of the brain stem characterizes what disease
myasthenia gravis
myasthenia gravis is most commonly caused by autoantibodies against _____
postsynaptic acetylcholine receptors
in myasthenia gravis, th reduced number of postsynaptic cation channels that can open in response to acetylcholine causes what change to the action potential
reduces the amplitude of the motor end plate potential and prevents muscle fiber depolarization
how do tricyclic antidepressents and SNRIs treat neuropathic pain
decrease of serotoninc and norepiniephrine reuptake –> inhibition of pain signals
how do anticonvullsants treat neuopathic pain
decrease depolarization of neurons in the CNS
how does Capsaicin (topical) treat neuropathic pain
loss of membrane potential in nociceptive fibers
how does lidocaine treat neuropathic pain
decreased depolarization of neurons in peripheral nerves
MOA of capsaicin
activation of TRPV1 (transmembrane cation channel) –> build up of intracellular calcium –> long lasting dysfunction of nociceptive nerve fibers (defunctionalization)
it also causes release and depletion of substance P
monocular scotoma is caused by lesion where
partial lesion of retina, optic disc, optic nerve
right anopia is due to a lesion where
right optic nerve
bitemporal hemianopia is due to lesion where
optic chiasm
