Neuro Flashcards
What makes up the brainstem (top to bottom)?
midbrain, pons, medulla
Myelination is done by what type of cells?
Schwann cells in PNS
Oligodendrocytes in CNS
_______ is communication between brain and thoracic and abdominal viscera.
Vagus nerve (CN X)
Describe pathway of corticospinal tract.
R motor cortex -> cross at medullary pyramids -> anterior horn -> L side muscle
Symptoms of Lower motor neuron lesion
weakness/paralysis flaccidity diminished reflexes fasciculations (twitches) muscle atrophy
Symptoms of Upper motor neuron lesion
weakness/paralysis
spasticity
increased reflexes
Babinski’s sign
What is an abnormal Babinski?
stroke bottom of adult foot and big toe goes up
*normal during infancy
clonus
repetitive, rhythmic contraction of muscle when it is stretched (commonly ankle)
What are two sensory pathways and what signals do they transmit?
Posterior columns: proprioception, discrimination, vibration
Spinothalamic: pain and temp
Where does each sensory pathway decussate?
Posterior columns: medulla
Spinothalamic: immediately in spinal cord
Trace pathway of proprioception, vibration, and discrimination sensation from left side to body to brain.
L body -> posterior spinal cord -> posterior column -> cross at medulla -> medial lemniscus -> R thalamus
If pain/temp sensation loss on left side of body, then where is possible lesion?
right spinal cord or right thalamus
What pathology destroys an entire half of the spinal cord?
Brown-Sequard Syndrome
C6 dermatome
thumb
lateral arm
C7 dermatome
digits 2 and 3
C8 dermatome
digits 4 and 5
medial arm
Dermatome that runs back of calf to lateral foot
S1
Dermatome that runs down posterior arm and hand
C7
Dermatome that runs down shin to top of foot
L5
Which cranial nerves exit from each division of brainstem?
2-4 midbrain
5-8 pons
9-12 medulla
- Olfactory and vision pathway don’t go to brainstem
Effects of optic nerve lesion
blindness in one eye, other eye unaffected
Effects of left optic tract lesion
blindness in right hemisphere of each eye
Which cranial nerves innervate the extraocular muscles?
CN III, IV, VI
IV: superior oblique
VI: lateral rectus
III: all the rest (IO, SR, IR, MR)
Effects of complete CN III lesion
ipsilateral eye is “down and out”
dilated pupil
ptosis (drooping eyelid)
Cranial nerves involved in pupillary light reflex
oculomotor (CN III) - allows eyes to constrict with light
optic (CN II) - allows consensual response if CN III intact
Signs of Horner’s Syndrome
ptosis
miosis (constricted pupil)
anhidrosis (loss of sweating)
- loss of sympathetic pathway to face and eyes
_____ is only cranial nerve to project contralaterally.
CN VI
What are functions of cranial nerves that innervate the face (sensory and motor)?
CN V sensory: 3 branches - ophthalmic, maxillary, mandibular
CN VII motor: chewing muscles
- both involved in corneal reflex
Bell’s Palsy vs Cerebral stroke
Bell’s Palsy: CN VII lesion, paralysis of entire ipsilateral face
Stroke: UMN lesion, facial droop on contralateral side but forehead unaffected
Lesion affecting CN VIII that causes unilateral hearing deficit?
acoustic neuroma (or vestibular schwannoma)
What is the vestibulo-ocular reflex?
vision steady while head rotates side to side
“doll’s eye” test in coma patient to determine if brainstem intact
What nerve may be damaged if absent gag reflex?
CN IX (glossopharyngeal)
If when patient says “ahhh” uvula deviates to the left, then where is the lesion?
Right side of CN X (vagal)
How is CN XI tested?
test strength of shoulder shrug and head rotation (trapezius and SCM muscles)
How is CN XII tested?
“stick out your tongue”
tongue will deviate toward lesion side
Effects of cerebellar lesion
“Errors of rate, range, force, and direction”
IPSILATERAL ataxia, intention tremor, nystagmus, vertigo
Effects of basal ganglia lesion
CONTRALATERAL chorea, resting tremor, akinesia, rigidity
Pathophysiology of Parkinson’s
shortage of dopamine due to degeneration of substantia nigra (midbrain)
motor regions of cerebral cortex inhibited
Hallmark signs of Parkinson’s
bradykinesia
resting tremor
lead-pipe or cogwheel rigidity
shuffling, hunched-over gait
Main treatment of Parkinson’s
L-Dopa
Side effects of anti-Parkinson meds
Hallucinations, Schizophrenia (too much dopamine)
dementia vs delirium
delirium is an acute change in mental status
dementia is progressive decline in cognitive function
CT/MRI results of Parkinson’s
NORMAL; used to r/o other causes
Lewy Bodies may be seen on an autopsy of the brain in…
Parkinson’s disease
Dementia with Lewy bodies
Alzheimer’s disease
Risk factors of cerebral aneurysm
Smoking ETOH HTN Obesity PCOS Marfan syndrome
A ruptured cerebral aneurysm (
Berry aneurysm) is common cause of ___________.
subarachnoid hemorrhage
How to manage a cerebral aneurysm?
Known aneurysms monitored:
BP control
Cholesterol control
F/U imaging
Location of cerebral vs epidural vs subdural vs subarachnoid hemorrhages
cerebral - within parenchyma or ventricle
epidural - btwn dura and skull
subdural - btwn dura and arachnoid mater
subarachnoid - btwn arachnoid and pia mater
Which brain bleed most often caused by trauma?
epidural
Severe headache “The Worst Headache of my life!” lasting hours to day =
subarachnoid hemorrhage
Gold standard for inter-hemorrhage bleeding dx
Non-contrast head CT
How are subdural and epidural hemorrhages differentiated?
crescent shape bleed on CT = subdural
biconcave/rounded bleed = epidural
Inter-hemorrhage bleeding treatment
Reduce ICP (steroids, Mannitol) Control BP Pain killers Anti-seizure meds Surgery: Craniotomy, surgical clipping, endovascular coiling
Risk factors of stroke/TIA
Increasing age African American, American Indian, Hispanics HTN Smoking Diabetes Oral contraception ETOH Afib Heart valve issues Endocarditis
2 types of stroke? Which more common?
Ischemic (85%)
Hemorrhagic
define dysarthria
motor speech disorder due to neurological injury
define apraxia
altered voluntary movements
Signs of increased intracranial pressure?
Vomit w/o nausea Headache Papilledema Seizures Behavior changes Cushing's response (HTN, bradycardia)
“FAST” exam to identify location and severity of stroke
Face: facial droop
Arms: unilateral weakness
Speech: slurred
Time: seek immediate medical attention
What PE exam is used to assess stroke risk?
Look for bruit with U/S Doppler of carotids
How to treat ischemic stroke?
Aspirin immediately
tPA within 4.5 hours
Angioplasty and stents
How to treat hemorrhagic stroke?
Surgery: clipping, coiling, hemicraniectomy
Meds: Mannitol, corticosteroids
Contraindications to tPA use in strokes
Suspected intracranial bleed Recent surgery Recent head trauma Active bleeding Intracranial neoplasm HTN > 185/110
How is TIA different than full stroke?
- No brain tissue death
- Symptoms typically resolve in an hour
Define amaurosis fugax
temporary loss of vision (possible TIA or carotid stenosis)
DDX of altered mental status
High ICP Dehydration (or insulin overdose) Hypoglycemia Uremia Hyper/hypothermia Meningitis Stroke/TIA Concussion/brain injury Meds/Drugs
Work up of altered mental status
- Neuro exam: AAOx3, LOC, GCS
- Pulse ox
- Serum glucose
- CBC
- CMP (liver, kidney fxtn)
- Tox screen
- Head CT or MRI
Glasgow Coma Scale
Eye movement 1-4
Verbal response 1-5
Motor response 1-6
“less than 8 intubate”
13-15 = concussion
3 = dead
How to treat altered mental status from hypoglycemia?
IV Dextrose
Mother brings in 12 month old son because he is not showing signs of delayed development - poor muscle tone, has not started walking or talking, and has not been feeding well. He was born premature and at low birth weight. What is likely dx?
Cerebral Palsy
Cerebral Palsy treatment
SYMPTOMATIC
Benzos (Diazepam) muscle spasms IM Botulinum toxin injection – muscles with spasticity Antiepileptic meds – minimize seizures PT/OT Special ed and learning strategies Behavior therapy and counseling
What is the #1 risk factor for a child having CP?
prematurity
Causes of dementia
Alzheimer's (75%) Brain injury Lewy Body dementia Hypothyroidism Vit B12 deficiency Lyme Disease Neurosyphilis
Labs to run to determine cause of dementia
Vit B12 Folic acid TSH CRP CBC Electrolytes Renal function Liver function
Possible medical treatment of dementia
Acetylcholinesterase inhibitor (Donepezil)
Antipsychotics (Risperdal)
SSRIs
What meds can cause delirium?
anticholinergics
opioids
A patient presents with very poor attention. Is this likely dementia or delirium?
delirium
Pathology with rapid bilateral ascending paralysis =
Guillain-Barre Syndrome
Signs of autonomic fiber deficit
Orthostatic hypotension
Changes in heart’s rate and rhythm
Fluctuating BP
Dry eyes and mouth
Lumbar puncture results of Guillain-Barre syndrome
elevated proteins
no increase in WBC
Pathophysiology of Gullain-Barre syndrome
rapid demyelination of peripheral nerves
- MS is demyelination of CNS
Gullain-Barre treatment
Immediate IVIG or plasmapheresis
ventilator support
Pathophysiology of Multiple Sclerosis
Loss of myelin in CNS (PNS is normal)
Possibly autoimmune, infection, genetics???
Hallmark signs of multiple sclerosis
Uthoff’s phenomena = worsening of sx in the heat
L’Hermitte sign = electrical sensations down spine with patient flexes neck
Optic neuritis
Bladder dysfunction
Clinical course of MS
relapsing-remitting; series of normal periods with intermittent flares
How to treat acute MS attacks?
HD corticosteroids (prednisone, IV Solu-Medrol) Plasma exchange (IVIG)
How to slow progression of MS?
Beta interferons Monoclonal antibodies (-umab) Vitamin D
Pathophysiology of Myasthenia Gravis
Autoimmune disorder where ACh receptors are blocked by antibodies
Patient comes in c/o increased weakness causing ptosis, diplopia, and SOB. The sx’s seem to improve with rest. There are NO sensory deficits. What must be considered?
Myasthenia Gravis
How to differentiate Myasthenia Gravis and Guillain-Barre Syndrome?
Check reflexes and sensation
MG = normal GBS = areflexia, loss of proprioception
Dx testing for Myasthenia Gravis
Blood: ACh receptor antibodies
EMG: muscles fatigue with repetitive stimulation
CXR/CT/MRI: tumor or thymoma?
How is Lambert-Eaton Syndrome different than Myasthenia Gravis?
Lambert-Eaton autoimmunity against influx of calcium (ACh receptors in MG)
Repetitive stimulation on EMG will improve symptoms (EMG causes fatigue in MG)
Medical therapy for Myasthenia Gravis
Long acting anti-cholinesterase meds
Immunosuppressive drugs
Removal of thymus if thymoma
Clinical definition of epilepsy
recurrent seizures; 2 or more unprovoked seizures
2 broad categories of seizures and how they are different?
Generalized - involve entire brain
Partial - involve small region of brain
Which seizures are Generalized?
Grand mal Absence Clonic Myoclonic Tonic Atonic
Which seizures are Partial seizures?
Simple
Complex
Partial with secondary generalization
simple vs complex partial seizure
simple - conscious
complex - impaired awareness; can’t recall event, often with aura
Characteristics of grand mal seizure
unconscious
ictal cry at onset
convulsions of tonic and atonic
postictal phase after
Seizure of only a brief loss of consciousness without loss of postural tone =
absence (petit mal)
Most common epidemiology of absence seizures
children with epilepsy
What is an atonic seizure?
sudden loss of postural tone with brief LOC
eg. head drop
Peak incidence of febrile seizures
18-24 months old
Febrile seizures management
Reassure parent
Tylenol
Jacksonian March
seizure that spreads from distal limb to larger region
How to determine which type of seizure a patient has?
EEG (electroencephalogram)
- generalized: spikes and slow waves
- simple partial: focal rhythmic discharges
- complex partial: intricate spikes with slow waves
Why do lumbar puncture for seizure?
to diagnose possible CNS infection
A life-threatening neurologic disorder defined as 5 minutes or more of a continuous seizure activity or several clinical seizures without return to baseline in between
Status epilepticus
Medications for status epilepticus
Benzos 1st line - Lorazepam
Anticonvulsants - Phenytoin
Cardiac and non-cardiac causes of syncope
Cardiac: Arrhythmias, heart valves d/o, HTN, aortic dissection, cardiomyopathy
Non-cardiac: Postural hypotension, dehydration, high altitude, TIA, migraine, situational syncope (blood drawing, micturition, defecation, swallowing, coughing)
Pathophysiology of syncope
global cerebral hypoperfusion
Symptoms of syncope
Pale, cold skin Partial or complete LOC Lightheaded Nausea Blurred vision
Tilt table test
to elicit orthostatic syncope secondary to autonomic dysfunction
Syncope treatment
Position patient on ground, with legs slightly elevated or leaning forward with head between knees x 10-15 mi IV access Oxygen administration Advanced airway techniques Glucose administration Pharmacologic circulatory support Defibrillation or temporary pacing
Epidemiology of Tourette disorder
2-15 yo
Symptoms of Tourette disorder
Motor tics (blinking, tongue, jerking, etc.) Vocal tics (yelling, swearing, throat clearing)
How to rule out other conditions that may be causing tics in Tourette?
EEG – if tics and seizure activity exists MRI – brain abnormalities TSH levels - hypothyroidism Urine drug screen Serum Copper – Wilson’s disease
Treatment of Tourette disorder?
Deep brain stimulation
Behavioral therapy
Dopamine antagonists (fluphenazine, pimozide)
* Haloperidol is historically the drug of choice
Definitive way to differentiate syncope from seizure?
EEG to pick up abnormal firing patterns in brain
Main excitatory and inhibitory neurotransmitters in the brain
glutamate excitatory
GABA inhibitory
Why is CT done before a lumbar puncture?
CT to look for signs of increased ICP (e.g. ventricular dilation)
LP with increased ICP can cause negative pressure in spinal canal and possible herniation
How is equilibrium of CSF level in brain maintained?
choroid plexus produces it, while arachnoid granulations reabsorb it into the venous system
_______ is caused by increased CSF in the brain.
hydrocephalus
What is Cushing’s response?
HTN, bradycardia, and irregular respirations in response to increased ICP and/or hydrocephalus
What is pseudotumor cerebri? How is it treated?
signs of elevated ICP, but brain appears normal on CT
Tx: Acetazolamide (decreases CSF production), LP shunt to decrease ICP
Meningeal signs
Nuchal rigidity
Brudzinski’s sign: involuntary flexing of hip and knees when neck flexed
Kernig’s sign: flexing hip 90 degrees then extending knee causes pain
Layers of head from skull to brain
bone, epidural space, dura mater, subdural space, arachnoid membrane, subarachnoid space, pia mater, brain parenchyma
Most common offending organisms of meningitis in neonates, children, and adults?
Neonates: GB strep, E. coli, Listeria
Children/Adults: H flu, strep pneumo, N. meningitidis
Viruses that cause meningitis
Herpes simplex
CMV
HIV
Treatment of epidural bleed
Burr hole drainage
Common organisms causing epidural and subdural abscesses
staph aureus
streptococcus
Typical cause of encephalitis
VIRAL - HSV, enterovirus, mumps, rabies, mosquito borne (West Nile, St. Louis Encephalitis)
Results of CSF exam for a bacterial infection
increased WBCs (neutrophils)
increased protein
decreased glucose
Blood on CSF exam indicates what?
bright red that goes away - trauma of spinal tap
yellowish blood (xanthochromia) - subarachnoid hemorrhage
Predominance of PMNs on lumbar puncture =
bacterial meningitis
Broca’s aphasia
deficit in language production (both spoken and written)
preserved comprehension
Wernicke’s aphasia
deficit in understanding language
“word salad”
Effects of middle cerebral artery stroke
face, arm > leg deficits on contralateral side
Broca and Wernicke aphasias if left MCA
Effects of anterior cerebral artery stroke
leg > arm deficits on contralateral side
lack of motivation due to frontal lobe ischemia
Effects of posterior cerebral artery stroke
vision changes on contralateral side
A pure sensory deficit can occur from infarct of _______.
thalamus
Ipsilateral CN III palsy
Contralateral hemiplegia
Location of stroke?
Midbrain (PCA ischemia)
Right-sided facial numbness and weakness
Loss of right eye abduction
Left-sided hemiplegia
Location of stroke?
Right pontine (basilar ischemia)
Deviation of uvula to right
Right-sided muscle weakness and loss of sensation
Signs of Horner’s syndrome
Location of stroke?
Left medullary stroke
Right-sided ataxia
Location of lesion?
Right cerebellum
Compression of what nerves can lead to incontinence and impotence?
S2-S4
Which nerves does the patellar reflex test?
L3/L4 (quad muscle)
Which nerves does the Achilles reflex test?
S1/S2 (gastrocnemius muscle)
Which nerves innervate the bicep?
C5/C6
Which nerves innervate the tricep?
C7/C8
DDX of weakness alone with no sensory changes
- Motor pathway deficit (pure motor stroke or ALS)
- NMJ deficit (Myasthenia Gravis)
- Muscle pathology
Signs of ALS
insidious, progressive motor weakness
mix of UMN and LMN findings
NO affect on sensory pathways, eyes, bladder/bowel like MS
shingles of CN VII that causes severe facial palsy and vesicular eruption in external auditory canal or pharynx
Ramsay Hunt Syndrome
Distal sensory loss and muscle weakness in “unathletic” child may be what inherited disease?
Charcot Marie-Tooth
Metabolic deficiency that can cause peripheral neuropathy
B12 deficiency
Medications that cause tardive dyskinesia?
dopaminergic antagonists - antipsychotics
Stroke with ipsilateral gaze preference =
middle cerebral artery
Spontaneous seizure and brain bleed in previously asymptomatic young patient. Likely dx?
AV malformation
Headache with “band-like” tightness
Tension HA
Preventative treatment of tension headaches
Amitriptyline
How are migraines differentiated from other headaches?
unilateral
N/V
photophobia
aura
Abortive treatment of tension HA
NSAID, Tylenol, Excedrin
Toradol if in ER
Abortive treatment of migraine HA
Mild: NSAID, Tylenol
Moderate: Excedrine, Triptans
Severe: Toradol, Metoclopramide, Ergotomines, Opioids
- must treat before HA starts
Possible prophylaxis for migraines
BB, CCB, Amitriptyline, SSRI, antiseizure, diet changes
Treatment for cluster headaches
100% oxygen x 15 min
What symptoms make you worry that tension HA may be a tumor?
new or different HA in adult
N/V
worse with exertion
signs of increased ICP
Descending paralysis + intact sensation and mentation =
Botulism
Pathophysiology of Botulism
Clostridium toxins block release of ACh at NMJ
When to do CT on head injury?
GCS less than 15 Basilar fx signs 2+ vomiting Age over 65 Amnesia over 30 min Dangerous injury Seizures Neuro deficits
Signs of basilar skull fracture?
Battle sign
Raccoon eyes
Hemotympanum
Otorrhea or rhinorrhea
Signs of Alzheimer’s Dementia
MEMORY LOSS
impaired formation of new memories
anosognosia (lack of insight)
executive dysfunction
Mainstay treatment of Alzheimer’s and its MOA
Donezepil - acetyl cholinesterase inhibitor to increase cholinergic function
GABA analog used to treat neuropathic pain, seizures, and anxiety
Pregabalin (Lyrica)
