Neuro Top 50+ Flashcards
Know this HIGH-YIELD stuff for to be extra smart.
The three components of the blood-brain barrier?
Which organs lack a BBB?
a. endothelial cells
b. basement membrane
c. astrocytic end feet
Circumventricular organs [i.e. area postrema, median eminence of the hypothalamus, neurohypophysis, pineal gland] lack a blood-brain barrier.
Myopathies are associated with what loss patterns?
proximal symmetric weakness, but no sensory loss.
Peripheral neuropathies result in what loss patterns?
distal asymmetric weakness with atrophy, fasciculations, sensory loss and pain.
Most commonly caused by diabetes and alcoholism.
Polyneuropathies result in what pattern?
sensory loss in a stocking/glove pattern.
Guillain-Barre syndrome
The most common motor neuropathy is Guillain-Barre syndrome (aka acute inflammatory demyelinating polyneuropathy [AIDP].
Characterized by ascending symmetric muscle weakness, areflexia and paresthesias in hands and feet 1-3 weeks following a viral respiratory or GI infection. CSF has elevated protein without elevated WBC.
amyotrophic lateral sclerosis loss patterns?
The most common (~2 per 100,000) motor neuron disease is amyotrophic lateral sclerosis which is characterized by both upper AND lower motor neurons signs.
multiple sclerosis
The most common demyelinating disease is multiple sclerosis which is characterized by neurological signs (weakness, spasticity > sensory loss > incontinence > vision loss) that resolve and return progressively worse (relapsing/remitting). The diagnosis of multiple sclerosis requires two separate symptoms at two different times, or lesions separated in time and space.
MRI shows white matter lesions
CSF oligoclonal bands on electrophoresis
Radiculopathies result in what loss patterns?
Radiculopathies result in pain/sensory loss in a dermatomal pattern and weakness in myotomal patterns (i.e. multiple affected nerves and muscle compartments).
Disease at the neuromuscular junction is distinguished by what?
fatigability; patients with myasthenia gravis show fatigue with repetitive stimulation of their muscles.
Upper motor neuron lesions manifestations?
Upper motor neurons are found mainly in the cerebral cortex (some in brainstem – red nucleus, reticular formation, vestibular nuclei) and DO NOT directly innervate skeletal muscle.
Upper motor neuron lesions result in spastic paralysis, hyper-reflexia (muscle stretch reflexes are 3-4/4), Babinski sign, Hoffman sign and clonus. Note that with an acute UMN lesion, there may be hyporeactive reflexes and flaccid paralysis!
Lower facial paralysis
(“can wrinkle their forehead but cannot smile”) is a sign of damage to the corticobulbar tract in the pons or higher (e.g. internal capsule or crus cerebri). This may be accompanied by a tongue that deviates away from the lesion on protrusion (but does demonstrate any signs/symptoms of lower motor neuron injury
Lower motor neuron lesions
Lower motor neurons innervate skeletal muscle and are located in the anterior horn of the spinal cord and motor nuclei of cranial nerves.
Lower motor neuron lesions result in flaccid paralysis, hyporeflexia (muscle stretch reflexes are 0-1/4), fasciculations and atrophy.
Cerebral Palsy
Cerebral Palsy is a disorder in the development of movement and posture which results in activity limitations attributed to non-progressive lesions in the developing fetal or infant brain CNS. Motor signs (present in the first year of life) can be attributed to injury to corticospinal tracts and/or basal nuclei (i.e. they can show signs of spasticity, flaccid paralysis or dystonia/choreoform movements). Motor difficulties are often accompanied by orthopedic complications (contractures, hip dislocation, scoliosis), seizures and/or disturbances of: sensation, cognition, communication, perception.
spinal shock
Sudden trauma to the spinal cord results in spinal shock (temporary flaccid paralysis, hyporeflexia, sensory loss and loss of bladder tone) – hyper-reflexia develops over a period of days to weeks.
anterior spinal artery syndrome
Occlusion of the artery of Adamkiewicz results in anterior spinal artery syndrome = bilateral weakness, loss of pain and temperature and hyper-reflexia below the lesion.
Cauda equina syndrome
weakness and sensory loss in the lower extremities, radicular pain, saddle anesthesia and urinary incontinence.
The most important spinal cord sensory levels are:
C6 C7 C8 T4 T6 T10 L4 L5 S1
C6 = thumb C7 = middle finger C8 = little finger T4 = nipple T6 = xiphoid T10 = umbilicus L4 = medial knee L5=big toe S1 = little toe
The most important muscle stretch reflexes are: C5 C6 C7 L4 S1
The most important muscle stretch reflexes are: C5 = biceps C6 = brachioradialis C7 = triceps L4 = quadriceps S1 = Achilles
Explain the muscle stretch reflex scale
0 = absent 1 = trace or only with reinforcement 2 = normal 3 = brisk 4 = clonus
Cutaneous Reflexes:
Babinski sign Bing sign Abdominal reflex Cremaster reflex Hoffman sign Anal wink
Babinski sign (aka plantar reflex) – scrap sole of the foot, flexion of toes is normal; upper motor neuron lesion = extension of big toe (“upgoing” big toe) and fanning of digits 2-5.
Bing sign – stab dorsum of foot with pin, normal = plantar flexion; upper motor neuron lesion = dorsiflexion
Abdominal reflex – scratch abdominal skin, absent in UM neuron lesion
Cremaster reflex – absent in UM neuron lesion
Hoffman sign – scrape tip of 3rd digit, thumb and 2nd digit flex in UM neuron lesion
Anal wink – scratch perineum to elicit contraction of external anal sphincter
Syringomyelia/Hyromelia
cavitation of the central spinal cord, impinges the anterior white commissure producing bilateral loss of pain and temperature in a dermatome distribution
Brown-Sequard syndrome
hemisection of the spinal cord producing ipsilateral UMN paralysis and loss of discriminative touch and contralateral loss of pain and temperature
Anterior cord syndrome
results from compression of anterior spinal artery, affects the neurons of the anterior horn, spinothalamic tract and lateral corticospinal tract
Tabes dorsalis (spine)
loss of posterior columns (discriminative touch, proprioception and vibration)
Subacute combined degeneration (spinal cord lesion)
B12 deficiency, peripheral neuropathy that can progress to cord (posterior columns and lateral corticospinal tracts)
Medial medullary syndrome
contralateral [spastic] hemiparesis (corticospinal tract)
ipsilateral deviation of tongue on protrusion (hypoglossal nucleus or nerve)
contralateral loss of discriminative touch, proprioception and vibration (medial lemniscus)
From blockage of anterior spinal artery!
Lateral medullary syndrome
ipsilateral loss of pain and temperature on face (spinal trigeminal tract)
contralateral loss of pain and temperature on body (spinothalamic tract)
nystagmus, dizziness, nausea (vestibular nuclei)
hoarseness, ipsilateral sagging palate, dysphagia (nucleus ambiguous)
loss of taste (solitary nucleus)
ataxia (restiform body, inferior cerebellar peduncle)
Horner syndrome (hypothalamospinal fibers);
From posterior inferior cerebellar artery!
Tonsillar Herniation
central apnea, hypertension, hyperventilation, loss of consciousness
Foville Syndrome (pons)
contralateral [spastic] hemiparesis (corticospinal tract)
diplopia, paralysis of abduction (CN VI; maybe also intranuclear ophthalmoplegia)
ataxia (middle cerebellar peduncle)
contralateral loss of discriminative touch, proprioception and vibration
paramedian branches of basilar
Gubler Syndrome (pons)
contralateral [spastic] hemiparesis (corticospinal tract)
ipsilateral facial paralysis (facial nerve or nucleus)
ipsilateral loss of pain and temperature on face (CN V)
contralateral loss of pain and temperature on body (spinothalamic tract)
paramedian branches of basilar
Midpontine base syndrome
contralateral [spastic] hemiparesis (corticospinal tract)
paralysis of jaw muscles (CN V)
loss of sensation on face (CN V)
ataxia (middle cerebellar peduncle)
paramedian and short circumferential branches of basilar.
Vestibular neuroma
tumor in the vestibular division of CNVIII; affects balance and hearing first (ipsilateral hearing loss), CN VII later, maybe CN V
Locked in syndrome
bilateral lesion of basilar pons (basilar or vertebral a.); only CN III and IV are intact, vertical eye movements and blinking are intact
Injury to the facial nerve (or nucleus) results in what?
complete facial paralysis
corticonuclear lesions (at pons or above, e.g. internal capsule) results in what?
lower facial paralysis
Parinaud syndrome (midbrain)
paralysis of vertical gaze (verticalgazecenter), obstructive hydrocephalus (pinealoma)
Weber syndrome (midbrain)
contralateral [spastic] hemiparesis (corticospinal tract)
diplopia, dilated pupil (CN III)
paralysis of lower face, deviation of tongue to contralateral side, weakness of ipsilateral SCM and trapezius (corticonuclear tract)
tremor (substantia nigra)
From branches from posterior cerebral artery!
Claude syndrome (midbrain)
diplopia, dilated pupil (CNIII)
tremor, hyperkinesia (rednucleus)
ataxia (cerebellothalamic fibers)
branches from posterior cerebral artery.
Benedikt syndrome (midbrain)
Weber + Claude syndromes, may include contralateral loss of discriminative touch, proprioception and vibration (medial lemniscus).
Uncal herniation (midbrain)
diplopia, dilated pupil (CNIII)
contralateral hemiparesis (corticospinaltract)
paralysis of lower face, deviation of tongue to contralateral side, weakness of ipsilateral SCM and trapezius (corticonuclear tract).
Anisocornia
(unequal pupils) = lesion to CN III or sympathetics; a dilated pupil indicates injury to CN III.
Lesion to retina or optic nerve results in what?
ipsilateral blindness
Optic chiasm lesion results in what?
Bitemporal hemianopsia
Optic tract lesion results in what?
contralateral homonymous hemianopsia
Optic radiations lesion results in what?
contralateral homonymous hemianopsia, maybe quadrantanopia (“pie in the sky”)
Marcus-Gunn pupil
a pupil that appears to dilate with direct stimulation of light on a swinging light test; indicates lesion to optic nerve
Intranuclear ophthalmoplegia is characterized by
an eye that fails to adduct on lateral gaze [but convergence is intact]; lesion of the medial longitudinal fasciculus (in the pons or caudal midbrain); One- and-a-half syndrome is characterized by, on testing of horizontal gaze, one eye that can only abduct and the other eye that cannot abduct or adduct; lesion involving medial longitudinal fasciculus and abducens nucleus.
Argyll-Robertson pupil
is seen in tabes dorsalis and is characterized by eyes that can accommodate but with weak or absent pupillary light reflex.
Decorticate posturing
UL flexed, LL extended [rubrospinal tract intact]
Decerebrate posturing
all limbs in extension [rubrospinal tract damaged]; progression from decorticate to decerebrate is an ominous sign.
The reticular formation functions mainly in what?
Damage results in what?
muscle tone and state of consciousness (e.g. damage to the reticular formation can result in coma).
Meniere’s syndrome
episodic vertigo, tinnitus and hearing loss; caused by excess endolymph in the scala media
Benign positional vertigo
outbursts of vertigo and nystagmus with particular positions of the head; caused by free otoliths in the semicircular canals
Caloric testing
cold = nystagmus to opposite side
warm = nystagmus to same side
[COWS]
Parkinson disease
characterized by loss of pigmented dopaminergic neurons in the substantia nigra, a 3-5 Hz resting tremor, bradykinesia and rigidity and Lewy bodies.
Huntington disease
(characterized by choreiform movements and cognitive decline) – degeneration of neostriatum, especially caudate nucleus.
Wilson disease
impaired copper metabolism, Kayser-Fleischer rings in cornea; tremor, dysarthria and rigidity
Ballismus
lesion to subthalamic nucleus; hemiballismus = subthalamic nucleus on opposite side.
Cerebellar disease causes what?
ataxia and “intention tremor” – clumsiness on finger-to-nose and heel-to-shin testing. Lesions of the cerebellar hemisphere impair movement on the ipsilateral side of the body.
Romberg test
patient stands with feet together; compare stability of trunk with eyes open vs. eyes closed
in sensory ataxia, the patient sways considerably when eyes are closed
in cerebellar ataxia, the patient sways with eyes open
Friedreich’s ataxia
most common autosomal recessive ataxia and is characterized by progressive limb and gait ataxia, dysarthria, loss of joint position and vibration senses, absent tendon reflexes in the lower extremity and Babinski sign; results from degeneration of posterior columns and spinocerebellar tracts
Blockage of the anterior choroidal artery produces what?
contralateral hemiparesis (corticospinal tract) and contralateral homonymous hemianopsia (optic tract).
Blockage of the lenticulostriate arteries produces what?
contralateral hemiparesis and hemianesthsia (posterior limb of internal capsule).
Blockage of the middle cerebral artery
main stem – includes blockage of lenticulostriate arteries + superior and inferior divisions
superior division – produces motor and sensory symptoms involving the contralateral face [lower facial paralysis], upper limb and trunk (lower extremity is spared); on the left will produce expressive (Broca’s) aphasia
inferior division – contralateral homonymous hemianopsia; on left receptive (Wernicke’s) aphasia
Blockage of the anterior cerebral artery produces
motor and sensory symptoms involving the contralateral trunk and lower limb (upper limb and face are spared) with frontal lobe signs (magnetic gate, personality changes, release of primitive reflexes [grasp, root, suck])
Blockage of the posterior cerebral artery produces
visual symptoms – contralateral homonymous hemianopsia, macular sparring is possible; may infarct thalamus (thalamogeniculate and thalamoperforating) = contralateral homonymous hemianopsia/somatosensory loss
Broca’s aphasia is indicated by what?
Also called motor, expressive, or nonfluent. Impaired comprehension, repetition, naming and speech output (left inferior frontal gyrus – pars triangularis and opercularis). Dysarthria is a defect in the way speech sounds; aphasia is a defect in the use of language.
Wernicke’s aphasia is characterized by what?
Also called sensory, receptive, or fluent. Fluent speech full of nonsense words and phrases (left temporal / parietal lobe). Word salad.
Conductive aphasia
results from damage to the arcuate fasciculus and is characterized by poor repetition.
Strokes in the anterior watershed area produce what?
expressive aphasia and lower limb affects
strokes in the posterior watershed area produce what?
receptive aphasia and visual loss.
Apraxia
loss of the ability to perform a learned and familiar motor task.
Agnosia
inability to recognize a familiar object regardless of intact sense.
Gerstmann syndrome is indicated by what?
acalculia, agraphia, finger agnosia and left-right confusion. It is caused by damage to the angular gyrus in the dominant hemisphere.
Kluver-Bucy syndrome is indicated by what?
docility, placidity, hypersexuality, hyperorality and hypermetamorphosis. It is caused by bilateral lesions of the amygdala.
