Neurology Flashcards
What does DAMNIT-VP stand for?
D: degenerative A: anomalous M: metabolic N: neoplastic, nutritional I: infectious, inflammatory, immune, iatrogenic, idiopathic T: traumatic, toxic V: vascular P: parasitic
What is the approach to solving neurological problems
- describe abnormalities
- localize
- charaacterize onset and progression
What is the approach to solving neurological problems
- describe abnormalities
- localize
- characterize onset and progression
- generate differential diagnoses
- use ancillary tests to rule in or rule-out each differential on your list
What are the three divisions of the brain (in this course)
forebrain
brainstem
cerebellum
What are the 4 important regions of the spinal cord?
C1-C5
C6-T2
T3-L3
L4-S2
What are the 4 important regions of the spinal cord?
C1-C5
C6-T2
T3-L3
L4-S2
What is a lower motor neuron?
a neuron that directly innervates the muscle
What are the components of a lower motor neuron?
- nerve cell bodies in ventral grey matter
- nerve roots
- peripheral nerve
- neuromuscular junction
What are lower motor neuron signs? (5)
- decreased muscle tone
- severe muscle atrophy
- weak and diminished reflexes
- gait typically weak
- short strides with feet under body
What are lower motor neuron signs? (5)
- decreased muscle tone
- severe muscle atrophy
- weak and diminished reflexes
- gait typically weak
- short strides with feet under body
What is the cauda equina?
the nerve roots arising from the terminal part of the spinal cord–course caudally within the vertebral canal to exit the canal as a spinal nerve caudal to the vertebral body of same number
What does C6-T2 contain?
The neres of the brachial plexus innervating forelimb muscles
What does C6-T2 contain?
The nerves of the brachial plexus innervating forelimb muscles
What nerves/muscle/reflex does L456 contain/control/mediate
femoral nerve, quadraceps muscle, patellar reflex
What nerves/muscles/reflex does L6-S2 contain/control/mediate
sciatic nerve, flexor muscles of rear leg, withdrawal reflex
What does S1-S3 control?
anus, bladder
What does S1-S3 control?
anus, bladder
What are UMN responsible for?
initiation and continuatio nof movement and regulation of normal tone in extensor muscles of limbs
What is proprioception?
the ability to sense where the limbs are in space
Where do the long tracts cross the midline and what are the implications?
just above the brainstem. Lesions in the forebrain
Where do the long tracts cross the midline and what are the implications?
just above the brainstem. Lesions in the forebrain an diencephalon will cause UMN on the contralteral forelimb and rear limb while lesions of the brainstem or spinal cord will cause UMN signs in the limbs on the same side
What are UMN signs?
- paresis/paralysis
- loss of proprioception
- loss of coordination
- increased extensor tone
- increased reflexes
- basewide stance
- excessive limb abduction during turning
- long strides
What tracts are more superficial? more deep
proprioception–superficial, most susceptible to injury
What tracts are more superficial? more deep
proprioception–large, superficial, most susceptible to injury
motor–medium, deeper–less susceptible to injury
deep pain–small, wiry–very resistant to injury
What is the order of loss with a lesion compression the UMN tracts in the spinal cord
- conscious proprioception
- voluntary motion
- deep pain sensation
Distinguish UMN and LMN signs
- muscle tone
- spinal reflexes
- motor function
- muscle atrophy
- gait
- lesion
- UMN: normal or increased LMN: decreased
- UMN: normal or increased LMN: decreased
- UMN: spastic
Distinguish UMN and LMN signs
- muscle tone
- spinal reflexes
- motor function
- muscle atrophy
- gait
- lesion
- UMN: normal or increased LMN: decreased
- UMN: normal or increased LMN: decreased
- UMN: spastic paresis to paralysis caudal to lesions LMN: flaccid paresis to paralysis at site of lesion
- UMN: muscle atrophy mild from diffuse LMN: severe neurogenic muscle injury
- UMN: delayed protraction, stiff spastic long stride, ataxic, exessive abduction of limbs during turning; LMN: weak, unable to suppport weight short strided apperas lame, may bunny-hop
- UMN: above spinal cord segments; LMN: at spinal cord segments or nerve roots or peripheral nerves
What does change in mentation suggest?
- decreased levels of consciousness may occur during metabolic disturbance or disease of cerebrum
- change in mentation suggests lesion in cerebrum
What can weakness or paresis be caused by ?
- metabolic disturbances
- muscle disease
- LMN disease
- UMN disease–gait very different than LMN
What can weakness or paresis be caused by ?
- metabolic disturbances
- muscle disease
- LMN disease
- UMN disease–gait very different than LMN
What is ataxia or incoordination an indication of?
UMN disease. caused by lesion in cerebellum, vestibular system of general proprioceptive sensory tracts
What can circling be caused by?
lesions in the forebrain or ccestibular system.
What is ataxia?
loss of coordination of muscular function
What is spinal cord/brainstem proprioceptive ataxia?
animals lose awareness of where limbs are in space and have a wide brased stance, long strides, excessive abduction of limbs during turning and exaggerated limb movements. tend to scuff or knuckle
What is vestibular ataxia?
animals with vestibular lesions have a profound loss of balance with head tilt and wide based crouched stance with a tendency to lean, drift, fall or roll to the side. often accompanied by abnormal nystagmus. normal conscious proprioception if peripheral but may have deficits if is a brain stem lesions
What is cerebellar ataxia?
inability to control rate, range and force of movement. animals have wide based stanec, sway from side to side and exaggerated (hypermetric) limb movements with normal strength. Knuckling, hopping remain normal. hypermetria of all 4 limbs results in goosestepping and may have intention tremor of head.
What is cerebellar ataxia?
inability to control rate, range and force of movement. animals have wide based stanec, sway from side to side and exaggerated (hypermetric) limb movements with normal strength. Knuckling, hopping remain normal. hypermetria of all 4 limbs results in goosestepping and may have intention tremor of head.
What are postural reactions?
complex series of responses that maintain an animal in an upright position
what is postural reaction testing?
used to determine if an animal can recognize the position of their limbs in space (conscious proprioception)
What are four postural reaction tests?
- proprioception (knuckling, placing)
- hopping
- wheelbarrowing
- hemi-walking
What is the main purpose of assessing postural reactions?
being able to decide if each limb is neurologically normal or abnormal. if abnormal can use spinal reflexes and muscle tone/atrophy to definitively characterize each limb as having UMN or LMN disease
What is the grading for spinal reflexes
0-absent 1-diminished 2-normal 3-increased 4-clonus
What is the grading for spinal reflexes
0-absent 1-diminished 2-normal 3-increased 4-clonus
What is the stimulus, response and SC segments of the thoracic limb withdrawal
pinch toe
withdraw limb
C6-T2
What is the stimulus, response and SC segments of the patellar reflex?
tap patellar tendon
extend stifle
L456
What is the stimulus, response and SC segments in the rear limb withdrawal
pinch toe
flex stifle and hock
What is the stimulus, response and SC segments in the rear limb withdrawal
pinch toe
flex stifle and hock
What is the stimulus, response and SC segments in the sciatic reflex?
tap on nerve between greater trochanter and ischium
flex stifle and hock
L6-7, S1-2
What occurs with lesions in L4-S3?
LMN signs of rear limbs, diminished perineal sensations and reflexes
loss of sciatic nerve function
loss of perineal sensation and reflexes
What occurs with lesions in S1-S3
normal patellar reflexes
loss of sciatic nerve function
loss of perineal sensation and reflexes
What is seen in animals with muscle disease, incomplete postsynaptic NMJ blockade or severe metabolic disorders
generalized weakness with normal postural reactions, normal reflexes, no ataxia
What is the panniculus/cutaneous trunci reflex used for?
to further localized severe spinal cord lesions in T3-L3. travels from the skin up spinal cord to C8-T1. If disrupted between stimulus and T1 then no twitch. Where you get a twitch is approx site of lesion
Neck pain is common in what?
patients with meningitis
How is superficial pain assessed?
by pinching skin with a hemostat
how is deep pain assessed?
apply hemostat to nail base
What happens if olfactory nerve is affected?
loss of ability to smell
what happens if optic nerve is affected?
loss of vision, menace repsonse and pupillary light reflex
what happens if occulomotor nerve is affeced?
dilated pupil, loss of pupillary light reflex
what happens if trochlear nerve is affected
dorsomedial eye rotation
What happens if the trigeminal nerve is affected?
dropped jaw (if bilateral motor) atrophy of tem
What happens if the trigeminal nerve is affected?
dropped jaw (if bilateral motor) atrophy of temporalis and masseter muscles analgesia of face, nasal mucosa
what happens if the abducent nerve is affected
medial strabismus, impaired lateral gaze
What happens if the facial nerve is affected?
lip, eyelid, ear droop, can’t blink or retract lip
What happens if the vestibulocochlear nerve is affected?
ataxia, head tilt, nystagmus, deafness
What happens if the vestibulocochlear nerve is affected?
ataxia, head tilt, nystagmus, deafness
what happens if the glossopharyngeal nerve is affected?
dysphagia, loss of gag reflex
what happens if the vagus nerve is affected?
laryngeal paralysis, dysphagia, loss of gag reflex
what happens if the accessory nerve is affected?
atrophy over trapezius, sternocephalicus, brachiocephalicus muscles
what happens if the hypoglossal nerve is affected?
loss of tongue strength
What are signs seen with central AND peripheral vestibular disease
- incoordination
- head tilt toward side of lesion
- falling/rolling toward side of lesion
- +/- ventral strabismus on side of lesion
- vomiting, salivation
- spontaneous nystagmus (fast phase away from lesion
- nystagmus may intensify with changes in body position
What are signs seen with central AND peripheral vestibular disease
- incoordination
- head tilt toward side of lesion
- falling/rolling toward side of lesion
- +/- ventral strabismus on side of lesion
- vomiting, salivation
- spontaneous nystagmus (fast phase away from lesion
- nystagmus may intensify with changes in body position
differentiate nyastagmus with peripheral and central vestibular disease
peripheral: horizontal or rotary
central: horizontal, rotary or vertical
differentiate changes in nyastagmus with position changes (peripheral vs cental)
peripheral: no changes in nystagmus direction
central: direction may change direction as head position changes
differentiate postural defects with peripheral and central vestibular disease
peripheral: postural reactions, proprioception normal
central: abnormal postural reactions and proprioception may be seen on side of lesion
differentiate concurrent signs of other nerves with peripheral and central vestibular disease
peripheral: may have concurrent horners, cranial nerve 7 paralysis with involvement of middle/inner ear, other cranial nerves normal
central: multiple cranial nerve deficits are common
What lesions can results in horner’s syndrome?
- central causes (rare): intracranial or cervical spinal cord lesion
- preganglionic: spinal cord T1-T3 lesion, brachial plexus avulsion, nerve root tumor, cranial mediastinal mass, cervical soft tissue neoplasia/trauma, skull base trauma
- postganglionic: otitis media/internal, neplasia in middle ear, retrobulbar injury, neoplasia
Lesions in the forebrain cause
- seizures
- altered behavior
- altered mentation
- gait usually normal
- pacing or circling to side of lesion
- contralateral-blindness (normal pupils and light reflex), subtle deccrease in skin/nasal/facial sensation
+- subtal postural reaction, proprioceptive defects on opposite side
+- changes in appetite, thirst, temp, electrolyte and water balance
Lesions in brainstem cause
- altered mental status (depression, stupor or coma)
- ipsilateral UMN hemiparesis or tetraparesis and ataxia
- postural reaction deficits ipsilateral limbs with normal or increased reflexes
- multiple ipsilateral cranial nerve deficits (3-12)
With nyastagmus in vestibular system lesions, is the fast phase toward or away from the lesion?
away
What do lesions in the cerebellum cause
- normal mental status
- cerebral ataxia: hypermetria
- normal strength
What do lesions in the cerebellum cause
- normal mental status
- cerebral ataxia: hypermetria
- normal strength
- normal knuckling and hopping (hypermetic?)
- normal spinal reflexes
- ipsilateral menace response may be lost
- possible paradoxical vestibular syndrome: head tilt to opposite lesions, CP deficites on side of lesion
What do lesions in the cerebellum cause
- normal mental status
- cerebral ataxia: hypermetria
- normal strength
- normal knuckling and hopping (hypermetic?)
- normal spinal reflexes
- ipsilateral menace response may be lost
- possible paradoxical vestibular syndrome: head tilt to opposite lesions, CP deficites on side of lesion
What causes peracute, nonprogressive signs?
- external trauma
- hemorrhage/infact
- internal trauma (disk, fracture)
What causes subacute progressive signs?
- infectious inflammatory disease
- noninfectious inflammatory disease
- rapidly growing tumors (lymphoma, metastatic neoplasia)
What causes chronic progressive signs?
- most tumors
2. degenerative disorders