how does CENTRAL vestibular syndrome present/ how is it different from peripheral?
central peripheral dz has all the signs of the peripheral vestibular disease (listing/leaning to one side, rolling, tight circling, head tilt, nystagmus, ventral strabismus) , PLUS that there ARE postural reaction deficits (ipsilateral to the lesion), the pathological nystagmus is usually positional (if head is in a certian position then there is nystagmus) OR it is a vertical nystagmus, and there can be hemi or tetra paresis. (usually there are also other signs of brainstem dysfunction)
sum up what's same and diff about peripheral vs central vestibular syndrome
BOTH have listing/leaning to one side, rolling, tight circling (ataxia), head tilt, nystagmus, strabismus. CENTRAL (is peripheral PLUS) also has postural deficits, the nystagmus is often postitional, or is vertical instead of horizontal. there is also hemi/tetra paresis and maybe other signs of brainstem dysfunction are present
why does the fast phase of the nystagmus flick to the opposite side when there is damage on the other side?
eyes flick quickly to the opposite side because there is no no input from the damaged side so it "looks toward" the side that has input
Paradoxical Vestibular Syndrome indicates what kinda lesion? what does this syndrome represent?
cerebellar lesion-- remember that the cerebellum is INHIBITORY on the vestibular system, so this syndrome is actually looking like an "overactive'" vestibular system because the inhibitory part of the brain is damaged
Paradoxical Vestibular Syndrome what other signs are there?
cerebellum lesion-- head tilt, falling, nystagmus, postural deficits
in PARADOXiCAL vestibular syndrome, which way does the animal have head tilt and fall?
contralateral (opposite) side of lesion
in PARADOXICAL vestibular syndrome, which way does the fast phase of the nystagmus go?
fast phase is ISPILATERAL(same side)!! to the lesion
headt tilt and fast phase nystagmus in.... PERIPHERAL vestibular syndrome? CENTRAL " " ? PARADOXICAL " " ?
PERIPHERAL: head tilt TOWARD, fast phase AWAY. CENTRAL: same as peripheral but nystagmus is positional/vertical. PARADOXICAL: head tilt AWAY, fast phase TOWARD
what can postural reactions tell you about the location of the lesion in PARADOXICAL vestibular syndrome?
they are abnormal ipsilateral (same side) to lesion
aside from CN VIII, what other nerve is assocaited with the middle ear and what does it do (in relation to the eye)?
CN VII and it does Sympathetic innervation for pupil (sympathetic system causes pupil dilation)
due to CN VII's close relation to the middle ear and CN VIII, what can you see along with peripheral vestibular syndrome?
facial nn defects and horners syndrome
what three things will you see if the PERIPHERAL vestibular syndrome is BILATERAL?
Wide-based, crouched stance (they will be very low to the ground), Wide head excursions, No vestibular-ocular reflexes
Wide-based, crouched stance (they will be very low to the ground), Wide head excursions, No vestibular-ocular reflexes is a sign of what?
Bilateral Peripheral Vestibular Syndrome
what are three major reasons you can get peripheral vestibular syndrome?
(1) middle/inner ear dz-- usually Bacterial otitis media/interna. You might see horners in this case also (bc of CN VII being in the same area). (2) neuropathies, esp hypothyroidism. (3) idiopathic (old dog vestibular dz)
what is meclizine? when would you use it?
it is an antihistamine drug, which is often used to treat the nausea/vertigo which is associated with vestibular syndrome (12.5mg PO for small dog/cat, 25mg PO for large dog)
why might physical therapy be useful in a dog with cerebellar/vestibular dz?
they can "relearn" proprioception
nugget for localizing vestibular syndrome--> what should you know about how the R and L side are in vestibular syndrome?
both R and L side are active
nugget for localizing vestibular syndrome--> how does the cerebellum affect the vestibular system?
it is INHIBITORY on the vestibular system
nugget for localizing vestibular syndrome--> vestibular input causes ___ (ipsilateral or contralateral) ___ (flexor or extensor) tone
nugget for localizing vestibular syndrome--> **what is the key to localizing vestibular syndrome lesions?
**changing or positional nystagmus is what kinda vestibular syndrome?
**vertical nystagmus is what kinda vestibular syndrome?
** if there are facial nn defects or horners syndrome with the vestibular syndrome, what kinda vestibular syndrome is it?
(1) Thalamus & hypothalamus (diencephalon) (2) Cerebral hemispheres (telencephalon) (3) Olfactory structures (4) Components of the limbic system (hippocampus and amygdala)
Cerebral Functions include... (big list)
Cognition, Intelligence, Behavior, Pain, touch, proprioception, Audition (hearing), Olfaction, Vision, Taste, Motor (minor role in quadrupeds)
describe the symptoms you'd see in cerebral syndrome?
Decreased intelligence, Disorientation, Behavior/attitude changes, Altered mentation, Contralateral decreased postural reactions, Contralateral deafness, blindness, anosmia, Circling toward the lesion (or head or body turn toward lesion), head pressing, seizures
if there is a lesion in the cerebrum, will signs be on the ipsi(same) or contra(opposite)lateral side of the body?
what is the diesncephalon what is in it?
actually the rostral brain stem, it contains the thalamus and the hypothalamus
what is the thalamus part of, and what does it do?
part of the diencephalon, it is a sensory relay station and helps with arousal of the cortex
what is the hypothalamus part of, and what does it do?
part of the diencephalon, it controls endocrine, affect+emotion, sleep/wake cycle, Homeostasis of many body functions
Diencephalic Syndrome--> does it affect mentation, behavior, emotion?
YES (part of thalamus/hypothalamus is damaged and these pertain to arousal, emotion, etc)
in Diencephalic Syndrome, will postural reaction deficits be on the same or opposite side
how might senses be affected in diencephallic sydrome, and why?
there will be Contralateral blindness, deafness (because diencephalon houses the thalamus which is a sensory relay station)
what is hemigeglect and when do you see it?
see it in diencephallic syndrome-- it's when the animal doesnt seem to realize that the other half of the vision field is there
when would you see endocrinopathies (which aprt of forebrain damaged)
Diencephalic Syndrome (because hypothalamus in the diencephalon)
describe the path of a LMN starting from where it starts in the spinal cord
starts in the grey matter of the ventral column in the ventral rootlet--> ventral root--> spinal nerve--> peripheral nerve--> exit via brachial plexus and lumbosacral plexus
what is the motor unit composed of? what does it control/have to do with?
the motor unit is the α motor neuron + the myocytes it innervates. It pertains with Strength of muscle contraction
neck ventroflexion in a cat might indicate what?
what are some clinical signs of myopathic syndrome?
Generalized weakness, exercise intolerance (in cats, neck ventroflexion), Muscle atrophy or hypertrophy (can lead to Joint contracture or Trismus), Stiff, stilted gait (look like theyre walking on eggshells), Muscle tremors, and there might be myalgia (mm pain)
what is trismus and when would you see it?
inability to open mouth, see it in myopathic syndrome
what kinda ataxia will you see in myopathic syndrome?
what kinda postural reaction abnormalities will you see in myopathic syndrome?
how are reflexes affected by myopathic syndrome?
they arent affected, but if there is joint contracture it might be difficult to gauge them
what dont you see in myopathic sydrome, and why?
dont see ataxia, postural reaction abnormalities or abnormal reflexes because only the mm are affected in this problem
what are Junctionopathies?
Generalized neurogenic muscle atrophy
what kinda paralysis do you see in junctionopathies? what other signs will you see related to t his kinda paralysis?
Ascending flaccid paralysis, INCLUDING the mm for respiration which leads to dyspnea
how are reflexes affected by junctionopathies?
Hypo- to areflexia (Reflexes may be present early on, and Cranial nerves may be involved)
how would you describe a neuropathic gait?
shuffling and slapping
how would a MOTOR neuropathy present?
Flaccid paralysis, Neurogenic muscle atrophy, Hypo- to areflexia, Muscle fasciculations
how would a SENSORY neuropathy present?
Hypalgesia, hypesthesia, paresthesia(these can lead to self-mutilation), ataxia (due to proprioceptive defects), and Hypo- to areflexia (no muscle atrophy or loss of strength though)
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