Vestibular disease

Question 1

what is the function of the vestibular system?

Answer 1

maintain balance
maintain normal orientation relative to gravitational field
maintain position of eyes, neck, trunk and limbs relative to the head

Question 2

what makes up the peripheral vestibular system?

Answer 2

3 ducts orientated at right angles to each other, filled with endolymph that flows as the head moves
vestibulocochlear nerve (CN 8)

Question 3

how does the vestibulocochlear nerves interact with the ducts of the vestibular system?

Answer 3

connected with hair cells of the receptors, as endolymph flows through the semicircular ducts it bends them leading to nerve impulses

Question 4

what makes up the central vestibular system?

Answer 4

brainstem - 4 nuclei that pass information on to the rest of the brain and spinal cord
cerebellum

Question 5

how does the cerebellum effect the central vestibular system?

Answer 5

inhibitory effect on vestibular nuclei in the brainstem

Question 6

what are the clinical signs of vestibular disease?

Answer 6

ipsilateral head tilt
head sway (both sides effected)
ataxia and wide base stance
leaning/falling
nystagmus
positional strabismus

Question 7

which way does the head tilt in vestibular disease cases?

Answer 7

towards the lesion (ipsilateral)

Question 8

which way does the head tilt if its a cerebellar lesion?

Answer 8

away from the lesion

Question 9

what is a paradoxical head lesion?

Answer 9

head tilt away from the lesion due to loss of inhibition of the ipsilateral extensors because of cerebellar disease

Question 10

how can you tell where the lesion is for nystagmus associated with vestibular disease?

Answer 10

the lesion is on the side of the slower phase

Question 11

where does vertical nystagmus suggest the lesion is if associated with vestibular disease?

Answer 11

central vestibular system

Question 12

how does positional strabismus help to localise the lesion associated with vestibular disease?

Answer 12

when the head is lifted the eye will drop on the side that the lesion is located

Question 13

what is paresis?

Answer 13

muscle weakness

Question 14

is paresis possible with vestibular disease?

Answer 14

yes - only central

Question 15

are proprioceptive deficits seen with vestibular disease?

Answer 15

yes - only central

Question 16

can animals with vestibular disease have cranial nerve deficits?

Answer 16

yes - central (V-XII) and peripheral (VII)

Question 17

can animals with vestibular disease present with Horners?

Answer 17

yes - central is rare but it is possible with peripheral

Question 18

what kind of nystagmus is seen in animals with central vestibular disease?

Answer 18

vertical, horizontal or rotary (can change direction)
vertical can only be central

Question 19

what kind of nystagmus is seen in animals with peripheral vestibular disease?

Answer 19

horizontal or rotary (fast phase is away from the lesion)

Question 20

what are the main differentials for peripheral vestibular disease?

Answer 20

otitis media/externa
idiopathic vestibular disease

Question 21

what are the main differentials for central vestibular disease?

Answer 21

cerebrovascular disease
MUEs, FIP
tumours

Question 22

what is cerebrovascular disease?

Answer 22

abnormality of the brain caused by disruption to blood supply

Question 23

how does cerebrovascular disease manifest?

Answer 23

strokes (cerebrovascular accident)

Question 24

what is the name for the area of necrotic tissue caused by ischaemia from cerebrovascular disease?

Answer 24

infarct

Question 25

what are the two types of stroke?

Answer 25

ischaemic (obstruction) haemorrhagic (rupture)

Question 26

how does cerebrovascular disease appear on an MRI?

Answer 26

well defined, sharply demarcated lesion with minimal to no mass effect

Question 27

what are the most concurrent diseases that can lead to cerebrovascular disease?

Answer 27

chronic kidney disease hypertension hyperadrenocorticism

Question 28

how are cerebrovascular diseases treated?

Answer 28

supportive and treating underlying condition

Question 29

what is the prognosis for cerebrovascular disease?

Answer 29

generally good outcomes (need less functional brain tissue than humans to exist)

Question 30

what are MUOs?

Answer 30

meningoencephalomyelitis of unknown origin

Question 31

what are the categories of MUOs?

Answer 31

GME - granulomatous ME NME - necrotising ME NLE - necrotising leukoencephalitis

Question 32

how rapid is the onset of MUOs?

Answer 32

subacute (and progressive)

Question 33

what does meningoencephalitis mean?

Answer 33

meningo - meninges encephalo - brain myelitis - spinal cord

Question 34

what breeds are MUO common in?

Answer 34

pug, frenchie, chihuahua (genetic susceptibility)

Question 35

do MUOs need treating?

Answer 35

yes - they are progressive and will get worse without treatment

Question 36

what are the main subtypes of MUOs?

Answer 36

granulomatous and necrotising

Question 37

what age are granulomatous MEs seen?

Answer 37

young adults (3-8 years old)

Question 38

where can granulomatous MEs be localised to?

Answer 38

often multifocal signs - spinal cord, brain, caudal fossa

Question 39

what are the main breeds necrotising encephalitis is seen in?

Answer 39

pug, Chihuahua, yorkie

Question 40

where can necrotising encephalitis be localised to?

Answer 40

cerebral cortex (many areas that often coalesce)

Question 41

what is the prognosis for necrotising encephalitis?

Answer 41

guarded - causes necrosis of brain causing cavitation which can't be reversed

Question 42

what are some clinical signs of necrotising encephalitis?

Answer 42

seizures, blindness (most common) altered behaviour, circling, depression

Question 43

how are MUOs treated?

Answer 43

immunosuppression - corticosteroids with other immunosuppressants

Question 44

what is the survival rate for MUOs?

Answer 44

very guarded

Question 45

why can FIP cause CNS signs?

Answer 45

results from immune-complex-mediated vasculitis

Question 46

why is FIP causing CNS signs hard to diagnose?

Answer 46

usually the dry version of FIP

Question 47

how can FIP be diagnosed when it is causing CNS signs?