Neuro

Question 1

brain oedema

Answer 1

flattened gyri
cerebellar coning - herniation
vascular occulsion

Question 2

wallerian degeneration

Answer 2

response of axons and myelin to injury

swollen axon
degeneration of myelin sheath
macrophage infiltration
proximal and distal axon degeneration
neuronal cell body degeneration

anything causing spinal cord compression - IVDD, cerebral compression

Question 3

thiamine deficiency

Answer 3

cerebrocortical necrosis

usually caused by sudden shift to concentrates or sulphur contamination of food or water

signs -
wandering, circling, cortical blindness, incoordination, head pressing, recumbancy, nystagmus, seizure

post mortem - swelling in brain, flourescence

Question 4

copper deficiency

Answer 4

lambs

congenital - sway back
acquired (as neonate) - enzootic ataxia

signs - ascending paresis, ataxia

caused by myelin degeneration

post mortem - collapsed brain, symmetrical cavitation of white matter

Question 5

tetanus

Answer 5

blocked transmission of nerves to muscles

muscle stiffness and spasm
protruding third eyelid
sweating
over reaction to bright lights or loud sounds

Question 6

botulism

Answer 6

clostridium botulinum

muscle paralysis - difficulty chewing and swallowing
death due to paralysis of lungs or heart

Question 7

TSEs

Answer 7

BSE - cattle - notifiable
Scrapie - sheep and goats - notifiable
chronic wasting disease - deer - notifiable
camelid prion disease - camelids
transmissible mink encephalopathy - mink

classical and atypical forms

classical -
transmissible - vertical and lateral
affects multiple animals
wide age range
detectable in lymph tissue - distal ileum and various nodes

atypical -
spontaenous
single animals affected
older animals
not detectible in lymphoid tissue

pathogenesis -
prion uptake into GIT
spread to CNS - vagal nerve, lymphoid or hematogenous spread
prions to obex in brain
spread to periphery
atypical - spontenous accumulation in brain
needs susceptibility gene

signs -
progressive neurological disease
changes in behaviour, sensation, and movement

(atypical - difficulty rising and positive scratch test)

diagnosis -
ELISA - no anatomical context
IHC - has anatomical context

Question 8

routes of nervous system infection

Answer 8

hematogenous - thrombotic meningoencephalitis, cryptococcus, strongylus vulgaris
direct extension - otitis media, aspergillosis, trueperella pyogenes, brucells (via spine)
retrograde axonal transport - listeria monocytogenes, rabies - transport up neuronal axons
leukocyte trafficking - in macrophages

Question 9

hydrocephalus

Answer 9

increased fluid in ventricles

usually congenital
deformed skull

signs - head pressing, inappetence, seizures, lethargy, altered mental state

BVD

Question 10

hydraencephaly

Answer 10

formation of cavity, filled with CSF

destruction of developing neural tissues

signs - lethargy, circling, head pressing, blindness

bluetongue, schmallenberg, akbane virus

Question 11

porencephaly

Answer 11

cystic structures in neutropil

akbane virus, BVD, malignant cathharal fever

Question 12

bluetongue and schmallenberg CNS findings

Answer 12

cerebellar hypoplasia
arthrogryposis
hydraencephaly

Question 13

aujeszky’s

Answer 13

pigs

herpes suid - viral inclusions

“mad itch”

signs - respiratory, dermal, neuro, repro

Question 14

myasthenia gravis

Answer 14

pathogenesis - reduced function of acetylcholine receptors
lack of communication from nervous system to muscle
brief relief when given chloride (tensilon test)

acquired - autoantibody production
congenital - gene mutations

rule out myopathy - CK levels
radiography for megaoesophagus

Question 15

horner’s

Answer 15

loss of sympathetic innervation to adnexa and globe of eye

3 potential sites -
1 - brain stem - T1-3
2 - T1-3 and joining vago-sympathetic trunk
3 - cranial cervical ganglion joining trigeminal nerve

signs - 3rd eyelid protrusion, ptosis (dropping eyelid), miosis (small pupil)

cause by species -
dog - idiopathic
cat - otitis media, nasopharyngeal, iatrogenic
horse - guttural pouch mycosis

diagnosis -
penyleprine in eyes - response in affected eye (mydriasia)
head radiography or CT
guttural pouch scope

Question 16

equine grass sickness

Answer 16

clostridium botulinum

degeneration of neurons in brain, ganglia and enteric nervous system

adult horses at grass

signs - tachycardia, ileus, colic, bilateral horners

biopsy - biopsy (rectal or ileal), histology of cervical ganglion post mortem

Question 17

listeria monocytogenes

Answer 17

sepsis, meningitis/meningoencephalitis, corneal ulcer, abortion, still birth
unilateral clinical signs - drooling, facial paralysis, micro abscesses

transmission to CNS in macrophages from GIT or retrograde axonal transport up vagus nerve

from contaminated silage via damage to oral mucosa

Question 18

nervous system neoplasms

Question 19

nervous system disorders caused by vascular disease

Answer 19

infarction cause by IVDD or orthopedic surgery
CKD or cushings - through causing hypercoagulability
feline hypertension encephalopathy or feline ischemic encephalopathy

Question 20

west nile virus

Answer 20

necrosis in grey matter

signs - incoordination, hind limb weakness, inability to stand, muscle weakness, muscle twitching, blindness, sudden death

blood test

vax available

Question 21

indications for cerebrospinal tap

Answer 21

suspicion of inflammatory or neoplastic lesions in CNS

don’t do collection high up if signs of brain herniation

advantages - often useful diagnostic findings
disadvantages - may be non-specific, need GA, risk of herniation or convulsions

test with PCR for infectious disease - neospora

Question 22

histophilus somni

Answer 22

calves
thrombotic meningioencephalitis

Question 23

cryptococcus

Answer 23

cats
neoformans and gati (infectious)

Question 24

strongylus vulgaris

Answer 24

horse

Question 25

coernurus cerebralis

Answer 25

tapeworm - goes to brain in sheep
gid - fatal, loss of balance
larval form of taenia multiceps

Question 26

otitis media

Answer 26

direct extension into brain

Question 27

nasal aspergillus

Answer 27

extension through nasal turbinates

Question 28

discospondylitis

Answer 28

bacterial or fungal infection of the intevertebral discs
back pain

extension from spine

trueperella pyogenes
brucella

Question 29

rabies

Answer 29

retrograde axonal transport
lyssavirus
zoonotic
notifiable

furious, dumb and paralytic forms

Question 30

cerebellar hypoplasia

Answer 30

several viruses -
BVD - CATTLE
Bluetongue - cattle and sheep
feline panleukopenia
swine fever

signs -
range from ataxia (in kittens) - learn to live with it
to opisthonus - incompatible with life - if infected very early of in utero

Question 31

hydrocephalus

Answer 31

increased volume of fluid in ventricles

usually idiopathic congenital disease
in young animals deforms the skull
brachys will have it in some degree with no clinical signs

head pressing, inappetencem seizures, lethargy, altered mental status

BVD

Question 32

hydrencephaly

Answer 32

loss of cortical tissue with a cranial vault of normal conformation - as result of destruction of developing neural tissues
usually associated with cerebellar hypoplasia and arthrogryposis
resultant cavity is filled with CSF

signs -
lethargy, circuling, head pressing, blindness

schmallenburg, bluetongue

Question 33

porencephaly

Answer 33

cystic structures in neuropil
usually do not communicate with ventricles
less common

akbane virus, BVD, malignent catarrhal fever

Question 34

aujeszkys

Answer 34

notifiable
mainly pigs
suid herpes virus - intranuclear inclusions
mad itch
respiratory, dermal, neuro and repro signs