Neurological conditions of ruminants Flashcards
List 3 spinal reflexes that can be performed in ruminants
flexor reflex
patellar reflex
perineal reflex
List 6 things to assess in neuro exam in ruminants
- Assess mental status
- Assess cranial nerves
- Assess gait and posture
- Assess postural reactions as far as possible
- Assess spinal reflexes as much as possible
- Assess responses to pain
DEcsribe a primary neurological condition
Conditions directly affecting the neurological system (e.g. brain abscesses, spinal cord injuries)
Describe a secondary neuological condition
Conditions that present with neurological signs but are not of neurological origin (e.g. hypomagnesaemia, twin lamb disease)
List the steps to approaching a farm animal neuro case
- is the disease primary or secondary origin
- Is the brain affected
- Further localise the lesion
what do you see with forebrain lesion
whole body affected
abnormal mentation
what do you see with cerebllum lesion
whole body affected
normal mentation
Describe what is seen with brainstem lesion
Face/head only.
Mentation usually normal mentation (can be depressed
if lesion is C1-T2 what do you see
All 4 limbs affected
Not head/face/mentation
what do you see if lesion is T3-L6
hindlimbs affected only
what do you see if S1-S3 lesion
tail/ perineum only
what do we see with central vestibular lesion
head tilt
nystagmus
proprioceptive deficits
depression (if brainstem involvemetn)
what do we see with peripheral vestibular lesion
head tilt
Falling/leaning/circling (towards lesion)
Nystagmus (slow phase to lesion
How can biochemistry and haematology help when diagnosing neurological conditions
only useful if secondary neuro condition suspected: e.g. Mg, Ca, Na, acid-base balance, specific assays (e.g. toxins)
where do obtain CSF from in ruminants
midpoint of lumbosacral space
Describe nervous ketosis
Is a secondary neurological condition
Increased ketones and decreased glucose = negative effects on brain function
Describe pregnancy toxaemia in sheep
Energy demands of foetus(es) in late gestation > energy obtained from diet
Primarily seen in ewes carrying twins/triplets in more intensive systems during last 2 weeks of gestation
List the clinical signs of early stages of pregnancy toxaemia
separation from group
apparent blindness
List the clinical signs of later stage of pregnancy toxaemia
marked drowsiness
star-grazing and ataxia
facial twitching
ketone breath
seizures
List the clinical signs of the final stages of pregnancy toxaemia
recumbency develops after 3-4 days
develops a comatose state
Describe how to treat pregnancy toxaemia
IV glucose
oral propylene glycol
supplement with calcium and potassium
supportive IV fluids?
Describe how to prevent pregnancy toxaemia in sheep
ensure rising plane of nutrition in 2nd half of pregnancy
scan and feeding singles/ twins/ triplets separately
List the clinical signs of nervous ketosis
sudden onset neuro signs
circling and aimless wandering
apparent blindness
crossing limbs and ataxia
hyperaesthesia
mild tremors
Describe how to diagnose nervous ketosis
clinical signs with BHB> 3.0mmol/L
Describe how to treat nervous ketonsis
IV glucose
oral propylene glycol
glucocorticoids - given with glucose
What causes CCN
thiamine (vitamin B1) deficiency/ inadequacy
But can get sulphur induce CCN - rarer
Descrieb the presentation in of CCN
sudden onset blindness
aimless wandering and circling
head pressing
star-grazing
Describe how to diagnose CCN
history and clinical exam
generally by response to treatment
Describe how to treat CCN
Thiamine (vit B1) treatment - needs high conc
ensure roughage in diet
Describe swayback (sheep and goats)
Copper deficiency of ewes/does in mid-pregnancy
List the 3 presentations of swayback
- congenital cerebrospinal swayback
- progressive spinal swayback - most common
- cerebral oedema - only wales
Describe congenital cerebrospinal swayback
Lambs born dead or weak and unable to stand
Liveborn lambs are recumbent with spastic paralysis of all limbs
Movement is uncoordinated and erratic
Describe progressive spinal swayback
Stiff staggering gait, hindlimb ataxia (swaying gait)
Signs develop at 3-6 weeks of age
Most common form
Describe how to diagnose swayback
history and clinical signs
treatment trial
Describe how to treat swayback
Treatment involves oral supplementation of copper
Describe how to prevent copper swayback
Ensure ewes/does have adequate copper supplementation in diet during mid pregnancy
Care for copper toxicity
Describe primary vitamin A deficiency
associated with diets insufficient in vitamin A
Describe secondary vitamin A deficiency
associated with chronic liver or enteric disease
List the clinical signs of vitamin A deficiency
night blindness
skeletal muscle paralysis
Corneal keratinisation, mucoid ocular discharge, photophobia
Describe how to treat vitamin A deficiency
vit A supplementation
response to treatment is rapid- blindness doe snot improve
Describe the acute form of hypomagnesium
hyperaesthesia, ataxia, collapse, seizures
Describe the signs of subactute hypomagnesium
wild facial expression, hypermetric gait, muscle tremors, spasmodic urination and defecation
how can you test for hypomagnesaemia in dead animal
vitreous humour
Describe how to treat hypomagnesaemia
sedate if seizuring
SC magnesium
IV calcium with magnesium added- DON’T GIVE WHOLE BOTTLE OF MAGNESIUM IV
what is CCN
Cerebrocortical necrosis
what is hydrocephalus
brain ventricle distension with fluid
hereditary in some breeds- holsteins, herefords and suffolks
what generally causes cerebellar hypoplasia and atrophy
Commonly secondary to BVDv infection in utero (100-200 days gestation)
Hereditary in some breeds- hereford, shorthorn, ayrshire, aberdeen angus
List the clinical signs of Cerebellar hypoplasia and atrophy
vary from recumbency and opisthotonos to generalised ataxia with hypermetric gait
Name 2 inherited neurological conditions in ruminants
Hydrocephalus
Cerebellar hypoplasia and atrophy - only cattle
List infectious diseases that can cause neurological signs(11)
BVDV
Borders disease
Listeria
Louping ill
Transmissible spongiform encephalopathies- scrapie and BSE
Nervous coccidiosis
Coenurus cerebralis (Gid) (parasitic)
tetanus
Botulism
Brain abscess
Neuro maedi-visna
what causes listeriosis
Listeria monocytogenes
All ruminants affected but especially seen in sheep
List the 3 most common syndromes of listeria
Encephalitis/meningitis
Abortion
Keratoconjunctivitis/uveitis (associated with ring/big bale feeders)
How do animals get listeria
Typically associated with feeding poorly made/poorly stored silage
Bacteria is ingested and ‘accesses’ trigeminal nerves through abrasions of buccal mucosa or gum lesions
List 3 risk factors of listeriosis
Poor nutritional status
Suppressed immunity (e.g. pregnancy/parturition)
Sudden weather changes (typically dry to very wet)
Decsribe how to diagnose listeriosis
clinical exam and history
ante-mortem confirmation not currently possible
List the clinical signs in initail stages of listeriosis
Depressed, separate selves from flock
When approached try to run away but are ataxic and fall easily
Pyrexia >40 °C in very early stages
List the clincal signs seen in later stages of listeriosis
Progression to recumbency and severe depression (appear sedated) – rapid in sheep/goats
Facial paralysis and hyperalgesia – drooling and flaccid tongue common
Absent palpebral reflex may lead to exposure keratitis
Describe how to treat listeriosis
early treatment needed
penicillin- 10-14 days
supportive care
NSAIDs?
what causes Louping ill
Tick borne (Ixodes ricinus) flavivirus
typically seen in sheep with rough hill grazing
List the clinical signs of louping ill
Muscle tremors, nibbling, ataxia, drooling, death after 1-3 days
Describe nervous coccidiosis
Neurological manifestation of Eimeria infection
Typically enteric signs (haemorrhagic diarrhoea) precede neuro signs (cerebral signs)
poor prognosis
Describe Coenurus cerebralis (Gid)
parasite - intermediate stage of T. multiceps ( dog tapeworm)
seen in sheep
poor prognosis
Decsribe how to prevent Coenurus cerebralis (Gid)
regular worming of dogs with praziquantel
don’t allow dogs to scavenge carecases
List the clinical signs of tetanus
inital muscle stiffness
inability to open mouth
tail held away from body
Progresses to recumbency and convulsions + opisthotonos
Death occurs due to respiratory arrest
Describe how to treat tetanus
tetanus antitoxin
high dose penicillin
supportive care
poor prognosis
List the clinical signs of botulism
cow- flaccid paralysis
sheep - initially muscle stiffness and ataxia then progress to flaccid paralysis
prognosis grave
Generally what causes brain/spinal abscesses
Haematogenous spread most common
Decsribe how to treat brain/ spinal abscesses
Treatment with antibiotics can be attempted but response often poor
Describe Visna (neuro form of Maedi-visna)
very rare in UK
Slow onset signs relating to demyelinating encephalitis
disease is always fatal
Name a inherited disease that affects the peripheral nervous system
spastic paresis
describe spastic paresis
Usually 1st seen from a few weeks old up to 6 months
Very straight hocks, excess tone in gastrocnemius, ‘tin soldier’ gait, tail elevated –> usually one leg worse than other (or unilateral)
Describe how to treat spastic paresis
partial tibial neurectomy
Describe the clinical signs seen with lead toxicity
acute- tremors, staggering, blindness, twitching of face
subacute form- GIT dysfunction, blindness, muscle twitching
death occurs in 3-4 days
Describe how to treat lead toxicity
Sedate animals with severe neurological signs
Provide IV fluid therapy
Remove animal from source of lead
Chelation therapy- calcium EDTA
add thiamine (vit B1)
List 4 cerebral conditions in calves
Cerebral corticonecrosis (CCN)
Septic meningitis
Hypernatremia (salt toxicity)
Brain abscesses
Decsribe hypernatremia in calves
Excessive sodium ingestion in absence of adequate water- generally due to home-made electrolyte solutions
difficult to treat- IV fluids but slowly reduce Na concentration
Describe how to treat obturator nerve injury
Manage conservatively
NSAIDs (for concurrent injuries)
Deep bed
Hobbles/shackles (maintain medial positioning of hindlimbs)
Describe sciatic nerve injury
Post-calving (typically dairy cows) and iatrogenic (typically calves and small ruminants)
causes dropped hock and knuckled fetlock
describe how to treat sciatic nerve injury
NSAIDs
Supportive care
prognosis good
Describe how tibial nerve injury presents
dropped hock with hyper-extended fetlock (cow walk on heels)
Describe femoral nerve injury
calves injured during birth
Calves are unable to extend stifle or bear weight on affected limb
Decsribe how to treat femoral nerve injury
Treatment is conservative –> remember to ensure adequate nutrition
What causes brachial plexus injuries
calf- birth injuries
sheep- accidents or harness injuries (rams)
Describe what is seen with brachial plexus injury
Inability to extend elbow, carpus or fetlock
Shoulder muscles atrophy
Describe how to treat brachial plexus injury
consevative
Describe what is seen with radial nerve injury
Occurs following prolonged lateral recumbency or traumatic injuries
Knuckling of carpus and fetlock but can still weightbear
Decreased sensation of antebrachium, metacarpus and foot
Describe how to treat radial nerve injury
conservative management
Prognosis depends on severity of injury
