Neurological diseases of cattle Flashcards
(46 cards)
1
Q
What should be done on clinical exam of neurologic cattle?
A
- History
- Inspection of surroundings
- Assessment from distance
- General clinical exam
- Neurological exam
- Acillary tests
2
Q
What should be examined regarding surroundings?
A
- Lead (old batteries / paint)
- Ration - quality of silage
- Poisonous plants
- Cadavers
3
Q
What should be observed from a distance?
A
- Behaviour - circling, head-pressing, blindness
- Consciousness - over-excited, stupour, coma
- Stance - rapid contractions of muscles
- Locomotion - decreased coordination, weakness
- Orthopaedic or neurological =
-if carrying limb = ortho
-if dragging limb = neuro
4
Q
What is normal function of the CNS?
A
- Brain = conscious functions = behviour, awareness, vision, eating, drinking, recognition of senses
- Brain stem / cranial nerves = cranial nerve functions, breathing
- Cerebellum = unconscious = proprioceptive, smoothing movements
- Spinal cord / peripheral nerves = limb strength + movement
5
Q
What nerves does the nasal septum stimulation test test?
A
- CN v + thalamocortex
-should pull its head away
6
Q
What does the menace response test?
A
- CN II + VII, cortex + cerebellum
-should be present from a week old
7
Q
What does the PLR test?
A
- CN II + III
8
Q
What are 3 types of ataxia?
A
- Vestibular
-always head tilt, hypermetra + hypertonia
-lesion on same side as head tilt - Cerebellar
-no proprioceptive deficits - Proprioceptive
-spinal cord disease, + weakness
9
Q
What are different spinal reflexes?
A
- Extensor reflex of the front limb
- Patellar reflex
- Flexor reflexes
- Muscle tone
- Perineal reflex
- Cutaneous trunci reflex
10
Q
What are different diagnostic tests?
A
- Biochem + haematology
- BOHB
- TP - colostrum transfer
CSF tap - lumbosacral - 4 inch needle
11
Q
What are CS of cerebrum lesions?
A
- Opisthotonos - stargazing
- Apparent blindness (intact PLR)
- Abnormal mentation
- Change in behaviour
- Aimless wandering or compulsive circling
- Seizures
- Abnormal vocalisation
12
Q
What are CS of cerebellar lesions?
A
- Ataxia without weakness – gait is controlled by the cerebellum, brainstem, spinal cord and peripheral nerves. Test for presence of absence of muscle strength – hold onto tail whilst the animal is moving can you pull it off course?
- Truncal sway – not specific as this can also happen in animals with spinal cord lesions
- Hypermetria – easiest to see in the front limbs
- Absent menace
- Wide base stance – not specific
- Intention tremors
13
Q
What are clinical signs of vestibular lesions? Peripheral vs central
A
- Peripheral =
-head tilt towards lesion
-falling/ circling towards lesion - Central =
-head tilt towards lesion
-falling/ circling towards lesion
-nystagmus
-proprioception deficits towards lesion
-depression / anorexia
14
Q
What are common CS localised to cranial nerves?
A
- CN II = blindness + absence of PLR + dilated pupils
- CN V = loss of sensation to head
- CN VI = ventromedial strabismus + inability to retract globe
- CN VII = motor muscles to face = droopy ears, eyelids, lips
- CN VIII = head tilt, circling, leaning towards lesion
- CN IX + X = inability to swallow
- CN XII = inability to retract tongue
15
Q
What are clinical signs of problems with thalamus, hypothalamus?
A
- Depression. Altered mentation
- Difficulty regulating body temperature
- Depressed Respiration
16
Q
What are clinical signs of spinal cord lesions?
A
- C1 - C5 – altered head and neck movements with no CN abnormalities. Reflexes of FL and HL are exaggerated
- C6 -T2 – depressed or absent reflexes with reduced muscle tone in the FLs and exaggerated HL reflexes with normal muscle tone in the HLs.
- T3 - L3 – Reflexes FLs normal, HL reflexes exaggerated. Pro-prioreceptive deficits in the HLs with ataxia
- L4 - L6 – absence of HL reflexes and decreased muscle tone
- S1 - S3 – decreased anal tone, loss of sensation to perineal region
17
Q
What are acute diseases of the cortex?
A
- Cerebro-Cortical Necrosis (CCN)
- Lead poisoning - APHA
- Nervous ketosis
- Hypocalcaemia
- Hypomagnesemia (Grass staggers)
- Salt poisoning
- IBR / MCF (sporadic)
- Pseudorabies (Aujesky’s) - APHA
- Rabies - APHA
18
Q
What are chronic diseases of the cortex?
A
- Brain abscess
- Bovine Spongiform Encephalopathy (BSE) - APHA
- Hypovitaminosis A
- Brain tumour (very rare) - APHA
19
Q
What is seen with meningitis in calves?
A
- Weakness, Lack of suck reflex, depression, head pressing
20
Q
How is meningitis diagnosed / treated? Prevention?
A
- Dx = CSF tap
- Tx = euthanasia
- Prevention = colostrum, hygiene
21
Q
What causes brain abscesses in cattle?
A
- Trueperella pyogenes
21
Q
What causes CCN? What animals?
A
- Thiamine deficiency
- Cattle 6-18months
22
Q
CS of CCN?
A
- Found dead
- Early signs: head up in the air and appear blind (negative
menace but has PLR) – animal disorientated and unaware of its surroundings; diarrhoea (concentrates?);
-hyperesthesia and muscle tremors also possible. - Late signs: opisthotonos, head-pressing, strabismus, miosis, excitement, recumbent,
-repetitive chewing, facial twitching, nystagmus, head tilt,
convulsions (leg paddling)
23
Q
Dx + Tx of CCN?
A
- Dx = Hx + CS, blood thiaminase assay, PME
- Tx = thiamine / vitamin B1 injections every 4 hrs
24
What are CS of lead poisoning?
* First stages: stand alone and depressed; hyperaesthesia, muscular fasiculations
* Progresses to ataxia, blindness (pupillary reflexes present), head pressing, episodic manic behaviour, convulsions, coma
* Also abdominal pain, rumen atony (bloat), diarrhoea, frothing at the mouth
* Severe will die 12-24 hrs; sudden death may also occur
25
What is Tx of lead poisoning?
* Control fits w IV pentobarbitone
26
What are CS of nervous ketosis? Dx? Tx?
* Acute onset of obsessive licking, circling, staggering,
head pressing, pica, aggression
* Signs last 1-2 hours; recur at ~ 10-hourly intervals
* Diagnosis – ketones blood - BOHB
* Treatment 40% dextrose i.v, propylene glycol BID,
corticosteroids
27
What animals get hypomagnesaemia?
* Beef = 3-6month old / 1st month post calving
* Spring / summer
28
CS of hypomagnesaemia?
* Hyperexcitable, may charge
* Erect ears, ear twitching, hyperaesthesia
* Muscle fasiculations / tremors
* Frenzied running turning into staggering
* Lateral recumbency with violent episodes of ophistotonos and convulsions (can be triggered by any stimulus... also by vet!)
* Dead within an hour of the seizure episodes
29
What is seen with salt poisoning?
* Dehydrated
* depression
* diarrhoea and colic
* star-gazing
* blindness
* aggressiveness
* hyperexcitability
* vocalisation
* head pressing, teeth grinding
30
What is pseudo rabies? What is seen?
* Pseudorabies (Aujesky’s disease, Mad Itch)
* CS =
-Depression
-ataxia
-conscious proprioceptive deficit
-circling
-nystagmus
-strabismus
-aggression
-pruritus (of the head), dead within 2 days.
* Contact with pigs
* APHA
31
What is seen with rabies?
* Hyperexcitability
* fear, rage, depression
* flaccid paralysis
* APHA
32
What are CS of BSE?
* 3-6 years
* Initial signs often subtle but always progressive, rate
of progression variable 2-3 weeks to several months
* Weight loss
* Hyperaesthesia, fine fasiculations of head and neck
shoulder flank, teeth grinding,
* Apprehensive when approached, reluctant to be
milked or moved through gate ways
* Ataxia
* Aggression
33
What is seen with hypovitaminosis A?
* thickening of dura mater = increase CSF pressure
* retinal degeneration = absent pupillary light reflex
* CS =
-calves born to deficient dams = blindness, weakness, domed forehead, thickened carpal joints
-deficient calves = blindness, anorexia, diarrhoea, pneumonia (ill thrift)
-older cattle = blindness, star-gazing, nystagmus, ataxia, convulsions, diarrhoea
34
What is Tx of hypovitaminosis A?
* Daily vit A
35
What animals get cerebellar hypoplasia? CS?
* Inherited Hereford, guernsey, holstein, shorthorn, ayrshire)
* Acquired (BVD) – infection dam 90-170 days gestation
* Severity varies
* Balance (ataxia, falling backward) or unable to stand,
tremor, hypermetria, nystagmus
* Severe opisthotonos
36
How do you treat listeria infection?
Penicillin
37
What are diseases causing spinal cord / peripheral signs?
* Spinal fractures
* Spinal abscess
* Spastic paresis
* Tetanus
* Botulism
* Peripheral Neuropathies
38
What can cause spinal abscess?
* T. pyogenes
* Staph. aureus
* P. haemolitica
* F. necrophorum
39
What are CS of spastic paresis?
* Excessive Tone of Gastrocnemius Muscle
* Hyperextended hock
* Unilateral or Bilateral
* If unilateral the affected leg is thrust out behind
during walking and advanced with a swinging motion
without touching ground
* Often spend longer lying down
40
What is treatment of spastic paresis?
* Neurectomy of the tibial nerve rootlets innervating the gastrocnemius
41
What are CS of tetanus?
* Incubation period variable, normally 2-4 weeks Progression of disease 4-5 days
* Stiffness, reluctance to move, muscle tremors
* Prolapse 3rd eyelid, RUMEN TYMPANY, elevation tail
* Progression to generalized muscular tetany and “rocking horse” position
* Recumbancy, convulsions, death
42
DX + Tx of tetanus?
* No test; no characteristic PM signs; identify site of
infection and attempt to culture.
* Full blown tetanus prognosis poor PTS
* Animal well bedded kept in dark and quiet
* Treatment?
* 1. Antitoxin not much help unless very early. 2.
Penicillin high doses. 3. Irrigation of infection site
penicillin, antitoxin.4. Muscle relaxants?
* Vaccination
43
CS of botulism?
* Characterised by muscle weakness, progressing to ataxia and
then paralysis
* Anorexia, dilated pupils
* Excessive drooling
* Droopy expression, tongue may hang out of mouth
* Decreased rumen motility, bloat, constipation
* Respiratory failure leading to death
44
Dx + Tx of botulism?
* Dx = Hx + CS
* Tx = supportive
45
What are different peripheral neuropathies?
* obturator = dystocia, foetal pressure - tx = chain hindlimbs
* Peroneal = hyperextension of hock, fetlock + digits - tx = bandage
* Sciatic = damage when cow recumbent, ddx = femoral fracture
