Neurological diseases of cattle Flashcards
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
Q
What are CS of lead poisoning?
A
- 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
Q
What is Tx of lead poisoning?
A
- Control fits w IV pentobarbitone
26
Q
What are CS of nervous ketosis? Dx? Tx?
A
- 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
Q
What animals get hypomagnesaemia?
A
- Beef = 3-6month old / 1st month post calving
- Spring / summer
28
Q
CS of hypomagnesaemia?
A
- 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
Q
What is seen with salt poisoning?
A
- Dehydrated
- depression
- diarrhoea and colic
- star-gazing
- blindness
- aggressiveness
- hyperexcitability
- vocalisation
- head pressing, teeth grinding
30
Q
What is pseudo rabies? What is seen?
A
- 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
Q
What is seen with rabies?
A
- Hyperexcitability
- fear, rage, depression
- flaccid paralysis
- APHA
32
Q
What are CS of BSE?
A
- 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
Q
What is seen with hypovitaminosis A?
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
Q
What is Tx of hypovitaminosis A?
A
- Daily vit A
35
Q
What animals get cerebellar hypoplasia? CS?
A
- 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
Q
How do you treat listeria infection?
A
Penicillin
37
Q
What are diseases causing spinal cord / peripheral signs?
A
- Spinal fractures
- Spinal abscess
- Spastic paresis
- Tetanus
- Botulism
- Peripheral Neuropathies
38
Q
What can cause spinal abscess?
A
- T. pyogenes
- Staph. aureus
- P. haemolitica
- F. necrophorum
39
Q
What are CS of spastic paresis?
A
- 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
Q
What is treatment of spastic paresis?
A
- Neurectomy of the tibial nerve rootlets innervating the gastrocnemius
41
Q
What are CS of tetanus?
A
- 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
Q
DX + Tx of tetanus?
A
- 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?
- Antitoxin not much help unless very early. 2.
Penicillin high doses. 3. Irrigation of infection site
penicillin, antitoxin.4. Muscle relaxants?
- Antitoxin not much help unless very early. 2.
- Vaccination
43
Q
CS of botulism?
A
- 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
Q
Dx + Tx of botulism?
A
- Dx = Hx + CS
- Tx = supportive
45
Q
What are different peripheral neuropathies?
A
- obturator = dystocia, foetal pressure - tx = chain hindlimbs
- Peroneal = hyperextension of hock, fetlock + digits - tx = bandage
- Sciatic = damage when cow recumbent, ddx = femoral fracture
