Nervous conditions Flashcards
What are the four major neuroanatomical locations?
Brain
Cranial Nerves
Spinal cord
Peripheral nerves
What three things should you assess before touching the animal?
Mental state- cerebral function
Behaviour
Stance and Gait
What does abnormal behaviour look like and what does it indicate?
Aimless walking, circling, aggression and head pressing
Indicates there is a lesion in the cerebrum
If circling, they circle towards the side of the lesion
What information is stance and gait going to give you?
Stance and gait give you information on cerebellar state. If there is a cerebellar problem you will see problems with proprioception. You will see ataxia and maybe a wide based stance
What is cranial nerve VII called and if it was damaged, what would you see?
Facial nerve
Drooping of the ear and upper lip
Nose pulled toward unaffected side
What is cranial nerve VIII called and if it was damaged, what would you see?
Vestibulocochlear nerve
Ataxia, head tilt and nystagmus
What is cranial nerve X called and if it was damaged, what would you see?
Vagus nerve
Paralysis of pharynx and larynx
What is cranial nerve XII called and if it was damaged, what would you see?
Hypoglossal nerve
Problems with prehension, mastication and swallowing
Tongue could be paralysed
Which nerves does the menace response test?
Optic and facial nerves
Which nerves does the palpebral reflex test?
Trigeminal and facial nerve
Which nerves does the corneal reflex test?
Trigeminal, facial and abducens nerves
Which nerves does the pupillary light reflex test?
Optic and oculomotor nerves
What will you see with UMN and LMN disease?
UMN- increased reflexes and muscle tone
LMN- decreased reflexes and muscle tone
Lesions seen above C6 will result in what?
UMN to fore and hind limbs
Lesions seen between C6 and T2 will result in what?
LMN- fore limbs
UMN- hind limbs
Lesions seen between T3 and L3 will result in what?
Normal fore limbs
UMN- hind limbs
Lesions seen between L4 and S2 result in what?
LMN- hind limbs, bladder and decreased anal and tail tone
What are the two types of paralysis?
Spastic- stiff paralysis
Flaccid- floppy paralysis and muscle wasting
What are the four categories of causes of neuro disease in cattle?
Exogenous toxic
Endogenous biochemical
Genetics
Infectious
How does a dam infected with BVD affect her calf?
Cerebellar hypoplasia of the calf causes wide based stance and ataxia
Depending on the stage of gestation when infected, the dam may abort
What are the defining features of a calf born with Akabane virus infection?
Hydraencephaly and arthrogryposis
What is the most common cause of calves with meningo-encephalitis?
Bacterial infection with E. coli and normally happens through the umbilicus
What are the most common signs in calves with meningo-encephalitis?
Recumbency, letharygy, droopy ears and no suckling reflex
Navel and joint ill
Haemorrhages on meninges on PM
How do you treat meningo-encephalitis and what is the prognosis like?
supportive care and NSAIDs are indicated along with ceftiofur but there is generally a poor prognosis
What is the most common sign of otitis media if compared with other neurological diseases?
Head tilt and possible history of respiratory disease
How are spinal abscesses formed and what will you see?
Normally haematogenously spread from the umbilicus and compresses the spinal cord
Not really a good prognosis
What is the most common route of infection for cattle with listeria monocytogens?
Normally infects young cattle at time of tooth eruptions and migrates up the trigeminal nerve. through infected silage or soil
What is the most common manifestation of listeria and what does the clinical presentation depend on?
Meningo-encephalitis
Depends on where the microabcesses occur as to which CNs are affected
What are the most general neurological signs of Listeria
Facial paralysis and head tilt that is normally only unilateral
What signs are almost pathognomonic for Listeria?
Circling, depression and facial paralysis
How are you able to treat listeria?
Pencillin twice daily for 7 days
Supportive fluids and NSAIDs
Prognosis is guarded
How can you prevent listeria?
Prevent soil contamination of silage and correct silage procedures
Can humans get listeria from treating cows?
Not normally directly unless dealing with foetal membranes you will get a rash
Normally from eating foods with it on
What is thrombo-embolic meningo-encephalitis?
Histophilus somni, bacteria get into the brain and joints
normally occurs after resp disease
What will be seen in a case of TEME?
Fever in early stages
Ataxia and knuckling
Ocular lesions and swollen joints
What is a pathognomonic feature of TEME on PM?
Brain infarcts
Should you attempt to treat animals with TEME?
Only if in the early stages
Penicillin and oxytet
Preventing resp disease is best
What causes tetanus and how does it work?
Clostridium tetani
Toxin produced by bacteria spreads via local motor nerves to the spinal cord to illicit its effects
How does the animal become infected with tetanus?
Castration, dehorning procedures or deep puncture wounds
If you think the animal has tetanus, should you go looking for a wound?
No, the would will probably not be found if there is clinical tetanus present (10-14d after infection)
What are the signs of a tetanus infection?
Spastic paralysis, erect ears and bulging eyes
Any noise will induce a spasm
Death
What are the steps to treating tetanus?
- Neutralise the toxin with an antitoxin
- Stop production of toxin with local and systemic penicillin
- Relax the muscles with ACP
Only treat animals in early stages
How can you prevent tetanus?
Vaccination with tetanus toxoid
What is idiopathic tetanus?
Organism enter the GIT by eating roots of infected plants and accumulate there to cause bloat
What is botulism?
Caused by Clostridium botulinum resulting in a flaccid paralysis
How do animals become infected with botulism?
Botulism bacteria grow and germinate in aerobic environments such as rotting carcasses and contaminated tinned food
Cows bone chew due to P def and ingest the toxin that way
Outbreaks are classed into two categories, what are they?
Bone chewing ingestion
Water or feed contamination
Do cows with botulism die due to toxicoses?
No, they die due to the paralysis of the cardiac and respiratory muscles
How do you diagnose and treat botulism?
There is an ELISA snap available
There is an antitoxin available that is only indicated in subacute cases but is rarely used
How is a pituitary abscess formed?
Hamatogenous spread and commonly from placing a bull nose ring
What is a common sign of a pituitary abcess?
Bradycardia
What is Polioencephalomalacia (PEM)?
This is a descriptive term only
Histo lesions in the brain such as necrosis of grey matter
In what kind of cattle does PEM normally occur?
Well fed young growing animals
What are some causes of PEM?
Thiamine def- most common
Lead posionging
Salt/water intoxication
What is the pathogenesis of thiamine defincicy causing PEM?
Abrupt change in diet causes changes in the rumen flora to produced thiaminase type 1 that induces a thiamine (Vit B1) def
What are the classical signs of PEM
Diarrhoea followed by neuro signs
Proprioceptive def, blindness and depression
Hyperaesthetic
Rumen functions normal as oppose to lead poisoning
How do you diagnose PEM?
Signs aren’t specific so you have to get a good history and trial response to IV thiamine admin
When will you not see hypovitaminosis A?
When you have green feed on the ground
Need to be def for at least 6mths
What are the clinical signs of hypovitaminosis A in calves?
Anorexia, illthrift, tapetal bleeding, head pressing and convulsions
What are the clinical signs of hypovitaminosis A in adults?
Abortion and RFM in cows
Low sperm counts in bulls
What is the treatment and prognosis of hypovitaminosis A?
Single injection of vitamin A causes a rapid response but if animals are blind, slaughter is the best option
What age is most affected and what are the sources of lead poisoning?
Younger cattle are more often affected because of their inquisitiveness
Batteries are the most common source
What is a good indication of lead poisoning?
Signs of PEM but has rumen stasis
What are the best samples for diagnosis of lead poisoning?
Whole blood as the lead binds to RBCs
Renal cortex of the kidney on PM contains the highest concentration
Is treatment indicated in lead poisoning?
Can use chelating agents but will have to get them made up
Control seizures with pentobarbitone
How does salt/water intoxication occur?
Water restriction for a period of time followed by unlimited access to it
How does water intoxication cause neuro signs?
Fluid is drawn away from the CNS during deprivation then with rapid rehydration the fluid rushes into the CNS causing cerebral oedema and increased intracranial pressure
What are the most common signs of water intoxication?
Nystagmus, tremor and weakness, head pressing
Red water after ingestion of large amounts of water
How do you diagnose salt or water intoxication?
History
PM: looks like PEM
How does urea poisoning occur?
Urea is soluble so can wash out of the feed and onto the ground into puddles. The cattle can then come along and drink out of these high concentration urea puddles
Urea then bypasses the liver to cross the BBB
What are the initial signs of urea poisoning?
Can be found dead near the source of urea as it can kill in 20mins
Twitching, salivation, bruxism and urination followed by forced and rapid breathing
What is the best way to diagnose urea poisoning?
History and high rumen pH
How can you treat urea poisoning?
Cold water and lots of vinegar
May want to do a rumenotomy and get it out if the animal is valuable
What is perennial rye grass staggers and when is it most likely to occur?
Toxins are lolitrem B and paxilline from a fungus that grows on the plant
Most likely to occur in Jan-Mar when feed is low
What are the signs of PRGS?
Fine until pressure is put on them to move and can have a shakey head and limb movements, ataxia and collapse
How can you diagnose and treat PRGS?
There is no diagnostic test in the live animal
Changes caused by the toxin are reversible if you remove them from the affected pasture
What effect does the ergot alkaloid from rye grass have on cows?
Causes vasoconstriction and subsequently aggravating foot rot
What is paspalum staggers?
No different to PRGS except a different plant
Plant grows in swapy areas and young cattle develop a taste for it
What are the two things needed for Annual ryegrass toxicoses (ARGT) to occur?
Nematode must carry the bacteria to the plant and both must be present for toxicoses to occur
What does ARGT look like?
Can be the sudden death of a healthy animal to start with then you may see animals with wide based stance, hypermetria in forelimbs and ataxia
