Equine Neuropathies

Question 1

Which pathoegn causes tetanus and how does it usually enter the body?

Answer 1

Clostridium tetani
Entry via a deep wound

Question 2

Describe how clostridium tetani causes spastic paralysis

Answer 2

Necrosis and pus is anaerobic allowing for spore formation.
Exotoxin is produced
This enters the bloodstream and nerve axons.
They move to the CNS presynpatic inhibitory interneurones, inhibiting neurotransmitter release here.
Inhibits inhibition.
Spastic paralysis

Question 3

List the four parts of the treatment of tetanus

Answer 3

Interruption of toxin production
Neutralising unbound toxin
Control of muscular spasms
Supportive care

Question 4

How should pregnanct mares be vaccinated for tetanus?

Answer 4

Booster 4-6 weeks before foaling

Question 5

Describe how the botulism toxin works in a horse to cause disease.

Answer 5

Toxin acts pre-synaptically at the peripheral cholinergic neuromuscular junction.
Prevents synaptic vesicle from releasing acetylcholine
Flaccid paralysis
Once toxin is bound, recovery only by regeneration of new motor end plates

Question 6

What are the three mechanisms of clinical botulism in horses?

Answer 6

Forage poisoning
Wound botulism
Toxicoinfectious botulism

Question 7

What is the pathogenesis of equine grass sickness?

Answer 7

Altered autonomic activity
Decreased intestinal peristalsis
Decreased ileus leading to colonic impaction

Question 8

What is the best method of diagnosis of equine grass sickness?

Answer 8

Ileal biopsy

Question 9

What is trigeminal-mediated headshaking?

Answer 9

Neuropathic facial pain conditions due to threshold potential of infraoribtal nerve being lower than other normal nerves