Toxicology (Yr 3)

Question 1

what are some neurotoxins?

Answer 1

deadly nightshade
hemlock
flatweed
bracken fern
mares tail
endophyte infected ryegrass
mouldy corn
botulism
blue-green algae
lead

Question 2

what toxin does does deadly nightshade have in it?

Answer 2

tropane alkaloid (anticholinergic)

Question 3

what are the clinical signs of deadly nightshade poisoning?

Answer 3

(atropine related)
mydriasis
shivering/spasms
tachycardia
dry mucous membranes
colic
haematuria

Question 4

is there an antidote for deadly nightshade?

Answer 4

yes - neostigmine (easy to overdose)

Question 5

how can hemlock be distinguished from cow parsley?

Answer 5

hemlock has irregular purple blotches on the stems

Question 6

how does hemlock cause poisoning?

Answer 6

paralysing skeletal muscle motor nerve endings

Question 7

what are the clinical signs of hemlock poisoning?

Answer 7

agitation, nervousness, twitching
seizures
salivation
dilated pupils
muscle weakness, cardiac abnormalities, breathing difficulty (die from this)

Question 8

how does hemlock cause death?

Answer 8

paralysis of respiratory muscles

Question 9

what are the clinical signs of flatweed similar to?

Answer 9

stringhalt (sudden hyperflexion of hindlimbs)

Question 10

how is bracken fern toxic?

Answer 10

thiaminase activity (leads to vitamin B1 deficiency)

Question 11

what are the clinical signs of bracken fern poisoning?

Answer 11

anorexia
cardiac dysrhythmias
crouched stance, arched neck
incoordination, convulsions

Question 12

what is the pathogenesis of mares tail?

Answer 12

thiaminase (cause B1 deficiency)

Question 13

what are the clinical signs of rye grass staggers (ergot)?

Answer 13

trembling, unsteadiness
erratic/anxious behaviour

Question 14

how is rye grass staggers treated?

Answer 14

remove them from infected pasture

Question 15

what causes botulism?

Answer 15

Clostridium botulinum

Question 16

what are the clinical signs of botulism?

Answer 16

flaccid paralysis and dysphagia

Question 17

what is the main sign of lead poisoning?

Answer 17

dysphagia

Question 18

what are the clinical signs of lead poisoning?

Answer 18

peripheral nerve dysfunction
depression
laryngeal/pharyngeal paralysis
facial paralysis
blindness, seizures, death

Question 19

what are the main cardio-respiratory toxins?

Answer 19

sorghum
foxglove
oleander
yew
rhododendron
monensin

Question 20

what is monensin?

Answer 20

coccidiostat used in poultry

Question 21

when does monensin poisoning occur in horses?

Answer 21

when horses eat chicken feed containing monensin

Question 22

what are the main hepatotoxins of horses?

Answer 22

pyrrolizidine alkaloid containing plants
aflatoxins

Question 23

what are the signs of liver failure from pyrrolizidine alkaloid toxicity?

Answer 23

weight loss
jaundice
dull/depressed
muscles tremors/weakness
yawning
inappetence
photosensitisation
neurological

Question 24

what is the most common plant containing pyrrolizidine alkaloid?

Answer 24

ragwort

Question 25

what is the main myotoxin?

Answer 25

sycamore

Question 26

what are the clinical signs of sycamore poisoning?

Answer 26

weakness/fasciculations recumbency red urine marked elevation of muscle enzymes

Question 27

what is the main enterotoxin plant?

Answer 27

oak

Question 28

what are the clinical signs of oak poisoning?

Answer 28

colic, tenesmus haemorrhagic diarrhoea

Question 29

how can you tell a horse has leukocytoclastic vasculitis rather than photosensitisation?

Answer 29

will be on the medial and lateral aspect of the limb (photosensitisation will mainly be on the lateral aspect)