Dysautonomias- grass sickness and DPJ

Question 1

what is grass sickness

Answer 1

a generalised dysautonomia affecting primarily the enteric nervous system - causes a decrease in GI motility and secretions
Cause unknown

Question 2

what age range is most affected by grass sickness

Answer 2

2-7 years

Question 3

which months of the year is grass sickness most common

Answer 3

april- july
peak in may

Question 4

List 6 risk factors for grass sickness

Answer 4

Horses on pasture
Stress
Domesticated birds in the same field
Good-fat BCS
Cool, dry weather between 7-11 degrees
Frequent worming

Question 5

How does grass sickness cause disease

Answer 5

Decrease in GI motility from mouth to anus with a decrease in GI secretions

Question 6

List the 3 types of grass sickness and what are the survival times associated with them

Answer 6

Acute - die rapidly/found dead- >2 days
Sub acute - > 7 days
Chronic - some survive

Question 7

List 7 clinical signs associated with acute grass sickness

Answer 7

Severe gut paralysis - colic
Dysphagia
Nasogastric reflux
Mucous coated droppings
Muscle tremours
Sweating
Tachycardia (60-80bpm)

Question 8

List 6 clinical signs associated with sub-acute grass sickness

Answer 8

Similar to acute but less severe
Dysphagia
Mild-moderate colic
sweating
Muscle tremors
Rapid weight loss
tucked up appearance

Question 9

What is the prognosis for a horse with acute grass sickness

Answer 9

prognosis for recovery= hopeless
Usually die or are euthanised within 2 days of clinical signs

Question 10

what is the prognosis for a horse with sub-acute grass sickness

Answer 10

May die or be euthanised within 1 week of clinical signs- still bad prognosis

Question 11

List 4 clinical sign associated with chronic grass sickness

Answer 11

Mild/intermittent colic
Reduced appetite
Difficulty eating
Rapid/severe weight loss/emaciation

Question 12

Describe the prognosis of chronic grass sickness

Answer 12

some may recover

Question 13

What are the diagnositic tests for grass sickness

Answer 13

Ileal biopsy- best
rectal biopsy- not used as much as lower sensitivity

Question 14

what do you require to do an ileal biopsy

Answer 14

requires a laparotomy - which decreases the likelihood of survival

Question 15

where is the pathology found in acute and chronic grass sickness

Answer 15

chronic= localized to ileum
acute= generalized intestinal pathology

Question 16

Describe what will you see on histology on an ileal biopsy

Answer 16

Neuronal degeneration within ganglia
Depletion of ganglia
Vacuolation

Question 17

What is the phenylephrine test

Answer 17

Topical application of 0.5% phenylephrine to one eye​
examination 30 minutes later ​

used to help diagnose grass sickness

Question 18

what is a positive result to the phenylephrine test

Answer 18

reversal of the ptosis in that eye, increase in angle between the corneal surface and the eyelash

Question 19

list a disadvantage of phenylephrine test for using to diagnose grass sickness

Answer 19

false positives seen

Question 20

What can you see on oesophageal endoscopy which can help confirm diagnosis of grass sicknesss

Answer 20

Linear oesophageal ulcers
Many don’t have these though

Question 21

Describe how to treat grass sickness

Answer 21

Intensive and prolonged Nursing
Symptomatic therapy
Analgesia
Feeding
Appetite stimulation - diezepam
prokinetics- neostigmine

Question 22

why is giving analgesia important to treat grass sickness

Answer 22

Promotes voluntary feeding – reduces pain associated with swallowing and abdominal pain

Question 23

describe how to feed a horse with grass sickness

Answer 23

small feeds every 30-60mins
hand grazing
varied diets
hand feeding (don’t leave horse to eat)

Question 24

How is a diagnosis of grass sickness fully confirmed

Answer 24

At post-mortem
samples from cranial cervical ganglion and tested

Question 25

List 3 ways to prevent grass sickness

Answer 25

Cause unknown
Stabling the animals during the spring and early summer
Stable during prolonged dry weather around 7-11 degrees
Don’t use “bad” pastures where cases have occurred before