Causes of diarrhoea in the adult horse

Question 1

Define what we mean by diarrhoea

Answer 1

Increased frequency and change in consistency of faeces
Some may use it interchangeably with colitis.

Question 2

List 9 causes of acute diarrhoea in adult horses

Answer 2

Salmonella spp.
Clostridium difficile
Clostridium perfringens
Coronavirus
Cyathostomiasis
Antimicrobial Associated
Right Dorsal Colitis
Grain overload
Dietary

Question 3

List 8 clinical signs of diarrhoea

Answer 3

Cow pat to high volume hosepipe D+++
Quiet to depressed
Colic
Fever
Hypovolaemia
SIRS
Laminitis
Secondary infections

Question 4

Why can salmonella be difficult to test for

Answer 4

Is intermittently shed

Question 5

What are the 2 main types of clostrium that cause acute diarrhoea in horses

Answer 5

Clostridium difficile
Clostridium perfringens

Question 6

During a clostridiosis infection what causes disease

Answer 6

toxins produced
they are part of the normal flora in all ages - at these low numbers they don’t produce toxins

Question 7

What is the most important equine parasitic disease

Answer 7

Cyathostomiasis

Question 8

When is Cyathostomiasis most commonly seen

Answer 8

spring –> sudden mass emergence –> clinical disease

Question 9

How does antimicrobial associated colitis cause disease

Answer 9

Disruption of GI flora –> Lack of competition for nutrients –> Pathogenic bacteria able to proliferate

Question 10

What causes right dorsal colitis

Answer 10

NSAID toxicity
often in horses receiving higher than licensed doses
causes ulceration of right dorsal colon

Question 11

Describe how grain overload causes diarrhoea

Answer 11

SI digestion overwhelmed and soluble CHO enters LI
Rapid fermentation by lactic acid producing bacteria lowers pH —>Gram negative bacteria die —-> endotoxin released
Other bacteria overgrow and gut wall becomes compromised —-> Bacteria and toxins enter the circulation

Question 12

List 8 risk factors of acute diarrhoea in adult horses

Answer 12

Gastrointestinal disease
Immunosuppression
Antimicrobials
General anaesthesia
Recent abdominal surgery- especially colic
Hospitalisation
Other horses- silent carriers, or other infected horses
Dietary changes

Question 13

List 6 causes of chronic diarrhoea in adult horses

Answer 13

Salmonella spp.
Cyathostomiasis- can affect colon wall
Right Dorsal Colitis
Sand enteropathy
Inflammatory Bowel Disease
Dietary

Question 14

List 7 clinical signs that can be seen with adult horses with chronic D+

Answer 14

Cow pat to D+++
Bright to depressed
Colic
Fever
Ventral oedema
Weight loss
Electrolyte imbalances

Question 15

what is chronic diarrhoea due to sand also associated with

Answer 15

acute intestinal obstruction

Question 16

list 3 risk factor of sand enteropathy

Answer 16

Pasture access on sandy soil
Overgrazed pastures
Fed on the ground