Diarrhoea in Horses and Foals Flashcards Preview

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Flashcards in Diarrhoea in Horses and Foals Deck (18)

How does the function of the colon in foals differ to that of adult horses? In this case, how does the pathophysiology of diarrhoea in these age groups differ?

Foals have a less well developed colon as they gain nutrition from milk. Therefore most of their nutrient and fluid absorption occurs in the small intestine.

Horses - LI problems result in diarrhoea
Foals - SI mainly but also LI


How is the differential list narrowed down in equids?

AGE of animal
Duration of signs - less helpful
History/risk factors


What are the most common causes of diarrhoea in neonatal foals, and which are not exclusive to this age group(indicated by *)?

Foal heat diarrhoea
Viral (rotavirus - generally <6mo)


What are older foals more likely to be affected by?

Proliferative enteropathy

(Infection by Lawsonia intracellularis which invades enterocytes and causes hyperplasia of immature crypt cells so malabsorption ensues)


How likely is diagnosis of a specific condition in horses?

Unlikely - most cases of diarrhoea go undiagnosed.


What questions need to be asked at history taking to narrow down the differential list for equine diarrhoea? Think about risk factors.

Regular anthelmintics (may want to include management and whether anthelmintics are swapped frequently)
Antibiotic treatment
Other animal contact


Why might a specific diagnosis be useful?

Incase the cause is infectious or zoonotic or whether there is a specific treatment available.


What are the principles of therapy for diarrhoea?

Address fluid loss, inflammation/endotoxaemia, address the specific cause.


What needs to be included when assessing how much fluids to replace?

Replace losses
Ongoing losses


When will a horse suffer from endotoxaemia?

When the normal mucosal barrier breaks down.


How does endotoxin lead to its clinical signs?

Endotoxin interacts with cells e.g. macrophages. This initiates systemic inflammation which can lead to CV and GI dysfunction, shock and organ failure and death.


What are the clinical signs of endotoxaemia?

Depression, tachycardia, tachypnoea, fever, colic, diarrhoea, hyperaemic 'toxic' MMs.


What is seen on a leukocyte profile of a horse with endotoxaemia?

Low WBCs, neutrophils and increased band neutrophils


What are the principles of endotoxaemia treatment?

Prevent access to circulation (surgery)
Neutralise endotoxin
Prevent synthesis/release of inflammatory mediators
Prevent endotoxin induced cellular activation


Which drugs are available in the UK that can treat endotoxaemia and what do they do?

Polymixin B - directly binds endotoxin
Pentoxifylline - prevents cellular release of inflammatory mediators (but not that effective)
Flunixin - an NSAID so prevents PG synthesis.


How does endotoxaemia differ in pathogenesis in foals?

In foals it is likely a result of a systemic bacterial infection.


How does treatment for foals with endotoxaemia differ to that of adults and why?

More concern with nephrotoxicity so anti-endotox drugs not as safe.

Treatments include plasma and antibiotic application


Outline how a decision to refer a horse suffering from diarrhoea is made.

Horses needing constant attention probably need to be referred as they need lots of fluid - not feasible in practice.

Foals don't need as much fluid so it is a bit more practical to treat at home. Would need to bolus if doing this though and they can deteriorate very rapidly!

If contagious then need good isolation facilities which may only be available in hospital.