Diarrhoea in the adult horse Flashcards
What is diarrhoea?
▪Increased frequency and change in consistency of faeces
▪Some may use the term interchangeably with colitis.
Causes of acute d+ in adult horses
▪Salmonella spp.
▪Clostridium difficile
▪Clostridium perfringens
▪ Coronavirus ▪Cyathostomiasis
▪Anti-microbial Associated
▪Right Dorsal Colitis
▪Grain overload
▪ Dietary
Clinical Signs + Complications of acute d+
▪Cow pat to high volume hosepipe D+++
▪Quiet to depressed
▪Colic
▪ Fever
▪ Hypovolaemia
▪ SIRS
▪ Laminitis
▪Secondary infections
▪Have a significant risk of deteriorating rapidly
Salmonella spp
- Some serovars are zoonotic
- Nosocomial
- Common to have large volume watery D+
– Bacteraemia - Intermittent shedding
Clostridiosis
- Most commonly: Antimicrobial associated and nosocomial
- Part of the normal flora in all ages→Low numbers (Do not produce toxins)
– Toxins produced→disease - Clostridium difficile and Clostridium perfringens mainly
Coronavirus
- Recently emerged as a enteric pathogen→Adults 2011
- Can be associated with outbreaks
- Risk factors not fully understood → Similar to others?
Cyathostomiasis
- MOST important equine parasitic disease
– High prevalence
– Can have severe clinical signs - Pre-patent disease
- Most commonly seen in spring
→ Sudden mass emergence → Clinical disease
– mucosal injury
– ulceration
– inflammation
Antimicrobial associated colitis
- Disruption of GI flora → Lack of competition for nutrients → Pathogenic bacteria able to proliferate
- Obligate anaerobe population of the flora is most important →Antibiotics affecting these have a higher incidence of causing D+
Right Dorsal Colitis
- NSAID Toxicity →Often in horses receiving higher than licensed doses
– Can still occur with normal dose
– Does not have to be long term use
– Can occur in normovolaemic horses at normal doses - Changes GI blood flow
– Affects protective mechanism
– (Multifactorial)
Grain Overload
- History of horse gaining access to large quantity of hard feed
- 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
Dietary
- Imbalance?
- Abnormal fermentation?
- Change in flora?
Risk factors for acute d+
▪ Gastrointestinal disease
▪ Immunosuppression
▪ Antimicrobials
▪ General anaesthesia
▪ Recent abdominal surgery
▪ Hospitalisation
▪ Other horses
– e.g. those acutely infected and actively shedding, or silent carriers intermittently shedding it
▪ Dietary changes
Causes of chronic d+ in adult horses
▪Salmonella spp.
▪Cyathostomiasis
▪Right Dorsal Colitis
▪Sand enteropathy
▪Inflammatory Bowel Disease
▪ Dietary
Clinical Signs + Complications of chronic d+
▪Cow pat to D+++
▪Bright to depressed
▪Colic
▪ Fever
▪Ventral oedema
▪Weight loss
▪Electrolyte imbalances
▪Often normovolaemic
– As able to cope and maintain their hydration status
Sand
▪Often associated with acute intestinal obstruction
▪ However
– Chronic sand-induced D+ is a separate syndrome
– Abnormal accumulation of sand in the large intestine
Risk factors of san causing d+
▪Pasture access on sandy soil
▪Overgrazed pastures
▪Fed on the ground
Inflammatory Bowel Disease
▪Multisystemic eosinophilic epitheliotropic disease (MEED)
▪Granulomatous enteritis
▪Lymphocytic/plasmocytic enteritis/colitis
▪ Lymphosarcoma
Salmonellosis – Risk Factors
- Recent abdominal surgery
- GI dz (small colon impaction)
- Immunosuppression
- Antimicrobials
- GA
- High ambient temp
- Prolonged hospital stay
- Horses actively shedding or carriers
C.difficile
▪More common than perfringens
▪Often associated with antimicrobial associated colitis
▪Could be a reservoir
for human Clostridium
difficile infection
C.perfringens
▪Type A and C most common
▪Toxins produced→disease
▪Seen with haemorrhagic D++
– Mainly neonates but adults too
Clostridiosis – Risk Factors
- Dietary changes
- Hospitalisation
- Antimicrobials
- GI dz
- Not fully understood
Cyathostomins – Life cycle
▪Pre-patent period 6 - 14 weeks
▪Can remain encysted from weeks to 2 Years
▪Encysted, hypobiotic larvae unaffected by most anthelmintics
▪For various reasons, IL3 emerge in Spring, often many many at once
Cyathostomiasis- Risk Factors
▪ Age
▪ Season
▪Period since last anthelmintic
▪Altered host immunity
▪ Stress?
▪Dietary changes?
▪Unknown factors
NSAID side effects in adult horses
Gastrointestinal
* Right dorsal colitis
* MUCH MUCH more common than causing gastric ulceration
Renal
* Medullary crest necrosis
Are ponies or horses more susceptible to NSAID toxicity?
- Ponies
RDC risk factors
▪ NSAID administration
▪ More common with oral phenylbutazone
– Less so with COX-2 selective drugs
Signs of grain (carb) overload
- SIRS
- osmotic d+ due to lactic acid being poorly absorbed
- severe (often-fatal) laminitis
Grain overload- Risk Factors
▪Access to large quantity of grain
▪Amount needed to cause D+ varies
– Horses that are fed diets high in soluble CHO are more resistant
What is a nosocomial infection?
- picked up from or giving it to a hospital
Do dietary causes of d+ tend to cause a mild or severe d+?
- milder
Why can you get ventral oedema as a complication of chronic d+?
- due to chronicity and loss of albumin -> decreased osmotic pressure
Why can sand cause chronic d+?
- irritation of the mucosa
