Equine Diarrhoea Flashcards
How much goes in and is absorbed by the horse intestine?
125 litres per day food and water into proximal GIT
100L/day water absorbed by large colon
Normal horse
poos, weight of poo and % water
8-10 X/day
10-15kg/day
75% water
Normal horse
poos, weight of poo and % water
Diarrhoea in simple terms
8-10 X/day
10-15kg/day
75% water
D+- COLON and LARGE volumes
Usually colitis - inflammation colon or typhlocolitis = inflammation caecum AND colon
The 5 mechanisms that result in D+
- malabsorption
- inc secretion (inflame and toxin elements increasing secretion into GI lumen)
- Osmotic overload
- Abnormal motility
- Extravasation of fluid (oedema)
What part of intestine affected when D+ in horses/
ADULTS- LI must be affected. Just SI = no D+
Foals can occur with just SI disease e.g. rotavirus. More like monogastric! - osmotic d+
Ddx for diarrhoea
- Dietary causes -abnormal fermentation
- Dental disease
- Parasitism e.g. strongylosis(cyathostomosisusually more acute)
- Sand ingestion
- Antimicrobial associated diarrhoea
- Non-steroidal anti-inflammatory toxicity (right dorsal colitis)
- Non-gastrointestinal causes (kidney, liver, heart)
- Infiltrative disorders (chronic inflam. bowel disease)
- Neoplasia (e.g. lymphosarcoma)
- (Chronic salmonellosis)
Ddx for chronic diarrhoea
MUST be extensive colonic pathology - where majority water absorbed and where high bacterioload
• Dietary causes -abnormal fermentation: inc and dec! abnormal motility
• Dental disease - failure to masticate
• Parasitism (one of the most common)e.g. strongylosis(cyathostomosisusually more acute)
• Sand ingestion
• Antimicrobial associated diarrhoea
• Non-steroidal anti-inflammatory toxicity (right dorsal colitis)
• Non-gastrointestinal causes (kidney, liver, heart)
• Infiltrative disorders (chronic inflam. bowel disease)
• Neoplasia (e.g. lymphosarcoma)
• (Chronic salmonellosis- she has never seen)
Presenting clinical signs of chronic D+
- No/Mild dehydration
- Bright/Eating well (NOT SIRS)
- +/-Weight loss
- +/-Polydipsia
- +/-Oedema
Presenting clinical signs of chronic D+
- No/Mild dehydration
- Bright/Eating well (NOT SIRS)
- +/-Weight loss
- +/-Polydipsia
- +/-Oedema (low protein in blood)
Diagnostic investigation D+
• *If pyrexic, rule out Salmonella, Coronavirus (5 faecal
samples for culture, PCR faeces/isolate till sure)
• Check for parasites, sand, teeth (3 most common)
• Check haematologyand biochemistry for inflammation: WBC elevation, acute inflammatory markers: fibrinogen and SAA, inc total protein
• Check plasma protein concentration (often low)
• Peritoneal fluid
• Ultrasound
• Rectal biopsy
• Absorption tests
• Diagnosis < 50% of time
Equine acute D+ aka
SIRS which is interchangeable with Endotoxaemia (endotoxins)
systemic inflammatory response syndrome
Colonitis
Ddx for acute D+ in horse under 9 months
• Important causes – Idiopathic* most common must rule out infectious causes first – Salmonella – Clostridia – Drug-induced: • antibiotics – (Larval cyathostominosis) – (Carbohydrate overload) • OTHERS – Coronavirus – Neoricketsia(USA) = Potomac horse fever
Predisposing factors to equine acute D+
- antibiotic treatment as alters GI flora. any antibiotic
- transport
- competition
- hospitalisation
- surgery
- any stress
Presenting clinical signs acute D+
SIRS cause vast majority of clinical signs. We treat SIRS • Depression - most important • Fever - most important • Tachycardia (80-100 bpm) • Tachypnoea • Congested to purple mm’s - abnormal vasodilation as prostaglandin activation • Slow CRT >2s • Anorexia • Dehydration • Reduced GI sounds • Colic • Diarrhoea – Note: endotoxaemia/SIRS can precede diarrhoea
Pathophysiology of acute D+
• Fluid Loss –multiple causes: –Excess secretion due to inflammation + enterotoxins –Malabsorption –Loss of Na, Cl, K, bicarb and albumin • Mucosal inflammation, ischaemiaand reperfusion injury • Breakdown of GI mucosal barrier –absorption of endo/exotoxins
What plays an important role in horses with acute diarrhoea?
and how
Endotoxaemia/SIRS
How:
Toxins/bacteria = inflamed colon
Straight into hepatic portal vein
Overwhelms the normal clearance mechanism of the liver
= systemic circulation =
SIRS = vicious cycle
How can SIRS lead to remote organ dysfunction?
Endothelium – Thrombosis/phlebitis espJUGULAR • Gastrointestinal – inhibits colonic progressive motility • Integument – equine hoof lamellae, inflammation/endothelial damage and damage to extracellular matrix LAMINITIS • Kidneys – At risk due to direct and indirect (haemodynamic) effects
Infectious causes of equine acute D+
Salmonella and Clostridialdiarrhoea • Salmonella has many serovars –S. Typhimuriummost commonly isolated • Clostridium perfringensand C. difficile –Different toxins confer pathogenicity • Coronavirus • See second year ID lecture
Sources of infection resulting in infectious Diarrhoea
give e.g.s
- asymptomatic shedders or diseased horses
- environmental factors or stressors including:
• High ambient temperature,
• hospitalisation,
• transport,
• antibiotics,
• gastrointestinal surgery,
• immunosuppression
Antibiotic induced diarrhoea
can be caused by any antimicrobial
- in UK particularly penicillin or erythromycin
Diagnostic approach
- determine risk of infectious disease (salmonellosis using faecal culture. Clostridail using ELISA, coronavirus using PCR. ISOLATE animal until results negative
- determine need for supportive therapy - remember we are treating SIRS
What supportive therapy?
- Fluid therapy number 1
- Determine hypovolaemia/ dehydration:
- HR, mentation, urination, PCV/lactate - Assess electrolyte/ albumin/ acid base status
How to work know %dehydration?
clinical signs:
inc HR, inc CRT, variable protein
How to work out the existing volume deficit?
DEFICIT, MAINTENACNE, LOSSES
%dehydration X BW = how much fluid required
Replace over 4-6 hrs
Maintenance requirement 2ml/kg/hr (4 if foal) and add this on top of fluid loss
what % of dehydration is treatable and what is life threatening?
Over 10% = life threatening
Less than 5 treatabe
Animal 12% dehydration, trying to die. What do you give?
FLUIDS, PROTEINS, ELECTROLYTESS
Give max of 4 blouses of isotonic crystalloids
10-20ml/kg over 20-30 mins
Severe hypovolaemia = hypertonic saline 2-4 ml/kh rapidly
colloids up to 10ml/kg esp if hypoalbuminaemia
Acute Diarrhoea given fluids, given protein then what
electrolytes - hartmanns solution
Offer electrolyte solution as well as fresh water. offer food with colitis
