Management of equine diarrhoea

Question 1

Aims of diagnostic investigation

Answer 1

▪Determine likely cause of D++
▪Determine need for supportive therapy
▪Determine need for specific therapy
▪Determine risk to in-contact horses and personnel

Question 2

How much fluid can a 500kg horse with profuse d+ lose a day? What would its fluid requirement be?

Answer 2

• It can lose 100L/day
• Fluid requirement = 125L/day

Question 3

Management – Acute D+ (Young and Adult Horses)

Answer 3

• Fluid Replacement and Electrolytes
• Anti-inflammatories
• Analgesia
• Antimicrobials
• Probiotics
• Adsorbents
• Nutrition

Question 4

Fluid replacement and electrolytes for acute d+ management

Answer 4

• Mild to moderate D+: May maintain hydration with voluntary drinking +/- NGT
• Moderate to severe: IVFT (Hartmans)
• Think about decreased osmotic pressure
  – generally with d+ and colitis they’ll have reduced albumin (losing it from GIT), so decreased oncotic pressure
  – care with rapid boluses for IVFT as decreased oncotic pressure increases their risk of developing oedema
• Many require KCl, some may require NaHCO3 and general Na supplementation

Question 5

Anti-inflammatories for acute d+ management

Answer 5

• Negative effects on colon?

Question 6

Analgesia for acute d+ management

Answer 6

• Minimal to severe abdominal pain
• NSAIDs: Flunixin meglumine (Other COX 2 selective?)
• Temporary relief: Xylazine, detomidine +/- butorphanol
• CRI: Butorphanol, Lidocaine +/- Ketamine

Question 7

Antimicrobials for acute d+ management

Answer 7

• Debateable
• If neutropaenic or signs of sepsis, or signs of complications
• Penicillin IM and Gentamicin IV
• Metronidazole PO for Clostridiosis

Question 8

Probiotics for acute d+ management

Answer 8

• Faecal Transfaunation (Poo soup via NGT)
• Debatable
  – need the right horse which hasn’t had antimicrobials recently
  – worry about other infectious dz that could pass

Question 9

Adsorbents for acute d+ management

Answer 9

• Di-Tri Octahedral Smectite (Biosponge®️)
• Very useful
  – helps bind some of the endotoxins (mainly from clostridia)
• Better to give SID-BID via NGT

Question 10

Nutrition for acute d+ management

Answer 10

• Vital
• Ideally complete pelleted diet- no grain and no hay
• If inappetent – good quality grass hay → anything
• Can add oil (corn oil) for added calories

Question 11

Management of RDC

Answer 11

• Misoprostal may be useful
• Psyllium may be useful

Question 12

Management of cyathostomiasis

Answer 12

• Anthelmintics: Moxidectin
• Pre-treatment with steroids (Dexamethasone or prednisolone)

Question 13

Management of sand enteropathy

Answer 13

• Psyllium
  – binds to the sand
• Magnesium sulphate is also used in combination with psyllium

Question 14

Management of Lawsonia intracellularis

Answer 14

• Doxycycline (antibiotic)
  – Course many weeks

Question 15

Management of Sepsis in acute D+

Answer 15

• Circulatory Support
• Flunixin
• Cryotherapy
• Plasma
• Pentoxyfyline
• Polymixin B

Question 16

Circulatory support for managing sepsis in acute d+

Answer 16

• Mild to moderate D+: May maintain hydration with voluntary drinking +/- NGT
• Moderate to severe: IVFT (Hartmans)
• Think about decreased osmotic pressure
• Many require KCl, some may require NaHCO3 and general Na supplementation
• ± Dobutamine (for bp support)

Question 17

Flunixin for managing sepsis in acute d+

Answer 17

• May help to block parts of the sepsis cascade
• Lower dose?
  – evidence for efficacy of lower dose to combat sepsis cascade, but generally use full dose

Question 18

Cryotherapy for managing sepsis in acute d+

Answer 18

• Critical
• Reduces incidence of laminitis in horses diagnosed with colitis
• Under-utilised
• Important: Constant low hoof temperature
• Often means replacing ice every 2 hours (24h a day)

Question 19

Plasma for managing sepsis in acute d+

Answer 19

• £££ as lots required to make a difference to the protein levels
  – 7-10L for a 500kg horse
• Toxin neutralisation (1-2L for a 500Kg adult horse) → debatable

Question 20

Pentoxyfyline for managing sepsis in acute d+

Answer 20

• ?supresses proinflammatory cytokines
• Increases RBC deformability
• Currently no published controlled clinical trials supporting its use

Question 21

Polymixin B for managing sepsis in acute d+

Answer 21

• Prevents initiation of the pro-inflammatory cascade - Debatable

Question 22

Management of a normovolaemic pt with mild d+

Answer 22

▪ Diet
– Simple grass diet
– Pelleted diet
– No grains
▪+/- Biosponge
▪ Monitoring

Question 23

Management of the neonate

Answer 23

▪Consider referral
▪ IVFT
– Care with sodium and acid base
▪Antimicrobials
– Mostly sepsis related
– FPT
▪GI Rest – 24-48h
– Partial parenteral nutrition (PPN)
– Total parenteral nutrition (TPN)
▪Supportive care ▪Secondary infections

Question 24

Acute Diarrhoea in Adult Horses – What to Test

Answer 24

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

Question 25

When to Isolate the D+ Case

Answer 25

▪2 out of 3 = Isolation
– Pyrexia
– Neutropenia
– Diarrhoea

But most places also recommend isolating pts who have had progressive d+ for over 24-48h, even if they don’t have 2/3^

Question 26

How to Isolate

Answer 26

▪At home vs hospital
▪Separate affected horse
▪Monitor in contact horses
▪ PPE
– overalls, wellies/boots, gloves, hairnet
▪Separate tack, grooming and cleaning equipment
▪Separate water source
– Ideally buckets so can also monitor intake

Question 27

Why is moxidectin the anthelmintic of choice for cyathostomiasis?

Answer 27

• It targets encysted larvae as well as the other lifecycles

Question 28

What can help reduce the volume of IVFT needed?

Answer 28

• variety of water: plain, molasses, electrolytes, etc