Diarrhoea and colitis in horses (Colitis (Diagnosis (Clinical signs,…
Diarrhoea and colitis in horses
Inflammation of the colon (and usually caecum) due to Clostridium (difficile, perfringens) and/or Salmonella spp. May be due to antimicrobial dysbiosis.
Salmonellosis occurs when there is appropriate host (immune status, pain), bacterial (pathogenicity, dose) and environmental (stress) factors. It invades caecal/colonic mucosa and produces enterotoxin.
Diarrhoea (+/- haemorrhage), depression, dehydration, endotoxaemia, abdominal distension/pain.
Hyponatraemia, hypoalbuminaemia, dehydration
Often indistinguishable from an intestinal accident. Consider cyathostomes and right dorsal colitis (e.g. NSAIDs).
Rectal exam/NGT - differentiate from intestinal accident or proximal colitis
Abdominocentesis: differentiate from abdominal accident
Ultrasound: thickened and fluid-filled colon
Faecal PCR/culture, but causative agent rarely identified
Antibiotics in acute undifferentiated diarrhoea contraindicated, but indicated if severe neutropaenia or septic foci. Specific pathogen ID warrants specific antimicrobial use - if Clostridial use metronidazole, if leukopaenic use Pen/Gent.
Fluid therapy usually 10-20 mL/kg/hr
Low-dose flunixin (if endotoxaemic)
Distal limb cryoptherapy to prevent endotoxaemic laminits
Isolation if Salmonellosis suspected or confirmed (zoonotic)
General diagnostic approach to acute febrile diarrhoea
Haemoconcentration, leukopaenia, azotaemia, hypoNa, hypoCl, hypoK, hypoCa, metabolic acidosis
Assess small/large intestinal wall thickness, peritoneal fluid/character (+/- fibrinous flecks)
Common DDx for diarrhoea in the adult horse
Refer to colitis
Refet to colitis
Anorexia, lethargy, fever +/- diarrhoea and colic
Diagnosed using faecal PCR
Treatment and supportive care for acute diarrhoea
Replace volume deficit at 10-20 mL/kg/hr
Contraindicated for undifferentiated diarrhoea
Indicated with ID of causal agent (not Salmonella)
Metronidazole for Clostridiosis
Pen/Gent if leukopaenic
0.25 mg/kg to limit endotoxaemia
Other supportive therapy
Distal limb cryotherapy
Enteral nutrition + electrolytes
Parenteral nutrition (sometimes)
Low-bulk diet (when eating again)