Colitis X

Description

Colitis X (so-called due to its unknown aetiology) is a peracute and highly fatal disease of horses. Is characterised by severe oedematous colitis, sudden watery diarrhoea and death within 24 hours. A number of possible underlying causes have been described, including drug or parasite hypersensitivity, salmonellosis and high-protein, low-cellulose diets. Recently a link has been demonstrated with the current human epidemic strain of C. difficile (ribotype 027/toxinotype III) clostridial enterocolitis. Stress (such as surgery or transport) has also been reported as a predisposing factor.

Signalment

Colitis X affects adult horses, usually between one and ten years old.

Clinical Signs

Abdominal pain
Acute onset watery to haemorrhagic diarrhoea
Tachycardia (Heart rate often greater than 100bpm)
Dehydration
Signs relating to hypovolaemic or endotoxic shock, e.g. congested mucous membranes, prolonged capillary refill time, cold extremities.
Dilated pupils
Collapse
Body temperature may vary from pyrexic to subnormal
Bowel sounds may be absent

The clinical signs are similar to those described for other forms of acute- peracute colitis, therefore a number of differential diagnoses may need to be considered.

Diagnosis and Pathology

Diagnosis is often made post-mortem, where a hyperaemic or oedematous caecum and ventral colon may be seen with necrosis of the intestinal in the later stages of the disease. Numerous gram negative bacteria may be identified in the mucosa and submucosa. The intestinal tract may be filled with a foul smelling and watery content. Macroscopic and microscopic findings include signs of disseminated intravascular coagulation and large numbers of bacteria in the devitalized parts of the intestine.

Treatment

Treatment is often unsuccessful and horses may often require euthanasia. Treatment methods previously reported include aggressive fluid therapy with electrolyte replacement, antibiotics and analgesics. It is recommended that flunixin is used for both its analgesic and anti-endotoxic properties.

Prognosis

The prognosis is usually poor, with a mortality rate approaching 90-100%. This may be lower for horses receiving intensive treatment.

References

Glenn Songer, J., Trinh, H.T., Dial, S.M., Brazier, J.S., Glock, R.D. (2009) Equine colitis X associated with infection by Clostridium difficile NAP1/027 Journal of Veterinary Diagnostic Investigation 21:377–380

Diakakis, N. (2008) Equine colitis X Journal of the Hellenic Veterinary Medical Society (Hellenic Veterinary Medical Society) 59:23–28(6)

Schiefer HB (1981). Equine colitis "X", still an enigma? The Canadian Veterinary Journal. La Revue Vétérinaire Canadienne 22 (5):162–5

White, N.A., Edwards, G.B. (1999) Handbook of Equine Colic Reed Educational and Professional Publishing Ltd

Knottenbelt, D.C. A Handbook of Equine Medicine for Final Year Students University of Liverpool

Edward Robinson, N and Sprayberry, K. A. (2009) Current Therapy In Equine Medicine Sixth edition Saunders Elsevier

Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial

Giles, C.J., Urquhart, K.A. and Longstaffe, J.A. (1985) Larval cyathostomiasis (immature trichonema-induced enteropathy): A report of 15 clinical cases Equine Veterinary Journal 17, 196-201

Murphy, D., Keane, M.P. and Goulding, R. (1997) Cyathostome associated disease in the horse: investigation and management of four cases Equine Veterinary Journal 9 247-252