Endurance horses with colic have ‘excellent’ prognosis
MedWire News: Competing endurance horses who develop colic can have a good prognosis if treated appropriately, say US veterinarians.
They say that owners of horses with colic can be reassured about their animals' likely outlook, even in the presence of severe clinical and laboratory derangements.
Colic is a major cause of morbidity in endurance horses and can lead to elimination during competition. Horses with colic frequently present for emergency medical care, but their management can be complicated by the presence of hydration and electrolyte derangements that are related to competition rather than colic per se.
In this case series, Langdon Fielding and Julie Dechant, from the University of California in Davis, describe 36 consecutive cases of horses presenting with colic to two equine referral centers during a 5-year period.
There were 27 geldings, eight mares, and one stallion, and 33 were Arabian horses. Their mean age was 12 years and they presented on average 8 hours after the onset of colic symptoms.
Initial physical examination revealed decreased gastrointestinal sounds in 30 horses and a prolonged capillary refill time in 14 horses. Rectal examination found a distended intestine in eight horses and hard/dry manure in nine, with the remainder being classified as unremarkable.
Ultrasound examination was performed in 26 horses and revealed decreased motility or distension of the small intestine in 12 cases. Other findings included increased abdominal fluid, a gas-distended large colon, and increased large colon wall thickness.
Nineteen horses underwent abdominal X-ray, which showed gas distension in 11 horses, sand in two horses, and small metallic foreign bodies in one horse. Abdominocentesis in 15 horses was abnormal in four animals, finding serosanguinous liquid.
In terms of treatment, horses received an average of 2 L/hour of intravenous (iv) fluids during the first 24 hours of hospitalization. Sixteen horses were given flunixin meglumine, 10 received intravenous lidocaine, and one had an infusion of metoclopramide.
The final diagnoses included salmonellosis in three horses and enteritis of the proximal intestine in another three horses. Four were diagnosed with large colon impaction and four with a large colon displacement. Ileus was considered the primary cause of colic in nine horses, gastric ulcers were diagnosed in two, and a large colon fecolith in five horses. Five horses underwent exploratory abdominal surgery.
Just one horse died. This animal presented with a perforated gastric ulcer and was euthanized. Analysis of the remaining animals identified two independent predictors for length of hospitalization: total quantity of intravenous fluids and prior metabolic eliminations, which positively and negatively correlated with the outcome, respectively.
Writing in the Equine Veterinary Journal, Fielding and Dechant say that endurance horses with colic "appear to have an excellent prognosis" although some require prolonged hospitalization.
"Amounts of gastric reflux can be substantial and large volumes of iv fluids may be required to replace ongoing losses and deficits," they write. "Surgical lesions are uncommon despite significant abdominal pain, and therefore medical management appears a viable option in most cases."
By Joanna Lyford