Page 815 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

790 CHAPTER 4

VetBooks.ir flutter, muscle fasciculation and weakness may be be administered until the horse has been rehydrated.
Analgesics may be required. Supplementation of
present as a result of hypocalcaemia. Sometimes,
horses may have a stiff gait suggestive of acute myo-
be required and is ideally based on repeated evalu-
sitis. Sudden death occurs in some cases. intravenous fluids with calcium borogluconate may
ation of serum calcium levels. Magnesium supple-
Differential diagnosis mentation is less commonly required. Sucralfate
Other causes of GI, urinary and systemic disease (20 mg/kg p/o q6–8 h) may be useful if gastritis
must be considered, depending on the clinical or EGUS has developed. Administration of broad-
presentation. spectrum antimicrobials is frequently recommended
based on concerns of bacterial translocation from
Diagnosis affected intestine; however, there is little evidence
Clinical and laboratory findings are non-specific. to support this concern. Nephrotoxic antimicrobials
A history of eating alfalfa hay or other alfalfa prod- such as aminoglycosides should be avoided.
ucts supports the suspicion in endemic regions. Treatment of other potentially exposed horses with
Identification of blister beetles in hay is highly sug- mineral oil or activated charcoal may be indicated.
gestive; however, a failure to identify blister beetles
does not rule out the disease. The PCV is usually Prognosis
elevated. Total protein level is usually normal or ele- The prognosis depends on the amount of toxin
vated initially, but hypoproteinaemia may develop ingested and the severity of disease at the time of treat-
over time. Neutrophilia may be present as may hypo- ment but is poor overall. Early and aggressive treat-
calcaemia, hyperglycaemia and hypomagnesaemia. ment is required. Persistent tachycardia, tachypnoea
Serum urea and creatinine levels may be elevated, and elevated CK levels are poor prognostic indicators.
and urinalysis should be performed to differentiate
pre-renal from renal disease. Hyposthenuria may SPASMODIC COLIC
be present for unknown reasons in some cases.
Microscopic haematuria will be evident early in the Definition/overview
disease, with gross haematuria occurring later. An Spasmodic colic is probably the most common type
elevation in creatine kinase (CK) may be present in of colic in adult horses.
severely affected animals and may indicate a poorer
prognosis. Oesophageal and gastric inflammation or Aetiology/pathophysiology
ulceration may be evident endoscopically. The specific aetiology is unclear. An association
Cantharidin can be identified in urine or intesti- between Anoplocephala perfoliata (tapeworm) infes-
nal contents in the first few days of disease; however, tation and spasmodic colic has been reported, and
availability of testing may be limited. Urine (mini- changes in diet and a history of recent anthelmintic
mum 500 ml) or gastric contents (minimum 200 g) administration are important risk factors. Individual
should be submitted. horses may be predisposed to recurrent spasmodic
colic for unknown reasons.
Management Abnormal contractions, or spasms, of the intes-
There is no antidote. Supportive therapy is essential. tine may result in the development of abdominal pain
The hay source should be changed to prevent further through stimulation of stretch receptors. Intestinal
intoxication. Removal of recently ingested canthari- spasms are transient and do not result in intestinal
din may be attempted via administration of mineral obstruction.
oil (4–6 litres per NG tube) or activated charcoal (1–3
g/kg per NG tube). Intravenous fluid therapy with a Clinical presentation
balanced electrolyte solution should be commenced. Affected horses usually display signs of mild to
Administration of diuretics (furosemide, 1 mg/kg moderate abdominal pain, including anorexia, roll-
i/v or i/m q6 h) has been recommended to increase ing, flank-watching, kicking at the abdomen, pawing,
cantharidin excretion; however, diuretics should not recumbency and straining to urinate or defaecate.