EQUINE VETERINARY EDUCATION / AE / JANUARY 2017
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Diagnosis
A presumptive diagnosis of EGUS requires a thorough history, physical examination and response to treatment, but a definitive diagnosis can only be made with a gastroscopic examination. There are no pathognomonic signs that suggest a diagnosis of EGUS. A definitive diagnosis for gastric ulcers requires an endoscope (video or fibreoptic) of 2.5–3.0 m in length. Standing gastroscopy procedures have been described in detail elsewhere in the literature and a 2.5 m or longer endoscope is required to examine the squamous and glandular mucosa adequately and a 3.0 m endoscope to visualise the pylorus antrum and proximal duodenum in most mature horses (Murray et al. 2001; Andrews et al. 2002). With the recognition that populations of horses have lesions around the pyloric antrum, every attempt should be made to visualise this area. Use of a gastric ulcer scoring system allows clinicians to compare gastroscopic findings, monitor ulcer healing and evaluate treatment efficacy (MacAllister et al. 1997; Andrews et al. 1999a,b).
Management
Pain relief, healing and prevention of secondary complications are the primary goals of antiulcer therapy and management changes. The mainstay of pharmacological EGUS treatment is to increase stomach pH by suppressing HCl acid secretion. Because of a high recurrence of squamous ulcers after successful treatment, effective acid control should be followed by nutritional and dietary management strategies, which might include preventative doses of antiulcer medications (Andrews et al. 1999b; McClure et al. 2005).
Pharmacological therapy To the authors’ knowledge, the efficacy of management changes has not been specifically documented in the peer reviewed literature and the high prevalence (48%) of squamous ulcers observed in endurance horses during the noncompetition season (Tamzali et al. 2011) suggests that a reduction in work alone is not enough to prevent the disease. Theoretically, removal of the horse from the risk factors that caused the condition in the first place and re-establishment
Dosage
of a normal pH gradient in the stomach should result in healing. However, anecdotally it appears that even when removal from the risk factors is possible, acid suppression therapy is often required to restore a normal appetite so that enough roughage is consumed to re-establish the pH gradient in the stomach providing a permissive environment to allow healing, especially in horses with weight loss and/or decreased appetite. Furthermore, the ability to remove risk factors, such as exercise and concentrate diets is often limited, so the use of acid suppression therapy remains a cornerstone in the management of squamous ulcers. Therefore, once ulcers are observed, pharmacological therapy – omeprazole or other effective agents – should be initiated, especially while horses remain in athletic training (Murray et al. 1995; Andrews et al. 1999b) (Table 1).
Environmental, nutritional and dietary management Without alterations in management or initiation of preventative therapy, squamous ulcers will quickly return if horses are maintained in training (Andrews et al. 1999b). Unfortunately, glandular ulcer recurrence has not been evaluated. Reducing exercise intensity, increasing pasture turnout and amending dietary risk factors might help decrease ulcer severity and the risk of recurrence in squamous ulcers, but it is unknown if this will prevent recurrence of glandular ulcers. The following recommendations are primarily for squamous ulcers, but might have a positive effect on glandular ulcers.
Modification of exercise intensity and duration Intense exercise, racing, and race training have been shown to contribute to worsening of squamous ulcers in horses (Vatistas et al. 1999a,b; Nieto et al. 2009) and pasture turnout or change in management might improve the condition.
Pasture turnout Horses housed in pastures and constantly grazing, overall, seem less likely to have squamous ulcers. Stall-confinement generally has been associated with an increased risk of squamous ulcers, which therefore might not improve in stall- confined horses even when horses are fed grass hay ad libitum. While pasture turnout may be helpful in controlling squamous ulcers, the presence of certain other ‘stressors’ and
TABLE 1: Currently suggested pharmaceutical therapy for treatment and prevention of EGUS Drug*
Omeprazole Ranitidine
Famotidine Misoprostol†,‡
Sucralfate
AlOH/MgOH antacids Bethanecol
Erythromycin lactobinate 0.5–1.0 mg/kg bwt
4 mg/kg bwt (treatment) 1 mg/kg bwt (prevention) 1.5 mg/kg bwt 6.6 mg/kg bwt 10.0 mg/kg bwt 0.3 mg/kg bwt 2.8 mg/kg bwt 5 lg/kg bwt
20–40 mg/kg bwt
30 g AlOH/15 g MgOH 0.025–0.3 mg/kg bwt 0.3–0.45 mg/kg bwt 0.1–1.0 mg/kg bwt
Orally
Intravenously Orally Orally
Intravenously Orally Orally Orally Orally
Subcut. Orally
Intravenously
Route of administration Intravenously
Dose interval q. 24 h
q. 24 h
q. 6 h q. 8 h
q. 12 h q. 12 h q. 12 h q. 8 h q. 8 h q. 2 h
q. 3–4h q. 6–8h
Undetermined
*Cimetidine is not recommended for treatment or prevention of EGUS. †May cause colic signs. ‡Do not give to pregnant mares as it may cause premature delivery or spontaneous abortion.
© 2015 EVJ Ltd
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