Gayle Hallowell

A comparison of two doses of omeprazole in the treatment of equine gastric ulcer syndrome: A blinded, randomised, clinical trial

REASONS FOR PERFORMING THE STUDY Studies on omeprazole have reported that doses as low as 0.7 mg/kg bwt per os are potent suppressors of acid production. Yet, to date, no studies have compared treatment efficacy of different doses in clinical cases of equine gastric ulceration. Furthermore, no studies have been performed to compare the healing response of the squamous and glandular mucosa to acid suppression therapy. OBJECTIVES To compare: 1) the efficacy of 2 doses of omeprazole in the treatment of primary squamous and glandular gastric ulceration; and 2) the healing response of primary squamous and glandular gastric ulceration to acid suppression therapy. STUDY DESIGN A blinded, randomised, dose-response clinical trial. METHODS Twenty Thoroughbred racehorses with grade ≥2/4 glandular ulceration were identified on gastroscopy. Seventeen horses also had grade ≥2/4 squamous ulceration. Horses were randomly assigned to one of 2 groups. Horses received either 2.0 g (high dose: 4.0 mg/kg bwt) or 0.8 g (low dose: 1.6 mg/kg bwt) of oral omeprazole per os once daily. Gastroscopy was repeated at 28-35 days. RESULTS Time and dose significantly affected grades of squamous (P<0.0001, P = 0.02) and glandular (P = 0.006 and 0.005) ulceration. Data analysis did not support our hypothesis that the lower dose would have similar effects (i.e. be noninferior) to the higher dose when considering ulcer healing and ulcer improvement. Improvement was more likely with the high dose for the squamous (P = 0.05) but not glandular (P = 0.4) mucosa. The percentage of glandular ulcers that improved was less than squamous ulcers (P = 0.02). CONCLUSIONS The results suggest that a dose-response exists for the treatment of both squamous and glandular ulcers. Improvement of glandular ulcers was not as complete as observed with squamous ulcers and current equine gastric ulcer syndrome treatment recommendations may not be appropriate for glandular disease.

A comparison of three doses of omeprazole in the treatment of equine gastric ulcer syndrome: A blinded, randomised, dose–response clinical trial

REASONS FOR PERFORMING THE STUDY A previous study demonstrated that a dose effect between 1.6 and 4.0 mg/kg bwt of omeprazole per os s.i.d. is present in the treatment of equine gastric ulceration. In the same study, healing of glandular ulceration appeared inferior to healing of squamous ulceration. However, several limitations were recognised in that study and further investigation is warranted. OBJECTIVES To further investigate the presence of a dose relationship in the treatment of gastric ulceration under conditions that may favour omeprazole efficacy such as administration prior to exercise and after a brief fast, and potential differences between the response of squamous and glandular ulceration to omeprazole therapy. STUDY DESIGN A blinded, randomised, dose-response clinical trial. METHODS Sixty Thoroughbred racehorses with grade ≥2/4 squamous and/or glandular ulceration were identified by gastroscopy. Horses were randomly assigned to receive either 1.0, 2.0 or 4.0 mg/kg bwt of enteric coated omeprazole per os s.i.d. 1-4 h prior to exercise. Gastroscopy was repeated at approximately 28 days. RESULTS The lower doses studied (1.0 and 2.0 mg/kg bwt) were noninferior to the reference dose (4.0 mg/kg bwt) in the treatment of squamous ulceration. Healing was greater in squamous ulceration than glandular ulceration (86% vs. 14%; P<0.0001). Improvement in ulcer grade was more likely in squamous lesions than glandular lesions (96% vs. 34%; P<0.0001). Worsening of the glandular ulcer grade was observed in 36% of horses. CONCLUSIONS The results of this study suggest that, under the conditions studied, where omeprazole is administered before exercise and following a brief fast, doses of omeprazole as low as 1 mg/kg bwt per os s.i.d. may be as effective as higher doses. The proportion of glandular ulceration that heals with 28 days of omeprazole therapy is less than that of squamous ulceration.

Retrospective study assessing efficacy of treatment of large colonic impactions

Cases with a history of colic due to a large colonic impaction were recruited retrospectively to assess the treatment efficacy and complications of oral and parenteral fluid therapy regimes for correction of primary large colon impactions. Oral isotonic fluids had been administered at varying intervals following initial treatment with magnesium sulphate and water. There was no significant difference in complication rates between groups. Considering complication rates with impaction clearance, hourly administration of oral fluids appears to be the most appropriate treatment regime of those investigated.

Reliability of quantitative echocardiography in adult sheep and goats.

BackgroundEchocardiography is a non-invasive method for assessment of the ovine and caprine heart. Complete reference ranges for cardiac dimensions and time indices for both species are not currently available and reliability of these measurements has not been evaluated. The objectives for this study are to report reliability, normal cardiac dimensions and time indices in a large group of adult sheep and goats.Fifty-one adult sheep and forty adult goats were recruited. Full echocardiographic examinations were performed in the standing unsedated animal. All animals underwent echocardiography four times in a 72-hour period. Echocardiography was performed three times by one author and once by another. Images were stored and measured offline. Technique and measurement repeatability and reproducibility and any differences due to animal or day were evaluated. Reference ranges (mean ± 2 standard deviations) were calculated for both species.ResultsMajority of the images obtained were of good to excellent quality. Image acquisition was straightforward with 5.4% of animals demonstrating a small scanning window. Reliability was excellent for majority of dimensions and time indices. There was less variation in repeatability when compared with reproducibility and differences were greater for technique than for measurements. Dimensions that were less reliable included those for right ventricular diameter and left ventricular free wall. There were many differences in cardiac dimensions between sheep and goats.ConclusionsThis study has demonstrated that specific reference ranges are required for these two species. Repeatability and reproducibility were excellent for the majority of cardiac dimensions and time indices suggesting that this technique is reliable and valuable for examination of clinical cases over time and for longitudinal research studies.

Administration of trimethoprim-sulphadimidine does not improve healing of glandular gastric ulceration in horses receiving omeprazole: a randomised, blinded, clinical study

BackgroundInterest in Equine Gastric Ulcer Syndrome (EGUS) has recently increased in part due to a growing awareness of the differences between squamous and glandular disease. The pathophysiology and epidemiology of squamous and glandular disease are different and recently it has been shown that the response of glandular gastric ulceration to monotherapy with omeprazole is poor. Given these differences it has been recommended that specific treatment guidelines be formulated for equine glandular disease and that adjunctive therapies be investigated. Along these lines it has been suggested that the addition of antimicrobials may enhance healing. The objective of this study was to investigate whether the addition of trimethoprim-sulphadimidine to omeprazole therapy would result in superior healing of naturally occurring equine glandular ulceration compared with omeprazole monotherapy.ResultsCombination therapy of omeprazole plus trimethoprim-sulphadimidine could not be demonstrated to be superior to omeprazole monotherapy. Healing of the glandular mucosa was observed in 7/15 (47%; 95% CI 24 to 71%) and 3/13 (23%; 95% CI 7% to 50%) of horses in the TMPS and OMEP groups, respectively (OR = 1.8; 95% CI 0.32 to 10.0; p = 0.67). Improvement of the glandular mucosa was observed in 12/15 (80%; 95% CI 56 to 94%) and 9/13 (69%; 95% CI 42 to 89%) of horses in the TMPS and OMEP groups, respectively (OR = 2.9; 95% CI 0.6 to 15.0; p = 0.25).ConclusionsThe results of the present study do not support the addition of trimethoprim-sulphadimidine to therapeutic protocols for equine glandular ulceration. Several limitations were present in the study and the use of antimicrobials as an adjunctive treatment warrants further investigation. However, given the potential deleterious consequences associated with the indiscriminate use of antimicrobials, the inclusion of antimicrobials in treatment regimes for EGUS is not justified until their efficacy is further validated.

Labial fusion causing urinary tract obstruction in an alpaca cria.

CONGENITAL vulval deformities have been reported in many species, including human beings (Klein and others 1989, Norbeck and others 1993), camels (Ramadan 1997), cattle (Oettle and Coubrough 1985), llamas (Lopez and others 1998) and marmosets (Isachenko and others 2002). Wilkins and others (2006) reported six cases of congenital vulval abnormalities in alpacas seen in the USA. To the authors’ knowledge, this short communication describes the first case reported in alpacas in Europe. A six-hour-old female alpaca cria was presented at the Royal Veterinary College as an out-of-hours emergency due to a vulval swelling. The referring veterinary surgeon suspected an imperforate vulva, and the owners reported that they had not seen the animal urinate. The cria had had an uneventful birth and had behaved normally. It came from a large commercial establishment, where other congenital anomalies, such as cleft palate, had been reported, but not ones involving the urogenital system. Physical examination was unremarkable, other than the swollen vulva and no identifiable vulval opening. The cria was bright, alert and responsive, in average body condition, and weighed 8 kg. At admission, haematology was unremarkable. Serum biochemistry revealed an increased lactate concentration (3·6 mmol/l; normal range <1·5 mmol/l), reduced total protein (40 g/l; normal range 58 to 70 g/l) and increased urea (10·2 μmol/l; normal range 3·5 to 8·9 μmol/l) and creatinine (327 μmol/l; normal range 136 to 205 μmol/l) concentrations. The cria had partial failure of passive transfer (IgG concentration 2·5 g/l; normal range >10 g/l). Abdominal ultrasonography revealed dilation of the left renal pelvis and ureter and an enlarged bladder, but no other abnormalities were noted. At this stage, a diagnosis of labial fusion was made with secondary azotaemia and partial failure of passive transfer. A 16 G catheter (Mila International) was placed in the right jugular vein using aseptic technique. The cria was then sedated with 0·3 mg/kg midazolam (Hypnovel; Roche), administered intravenously, and positioned in ventral recumbency. The vulval skin was aseptically prepared with a weak solution of chlorhexidine scrub and surgical spirit. Local analg esia was provided by infiltrating the fused labia with 2 ml mepivicaine (Intra-epicaine; Arnolds Veterinary Products). The imperforate tissue was opened surgically using a number 11 scalpel blade by incising through the midline of the fused labia. Artery forceps and digital palpation were used to ensure that only vulval tissue was incised. At this stage, urine was passed. Urinalysis revealed a specific gravity of 1·023 with 1+ protein and 4+ blood (MultiStix SG; Bayer). Digital palpation of the vestibule revealed no other anomalies. The cria received an infusion of plasma from the dam, and was treated with 10 mg/kg trimethoprim-sulfadiazine (Norodine; Norbrook Laboratories) administered intravenously every 12 hours, and 6·6 mg/kg ranitidine (Zantac syrup; GlaxoSmithKline), administered orally every eight hours. Once the sedation had worn off, the cria was united with its dam and was allowed to nurse. Repeat ultrasonography, 24 hours after admission, revealed that both kidneys had a normal appearance. Serum biochemistry revealed a reduction in blood urea (6·5 mmol/l) and creatinine (165 mmol/l). At this stage, the level of IgG was deemed adequate (>10 g/l). Urinalysis revealed no blood or protein and a specific gravity of 1·008. The animal was seen to urinate normally and was discharged three days after presentation with a further three days of oral trimethoprim-sulfadiazine (10 mg/kg every 12 hours) and ranitidine (6·6 mg/kg every eight hours). No further problems were reported with the animal, and eight weeks later it was doing well. To the authors’ knowledge, this is the second reported case of azotaemia secondary to labial fusion. In the other reported cases of labial fusion in alpacas, two of six animals developed urometra, which was not present in this case. However, the bladder was dilated and backflow of urine causing dilation of the renal pelvis was present. It is likely that increased pressure within the bladder, and then further proximally within the urogenital tract, resulted in a decreased glomerular filtration rate due to increased pressure within Bowman’s capsule. There was likely prerenal involvement, as the blood lactate concentration was increased, but the degree of azotaemia seems too severe to be completely explained by this. It was also interesting to note that at no point had the cria been straining, even though its bladder was distended. The only reason that the animal was noted to be abnormal was the marked vulval swelling. Other causes of postrenal obstruction generally cause stranguria, as was reported by Wilkins and others (2006). The authors speculate that stranguria would have developed had the problem not been noticed so promptly. Labial fusion is thought to be heritable in other species (Wilkins and others 2006), and the owner was therefore advised not to breed from the affected animal or to use the same dam and sire combination again.

REFERENCE RANGES AND RELIABILITY OF TRANSABDOMINAL ULTRASONOGRAPHIC RENAL DIMENSIONS IN THOROUGHBRED HORSES

The aims of this study were to establish a normal reference range (mean ± 2 SD) and assess reliability of renal dimensions obtained using transabdominal ultrasonography in Thoroughbred horses (n = 7). A minimum of three ultrasonographic cineloops were obtained from each intercostal space and the left paralumbar fossa by two observers daily for three consecutive days. Renal length, width, and thickness and cortex, medulla, and pelvic dimensions were obtained. Measurements were undertaken by both observers, who were unaware of prior measurements, to assess reproducibility and measured on three separate occasions to evaluate short-term measurement repeatability. Measurements from images obtained by both operators were compared to evaluate image repeatability. The left kidney was consistently identified in the left 15th-17th intercostal space and the paralumbar fossa with maximal length in the 16th intercostal space (12.7 ± 2.0 cm) and maximal width in the paralumbar fossa (7.9 ± 1.1 cm). The right kidney was consistently identified in the right 15th-17th intercostal space with maximal length and maximal width in the 15th intercostal space (16.0 ± 0.7 cm and 7.9 ± 1.0 cm). Reproducibility, image repeatability, measurement repeatability were good to excellent, although were less good for the smaller structures. There were no differences in renal dimensions between horses. Overall renal ultrasonography was reliable and a normal reference range for Thoroughbred horses was established. Renal dimensions vary between rib spaces. As repeatability and reproducibility were excellent for renal length and width, it may be prudent to use those measurements in rib spaces where parameters were maximal.

Primary cardiac lymphoma in a 10-year-old equine gelding

PRIMARY cardiac lymphoma (PCL) is a rare tumour in all species (Sims and others 2003, Shinohara and others 2005, Miguel and Bestetti 2011, Petrich and others 2011) affecting the myocardium and/or pericardium (Shinohara and others 2005, Petrich and others 2011). PCL has been reported in cats, dogs and human beings, but prior case descriptions in horses were not identified in the literature. In horses, four categories of equine lymphoma are described: multicentric, thymic, alimentary and cutaneous (van den Hoven and Franken 1983) plus occasional anomalous cases (Meschter and Allen 1984, Staempfli and others 1988, Rhind and Dixon 1999, Taintor and Schleis 2011). A 10-year-old Cob gelding was presented with lethargy, weight loss and anorexia. On initial assessment, the horse was quiet, dull but responsive. Clinical examination revealed sinus tachycardia (64 bpm), which was confirmed by electrocardiography. A grade IV/VI pansystolic decrescendo murmur and a grade II/VI holodiastolic murmur, both loudest over the left fourth intercostal space, were auscultated. Jugular pulse quality and filling, and capillary refill time and colour were normal. The horse was tachypnoeic (20 bpm) with bronchovesicular sounds over both hemithoraces, more so on the right-hand side. Rectal temperature was normal. Muscle fasciculations of the proximal forelimb and weakness were observed, but no proprioceptive deficits suggestive of neurological disease were noted. Two-dimensional and M-mode echocardiography revealed normal cardiac dimensions with increased contractility (fraction shortening of 60 per cent; normal range 27 to 47 per cent) and …

VALIDATION OF A NOVEL TRANSLUMBAR ULTRASOUND TECHNIQUE FOR MEASURING RENAL DIMENSIONS IN HORSES

A reliable method for obtaining renal ultrasonographic measurements in the horse is important for diagnosis and monitoring of clinical renal disease. The aims of this prospective study were to develop and validate a novel translumbar ultrasound technique for measuring renal dimensions in horses. Six Thoroughbred or Thoroughbred part bred horses were recruited. All horses were scheduled for euthanasia due to reasons unrelated to the kidneys. Two observers recorded renal length, width, and depth; and dimensions of the cortex, medulla, pyramids, and pelvis for both kidneys in each horse using novel translumbar and conventional transabdominal ultrasound methods. The same measurements were recorded from post-mortem renal specimens. Both kidneys were consistently identified by both methods in the 15-17th intercostal spaces and paralumbar fossa. Using the translumbar technique, maximal dimensions were obtained for the left kidney in the 16th intercostal space (length 16.2 ± 2.0 cm, width 11.8 ± 0.5 cm, depth 6.4 ± 0.9 cm) and for the right kidney in the 15th intercostal space (length 16.1 ± 1.2 cm, width 13.4 ± 1.2 cm, depth 6.7 ± 0.7 cm). Renal dimensions obtained by transabdominal and translumbar projections did not differ (P > 0.05). Good correlations were found between overall renal dimensions and post-mortem measurements for both ultrasound techniques (r(2) > 0.8), but were better for the translumbar method (mean r(2) = 0.92 cf. 0.88). Good-to-excellent reliability was found for all translumbar ultrasound measurements except for the renal cortex. Reproducibility was better for the larger (overall length, width, and depth) than the smaller (cortex, medulla, and pyramids) structures. Findings indicated that translumbar ultrasonography is a valid method for measuring renal dimensions in horses.

Medical support for cattle and small ruminant surgical patients

While the initial assessment of cattle and small ruminants presented for surgery is similar to that in other species, it can be more challenging because farm animals are often sicker than they appear to be. This article outlines how to identify and manage potential medical problems in large animal surgical patients, including practical fluid therapy, analgesia, sedation, anaesthesia and rational antimicrobial use.