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Featured researches published by Michael Hewetson.


Journal of Veterinary Internal Medicine | 2015

European College of Equine Internal Medicine consensus statement-Equine Gastric Ulcer Syndrome in adult horses

B. W. Sykes; Michael Hewetson; R.J. Hepburn; N. Luthersson; Y. Tamzali

The term Equine Gastric Ulcer Syndrome (EGUS) was first used in 1999 to describe gastric ulceration in the horse. However, as discussed by Merritt, the terminology is commonly misused. The committee reinforces the importance of distinguishing between diseases of the squamous and glandular mucosa because, as discussed in this statement, important differences exist between the two. In human medicine, the term peptic ulcer disease (PUD) is used as an umbrella term to describe erosive and ulcerative diseases of the stomach and it is recognized that a large number of individual diseases are present under the term. Furthermore, while some different diseases might share similarities in pathophysiology and treatment regimens, it is recognized in human medicine that the direct extrapolation of either from one specific disease (such as NSAID-associated ulceration) to another (such as Helicobacter pylori associated ulceration) is inappropriate. The committee recognizes that the terminology for EGUS requires clarification and proposes that the nomenclature be: Equine Gastric Ulcer Syndrome (EGUS) as a general all encompassing term to describe erosive and ulcerative diseases of the stomach consistent with the use of the term PUD in man; Equine Squamous Gastric Disease (ESGD) and Equine Glandular Gastric Disease (EGGD) as terms that more specifically describe the affected region anatomically.Within ESGD, both primary and secondary disease is recognized. Primary ESGD, the more common of the 2 forms, occurs in animals with an otherwise normal gastrointestinal tract. In contrast, secondary ESGD occurs in animals with delayed gastric outflow secondary to an underlying abnormality such as pyloric stenosis. The pathophysiology of EGGD remains to be elucidated and as such further subclassification of lesion type is not possible at this time. Instead, the committee recommends the use of descriptive terminology with a clear distinction of the anatomical region affected (cardia, fundus, antrum, or pylorus as shown in Figure 2) and the gross appearance of the lesion. The committee emphasizes that the affected region of the stomach should be clearly identified when communicating research and clinical findings. A summary of the proposed terminology is depicted in Figure 1. Recommendation: Expansion of the existing EGUS terminology to specifically identify squamous and glandular disease as ESGD and EGGD, respectively, as shown in Figure 1.


Veterinary Journal | 2014

Comparison of the effects of enteral psyllium, magnesium sulphate and their combination for removal of sand from the large colon of horses.

Kati Niinistö; Michael Hewetson; Ritva Kaikkonen; Ben W. Sykes; Marja Raekallio

Prospective studies documenting the efficacy and side effects of medical treatment for colonic sand accumulation in horses are limited. The purpose of the study was to compare the effect of enteral administration of magnesium sulphate (MgSO4), psyllium mucilloid (psyllium), and a combination of MgSO4 and psyllium on the evacuation of large accumulations of sand in the large colon of adult horses. Thirty-four horses with naturally acquired, large sand accumulations (>5 cm × 15 cm) identified on abdominal radiography were randomly allocated to one of three treatment groups: (1) 1 g/kg psyllium (n = 12); (2) 1 g/kg MgSO4 (n = 10), or (3) their combination (n = 12). Treatments were administered once a day via nasogastric intubation and continued for a total of 4 days. Lateral radiographs of the ventral abdomen were repeated on day 4 of treatment. If the area of sand in the radiographic image was <25 cm(2) on day 4, the sand accumulation was considered resolved. Of 12 horses treated with a combination of psyllium and MgSO4, nine evacuated the sand from the ventral colon within 4 days. In comparison, only 3/12 horses treated with psyllium and 2/10 horses treated with MgSO4 resolved (both significantly different from the combination; P <0.05). Large accumulations of sand in the large colon of horses can be treated medically. Administering a combination of psyllium and MgSO4 via nasogastric intubation once daily for a total of 4 days was a more effective treatment than either constituent alone.


Journal of Veterinary Internal Medicine | 2016

Risk factors for Equine Gastric Glandular Disease: A case-control study in a Finnish referral hospital population

J. Mönki; Michael Hewetson; A.-M. K. Virtala

Background Equine gastric glandular disease (EGGD) is a term used to classify erosive and ulcerative diseases of the glandular mucosa of the equine stomach. Epidemiologic studies of risk factors for EGGD have not been reported. Objective To determine risk factors for EGGD. Animals Cases (n = 83) had endoscopic evidence of EGGD; controls (n = 34) included healthy horses and horses with equine squamous gastric disease (ESGD) without EGGD. Methods Retrospective case‐control study. The data were analyzed by multivariable logistic regression modeling. Analysis was performed on the full dataset. An additional analysis compared horses with glandular lesions (n = 43) against healthy horses (n = 22). Results On first analysis, Warmblood breed (OR = 13.9, 95% CI 2.2–90.9, P = .005) and an increasing number of caretakers (OR = 7.3, 95% CI 0.98–55.6, P = .053) were associated with an increased risk of EGGD. On analysis of the subset of data, Warmblood breed (OR = 28.6, 95% CI 2.96–250.0, P = .004) and increasing number of riders (OR = 12.99, 95% CI 0.94–166.7, P = .056) were risk factors. The presence of sand in the colon appeared to have a protective effect against EGGD (OR = 0.195, 95% CI 0.04–1.0, P = .051 for sand versus not having sand). Conclusions and clinical importance This study suggests that Warmbloods are predisposed to EGGD and multiple handlers/riders might increase the risk of EGGD. Identification of risk factors allows speculation on potential pathophysiological mechanisms of EGGD.


Journal of Veterinary Diagnostic Investigation | 2014

Development and validation of a gas chromatography-flame ionization detection method for quantifying sucrose in equine serum

Michael Hewetson; Kaisa Aaltonen; Riitta-Mari Tulamo; Satu Sankari

A simple and accurate method for quantifying sucrose in equine serum that can be applied to sucrose permeability testing in the horse was developed and validated using gas chromatography with flame ionization detection. The assay provided an acceptable degree of linearity, accuracy, and precision at concentrations of sucrose as low as 2.34 μmol/l and as high as 20.45 μmol/l. Percentage recovery of sucrose from serum ranged from 89% to 102%; repeatability and intermediate precision (relative standard deviation) ranged from 3.6% to 6.7% and 4.1% to 9.3%, respectively. The limit of detection was 0.73 μmol/l. No interfering peaks were observed except lactose, which gave 2 peaks, one of which overlapped partially with sucrose. To evaluate the suitability of the method for quantifying sucrose in serum samples from horses with naturally occurring gastric ulceration, 10 horses with and without naturally occurring gastric ulceration were subjected to sucrose permeability testing. All horses demonstrated an increase in serum sucrose concentration over time following oral administration of sucrose; however, the increase from baseline was significant for horses with gastric ulceration at 45 min (P = 0.0082) and 90 min (P = 0.0082) when compared with healthy horses. It was concluded that gas chromatography with flame ionization detection is a valid method for quantifying sucrose in equine serum and can be applied directly to the analysis of sucrose in equine serum as part of a larger validation study aimed at developing a blood test for the diagnosis of gastric ulcers in horses.


Journal of Veterinary Emergency and Critical Care | 2017

Retrospective evaluation of 155 adult equids and 21 foals with tetanus from Western, Northern, and Central Europe (2000–2014). Part 2: Prognostic assessment

Gaby Van Galen; Joke Rijckaert; Tim Mair; Hélène Amory; Lara Armengou; Barbora Bezdekova; Inge Durie; Rikke Findshøj Delany; Nathalie Elisa Fouché; Laura Haley; Michael Hewetson; René van den Hoven; Anna Kendall; Fernando Malalana; Jessika Muller Cavalleri; Tresemiek Picavet; Katja Roscher; Denis Verwilghen; C.M. Westermann; Claude Saegerman

OBJECTIVE To identify prognostic variables for adult equids and foals with tetanus. DESIGN Multicenter retrospective study (2000-2014). SETTING Twenty Western, Northern, and Central European university teaching hospitals and private referral centers. ANIMALS One hundred fifty-five adult equids and 21 foals with tetanus. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Variables from history and clinical examination were statistically compared between survivors and nonsurvivors (adults: 49 survivors, 85 nonsurvivors; foals: 7 survivors, 10 nonsurvivors). Cases euthanized for financial reasons were excluded. Mortality rates in adults and foals were 68.4% and 66.7%, respectively. Variables associated with survival in adults included: standing, normal intestinal sounds and defecation, voluntarily drinking, eating soft or normal food, lower heart and respiratory rates, high base excess on admission, longer diagnosis time, treatment and hospitalization delay, and mild severity grade. Variables associated with death included: anorexia, dysphagia, dyspnea, low blood potassium concentration on admission, moderate and severe disease grading, development of dysphagia, dyspnea, recumbency and seizures during hospitalization, treatment with glycerol guaiacolate, intravenous fluids, and intravenous glucose solutions. Variables associated with survival in foals included standing on admission, voluntarily eating soft food and drinking, older age, and longer hospitalization delay. Outcome was not different between different tetanus antitoxin (TAT) dosages, although there was a trend of increasing survival rate with increasing TAT dosages. Cases with appropriate vaccination prior to development of tetanus were rare, but had improved outcome and shorter hospitalization. CONCLUSIONS Prognosis for equine tetanus is poor with similar outcome and prognostic factors in foals and adults. The prognostic assessment of cases with tetanus provides clinicians with new evidence-based information related to patient management. Several prognostic indicators relate to the ability to eat or drink, and more severe clinical signs relate to poor outcome. Increasing intravenous dosages of TAT has no significant effect on outcome, but the positive trend identified may support a recommendation for high intravenous TAT dosages. Further evaluation is warranted.


Journal of Veterinary Emergency and Critical Care | 2017

Retrospective evaluation of 155 adult equids and 21 foals with tetanus in Western, Northern, and Central Europe (2000–2014). Part 1: Description of history and clinical evolution

Gaby Van Galen; Claude Saegerman; Joke Rijckaert; Hélène Amory; Lara Armengou; Barbora Bezdekova; Inge Durie; Rikke Findshøj Delany; Nathalie Elisa Fouché; Laura Haley; Michael Hewetson; René van den Hoven; Anna Kendall; Fernando Malalana; Jessika Muller Cavalleri; Tresemiek Picavet; Katja Roscher; Denis Verwilghen; Meret Wehrli Eser; C.M. Westermann; Tim Mair

OBJECTIVE To describe clinical data of hospitalized adult equids and foals with tetanus. DESIGN Multicenter retrospective study (2000-2014). SETTING Twenty Western, Northern, and Central European university teaching hospitals and private referral centers. ANIMALS One hundred fifty-five adult equids (>6 months) and 21 foals (<6 months) with tetanus. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Information on geographic, annual and seasonal data, demographic- and management-related data, clinical history, clinical examination and blood analysis on admission, complications, treatments, and outcomes were described and statistically compared between adults and foals. The described cases were often young horses. In 4 adult horses, tetanus developed despite appropriate vaccination and in 2 foals despite preventive tetanus antitoxin administration at birth. Castration, hoof abscesses, and wounds were the most common entry sites for adults; umbilical cord infections and wounds for foals. Stiffness was the commonest observed initial clinical sign. Blood analyses frequently revealed an inflammatory response, hemoconcentration, muscle damage, azotemia, negative energy balance, liver damage, and electrolyte and acid base disturbances. Common complications or clinical signs developing during hospitalization included dysphagia, dyspnea, recumbency, hyperthermia, seizures, hyperlipemia, gastrointestinal impactions, dysuria, and laryngeal spasms. Cases were supported with wound debridement, antimicrobial treatment, tetanus antitoxin, muscle spasm and seizure control, analgesia, anti-inflammatory drugs, fluid therapy, and nutritional support. Mortality rates were 68.4% in adult horses and 66.7% in foals. Foals differed from adult horses with respect to months of occurrence, signalment, management-related data, potential causative events, clinical signs on admission, blood analysis, complications, and severity grades. CONCLUSIONS This is the first study that rigorously describes a large population of equids affected by tetanus. The information provided is potentially useful to clinicians for early recognition and case management of tetanus in adult horses and foals. Tetanus affects multiple organ systems, requiring broad supportive and intensive care. Neonatal and adult tetanus in the horse should be considered as distinct syndromes, as in human medicine.


Journal of The South African Veterinary Association-tydskrif Van Die Suid-afrikaanse Veterinere Vereniging | 2017

Corrigendum: Ileal hypertrophy and associated true diverticulum as a cause of colic in a horse

Arnold Theofilus Mahne; Drienie Janse van Rensburg; Michael Hewetson

No abstract available.


Journal of The South African Veterinary Association-tydskrif Van Die Suid-afrikaanse Veterinere Vereniging | 2017

Ileal hypertrophy and associated true diverticulum as a cause of colic in a horse

Arnold Theofilus Mahne; Driene Janse van Rensburg; Michael Hewetson

A 4-year-old Thoroughbred gelding underwent an explorative celiotomy for a suspected small intestinal obstruction. During surgery, an impacted diverticulum of the ileum was suspected, necessitating a jejunocaecostomy. The owner opted for euthanasia. On post-mortem examination and histopathology, a true diverticulum on the mesenteric side of the ileum, with ileal hypertrophy, was diagnosed.


Acta Veterinaria Scandinavica | 2017

Diagnostic accuracy of blood sucrose as a screening test for equine gastric ulcer syndrome (EGUS) in adult horses

Michael Hewetson; B. W. Sykes; Gayle Hallowell; Riitta‑Mari Tulamo


Equine Veterinary Education | 2016

Disseminated alimentary mycobacteriosis in the horse: a retrospective study of nine cases

J. Mönki; Michael Hewetson; S. Hahn; K. Vainio; T. Skrzypczak

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B. W. Sykes

University of Queensland

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J. Mönki

University of Helsinki

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