Risk factors for epiploic foramen entrapment colic: an international study

REASON FOR PERFORMING STUDY: Epiploic foramen entrapment (EFE) is one of the most common causes of small intestinal strangulation in the horse. Identification of risk factors would generate hypotheses about causation and may suggest preventive strategies. HYPOTHESIS: Horses exhibiting certain behavioural patterns and those exposed to particular management practices are at increased risk of EFE. METHODS: A matched case-control study was conducted on EFE cases admitted to hospitals in the UK, Ireland and USA. Data on 109 cases and 310 control horses were obtained by telephone questionnaire and conditional logistic regression was used to identify associations between horse- and management-level variables and the risk of EFE. RESULTS: Crib-biting/windsucking behaviour was strongly associated with increased risk of EFE (OR 67.3, 95%CI 15.3-296.5). A history of colic in the previous 12 months (OR 4.4, 95%CI 1.5-12.7) and horses of greater height (OR/cm 1.05, 95%CI 1.01-1.08) were also at increased risk. The person(s) responsible for horses' daily care (nonowner/relative/spouse OR 5.5, 95%CI 2.3-13.3) and a number of behavioural features, including response to a stimulus causing fright (easily frightened OR 0.4, 95%CI 0.1-1.0) or excitement (sweats up easily/occasionally OR 0.3, 95%CI 0.1-0.8), reaction to their surroundings (inquisitive OR 0.4, 95%CI 0.2-0.8) and feeding behaviour when stressed (goes off food in full/part OR 0.3, 95%CI 0.1-1.0) were also associated with altered risk of EFE. CONCLUSIONS: The association between horses of greater height and those with a previous history of colic and increased risk of EFE suggests that some horses may be inherently predisposed to EFE. Furthermore, a behavioural pattern has been characterised that is common to horses at increased risk of EFE. Further research is required to investigate the causal pathway linking behavioural traits with gastrointestinal dysfunction and to determine whether behavioural modification reduces the risk of EFE. POTENTIAL RELEVANCE: The findings of the present study have relevance to horses in the UK, Ireland and USA.     

Surgical colic in racing endurance horses

A retrospective study was performed of horses that developed colic during endurance racing, and subsequently required surgery. Fifteen horses met the inclusion criteria, of which 13 (87%) had small intestinal volvulus. Nine of the 15 horses (60%) had a small intestinal resection and anastomosis performed. Post operative ileus, particularly in those horses that had a resection performed, was a common complication. Eleven of the 15 (73%) survived, and 4 (27%) have since raced.     

Cardiorespiratory effects of enoximone in anaesthetised colic horses

Reasons for performing study: No studies have been reported on the effects of enoximone in anaesthetised colic horses. Objective: To examine whether enoximone improves cardiovascular function and reduces dobutamine requirement in anaesthetised colic horses. Methods: Forty‐eight mature colic horses were enrolled in this prospective, randomised clinical trial. After sedation (xylazine 0.7 mg/kg bwt) and induction (midazolam 0.06 mg/kg bwt, ketamine 2.2 mg/kg bwt), anaesthesia was maintained with isoflurane in oxygen and a lidocaine constant rate infusion (1.5 mg/kg bwt, 2 mg/kg/h). Horses were ventilated (PaCO₂<8.00 kPa). If hypotension occurred, dobutamine and/or colloids were administered. Ten minutes after skin incision, horses randomly received an i.v. bolus of enoximone (0.5 mg/kg bwt) or saline. Monitoring included respiratory and arterial blood gases, heart rate (HR), arterial pressure and cardiac index (CI). Systemic vascular resistance (SVR), stroke index (SI) and oxygen delivery index (DO₂I) were calculated. For each variable, changes between baseline and T10 within each treatment group and/or colic type (small intestines, large intestines or mixed) were analysed and compared between treatments in a fixed effects model. Differences between treatments until T30 were investigated using a mixed model (α= 0.05). Results: Ten minutes after enoximone treatment, CI (P = 0.0010), HR (P = 0.0033) and DO₂I (P = 0.0007) were higher and SVR lower (P = 0.0043) than at baseline. The changes in CI, HR and SVR were significantly different from those after saline treatment. During the first 30 min after enoximone treatment, DO₂I (P = 0.0224) and HR (P = 0.0003) were higher than after saline administration. Because the difference in HR between treatments was much clearer in large intestine colic cases, an interaction was detected between treatment and colic type in both analyses (P = 0.0076 and 0.0038, respectively). Conclusions: Enoximone produced significant, but short lasting, cardiovascular effects in colic horses. Potential relevance: Enoximone's cardiovascular effects in colic horses were of shorter duration than in healthy ponies.     

Postoperative pharmacokinetics of meloxicam in horses after surgery for colic syndrome

NSAID s are often used in horses with colic syndrome during the postoperative period, due to their ability to contrast endotoxemia and to promote an analgesic and anti‐inflammatory effect. As the pharmacokinetics of a drug are often modified in unhealthy animals compared to healthy subjects, the aim of this study was to evaluate the pharmacokinetic profile of meloxicam after i.v. administration in horses undergoing laparotomy for colic syndrome. Eight horses received 0.6 mg/kg of meloxicam i.v. towards the end of surgery. Blood samples were taken at scheduled time points during the following 24 hr. The serum concentration of the drug was determined by HPLC . Terminal half‐life (6.88 ± 2.96 hr), volume of distribution at steady‐state (186.53 ± 61.20 ml/Kg) and clearance (27.91 ± 5.72 ml kg^?1 hr^?1) were similar to those reported in literature for healthy horses. This result suggests that no adjustment of the approved dose should be necessary when meloxicam is used to treat horses in the immediate postoperative period after surgery for colic syndrome.     

A farm-based prospective study of equine colic incidence and associated risk factors

Abdominal pain (colic) in the horse is one of the most acute problems facing equine practitioners. Several causes and risk factors are associated with colic. The current study evaluated the incidence and associated risk factors of colic during a 1-year evaluation in horse farms of Kerman, Iran. The study investigated age, sex, breed, anthelmintic control program, and nutritional status of 128 horses of four breeds on six farms that took part in the study. The mean incidence density rate of colic in the horse population was 8.6% (11/128) in a year. Crossbred horses had more chance of developing colic (P < .05). Horses between the ages of 2 and 10 years also had more risk of developing colic (P < .05). There was no significant difference between sexes (P < .05), and nutritional factors were the most associated risk factors in the cases under study.     

Risk factors for epiploic foramen entrapment colic in a UK horse population: a prospective case-control study

REASONS FOR PERFORMING STUDY: Epiploic foramen entrapment (EFE) is a common cause of small intestinal strangulation in the horse and its epidemiology requires further investigation. OBJECTIVES: To identify horse- and management-level risk factors for EFE and to explore reasons for the apparent seasonality of this condition. HYPOTHESIS: Horses exhibiting certain behaviours and those exposed to particular management practices that vary seasonally are at increased risk of EFE. METHODS: A prospective unmatched, multicentre case-control study was conducted over 24 months in the UK. Data on 77 cases and 216 control horses were obtained from 9 collaborating clinics and logistic regression was used to identify associations between horse and management variables and the likelihood of EFE. RESULTS: In a final multivariable model crib-biting/windsucking behaviour was associated with the largest increase in likelihood of EFE. A history of colic in the previous 12 months, increased stabling in the previous 28 days and height of the horse also increased the likelihood of EFE. Horses with access to a mineral/salt lick, those easily frightened and horses not fed at the same time as others were at reduced risk of EFE. CONCLUSIONS: Horses exhibiting certain behaviours, those with a previous history of colic and horses of greater height appear to be at inherently greater risk of EFE. The increase in likelihood of EFE with increased duration of stabling may explain the apparent seasonality of this condition.     

Clinical comparison of two regimens of lidocaine infusion in horses undergoing laparotomy for colic

ObjectiveTo compare, in horses undergoing laparotomy for colic, the effects of administering or not administering a loading intravenous (IV) bolus of lidocaine prior to its constant rate infusion (CRI). Effects investigated during isoflurane anaesthesia were end-tidal isoflurane concentration (Fe’ISO), cardiovascular function, anaesthetic stability and the quality of recovery.Study designProspective, randomized clinical study.AnimalsThirty-six client-owned horses.MethodsHorses were assigned randomly to receive lidocaine as a CRI (50 μg kg⁻¹ minute⁻¹) either preceded (LB) or not preceded (L) by a loading dose (1.5 mg kg⁻¹ IV over 15 minutes). Lidocaine infusion (LInf) was started (T0) within 20 minutes after induction of general anaesthesia and discontinued approximately 30 minutes before the end of surgery. Anaesthetic depth, Fe’ISO, intra-operative physiological parameters and quality of recovery were assessed or measured. Data were analysed using one-way anova, t-test, Fisher test, Wilcoxon and Kruskal–Wallis tests as appropriate (p < 0.05).ResultsMean ± SD Fe’ISO was 1.21 ± 0.08% in group LB and 1.23 ± 0.06% in group L. Heart rate was significantly higher in group L than in group LB at times T5-T15, T25, T35 and T95. No difference was found between groups in other measured physiological values, nor in any measure taken to improve these parameters. Recovery phase was comparable and satisfactory in all but one full term pregnant horse in group L which fractured a femur during recovery.ConclusionPreloading with a lidocaine bolus prior to a CRI of lidocaine did not influence isoflurane requirements, cardiopulmonary effects (other than a reduction in heart rate at some time points) or recovery compared to no preloading bolus.Clinical relevanceA loading dose of lidocaine prior to CRI does not confer any advantage in horses undergoing laparotomy for colic.     

Extraperitoneal incisional abscess formation after colic surgery in 3 horses

In this article we report 3 horses that developed an extraperitoneal abscess after colic surgery at the incision site. All 3 horses presented with nonspecific clinical signs and extraperitoneal abscess was diagnosed from ultrasound evaluations and cytological examination of abscess aspirates. One horse developed dehiscence of the incision after drainage of the abscess through the incision. In 2 cases a small standing paramedian incision was performed through which the abscess was drained and lavaged; complete resolution of the abscess and healing of the incision was achieved in both cases. Extraperitoneal abscess is a previously unreported incisional complication after colic surgery in horses. Early and careful ultrasonographic examination of the abdominal incision is required for diagnosis in cases with nonspecific clinical signs. A paramedian incision through the rectus abdominis muscle into the abscess cavity permitted adequate drainage and debridement of the abscess in 2 cases.     

Nutritional management of recurrent colic and colonic impactions

Although diagnosis and treatment of horses with colic have improved in the last 30 years, horses with recurrent colic can be a diagnostic and management challenge for both owners and veterinarians, and colic remains a high priority health concern of owners (Mellor et al. 2001 ). Nutritional management of these cases is often based on previous experience combined with recommendations from the evidence‐based literature. This review will briefly summarise the aetiologies of recurrent colic and primarily focus on evidence‐based nutritional management of colonic impactions, sand enteropathy, inflammatory bowel disease, and idiopathic recurrent colic, which is limited. Additional topics to be covered elsewhere in this series that are relevant to this topic include nutritional management of gastric ulceration, liver disease, colitis, geriatric horses, and feeding the horse pre‐ and post surgery.     

Risk factors associated with equine gastric ulceration syndrome (EGUS) in 201 horses in Denmark

Reasons for performing study: The prevalence (up to 93% in Thoroughbred racehorses) and severity of equine gastric ulceration syndrome (EGUS) has been associated with type of training and differing management practices. However, there have been few studies to confirm these findings in nonracehorses in Europe. Objectives: To investigate the prevalence of EGUS in a population of Danish horses, during winter when the horses had been housed and fed for at least 8 weeks and to analyse the influence of feed, work level and environment on the risk of EGUS of §grade 2 in severity. Methods: A total of 201 horses, not in active race‐training, were evaluated, representing 23 different stables from all 5 regions within Denmark. All horses were considered to be healthy and not on medical treatment for EGUS. Endoscopically observed ulcer lesion scores were based on the number present (0–4) and severity (0–5). Univariate and multivariable mixed effects logistic regression models were developed using EGUS score as the dependent variable. An ulceration severity score of §2 was regarded as being clinically significant. Separate models were developed for horses with ulcers in either the glandular or nonglandular regions of the stomach graded §2 (EGUS §2) and for those horses that had nonglandular ulcers graded §2 (NG §2). Results: In this population, 53% (107/201) of horses were graded as having EGUS §2 with 95 (47%) horses having NG §2. Three variables were significantly (P<0.05) associated with EGUS §2: straw being the only forage available; exceeding 2 g/kg bwt of starch intake/day or §1 g/kg bwt/meal; and water not being available in the turn out paddock. Risk of NG §2 significantly increased when straw was the only forage available, 1 g/kg bwt of starch/meal was exceeded, water was not available in the turnout paddock and the interval between forage feeding was <6 h. Conclusion and potential relevance: This study has confirmed that components of the diet, readily modifiable, may have an important impact on the risk of EGUS in the nonracehorse. Differences in the multivariable models produced for all ulcers and nonglandular ulcers support differences in the aetiology of ulcers in different locations of the stomach.     

Pulsed inhaled nitric oxide improves arterial oxygenation in colic horses undergoing abdominal surgery

Objective

To evaluate the effect of pulsed inhaled nitric oxide (INO) on arterial oxygenation in horses during abdominal surgery.

Distal limb cast sores in horses: Risk factors and early detection using thermography

Reasons for performing study: There is a lack of evidence‐based data on the prevalence, outcome and risk factors of distal limb cast sores, and no objective tool has been described for the early detection of cast sores. Objectives: To investigate the prevalence, location, outcome and risk factors of cast sores after application of a distal limb cast and to determine whether static thermography of the cast is a valuable tool for the assessment of sores. Methods: A prospective study was conducted on horses treated with a distal limb cast. At each cast removal, cast sores were graded as superficial sores (SS), deep dermal sores (DS) or full thickness skin ulcerations (FS). In several cases, a thermographic evaluation of the cast was performed immediately prior to removal and differences in temperature (ΔT) between the coolest point of the cast and 2 cast regions predisposed for sore development (dorsoproximal mc/mtIII and palmar/plantar fetlock) were calculated. Results: Mean ± s.d. total casting time of 70 horses was 31 ± 18 days. Overall, 57 legs (81%) developed at least SS. Twenty‐four legs (34%) ultimately developed DS and one horse had an FS. Multivariable analysis showed that the severity of sores was positively associated with increasing age (OR: 1.111, P = 0.028), a normal (vs. swollen) limb (OR: 3.387, P = 0.023) and an increase in total casting time (OR per week: 1.363, P = 0.002). The thermographic evaluation (35 casts) revealed that the severity of sores was positively associated with increasing ΔT (OR: 2.100, P = 0.0005). The optimal cut‐off values for the presence of SS and DS were set at, respectively, ΔT = 2.3 and 4.3°C. Conclusion and potential relevance: Distal limb cast is a safe coaptation technique with increasing risk of developing sores with time. Thermography is a valuable and rapid clinical tool to monitor the development of cast sores.     

Initial investigation of mortality rates and prognostic indicators in horses with colic in Israel: A retrospective study

Reasons for performing study: Initial assessment of the mortality rates and prognostic indicators in horses with colic presented to a referral hospital in Israel. Objectives: To determine mortality rates and to identify potential prognostic indicators in horses undergoing treatment for colic. Methods: The medical records of 208 colic cases were reviewed and mortality rates calculated including 95% confidence intervals. Mortality rates in surgical cases were calculated separately for strangulating and nonstrangulating lesions as well as for lesions of the large and small intestines. Potential prognostic indicators were identified and evaluated by Student's t test or X² test, where appropriate. Those found to be significant (P<0.05) were evaluated in 2 logistic regression models; one including all horses with colic and one for surgical cases only. Results: The overall mortality rate was 51/208 (25%); 5/72 (7%) in medically treated cases, 46/136 (34%) in surgical cases, 30/50 (60%) in strangulating lesions and 15/85 (18%) in nonstrangulating lesions, 17/27 (63%) in cases involving small intestinal lesions and 28/108 (26%) in cases with large intestinal lesions. Clinical parameters found to be significantly associated with death by univariate analysis were medical/surgical treatment, location of lesion, severity of lesion, mucous membrane colour (MM), capillary refill time (CRT) and heart rate. Using a multivariate logistic regression model, including all cases, medical/surgical treatment, CRT and MM were found to be prognostic indicators and when using the surgical cases alone, only CRT and lesion severity remained related to mortality. Conclusions: Mortality rates were similar or better than those previously reported in most cases, however, studies from the USA and the UK published better success rates for small intestinal surgeries. Cultural attitudes toward euthanasia may be associated with mortality rates. Potential relevance: These results assist clinicians in providing an immediate prognosis based on clinical findings at presentation and contribute to an international database that may aid future research in improving treatment of colic.     

A retrospective evaluation of the effect of perianesthetic hydromorphone administration on the incidence of postanesthetic signs of colic in horses

ObjectiveTo describe the incidence of postanesthetic signs of colic (PASC) in horses and determine if perianesthetic administration of hydromorphone was associated with an increased risk of PASC.Study designRetrospective, cohort study.AnimalsA total of 409 horses.MethodsAnesthesia and clinical records of horses admitted for various procedures from July 2018 to September 2019 were reviewed. Signs of colic and interventions were recorded up to 48 hours after anesthesia. A binomial logistic regression model was used to evaluate the association between the type of surgery, administration of hydromorphone, the duration of anesthesia and the incidence of PASC.ResultsOverall, 25 (6.1%) horses developed PASC within 48 hours of general anesthesia. Of 60 horses that underwent colic surgery, 16 (26.7%) developed PASC. Of 349 horses that underwent noncolic procedures, nine (2.6%) developed PASC. Thus, the incidence of PASC was higher in horses that underwent colic surgery than in horses that underwent noncolic procedures [odds ratio (OR) = 13.74 (5.73–32.95)]. No effect of hydromorphone on the incidence of PASC was identified [OR = 1.61 (0.71–3.62)]. Longer procedures (>2 hours) were identified as an independent risk factor for PASC [OR = 4.13 (1.52–11.22)].ConclusionsNo association between hydromorphone and an increase in the incidence of PASC was identified. Anesthesia for colic surgery and duration of anesthesia were associated with an increased risk of PASC.Clinical relevanceHydromorphone did not increase the incidence of PASC in this population.     

Risk factors associated with colic in horses

Many factors have been identified as risk factors for colic in horses in several epidemiological studies. The aim of our paper was to review the results of 12 epidemiological studies, in order to assess the impact of each risk factor for colic. According to the literature, the factors that increase the risk of colic are feeding practices (type and quality of food, type and changes of feeding), the intrinsic factors of horses (sex, age and breed), management (type and changes of housing and activity), medical history (a previous colic, administration of a medical treatment) and parasite control (the presence of worms and type of deworming program). Several individual factors were incriminated as risk factors by all the studies. Nevertheless, the different studies did not always agree on the role of other risk factors. The conclusions were tightly related to several criteria in the selection of the study population, like the type of the epidemiological study, the number and the origin of horses included and the location of the study.     

Risk factors for equine acute abdominal disease (colic): Results from a multi-center case-control study

Many causal hypotheses for acute equine abdominal disease (colic) have been proposed. However, few epidemiologic studies have been undertaken to identify risk factors for the syndrome. Risk factors for equine colic were identified using a hospital-based, multi-center, case-control study. Horses admitted with abdominal pain to Cornell, Guelph, Ohio State, Pennsylvania or Tufts university veterinary hospitals between March and December 1991 were selected. Control horses were randomly selected from a list of all other non-colic admissions. The person(s) responsible for the day-to-day care of the horse completed a telephone questionnaire. Risk factors were identified using multivariable logistic regression analysis.

A total of 406 colic and 406 control horses were used in the final analysis. Age, breed, outdoor access (pasture or drylot), outdoor water supply, use of a daily worming product, amount of concentrates and whole-grain corn consumed, type of person responsible for the day-to-day care of the horse and previous colic history were all significantly associated with colic risk. Arabian horses were more than twice as likely to be colic cases (OR = 2.0, 95% CI = 1.0–3.9), whereas Standardbred horses were nearly half as likely (OR = 0.6, 95% CI = 0.4–1.0) to be colic cases compared with the comparison Thoroughbred group. Horses that had access to outdoor enclosures without a continuous supply of water were more than twice as likely (OR = 2.2, 95% CI = 1.2–4.3) to be colic cases compared with horses that had an adequate supply of water on outside enclosures. The use of a daily worming product for at least 60 days during the 12-month period prior to presentation was associated with a significantly lower colic risk (OR = 0.11, 95% CI = 0.02–0.55). Colic risk increased with greater consumption of whole-grain corn; however, when all non-roughage concentrate feeds were combined, colic risk decreased with increased intake of concentrates. Significant interactions were identified between age and drylot use and between the type of care-person responsible for the day-to-day care of the horse (owner or non-owner) and previous colic history.

The findings of this study illustrate the complex multi-factorial nature of equine colic and point towards the importance of the overall quality of stable management and care, as well as the type of outdoor enclosure (pasture or drylot), water access, carbohydrate intake, parasite control and intrinsic (breed-related) factors.     

Return to use and performance following exploratory celiotomy for colic in horses: 195 cases (2003–2010)

Reasons for performing study: There are few objective data on return to use and performance in horses following colic surgery. Objective: To investigate return to functional use of horses following colic surgery and factors associated with a negative outcome. Methods: The North Carolina State University Equine Colic Database was reviewed for horses that underwent exploratory celiotomy for colic (2003–2010). Horses were excluded from the study if they survived <6 months, had no intended use preoperatively, or if further data were not available at attempted follow‐up. Information retrieved included history, background, use, and selected pre‐, intra‐, and post operative factors. Telephone interviews were used to obtain follow‐up data. Logistic regression was used to investigate associations between clinical data and outcome, reported as odds ratios with a 95% confidence interval and corresponding P value. Results: Of patients surviving to 6 months, 133/195 (68%) were performing their intended use and 85/156 (54%) were at or above preoperative performance. At one year, 145/190 (76%) horses were performing their intended use and 101/153 (66%) were at or above preoperative performance. Animals were significantly less likely to return to use/performance if they had a previous celiotomy, stall rest for an orthopaedic condition, a nonstrangulating lesion type, incisional hernia, diarrhoea or laminitis. Conclusions: The overall prognosis for return to use and performance following colic surgery is fair to good. Multiple pre‐ and post operative factors may affect the likelihood of return to use and performance. Potential relevance: Targeted owner education regarding preoperative lameness, post operative rehabilitation and treatment for complications, such as incisional hernioplasty, may help inform owners about their horse's potential for return to use and performance following colic surgery.