Ponies, miniatures, and younger equids are at higher risk of fecalith obstruction compared to a general colic population

OBJECTIVE

To determine breed, age, and sex predispositions for fecalith obstruction and to evaluate short-term survival and prognostic factors following surgical treatment of fecalith intestinal obstruction in equids.

ANIMALS

151 equids.

METHODS

Medical records of equids undergoing surgery for fecalith obstruction from 2000 to 2020 were reviewed. Signalment, history, presenting clinicopathological data, surgical findings, complications, and short-term survival were recorded and compared between survivors and nonsurvivors. Signalment of the fecalith population was compared to a contemporaneous colic population. Clinical factors were assessed for association with outcome.

RESULTS

64 females, 53 castrated males, and 31 intact males were included. Three equids presented twice. Miniature horses, ponies, and miniature donkeys/mules represented 48% (71/148) of fecalith population and full-sized breeds represented 52% (77/148). Miniature horses and ponies were overrepresented and equids ≤ 1 year of age were overrepresented in the fecalith population compared to the colic population. One hundred thirty-nine equids (92%) survived to discharge, 6% (9/148) were euthanized intraoperatively, and 2% (3/148) were euthanized during hospitalization. Nonsurvivors showed more severe colic signs on admission, tachycardia on admission, and hyperlipemia. Equids with postoperative colic (P = .01) and complications (P = .002) were less likely to survive.

CLINICAL RELEVANCE

Miniature horses and ponies were overrepresented compared to the colic population; however, full-sized breeds were also affected. Surgical treatment had an excellent short-term prognosis. Severe colic signs, tachycardia, hyperlipemia, postoperative colic, and surgical complications negatively affected short-term survival.

Prevalence of and risk factors associated with Salmonella shedding among equids presented to a veterinary teaching hospital for colic (2013-2018)

BACKGROUND

Gastrointestinal disease has been associated with shedding of Salmonella with previous studies demonstrating that horses with colic have a higher risk of acquiring and shedding Salmonella organisms.

OBJECTIVES

The purpose of this study was to determine the prevalence of and risk factors associated with Salmonella shedding in a colic population at a referral clinic.

STUDY DESIGN

Retrospective case-control study.

METHODS

For each colic case that was positive for Salmonella (n=56), two colic cases (n=112) that tested negative for Salmonella, were enrolled as controls. Associations between variables and Salmonella shedding were identified using logistic regression. Univariate and multivariable models were developed pertaining to 1) presenting clinicopathological data and 2) clinical variables that developed during hospitalisation.

RESULTS

Of the equids presenting with colic, 1585/1917 had a sample submitted for Salmonella testing. Of these, 56 were positive for Salmonella yielding a prevalence of 3.5%. Equids shedding Salmonella were more likely to present in July (OR=7.2, 95% CI=1.63-32.13, p=0.009) and present with a history of fever (OR=53.5; 95% CI=2.57-1113.03; p=0.01), increased lactate (OR=1.6; 95% CI=1.14-2.29; p=0.007) and/or neutropenia (OR=0.79; 95% CI=0.65-0.97; p=0.02). Hospitalised equids shedding Salmonella were more likely to be febrile (OR=4.8; 95% CI=1.47-15.8; p=0.01) and 10 times more likely to develop reflux (OR=10.1; 95% CI=1.67-61.43; p=0.01) compared to colic controls.

MAIN LIMITATIONS

Retrospective nature of the study and bias inherent to the retrieval of data from medicals records cannot be discounted. Classifying Salmonella status based on a single sample may have resulted in misclassification bias.

CONCLUSIONS

The prevalence of Salmonella shedding in this colic population was low compared to earlier reports. Certain predictors such as the development of a fever or reflux in hospitalised colic cases were associated with Salmonella shedding and may help the clinician to promptly identify horses likely to shed, thus helping institute effective use of barrier nursing precautions.

Multi-Institutional Retrospective Case-Control Study Evaluating Clinical Outcomes of Foals with Small Intestinal Strangulating Obstruction: 2000–2020

Simple Summary

Lower survival rates have been reported in foals than adults with severe colic lesions obstructing blood flow to the small intestine, but this has not been compared directly. These survival rates are important to horse owners making medical decisions surrounding colic, for both the foal’s wellbeing and the owner’s finances. In this retrospective case-control study, hospital records of surgical colic cases were collected from five US academic referral hospitals to directly compare foal and adult survival following surgery for specific colic lesions. It was hypothesized that foals would exhibit lower survival than case-matched adults. This study was limited by incomplete medical and surgical records, relatively small sample size, and lack of long-term follow-up. Short-term survival in foals was not significantly different than in adults with comparable colic lesions and may have been partly driven by decision-making on the farm prior to referral. More optimism toward surgical treatment of foals with suspected SISO may be warranted.

Abstract

Lower survival has been reported in foals than adults with small intestinal strangulating obstruction (SISO), but age-dependent outcomes have not been examined directly. Hospital records were collected from five US academic referral hospitals. It was hypothesized that foals would exhibit lower survival than case-matched adults. Foal cases 6-months-of-age or younger, and adult cases between 2- and 20-years-of-age were collected. Data revealed 24 of 25 (96.0%) foals and 66 of 75 (88.0%) adults that were recovered from surgery for SISO survived to hospital discharge. Sixteen of the total 41 (39.0%) foals studied were euthanized intraoperatively, whereas 30 of 105 (28.6%) adults were euthanized intraoperatively. Common lesions in foals that were recovered from surgery were volvulus (n = 13) and intussusception (n = 5), whereas common lesions in adults were volvulus (n = 25) and strangulating lipoma (n = 23). This study was limited by incomplete medical records, relatively small sample size, and lack of long-term follow-up. Unexpectedly, short-term survival tended to be higher in foals than adults and may have been partly driven by case selection prior to referral or surgery or decision-making intraoperatively. More optimism toward surgical treatment of foals with SISO may be warranted.

Acute abdominal dehiscence following laparotomy: A multicentre, international retrospective study

BACKGROUND

Incisional complications are a common cause of morbidity following laparotomy. Although uncommon, acute abdominal dehiscence (AAD) is a potentially fatal post-operative complication. However, few AAD cases are described in the literature.

OBJECTIVES

To describe common features of cases of AAD following ventral midline laparotomy, management and outcomes.

STUDY DESIGN

Retrospective case series.

METHODS

Hospital records of horses that underwent a ventral midline laparotomy at nine hospitals in the UK, Ireland and USA over a 10-year period (2009-2019) were reviewed. Data were collected for pre-, intra- and post-operative factors that were considered relevant. Descriptive statistical analysis was performed.

RESULTS

A total of 63 cases of AAD were identified. AAD occurred due to tearing of sutures through the linea alba or rupture of the body wall adjacent to the suture line in 46 horses (73%). AAD occurred at a median of 5 days (0.5-70 days) post-operatively and broodmares accounted for 25% of the cases (n = 16). Surgical site infection developed prior to AAD in 28 horses (44%); leakage of peritoneal fluid occurred in 5% of horses prior to AAD being identified. Surgical repair was performed in 27 horses (43%), 10 (16%) were treated conservatively and 26 (41%) were euthanised immediately. Repair was most frequently performed using suture (n = 14), wire (n = 5) or a combination (n = 5). Overall survival to hospital discharge was 39% (24/63). Where surgical repair was performed, 15 horses (56%) survived to hospital discharge; 9 horses (90%) managed conservatively survived to hospital discharge.

MAIN LIMITATIONS

Follow-up was not performed for all cases following hospital discharge and some data were incompletely recorded in hospital files.

CONCLUSIONS

Previously stated causative factors for AAD were not consistent features in the present study. Surgical site infection following laparotomy and pregnant or early post-partum mares may be important risk factors for AAD and warrant further investigation.

A preliminary study on assessment of wellbeing among veterinary medical house officers

Mental wellness is an important topic among practicing veterinarians. Peer reviewed studies focusing on veterinary house officers' wellbeing are lacking in veterinary medicine. The aim of this study was to assess wellbeing of house officers using validated surveys for anxiety, burnout, depression, and quality of life. A cross-sectional survey of 103 house officers (residents, interns, and fellows) was performed. Respondents were invited to voluntarily complete the online surveys. Anxiety, burnout, depression, and quality of life were assessed using the Generalized Anxiety Disorder (GAD-7), Maslach Burnout Inventory (MBI), Patient Health Questionnaire (PHQ-9), and Short Form-8 (SF-8), respectively. Descriptive statistics were calculated. For qualitative analysis, respondents were requested to rate their perception of the level of stress regarding various work-related stressors. The first survey was completed in 2017 with 60 respondents of which 51 (85%) identified as females and nine (15%) identified as males. The second survey was completed in 2018 with 43 respondents of which 35 (81.4%) identified as females and 8 (18.6%) identified as males. Respondents reported high levels of burnout characterized by high levels of emotional exhaustion and lack of personal accomplishment but reported mild levels of anxiety and depression. The mental component of their quality of life score was lower than the general US population, whereas the physical component score was consistent with the general US population. Respondents indicated moderate scores of stress for concerns regarding patient management, research, teaching, work-life balance, relationships, organizational skills, time management, finances, and the mental and emotional impact of the work environment. The high levels of burnout, and low mental quality of life in house officers require specific intervention programs to improve wellbeing.

Approach to Toxicologic Emergencies

Equine toxicologic emergencies are relatively uncommon but can cause significant morbidity and mortality in a group of comanaged horses. The field veterinarian's role is to triage the situation, as well as the individual animal. Individual patient stabilization should focus on support of essential organ functions, providing time for treatments to have an effect or for elimination of the toxicant. Decontamination procedures can follow patient stabilization, if appropriate. Antidotes are often not available or feasible for equine intoxications. The field veterinarian should emphasize triage and stabilization before referral and on-site identification and collection of diagnostic samples to support the diagnosis.

Time required to achieve maximum amikacin concentration in the synovial fluid of the tarsocrural joint following administration of the drug by intravenous regional limb perfusion in horses

OBJECTIVE

To determine the median time to maximum concentration (t_max) of amikacin in the synovial fluid of the tarsocrural joint following IV regional limb perfusion (IVRLP) of the drug in a saphenous vein of horses.

ANIMALS

7 healthy adult horses.

PROCEDURES

With each horse sedated and restrained in a standing position, a 10-cm-wide Esmarch tourniquet was applied to a randomly selected hind limb 10 cm proximal to the point of the tarsus. Amikacin sulfate (2 g diluted with saline [0.9% NaCl] solution to a volume of 60 mL) was instilled in the saphenous vein over 3 minutes with a peristaltic pump. Tarsocrural synovial fluid samples were collected at 5, 10, 15, 20, 25, and 30 minutes after completion of IVRLP. The tourniquet was removed after collection of the last sample. Amikacin concentration was quantified by a fluorescence polarization immunoassay. Median maximum amikacin concentration and t_max were determined.

RESULTS

1 horse was excluded from analysis because an insufficient volume of synovial fluid for evaluation was obtained at multiple times. The median maximum synovial fluid amikacin concentration was 450.5 μg/mL (range, 304.7 to 930.7 μg/mL), and median t_max was 25 minutes (range, 20 to 30 minutes). All horses had synovial fluid amikacin concentrations ≥ 160 μg/mL (therapeutic concentration for common equine pathogens) at 20 minutes after IVRLP.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that, in healthy horses, maintaining the tourniquet for 20 minutes after IVRLP of amikacin in a saphenous vein was sufficient to achieve therapeutic concentrations of amikacin in the tarsocrural joint.

Clinical and diagnostic findings, treatment, and short- and long-term survival in horses with peritonitis: 72 cases (2007-2017)

OBJECTIVE

To identify etiology, clinical findings, diagnostic results, treatment, and short- and long-term survival and to report factors associated with nonsurvival and survival in horses with peritonitis.

STUDY DESIGN

Retrospective study.

ANIMALS

Horses (n = 72).

METHODS

Medical records at William R. Pritchard Veterinary Medical Teaching Hospital from 2007-2017 were reviewed for horses diagnosed with peritonitis. The essential inclusion criterion was a peritoneal nucleated cell count of ≥25 000 cells/μL. Gastrointestinal rupture and cases in which peritonitis occurred after abdominal surgery or castration were excluded. Information retrieved from medical records included signalment, history, clinicopathological and peritoneal fluid variables, diagnostic imaging findings, inciting cause, treatment, and short- and long-term survival. Data were analyzed by using Fisher's exact test, Wilcoxon rank sum test, and χ² test (P < .05).

RESULTS

Colic was the most common presenting complaint (34/72 [48%]). A definitive diagnosis could be made in 44 (44/72 [61%]) cases. The most common cause of peritonitis was infectious agents (31/72), followed by trauma (8/72), gastrointestinal thickening (3/72), and eosinophilic peritonitis (2/72). Idiopathic peritonitis was identified in 28 (28/72 [39%]) cases. Sixty (83%) horses survived to hospital discharge. Long-term follow-up was available for 49 horses, with 43 (88%) horses alive 1 year after discharge. Significant differences between nonsurvivors and survivors were history of colic, positive peritoneal fluid culture, and several hematological/peritoneal fluid variables.

CONCLUSION

Peritoneal fluid analysis was essential for a definitive diagnosis of peritonitis, and certain variables were useful for predicting outcome.

CLINICAL SIGNIFICANCE

Results of this study provide evidence of the value of peritoneal fluid analysis for identification of peritonitis, prediction of outcome, and successful treatment.

Clinical and biochemical factors associated with survival in equids attacked by dogs: 28 cases (2008-2016)

Background

Trauma from dog attacks has been associated with mortality rates as high as 23% in some species. However, the prognosis and clinical features of this type of injury have not been described in equids.

Hypotheses/Objectives

To describe survival rate, signalment, clinical features, and biochemical results in equids presented for emergency care after presumed dog attacks. We hypothesized there would be differences between survivors and nonsurvivors.

Animals

A total of 28 equids presented for presumed dog attacks from 3 referral centers.

Methods

A retrospective study was performed using data from 3 hospitals between 2008 and 2016. Survival was defined as survival at 14 days postdischarge. Variables were compared between survivors and nonsurvivors using a t test, Mann‐Whitney U test, or Fisher's exact test as appropriate.

Results

Overall mortality rate was 21%. Ponies and miniature horses represented 16/28 (57%) of the animals in the study. Full‐sized equids had a lower risk of nonsurvival as compared to smaller patients (odds ratio = 0.02; 95% confidence intervals = 0.00‐0.27; P < .005). Animals with lower body temperatures had increased risk for nonsurvival (P = .0004). Increased admission blood lactate concentrations (P = .003) and decreased serum total protein concentrations (P = .006) were associated with nonsurvival.

Conclusions

The mortality rate in equids attacked by dogs was similar to what is reported for other veterinary species. Smaller equids and those with increased admission blood lactate concentration, lower body temperature, and lower total serum protein concentrations were less likely to survive.

Incidence of incisional complications after exploratory celiotomy in equids affected with enterolithiasis

This study reports the prevalence of and risk factors for incisional complications in equids after ventral midline celiotomy for enterolithiasis. This study covered the years 2008 to 2015 and included 72 equids. Enteroliths were removed from the ascending or descending colon through 1 or more enterotomies. Complications were defined as surgical site infection and/or incisional hernia formation. Follow-up by telephone questionnaire or medical records determined that 10/72 (13.9%) equids experienced complications, with 6/72 (8.3%) developing a surgical site infection and 5/72 (6.9%) a hernia. Seven of ten were presented for chronic abdominal discomfort (> 24 hours), and 8/10 had right dorsal colon and pelvic flexure enterotomies. All equids that developed an incisional hernia and 4 with surgical site infection had enteroliths > 15 cm diameter removed from the right dorsal colon. Antimicrobial powder applied to the ventral midline incision during closure significantly reduced incisional complications. Removal of > 15 cm diameter enteroliths from the right dorsal colon may predispose to postoperative incisional complications.

Coccidioidomycosis in llamas and alpacas diagnosed at the University of California, Davis (1990-2016)

Given the predisposition of South American camelids to coccidioidomycosis, we sought to describe the disease presentation in alpacas and llamas and identify potential risk factors for these species. The records of 224 llamas and alpacas that were tested for Coccidioides infection using immunodiffusion serology at the Coccidioidomycosis Serology Laboratory of the University of California, Davis, between 1990 and 2016 were examined; of those, 46 alpacas and 42 llamas had positive test results. The remaining 99 alpacas and 37 llamas were used as control groups. We found that male llamas were at increased risk for Coccidioides infection when compared with female llamas and when compared with male alpacas. South American camelids living within California were at higher risk for infection than camelids living in other states. Alpacas were more likely than llamas to have subclinical infections. We documented five cases of abortion or neonatal mortality attributable to coccidioidomycosis in alpacas. Our study demonstrates that South American camelids are susceptible to Coccidioides infection in areas where the disease is endemic, lending support to the importance of vigilance for this disease in alpacas and llamas and suggesting a possible role for these animals as sentinel species.

LAY SUMMARY

We examined cases of Valley Fever and described the disease and risk factors for llamas and alpacas. Male llamas were at increased risk for infection as were animals living within California. Five alpacas had miscarriages or neonatal deaths as a result of Valley Fever infections.

Diagnostic value of plasma and peritoneal fluid procalcitonin concentrations in horses with strangulating intestinal lesions

OBJECTIVE

To assess the diagnostic value of plasma and peritoneal fluid procalcitonin concentrations for identification of horses with strangulating intestinal lesions.

ANIMALS

65 horses with signs of colic of intestinal origin and 10 healthy (control) horses.

PROCEDURES

For each horse, plasma and peritoneal fluid samples were obtained for a CBC and determination of total protein, procalcitonin, and lactate concentrations. Signalment and clinicopathologic findings were compared among control horses and horses with strangulating and nonstrangulating intestinal lesions.

RESULTS

Mean ± SD plasma (274.9 ± 150.8 pg/mL) and peritoneal fluid (277 ± 50.6 pg/mL) procalcitonin concentrations for horses with colic were significantly greater than the mean ± SD plasma (175.5 ± 46.0 pg/mL) and peritoneal fluid (218.8 ± 48.7 pg/mL) procalcitonin concentrations for control horses. Mean procalcitonin concentration in peritoneal fluid, but not plasma, differed significantly between horses with strangulating lesions and those with nonstrangulating lesions. A peritoneal fluid procalcitonin concentration ≥ 281.7 pg/mL had a sensitivity of 81%, specificity of 69%, positive predictive value of 56.7%, and negative predictive value of 87.9% for detection of strangulating lesions.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that peritoneal fluid procalcitonin concentration, when evaluated in conjunction with other clinicopathologic results, might be a sensitive indicator of intestinal ischemia and facilitate early identification of horses that require surgery to address a strangulating lesion.

Evaluation of the risk of incisional infection in horses following application of protective dressings after exploratory celiotomy for treatment of colic

OBJECTIVE To assess incidence of incisional infection in horses following management with 1 of 3 protective dressings after exploratory celiotomy for treatment of acute signs of abdominal pain (ie, colic) and determine the risk of complications associated with each wound management approach. DESIGN Prospective, randomized, controlled study. ANIMALS 85 horses. PROCEDURES Horses were assigned to 3 groups. After standardized abdominal closure, a sterile cotton towel (group 1) or polyhexamethylene biguanide-impregnated dressing (group 2) was secured over the incision site with 4 or 5 cruciate sutures of nonabsorbable monofilament, or sterile gauze was placed over the site and secured with an iodine-impregnated adhesive drape (group 3). Demographic and clinicopathologic data, intraoperative and postoperative variables, and development of complications were recorded and compared among groups by statistical methods. Follow-up information was collected 30 and 90 days after surgery. Incidence and odds of incisional complications were calculated. RESULTS 75 horses completed the study. Group 3 typically had dressing displacement necessitating removal during anesthetic recovery; dressings were in place for a mean of 44 and 31 hours for groups 1 and 2, respectively. Purulent or persistent serosanguinous incisional discharge (ie, infection) was detected in 11 of 75 (15%) horses (2/24, 0/26, and 9/25 from groups 1, 2, and 3, respectively). Odds of incisional complications were significantly greater for group 3 than for groups 1 or 2. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that risk of infection after celiotomy for treatment of colic is lower for incisions covered with sterile towels or polyhexamethylene biguanide-impregnated dressings secured with sutures than for incisions covered with gauze secured with iodine-impregnated adhesive drapes.

Gender Imbalance in Authorship of Veterinary Literature: 1995 versus 2015

Despite increasing representation of women in veterinary medicine, gender differences persist in pay and attainment of senior and leadership positions. In academia, scholarly publication is a measure of productivity and is emphasized in the promotion process. This study aimed to analyze gender differences in the authorship of veterinary research articles to understand factors that could influence women's advancement and standing in academic medicine. We hypothesized that the proportion of women authors would increase between 1995 and 2015 and be similar to employment rates of women in academia, and that gender differences would exist in authorship by species, veterinary specialty area, and role (junior versus senior author). We examined 2,086 articles published in eight prominent veterinary journals in 1995 and 2015, determined the gender of first authors, corresponding authors, and senior authors, and collected article information including study design, species, and veterinary specialty area. The proportion of women as first and corresponding author increased significantly between 1995 and 2015, and in both years studied, women authored a larger percentage of articles than the reported percentage of women working in academia. In 2015, women were first authors of 60.0% (95% CI 56.9-63.0) of articles but accounted for only 38.3% of senior authors (95% CI 33.4-43.3). Female first authors were concentrated in articles pertaining to small animal, equine, and internal medicine disciplines and under-represented among articles pertaining to livestock or surgical specialties. The gender gap in the authorship of veterinary clinical research articles has improved dramatically over the past 20 years, although gender disparities persist.

Predictive value of plasma and peritoneal creatine kinase in horses with strangulating intestinal lesions

OBJECTIVE

To determine the ability of plasma and peritoneal creatine kinase (CK) to predict the presence of a strangulating lesion in horses presented for colic.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Ten healthy control horses and 61 clinical colic cases.

METHODS

Creatine kinase activity was measured in peritoneal fluid and plasma of 10 healthy horses and 61 horses presenting for colic (40 horses with nonstrangulating lesions and 21 horses with strangulating lesions). Information on other blood and peritoneal fluid variables, signalment, results from the physical examination, outcome, requirement for surgery, and lesion location and type were retrieved from the medical records of horses presenting for colic.

RESULTS

A peritoneal CK cutoff level of 16 IU/L yielded a sensitivity of 95.2% and a specificity of 84.6% (positive predictive value [PPV] = 76.9% and negative predictive value [NPV] = 97%, respectively) for predicting a strangulating lesion. A peritoneal lactate cutoff level of 3.75 mmol/L yielded a sensitivity of 81% and a specificity of 92% (PPV = 85% and NPV = 90%, respectively) for predicting a strangulating lesion.

CONCLUSION

Peritoneal CK concentration was a sensitive indicator of the presence of a strangulating lesion in horses presenting with colic, whereas peritoneal lactate concentration was a more specific indicator.

CLINICAL SIGNIFICANCE

Measuring CK in peritoneal fluid may be a useful adjunct to clinical case presentation to accelerate the diagnosis and definitive treatment of horses presenting with strangulating intestinal lesions, thereby improving their outcome.

Evaluation of the effects of initial water temperature and curing time on fiberglass cast strength

OBJECTIVE

To determine the effects of water temperature and cure time on cast strength.

STUDY DESIGN

Prospective randomized experimental study.

METHODS

Two water temperatures were tested, 23°C (cold) and 42°C (warm). Cast constructs were made of 4-inch fiberglass casting material over a rubber mandrel. Each construct was divided into 3 segments and tested in 4-point bending at 0.5, 1, and 24 hours. Stiffness and bending moment, cumulative energy, and angular deformation at yield and failure were recorded and analyzed by using repeated measures ANOVA.

RESULTS

Mean time ± SD to complete the construct was 2.2 ± 0.8 and 2.3 ± 0.6 minutes for warm and cold water, respectively. Warm water and longer cure times produced constructs with greater stiffness (23.05 vs 20.88 newton-meter degrees [Nm°] at 0.5 hours), bending moment (121.75 vs 107.31 Nm° at 0.5 hours), and cumulative energy (557.33 vs 428.89 Nm° at 1 hour) at yield and failure. Longer cure time significantly increased angular deformation of rods at failure; however, water temperature did not. In general, the strongest casts were produced with warm water and after curing for 24 hours.

CONCLUSION

Fiberglass casts continued to gain strength for at least 24 hours. Use of warm water increased the rate of curing, resulting in stronger constructs at earlier time points.

CLINICAL SIGNIFICANCE

Use of warm water is recommended to initiate fiberglass cast curing, especially if the casted limb will be loaded soon after cast application.

Clinical findings and management of 153 horses with large colon sand accumulations

OBJECTIVE

To determine the influence of radiographic quantification of sand accumulation on the medical versus surgical management of large colon sand accumulations. To compare short- and long-term outcomes and complications associated with medical and surgical management of these horses.

STUDY DESIGN

Retrospective.

SAMPLE POPULATION

A total of 153 horses.

METHODS

Medical records and abdominal radiographs of horses presented for colic between 2004 and 2014 were reviewed. Severity of sand accumulation was quantified by tracing and measuring a region of interest with a commercial software program. Breed, weight, amount of sand, presence of diarrhea at presentation, treatment, and the development of complications were recorded.

RESULTS

Records from 153 horses were reviewed. The mean cross-sectional area of sand accumulation was 692.9 cm² (median = 658.7 cm² , 84.6-1780.7 cm² ). Increased accumulation of gas on radiographs and abnormal transrectal examination findings were associated with an increased likelihood of surgery. The most common complication was the development of diarrhea (20.3%) with only 4 (2.6%) horses positive for Salmonella spp. Horses had a favorable prognosis, with 94.8% of horses treated medically and 94.7% of those treated surgically surviving to discharge.

CONCLUSION

Increased accumulation of gas on radiographs and transrectal palpation of impaction or intestinal gas distension increase the likelihood of surgery. Both medical and surgical treatments carry a good prognosis.

CLINICAL RELEVANCE

The sheer quantity of sand is not a factor when determining surgical intervention. Attention should be paid to the presence of increased gas accumulation on rectal or radiographic examination.

Primary gastric rupture in 47 horses (1995-2011)

The purpose of this retrospective case-control study was to identify factors associated with primary gastric rupture and to investigate if there were differences between etiologies of primary gastric rupture. Compared to the general colic population, Quarter horses were under-represented and Friesians and draft breeds were over-represented in 47 cases of primary gastric ruptures. Horses with primary gastric rupture typically presented with severe clinical and clinicopathological derangements. There were 24 idiopathic gastric ruptures, 20 gastric impaction associated ruptures, and 3 perforating gastric ulcers. Thoroughbred horses were over-represented in the idiopathic gastric rupture group compared to other breeds and etiologies. This study suggests the presence of important breed predispositions for development of gastric rupture. Further study is necessary to identify if these predispositions are associated with management factors or breed-specific disorders.

Heterologous antigen selection of camelid heavy chain single domain antibodies against tetrabromobisphenol A

Tetrabromobisphenol A (TBBPA) is a ubiquitous flame retardant. A high-throughput immunoassay would allow for monitoring of human and environmental exposures as a part of risk assessment. Naturally occurring antibodies in camelids that are devoid of light chain, show great promise as an efficient tool in monitoring environmental contaminants, but they have been rarely used for small molecules. An alpaca was immunized with a TBBPA hapten coupled to thyroglobulin and a variable domain of heavy chain antibody (VHH) T3-15 highly selective for TBBPA was isolated from a phage displayed VHH library using heterologous coating antigens. Compared to the VHHs isolated using homologous antigens, VHH T3-15 had about a 10-fold improvement in sensitivity in an immunoassay. This assay, under the optimized conditions of 10% methanol in the assay buffer (pH 7.4), had an IC50 for TBBPA of 0.40 ng mL(-1) and negligible cross reactivity (<0.1%) with other tested analogues. After heating the VHH at 90 °C for 90 min about 20% of the affinity for coating antigen T3-BSA remained. The recoveries of TBBPA from spiked soil and fetal bovine serum samples ranged from 90.3% to 110.7% by ELISA and agreed well with a liquid chromatography-tandem mass spectrometry method. We conclude the many advantages of VHH make them attractive for the development of immunoassays to small molecules.

A preliminary study of silver sodium zirconium phosphate polyurethane foam wound dressing on wounds of the distal aspect of the forelimb in horses

OBJECTIVE

To determine if application of silver sodium zirconium phosphate polyurethane semi-occlusive foam (SPF) dressing would improve measures of wound healing and decrease bacterial contamination compared with a non-adherent, absorbent dressing applied to wounds created on the distal aspect of the equine limb.

STUDY DESIGN

Controlled randomized experimental study.

ANIMALS

Adult Quarter Horse and Thoroughbred horses (n = 5).

METHODS

One 6.25 cm(2) wound was created on the dorsomedial aspect of the proximal metacarpus on each forelimb. A SPF dressing was applied to 1 randomly assigned limb as a treatment and a non-adherent, absorbent dressing was applied to the opposite limb as control. Bandages were changed every 3 days for 60 days. Granulation tissue was scored every 3 days, wound area measured every 6 days, and wound bed was cultured every 12 days.

RESULTS

SPF-treatment wounds had significantly decreased wound area and decreased granulation tissue scores when evaluated <30 days and over the 60 day study, although complete wound healing times were not significantly different. Bacteria were cultured from all wounds at varying times throughout the study.

CONCLUSIONS

The SPF wound dressing improved some measures of wound healing compared with the control dressing, most significantly during the first 30 days. This suggests that the SPF wound dressing may be useful in the early management of wounds on the equine lower limb. Further studies using the SPF dressing are needed to characterize the temporal and cellular effects on wound healing and evaluate this dressing in a clinical environment.

Evaluation of 3 handheld portable analyzers for measurement of L-lactate concentrations in blood and peritoneal fluid of horses with colic

OBJECTIVE

To compare 3 portable handheld analyzers with a bench top blood gas analyzer for measurement of blood and peritoneal fluid L-lactate concentrations in horses admitted with signs of colic.

STUDY DESIGN

Prospective clinical study.

SAMPLE POPULATION

Blood and peritoneal fluid from horses with colic.

METHODS

L-lactate concentrations in heparinized blood and peritoneal fluid were measured serially on 10 occasions to evaluate repeatability of the portable analyzers. Blood and peritoneal fluid L-lactate concentrations were simultaneously evaluated by a bench top and 3 portable analyzers and the results compared by intraclass correlation coefficients and Bland Altman plots. L-Lactate concentrations in a subgroup of peritoneal fluid samples were evaluated by a chromogenic laboratory assay and compared with the bench top and the handheld analyzers.

RESULTS

Portable lactate analyzers had good intra-analyzer reliability for peritoneal fluid. Two portable analyzers had poor intra-analyzer reliability for mid concentrations of L-lactate in blood. L-lactate measurements from portable analyzers were closer to the bench top analyzer at low concentrations of L-lactate than at higher concentrations. Compared with the bench top analyzer, the Lactate Pro and Lactate Plus have the highest intraclass correlation coefficient and the smallest bias for peritoneal fluid and blood L-lactate, respectively. The bench top analyzer and the Lactate Pro had the highest level of agreement for peritoneal fluid compared with the chromogenic assay.

CONCLUSIONS

Although portable analyzers are alternatives for the measurement of L-lactate concentration in field situations, clinicians need to be aware of the variable results between analyzers, especially when extrapolating means or cutoff values from studies using different lactate analyzers.

Sinusitis associated with nasogastric intubation in 3 horses

Sinusitis has not been reported as a complication of long-term nasogastric intubation in horses. We describe 3 horses that developed nosocomial sinusitis following abdominal surgery with associated perioperative nasogastric intubation. Sinusitis was suspected by the presence of malodorous discharge and confirmed by percussion, upper airway endoscopy, radiographs (n = 3), and bacterial culture (n = 1).

Complications associated with perineal urethrotomy in 27 equids

OBJECTIVE

To report the clinical findings, incidence of complications, and outcome associated with perineal urethrotomy in equids.

STUDY DESIGN

Retrospective case series.

ANIMALS

Equids (n = 27).

METHODS

Medical records (January 2000 to December 2010) of equids that had a perineal urethrotomy were reviewed. Data retrieved and evaluated were breed, age, surgical technique, use of general anesthesia, complications, time from surgery to development of complications and their management, and outcome.

RESULTS

Perineal urethrotomy was performed for urolithiasis (n = 22), for treatment of urethral rents (3), severe balanoposthitis (1), and bladder atony caused by equine protozoal myeloencephalitis (1). The incidence of complications was 52%, including recurrence of urolithiasis in 5 (23%) equids. Horses that had postoperative cystoscopy and bladder lavage were significantly less like likely to have recurrence of urolithiasis (P = .039). Of equids that had postoperative indwelling urinary catheters, 75% developed complications.

CONCLUSIONS

Perineal urethrotomy can be an effective for treatment of urolithiasis, hematuria, and urethral trauma. Postoperative cystoscopy and bladder lavage significantly reduced the incidence of postoperative recurrence of urolithiasis.

Isolation of alpaca anti-idiotypic heavy-chain single-domain antibody for the aflatoxin immunoassay

Anti-idiotypic antibodies recognize the antigenic determinants of an antibody, thus they can be used as surrogate antigens. Single-domain antibodies from camlid heavy-chain antibodies with the benefit features of small size, thermostability, and ease in expression, are leading candidates to produce anti-idiotypic antibodies. In this work, we constructed an antibody phage library from the mRNA of an alpaca immunized with an antiaflatoxin monoclonal antibody (mAb) 1C11. Three anti-idiotypic VHH antibodies were isolated and applied to immunoassay toward aflatoxin as a coating antigen. The best immunoassay developed with one of these VHH antibodies shows an IC50 of 0.16 ng/mL toward aflatoxin B1 and cross-reactivity toward aflatoxin B2, G1, and G2 of 90.4%, 54.4%, and 37.7%, respectively. The VHH-based immunoassay was successfully applied to the analysis of peanuts, corn, and rice, which are the predominant commodities regularly contaminated by aflatoxins. A good correlation (r(2) = 0.89) was found between the data obtained from the conventional ELISA and the ELISA based on a VHH coating antigen for the analysis of aflatoxins in peanuts and feedstuff. The use of biotechnology in developing the surrogate, the absence of standard aflatoxin and organic solvents in the synthesis procedures, and the reproducibility of the VHH antibody makes it an ideal strategy for replacing conventional synthesized antigens.

Pharmacokinetics of ceftiofur crystalline free acid after single and multiple subcutaneous administrations in healthy alpacas (Vicugna pacos)

Six adult male alpacas received one subcutaneous administration of ceftiofur crystalline free acid (CCFA) at a dosage of 6.6 mg/kg. After a washout period, the same alpacas received three subcutaneous doses of 6.6 mg/kg CCFA at 5-day intervals. Blood samples collected from the jugular vein before and at multiple time points after each CCFA administration were assayed for ceftiofur- and desfuroylceftiofur-related metabolite concentrations using high-performance liquid chromatography. Pharmacokinetic disposition of CCFA was analyzed by a noncompartmental approach. Mean pharmacokinetic parameters (± SD) following single-dose administration of CCFA were Cmax (2.7 ± 0.9 μg/mL); Tmax (36 ± 0 h); area under the curve AUC0→∞ (199.2 ± 42.1 μg·h/mL); terminal phase rate constant λz (0.02 ± 0.003/h); and terminal phase rate constant half-life t1/2λz (44.7 h; harmonic). Mean terminal pharmacokinetic parameters (±SD) following three administrations of CCFA were Cmax (2.0 ± 0.4 μg/mL); Tmax (17.3 ± 16.3 h); AUC0→∞ (216.8 ± 84.5 μg·h/mL); λz (0.01 ± 0.003/h); and t1/2λz (65.9 h; harmonic). The terminal phase rate constant and the Tmax were significantly different between single and multiple administrations. Local reactions were noted in two alpacas following multiple CCFA administrations.

Isolation of alpaca anti-hapten heavy chain single domain antibodies for development of sensitive immunoassay

Some unique subclasses of Camelidae antibodies are devoid of the light chain, and the antigen binding site is comprised exclusively of the variable domain of the heavy chain (VHH). Although conventional antibodies dominate current assay development, recombinant VHHs have a high potential as alternative reagents for the next generation of immunoassay. We expressed VHHs from an immunized alpaca and developed a VHH-based immunoassay using 3-phenoxybenzoic acid (3-PBA), a major metabolite of pyrethroid insecticides as a model system. A phage VHH library was constructed, and seven VHH clones were selected by competitive binding with 3-PBA. The best immunoassay developed with one of these VHHs showed an IC(50) of 1.4 ng/mL (limit of detection (LOD) = 0.1 ng/mL). These parameters were further improved by using the phage borne VHH, IC(50) = 0.1 ng/mL and LOD = 0.01 ng/mL. Both assays showed a similar tolerance to methanol and dimethylsulfoxide up to 50% in assay buffer. The assay was highly specific to 3-PBA and its 4-hydroxylated derivative, 4-hydroxy 3-PBA, (150% cross reactivity) with negligible cross reactivity with other tested structural analogues, and the recovery from spiked urine sample ranged from 80 to 112%. In conclusion, a highly specific and sensitive VHH for 3-PBA was developed using sequences from immunized alpaca and phage display technology for antibody selection.

Colic in competing endurance horses presenting to referral centres: 36 cases

REASONS FOR PERFORMING STUDY

Colic is a common reason for elimination from equine endurance competitions and has recently been identified as the leading cause of mortality in this group of horses. Hydration and electrolyte derangements are often severe, but are probably related to endurance exercise and not necessarily the episode of colic. Better understanding of the causes of colic and the expected outcome is needed to guide treatment decisions in endurance horses.

OBJECTIVES

To describe the history, case details, clinical examination, laboratory, treatment and outcomes for horses presenting to equine referral centres for treatment of colic associated with endurance competition and to identify variables associated with prolonged hospitalisation.

METHODS

Thirty-six horses from 2 equine referral centres were included in the analysis. In addition to descriptive statistics, Cox proportional hazards models were used to evaluate factors associated with length of hospitalisation.

RESULTS

A diagnosis of open or ileus was made in the majority of horses (56%). Salmonellosis and enteritis (Salmonella negative) were also recognised (16%). Exploratory abdominal surgery was performed in 5 of the horses. Only one of 36 horses did not survive to discharge. Previous eliminations from competition (negative association) and total i.v. fluids within the first 24 h (positive association) of admission were both associated with length of hospitalisation.

CONCLUSIONS

Endurance horses with colic typically respond to medical treatment but in some cases hospitalisation may be prolonged. The role of Salmonella infections in endurance horses with colic requires further research.

POTENTIAL RELEVANCE

Despite potentially severe clinical and laboratory derangements, equine practitioners should make owners aware that the prognosis for competing endurance horses with colic is good when treated appropriately.

Peritoneal and plasma D-lactate concentrations in horses with colic

OBJECTIVE

To evaluate the association between peritoneal fluid and plasma d-lactate concentration with variables used in the diagnosis and prognosis of horses with colic.

ANIMALS

Clinically healthy horses (n=6) and 90 horses with colic.

STUDY DESIGN

Prospective cross-sectional study.

METHODS

D-lactate concentration was determined in peritoneal fluid and plasma of all horses. Information on other blood and peritoneal fluid variables, signalment, results from the physical examination, outcome, need for surgery, lesion location, and type was retrieved from medical records.

RESULTS

Peritoneal D-lactate concentration was strongly correlated with plasma D-lactate concentration (r=0.71; P<.001). Peritoneal and plasma D-lactate concentrations were positively correlated with peritoneal (r=0.8; P<.001) and plasma L-lactate (r=0.33; P=.001) concentrations, respectively. Peritoneal D-lactate concentration was negatively correlated with survival to discharge (U=430.5; P<.001). Median peritoneal D-lactate concentration of horses with septic peritonitis (455.2 μmol/L) and horses with gastrointestinal rupture (599.5 μmol/L) were higher compared with horses with nonstrangulating obstructions (77.7 μmol/L). A cut-off concentration of peritoneal D-lactate of 116.6 μmol/L had a sensitivity of 0.813 and a specificity of 0.651 to differentiate between nonstrangulating and strangulating obstructions.

CONCLUSIONS

Peritoneal D-lactate concentration may be more useful for identifying horses with strangulating obstructions (high sensitivity, low probability of a false negative) than to ruling out strangulating obstruction (moderate specificity, high probability of a false positive).

Comparison of pH, lactate, and glucose analysis of equine synovial fluid using a portable clinical analyzer with a bench-top blood gas analyzer

OBJECTIVE

To compare agreement between a portable clinical analyzer and laboratory-based bench-top analyzer for analysis of pH, lactate, and glucose concentrations in synovial fluid.

STUDY DESIGN

Prospective experimental study.

ANIMALS

Clinically normal horses (n=8); 6 horses euthanatized for reasons unrelated to the study; 11 horses that had synoviocentesis for reasons other than sepsis; 7 horses that had synoviocentesis for evaluation of sepsis; and 2 horses without recorded clinical data. Median age of horses was 8 years (range, 1 day to 24 years).

METHODS

Supernatant from each synovial fluid sample was analyzed for pH, lactate, and glucose concentrations using an ABL 705 laboratory-based bench-top analyzer and i-STAT portable clinical analyzer. Bland-Altman plots were constructed and concordance analysis performed to determine bias and agreement between the 2 analyzers.

RESULTS

There was acceptable agreement between analyzers for lactate and glucose concentrations, with biases of 0.198 mmol/L and 9 mg/dL and concordance correlation coefficients of 0.97 and 0.96 for lactate and glucose, respectively. The agreement between analyzers for pH was not acceptable, with a bias of -0.057 and concordance correlation coefficient of 0.89.

CONCLUSIONS

This study found that the portable clinical analyzer performed similarly to the bench-top blood gas analyzer for evaluation of lactate and glucose concentrations, but not pH, in synovial fluid.

Effects of aerobic and anaerobic fluid collection on biochemical analysis of peritoneal fluid in healthy horses and horses with colic

OBJECTIVE

To determine whether in healthy horses and those with colic, exposure of peritoneal fluid to room air affects values obtained on biochemical analysis.

STUDY DESIGN

Prospective study.

ANIMALS

Adult horses with a primary complaint of acute abdominal pain (n=29) and 12 healthy horses.

METHODS

Peritoneal fluid was aseptically collected under aerobic and anaerobic conditions. After collection, pH, PCO(2) , PO(2) , HCO(3) (-) , Na(+) , ionized Ca(2+) , K(+) , lactate, and glucose were immediately measured using a commercial blood gas analyzer. Biochemical variables were compared between aerobically and anaerobically obtained samples using a paired t-test.

RESULTS

In healthy horses, peritoneal fluid samples collected under anaerobic conditions had higher PCO(2) and ionized Ca(2+) and lower PO(2) , HCO(3) (-) , and pH compared with samples exposed to air. No differences were observed for K(+) , Na(+) , glucose, and lactate. In horses with colic, samples collected anaerobically had higher PCO(2) , ionized Ca(2+) , Na(+) , and glucose and lower PO(2) , HCO(3) (-) , and pH value compared with samples exposed to air. No differences were observed for K(+) and lactate.

CONCLUSION

Exposure of peritoneal fluid to room air had a significant effect on pH, PCO(2) , PO(2) , and variables associated or dependent on changes in pH such as HCO(3) (-) and ionized Ca(2+) . Interpretation of biochemical analysis of peritoneal fluid may be influenced by sample collection method.

Resection and anastomosis of the descending colon in 43 horses

OBJECTIVES

To determine (1) the short- (to hospital discharge) and long- (>6 months) term survival, (2) factors associated with short-term survival, and (3) the perioperative course for horses with resection and anastomosis of the descending colon.

STUDY DESIGN

Multicentered case series.

ANIMALS

Horses (n=43) that had descending colon resection and anastomosis.

METHODS

Medical records (January 1995-June 2009) of 7 equine referral hospitals were reviewed for horses that had descending colon resection and anastomosis and were recovered from anesthesia. Retrieved data included history, results of clinical and clinicopathologic examinations, surgical findings, postsurgical treatment and complications, and short-term survival (hospital discharge). Long-term survival was defined as survival > or =6 months after hospital discharge.

RESULTS

Of 43 horses, 36 (84%) were discharged from the hospital. Twenty-eight of 30 horses with follow-up information survived > or =6 months. No significant associations between perioperative factors and short-term survival were identified. Lesions included strangulating lipoma (n=27), postfoaling trauma (4), infarction (4), intraluminal obstruction (2), and other (6). Common postoperative complications included fever and diarrhea. During hospitalization 7 horses were euthanatized or died because of septic peritonitis (3), endotoxemia (3), and colic and ileus (1).

CONCLUSIONS

Descending colon resection and anastomosis has a favorable prognosis for hospital discharge and survival > or =6 months. The most common cause of small colon incarceration was strangulating lipoma.

CLINICAL RELEVANCE

Complications include postoperative fever and diarrhea but the prognosis is good after small colon resection and anastomosis.

Effects of glucosamine hydrochloride and chondroitin sulphate, alone and in combination, on normal and interleukin-1 conditioned equine articular cartilage explant metabolism

REASONS FOR PERFORMING STUDY

Clinical trials in human and veterinary literature have documented the benefits of oral nutraceutical joint supplements containing glucosamine (GU) and chondroitin sulphate (CS) to treat mild to moderate osteoarthritis, but the effects of these components have not yet been conclusively determined.

OBJECTIVES

To assess varying dosages of GU and CS on normal and interleukin-1alpha (IL-1) conditioned equine cartilage explants and rationalise the use of these products.

HYPOTHESIS

Treatment would not be detrimental to cartilage metabolism and higher dosages and the combination of GU and CS would be more beneficial than lower dosages and. GU or CS alone.

METHODS

Articular cartilage explants collected from the femoral trochlea and condyles were cultured in normal and IL-1 conditioned media. Treatment groups included 0, 12.5, 25,125 and 250 microg/ml concentrations of GU alone, CS alone, or GU+CS in combination. Glycosaminoglycan (GAG) synthesis and total GAG content in the explants and media were analysed.

RESULTS

There were no detrimental effects of GU, CS or GU+CS on cartilage metabolism. High dosages of GU+CS reduced total GAG release into the media (degradation).

CONCLUSIONS

Our results suggests that GU+CS may prevent cartilage GAG degradation.

POTENTIAL RELEVANCE

The combination of GU and CS may be more effective in preventing or treating osteoarthritis in horses than either product alone.

Fatal Bluetongue Virus Infection in an Alpaca (Vicugna Pacos) in California

In October 2008, a 15-year-old female alpaca ( Vicugna pacos) housed at a breeding farm in northern California died after a brief illness characterized by sudden onset of weakness, recumbency, and respiratory distress. Postmortem examination revealed severe hydrothorax and hydropericardium, marked pulmonary edema, and acute superficial myocardial hemorrhage affecting the left ventricle. Bluetongue virus (BTV) was detected in the spleen by quantitative real-time reverse transcription polymerase chain reaction and confirmed by sequence analysis. No antibodies against BTV were detected in the serum using a competitive enzyme-linked immunosorbent assay, confirming acute, fulminant BTV infection.

Suspected air embolism associated with post-anesthetic pulmonary edema and neurologic sequelae in a horse

A 523 kg Quarter Horse was anesthetized for unilateral eye enucleation. The anesthetic period was unremarkable. During anesthetic recovery the cap on the jugular venous catheter became dislodged. Clinical signs of pulmonary edema associated with moderate arterial hypoxemia subsequently developed. Although pulmonary edema resolved with medical therapy, the day following anesthetic recovery, clinical signs of vestibular disease and blindness developed. Treatment included nasal oxygen insufflation, flunixin meglumine, furosemide, dexamethasone, thiamine, dimethylsulfoxide, antimicrobials, and phenylbutazone. The horse recovered and was discharged from the hospital after 7 days of treatment and was neurologically normal at 6 weeks. While venous air embolism was not confirmed in this case, the catheter cap complication followed by signs of pulmonary edema and neurologic sequelae support the presumptive pathogenesis of this horse's complications. Diagnostic confirmation of air embolism in horses with compatible acute clinical signs should be documented with echocardiography.

Postmortem diagnosis of idiopathic hyperammonemia in a horse

A 6-year-old Quarter Horse stallion was referred to Oklahoma State University Veterinary Medical Teaching Hospital for evaluation of abdominal pain that developed after breeding activity earlier in the day. The horse developed diarrhea and progressively worsening neurologic signs (circling, ataxia, head pressing) within 22 hours of presentation and was subsequently euthanized due to severe self-destructive behavior. Antemortem biochemical and hematologic abnormalities included hypocalcemia but no evidence of hepatic disease. Idiopathic hyperammonemia and encephalopathy were suspected; cerebrospinal fluid (CSF) and aqueous humor were collected 10 hours postmortem for ammonia analysis using a colorimetric assay. Results were compared with those of 6 horses that also had been euthanized, for diseases unrelated to encephalopathy. Ammonia also was measured in plasma samples obtained antemortem. Ammonia concentrations in plasma (958 micromol/L), CSF (1566 micromol/L) and aqueous humor (1018 micromol/L) samples from the stallion were markedly increased compared to those in the 6 unaffected horses (plasma, 9-43 micromol/L; CSF, 370-532 micromol/L; aqueous humor, 70-483 micromol/L). Since the acute nature of hyperammonemic encephalopathy often does not provide sufficient time for an antemortem diagnosis, postmortem analysis of CSF and aqueous humor ammonia concentrations may be a useful alternative for documenting hyperammonemia in horses.

Effect of Intrathecal Amikacin Administration and Repeated Centesis on Digital Flexor Tendon Sheath Synovial Fluid in Horses

OBJECTIVE

To determine the effect of intrathecal amikacin administration and repeated tenovaginocentesis on the total nucleated cell count (TNCC), total protein (TP) concentration and cytologic characteristics of synovial fluid of the equine digital flexor tendon sheath (DFTS).

STUDY DESIGN

Randomized, cross-over experimental design.

ANIMALS

Adult horses (n=8).

METHODS

Synovial fluid was aseptically collected from the DFTS and either 1 mL amikacin sulfate (250 mg/mL) or lactated Ringer's solution (LRS) was injected into the DFTS. Serial synovial fluid samples were obtained at 0, 12, 24, 48, and 72 hours. The opposite treatment was administered to the contralateral DFTS after a washout period of 2 weeks.

RESULTS

Treatment increased TP concentration, TNCC, percentage of neutrophils, and neutrophil counts from baseline levels. There was no difference between treatment of the DFTS with amikacin or LRS. Values peaked at 12-24 hours after the initial centesis and then declined toward baseline levels.

CONCLUSIONS

Injection and repeat centesis of the normal DFTS with 250 mg amikacin or an equivalent volume of LRS resulted in mild increases in synovial fluid analytes from baseline. Synovial inflammation in this study was not accompanied by lameness at the walk and measured analytes returned toward baseline levels within 12-24 hours of first injection.

CLINICAL RELEVANCE

The effect of tenovaginocentesis and intrathecal administration of amikacin or LRS on DFTS synovial fluid values are modest in most horses; however, some horses can develop marked increases in synovial fluid values that may be interpreted as sepsis.

Comparison of One-Layer (Continuous Lembert) Versus Two-Layer (Simple Continuous/Cushing) Hand-Sewn End-to-End Anastomosis in Equine Jejunum

OBJECTIVE

To evaluate single and double layer end-to-end anastomosis in equine jejunum.

STUDY DESIGN

Experimental in vitro study.

ANIMALS

Mid-jejunal sections from 12 adult horses without gastrointestinal disease.

METHODS

Jejunal end-to-end anastomoses were performed by a continuous Lembert pattern or a simple continuous pattern oversewn with a Cushing pattern. Jejunal segments were distended with fluid at 1 L/min, and intraluminal pressure at failure, and mode of failure were recorded. Bursting pressure and bursting wall tension were calculated. Anastomosis construction time and degree of luminal reduction were recorded. Results- Single layer anastomoses were constructed in less time than 2-layer anastomoses. Both anastomotic techniques resulted in luminal reduction compared with control tissue; however, the reduction was smaller with a 1-layer continuous Lembert anastomosis. No differences were noted in bursting pressure or bursting wall tension between groups.

CONCLUSIONS

Anastomosis using a 1-layer continuous Lembert pattern resulted in a larger stoma, was faster to perform, and as strong as a 2-layer anastomosis.

CLINICAL RELEVANCE

Use of a 1-layer continuous Lembert pattern for jejunojejunosotomy may be beneficial by decreasing anastomosis time and produce a larger stoma than a 2-layer anastomosis.

Hemoperitoneum in horses: 67 cases (1989–2004)

OBJECTIVE

To evaluate clinical findings, underlying causes, and short-term outcome associated with hemoperitoneum in horses.

DESIGN

Retrospective case series.

ANIMALS

67 horses with hemoperitoneum.

PROCEDURES

Medical records of horses with hemo-peritoneum (excluding postoperative abdominal hemorrhage) from 1989 through 2004 were analyzed. Information obtained included history, signalment, physical examination findings, diagnostic test results, and short-term outcome.

RESULTS

Breed distribution was 28 Thoroughbreds, 13 Arabians, 10 Quarter Horses, 5 Warmbloods, 3 Appaloosas, and 1 each of 8 other breeds. There were 40 mares, 23 geldings, and 4 stallions. Median age was 12 years (range, 1 month to 40 years). Signs of abdominal discomfort were the primary complaint in 79% of horses. Clinical findings included shock (60%) and pale mucous membranes (60%). Median heart rate was 76 beats/min (range, 30 to 216 beats/min), median respiratory rate was 30 breaths/min (range, 8 to 92 breaths/min), median Hct was 31% (range, 10.5% to 73.0%), and total protein concentration was 5.8 g/dL (range, 3.3 to 8.7 g/dL). Cause of hemoperitoneum was attributed to trauma (25.4%), neoplasia (17.9%), uterine artery rupture (13.4%), mesenteric injury (11.9%), disseminated intravascular coagulopathy (6.0%), other causes (3.0%), and idiopathic causes (22.4%). Fifty-one percent of horses survived to hospital discharge, 37% were euthanized, and 12% died. Poor short-term outcome was significantly associated with high respiratory rate and certain underlying causes.

CONCLUSIONS AND CLINICAL RELEVANCE

Hemoperitoneum is an infrequent but important cause of abdominal discomfort in horses. Predominant underlying causes were trauma, neoplasia, and idiopathic causes. Identification of underlying cause is important because of its association with outcome.

Use of a three-drill-tract technique for arthrodesis of the distal tarsal joints in horses with distal tarsal osteoarthritis: 54 cases (1990-1999)

OBJECTIVE

To assess the long-term clinical outcome of horses with distal tarsal osteoarthritis (OA) in which a 3-drill-tract technique was used to induce arthrodesis of the affected joints, identify any preoperative or operative factors associated with outcome, and describe any complications associated with the technique.

DESIGN

Retrospective study.

ANIMALS

54 horses.

PROCEDURE

Medical records were reviewed for information on signalment, use, history, physical and lameness examination findings, surgical technique, and postoperative care. Radiographs were examined, and severity of OA was graded. Follow-up information was obtained through telephone interviews with owners at least 13 months after the procedure.

RESULTS

32 (59%) horses had a successful outcome, 6 (11%) improved but were not sound after surgery, and 16 (30%) did not improve following surgery. Outcome was negatively associated with the previous use of intra-articular injections. Few postoperative complications were evident.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that distal tarsal OA in horses can be successfully treated by means of distal tarsal arthrodesis with a 3-drill-tract technique. Horses with advanced distal tarsal OA are likely to have poorer outcomes, and the procedure will likely be of minimal benefit in horses with concomitant causes of hind limb lameness prior to surgery and in horses with preexisting proximal intertarsal joint disease.