Ultrasonographic findings of fluid accumulation and hyperechogenic spots suggestive of surgical site infection following laparotomy for colic in horses.

BACKGROUND: The aim of this study was to compare ultrasonographic findings of the ventral midline incision after exploratory laparotomy for colic in horses with and without surgical site infection (SSI). METHODS: Ultrasonographic examination of the surgical wound was performed on postoperative day 5 (D5) and day 10 (D10) to assess the presence of fluid accumulation, suture sinus formation, hyperechogenic spots and fistulous path. Clinical evaluation of the wound was used to classify horses with and without SSI. The accuracy, sensitivity, specificity and positive and negative predictive values of the ultrasonographic findings were then calculated. Multivariable logistic regression analyses were performed with SSI as a dependent variable and age, sex, breed and ultrasonographic findings as independent variables after univariate and collinearity analyses. RESULTS: Twenty-nine of the 84 horses examined had an SSI. Detection of fluid accumulation and hyperechogenic spots increased the odds for SSI at D5 (odds ratio [OR]: 4.99, 95% confidence interval [CI]: 1.53-16.33, p = 0.008; OR: 10.78, 95% CI: 1.75-26.59, p = 0.01, respectively) and D10 (OR: 11.51, 95% CI: 2.39-55.47, p = 0.002; OR: 12.34, 95% CI: 3.45-44.15, p < 0.001, respectively). LIMITATION: Ultrasonographic images were taken only on the longitudinal section. CONCLUSION: Ultrasonographic examination is helpful in evaluating the surgical incision after laparotomy, with the detection of fluid accumulation and hyperechogenic spots surrounding the sutures being strongly related to SSI.

Intrahepatic mucinous cholangiocarcinoma with recurrent colic in a horse case report and literature review of cholangiocarcinoma in horses.

A 17-y-old Arabian mare was presented to the Auburn Large Animal Veterinary Teaching Hospital with a long-term history of intermittent mild recurrent colic that responded to medical treatment. CBC revealed mild lymphopenia; serum biochemistry findings were of increased gamma-glutamyl transferase and creatine kinase activities, hyperferremia, hyperglycemia, hypomagnesemia, and hypokalemia. Abdominocentesis was compatible with low-protein transudate. Due to the progression and duration of clinical signs, the owner elected euthanasia. Postmortem examination and histopathology confirmed a cholangiocarcinoma. The neoplastic cells were arranged in large cysts containing lakes of mucin that comprised 90% of the tumor volume; thus, a mucinous variant was determined. The neoplastic cells had strong cytoplasmic immunolabeling for cytokeratin 19 and lacked immunolabeling for hepatocyte paraffin 1, supporting bile duct origin. Cholangiocarcinomas are infrequent tumors in horses with nonspecific and slow progressive clinical signs, including recurrent colic. Mucinous cholangiocarcinomas are seldom reported in veterinary medicine and, to our knowledge, have not been reported previously in horses.

Measuring tissue oxygen saturation in the orad intestinal segment during equine colic surgery may aid in predicting the occurrence of postoperative ileus.

OBJECTIVE: To assess the histological injury and intestinal microperfusion measured by laser Doppler flowmetry and spectrophotometry (LDFS) of the small intestine orad to a strangulation during colic surgery. ANIMALS: Horses with naturally occurring small intestinal strangulations undergoing colic surgery were included. METHODS: In this prospective clinical trial, intestinal tissue oxygen saturation (tSO2) and tissue blood flow (tBF) were measured by LDFS orad to the strangulation following release of the strangulation (n = 18). The number of horses with postoperative reflux (POR) and the cases that survived until discharge were compared between groups using Fisher's exact test (P < .05). Intestinal biopsies were taken in cases that underwent intestinal resection or intraoperative euthanasia (n = 28). Measurements were compared between injured and noninjured segments with a Mann-Whitney U or t test. RESULTS: The tSO2 and tBF of the orad intestine were lower than previously reported in healthy horses. Horses with low tSO2 of < 35% were significantly more likely to suffer from POR (6/6 cases) compared to cases with tSO2 > 69% (1/6). The number of horses that survived were not statistically different between these groups (2/6 and 6/6). All horses with mucosal injury developed POR (6/6), which was significantly more likely compared to horses without mucosal injury (3/13). No significant difference in tSO2 or tBF could be found between the segments with and without histological injury. CLINICAL RELEVANCE: The results suggest that measuring tSO2 in the orad segment during colic surgery may aid in predicting postoperative issues.

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.

Iron-related markers of inflammation in horses with colic.

The aim of the study was to compare and correlate levels of ferritin, transferrin, iron and APPs in healthy horses and those surgically treated for strangulating colic. On admission, measurements of inflammatory markers related to iron and total protein, fibrinogen, albumin, haptoglobin and ceruloplasmin were made. The study comprised 22 horses, divided into a control group (CG) of healthy horses (n = 10) and horses with surgically treated acute abdomen (n = 12), obstruction group (OG). The OG was subdivided according to the affected intestinal segment (small vs. large) and according to outcome (survivors vs. non survivors). The OG had higher haptoglobin (34.8±14.2 mg/dL vs 20.8±7.21 mg/dL) and transferrin (487±161 mg/dL vs 369±71.4 mg/dL) values and lower iron (96.9±65 µg/dL vs 218±105 µg/dL) values than the CG. The OG horses with large intestine obstruction had lower values of transferrin (374.6±130 mg/dL) than horses with small intestinal obstruction (598.6±98.9 mg/dL). There was no difference in outcome between horses with large and small intestinal obstruction. Ferritin levels were moderately correlated with total protein (r = 0.594; P = 0.042) and albumin (r = 0.584; P = 0.046) in OG. In the multivariate exploratory analysis, fibrinogen levels were higher in animals that did not survive. In conclusion, haptoglobin, transferrin and iron were useful inflammatory markers for colic in horses. The correlation of ferritin with other APPs shows a possible role of ferritin as an APP in horses. Fibrinogen levels are higher in horses with greater risk of death from strangulating obstructions.

Use of multiple admission variables better predicts intestinal strangulation in horses with colic than peritoneal or the ratio of peritoneal:blood l-lactate concentration.

BACKGROUND: Early identification of strangulating obstruction (SO) in horses with colic improves outcomes, yet early diagnosis of horses requiring surgery for SO often remains challenging. OBJECTIVES: To compare blood and peritoneal fluid l-lactate concentrations, peritoneal:blood l-lactate ratio, peritoneal minus blood (peritoneal-blood) l-lactate concentration and other clinical variables for predicting SO and SO in horses with small intestinal lesions (SO-SI) and then to develop a multivariable model to predict SO and SO-SI. STUDY DESIGN: Retrospective cohort. METHODS: A total of 197 equids admitted to a referral institution for colic between 2016 and 2019 that had peritoneal fluid analysis performed at admission were included. Twenty-three admission variables were evaluated individually for the prediction of a SO or SO-SI and then using multivariable logistic regression. Odds ratios (ORs) with 95% confidence intervals (CI) and area under the curve of the receiver operator characteristic (AUC ROC) were calculated. RESULTS: All variables performed better in the model than individually. The final multivariable model for predicting SO included marked abdominal pain (OR 5.31, CI 1.40-20.18), rectal temperature (OR 0.30, CI 0.14-0.64), serosanguineous peritoneal fluid (OR 35.34, CI 10.10-122.94), peritoneal-blood l-lactate (OR 1.77, CI 1.25-2.51), and peritoneal:blood l-lactate ratio (OR 0.36, CI 0.18-0.72). The AUC ROC was 0.91. The final multivariable model for predicting SO-SI included reflux volume (OR 0.69, CI 0.56-0.86), blood l-lactate concentration (OR 0.43, CI 0.22-0.87), serosanguineous peritoneal fluid (OR 4.99, CI 1.26-19.74), and peritoneal l-lactate concentration (OR 3.77, CI 1.82-7.81). MAIN LIMITATIONS: Retrospective, single-hospital study design. CONCLUSIONS: Blood and peritoneal fluid l-lactate concentrations should be interpreted in conjunction with other clinical variables. The relationship between peritoneal and blood l-lactate concentration for predicting SO or SO-SI was complex when included in a multivariable model. Models to predict SO probably vary based on lesion location.

Survival of formalin intoxication in a 13-year-old Thoroughbred gelding.

BACKGROUND: Formalin intoxication via the gastrointestinal route has not been previously reported in the horse. Whereas ingestion of formalin in humans, although rare, is well documented. Majority of human cases are either accidental, suicidal or homicidal and often lead to fatality, with a reported lethal formaldehyde dose equating to 0.12 - 0.16 g/kg bwt. OBJECTIVES: To describe a single case report of the clinical management of an adult horse referred to a veterinary teaching hospital following accidental administration of 10% formalin via nasogastric tube. METHODS: A 13-year-old Thoroughbred gelding originally presented to the referring veterinarian for colic where 1.8 L of 10% formalin was accidentally administered instead of mineral oil via nasogastric intubation, a potentially lethal dose of formaldehyde (0.12 g/kg bwt). Approximately 20-hours following 10% formalin administration the horse was admitted to the referral hospital with moderate tachycardia, occasional ectopic beats, tacky and hyperaemic mucous membranes, delayed capillary refill time, reduced borborygmi, and pronounced digital pulses. Diagnostic investigations included laboratory blood analysis, urinalysis, electrocardiogram, abdominal ultrasound, palpation per rectum and gastroscopy. RESULTS: Patient assessment found evidence of toxicity to the gastrointestinal tract, hypovolaemia and risk for laminitis. Intensive care included fluid and electrolyte therapy, anti-inflammatories and analgesia, continuous digital cryotherapy, gastro-protectants and other methods of gastrointestinal support. The horse was discharged from hospital on day 14 with no long-term complications and the client-veterinarian relationship was preserved. DISCUSSION: In human cases of ingestion, gastrointestinal injury is typically accompanied by severe metabolic acidosis and multiple organ dysfunction syndrome due to toxicity of other body systems that can contribute to non-survival. Formaldehyde toxicity in the present case predominantly affected the gastrointestinal tract, most likely a direct result of the route of administration. Aside from gastrointestinal injury, primary toxicity of other body systems was not confirmed. To prevent this medical error recurring, the referring veterinary clinic revised their labelling and storage of 10% formalin. CONCLUSION: This is the first report of systemic formalin intoxication in the horse. Following a high dose of 10% formalin (0.12 g/kg bwt formaldehyde) enterally, the horse survived having received intensive supportive care based on human guidelines for ingested formalin.

Cantharidin.

Cantharidin is the toxic component of blister beetles of the genus Epicauta. Cantharidin is a potent vesicant which causes blisters, erosions, and ulcerations in the gastrointestinal and urinary tracts, and can cause myocardial necrosis. Blister beetles are found over most of North America and specifically contaminate alfalfa at harvest. History of alfalfa feeding, with colic, dysuria, hypocalcemia, and hypomagnesemia are suggestive of blister beetle toxicosis. Myocardial damage causes increased serum cardiac troponin 1. Tentative diagnosis can be made by finding the beetles in feed or ingesta. Definitive diagnosis requires detection of cantharidin in urine or gastric contents. Treatment involves ending exposure, decreasing absorption, controlling pain, using gastroprotectants, and fluids and electrolyte replacement. Prognosis is guarded to poor.

Evaluation of substance P as a biomarker for pain in equine colic.

Equine colic is an important condition associated with acute abdominal pain and one of the leading causes of death in horses. As such, objectively evaluating pain is of interest for attending veterinarians. Pain scales for assessment are present, but no single pain-specific biomarker has been reported. The aim of this study was to determine if substance P (SP) could be a reliable biomarker to reflect pain and serve as a parameter to predict outcome in equine colic. The hypothesis was that horses displaying severe colic signs present with higher values of SP in contrast to those with mild colic signs. Thirty warmblood horses, aged between 3 and 20 years were recruited; evenly distributed (10 horses each) in three colic groups (mild, moderate, severe). To classify the colic signs, the horses were graded by the Equine Acute Abdominal Pain Scale (EAAPS). Clinical examination and EAAPS were performed at arrival in the hospital. Blood samples were collected four times in hourly intervals commencing from arrival. For comparison, already established parameters for prognosticating equine colic (heart rate, serum cortisol, and blood lactate concentration) were also measured. The assumption of increasing SP concentrations along with pain could not be confirmed. SP did not show any association with heart rate, cortisol, lactate, or EAAPS. Whereas the established parameters increased according to the EAAPS, SP remained stable in individual horses regardless of clinical signs, treatment, and disease progression. Consequently, SP was not a reliable parameter to reflect painful conditions or to predict outcome in equine colic.

Clinical findings, surgical techniques, prognostic factors for short-term survival and long-term outcome in horses with acquired inguinal hernias: Ninety-eight cases (2005-2020).

OBJECTIVE: To report findings, outcome and determine variables associated with survival in horses with acquired inguinal hernia (AIH). STUDY DESIGN: Retrospective study. ANIMALS: A total of 98 cases in 97 horses. METHODS: The medical records (2005-2020) of horses diagnosed with AIH were reviewed. Retrieved data included signalment, history, clinical variables, surgical aspects, postoperative complications, and short- and long-term outcomes. Logistic regression analyses were used to determine factors associated with short-term survival (p < .05). RESULTS: Manual reduction was attempted in a third of the cases (32/98, 33%) and emergency surgery to reduce the hernia was performed in 64 of 98 (65%) cases. Concurrent small intestinal (SI) volvulus was identified in 26 (26/98, 27%) cases. Castration was the most common technique used to prevent recurrence (64/94, 68%). Overall AIH recurrence rate was 11% (11/98). A total of 59 (59/98, 60%) cases survived to hospital discharge and 49 of 52 (94%) cases were still alive after 12 months. Cases admitted within 10 h of colic signs had increased odds of survival (72%) compared to those admitted after 10 h (26%; p < .001). Draft breeds (p = .021), high heart rate on admission (p = .001) and concurrent SI volvulus (p = .048) were associated with reduced survival to hospital discharge. CONCLUSIONS: Horses with AIH had a higher risk of concurrent SI volvulus and lower survival than reported. Draft breeds, high heart rate on admission and concurrent SI volvulus were associated with reduced short-term survival. CLINICAL SIGNIFICANCE: The results of this study should help in prognostication for horses with AIH.

A cross-sectional study of colic and rate of return to racing in Thoroughbreds at Seoul Racecourse in Korea between 2010 and 2020.

BACKGROUND: The incidence of colic and the outcomes of colic surgery have not been surveyed in racetracks in Korea. OBJECTIVES: This study examined the incidence, mortality, and case fatality of colic and investigated the effects of age and sex after an exploratory celiotomy on the long-term survival rate (return to racing), subsequent racing performance, and career longevity. METHODS: The incidence, mortality, and case fatalities of colic were examined over an 11-year period. The records of 40 horses that had undergone a celiotomy, after participating in at least one race and 75 race-matched control horses were analyzed. The racing performance and career length of the horses that returned to racing post-surgery were compared with a control group. RESULTS: The annual incidence, fatality rate of colic, and annual mortality rate at Seoul Racecourse were 6.5, 2.8 per 100 horse-years, and 0.2 deaths cases per 100 horse-years, respectively. Of the 40 horses that underwent colic surgery, 26 (65%) returned to racing. The likelihood of returning to racing decreased with increasing age of the horses, and geldings had a lower probability of returning. While the performance in the five preoperative races between the two groups was not significantly different, a significant decrease in racing performance was observed after the surgery date (p < 0.01). Horses that underwent colic surgery did not show a significant decrease in career length. CONCLUSIONS: Surgical treatment for colic at the age of three and four years had a negative impact on the racing performance. On the other hand, there was no significant difference in career longevity between the two groups.

Right dorsal colitis in horses: A multicenter retrospective study of 35 cases.

BACKGROUND: Right dorsal colitis (RDC) is a nonsteroidal anti-inflammatory drug (NSAID) induced, protein losing enteropathy in horses associated with a high case fatality rate. OBJECTIVES: To describe signalment, NSAID usage, clinical presentations, clinical pathology, ultrasonographic findings, treatments, outcomes, and factors associated with survival in horses diagnosed with RDC. ANIMALS: Thirty-five horses from 7 Australian equine hospitals diagnosed with RDC. METHODS: Retrospective case series. Clinical records of cases were accepted if definitively or presumptively diagnosed by an internist with RDC and had ≥3 of: hypoproteinemia or hypoalbuminemia; diarrhea with negative test results for infectious diseases; colic for which other diseases were excluded or right dorsal colon thickening on ultrasound. Descriptive data analysis was performed for categorical and continuous variables. Univariate binominal logistic regressions were used to assess factors associated with survival. RESULTS: An overdose of NSAIDs occurred in 84% (21/25) cases where dose was known. Common clinical presentations included diarrhea (69%; 22/32), colic (61%; 20/33), and tachycardia (53%, 17/32). Common clinicopathological findings included hypoalbuminemia (83%; 26/31), hypocalcaemia (79%, 23/29), and hyperlactatemia (77%, 14/18). The right dorsal colon wall appeared subjectively thickened in 77% (24/31) cases using ultrasonography. Case fatality rate was 43% (15/35). Odds of survival significantly decreased with increasing heart rate (odds 0.84, 95% CI = 0.71-0.92, P = .01), packed cell volume (odds 0.91, 95% CI 0.82-0.98, P = .05) and abnormal appearance of mucous membranes (odds 0.05, 95% CI 0.005-0.28, P = .001) on hospital presentation. CONCLUSIONS AND CLINICAL IMPORTANCE: An overdose of NSAIDs is common in horses diagnosed with RDC. Serum albumin concentrations should be monitored in horses receiving a prolonged course of NSAIDs. Overall prognosis for RDC remains fair.

Clinical presentation and outcome of gastric impactions with or without concurrent intestinal lesions in horses.

BACKGROUND: Gastric impactions (GI) have been identified as primary lesions (lone GI; LGI) or associated with other intestinal lesions (concurrent GI; CGI). Anecdotally, CGI resolve more rapidly with a better prognosis than LGI. OBJECTIVES: To determine clinical, laboratory, and ultrasonographic findings, and short- and long-term survival in horses with GI. We hypothesized that LGI carries a worse prognosis than CGI. ANIMALS: Seventy-one horses from 2 referral hospitals (2007-2022). METHODS: Retrospective cohort study. Gastric impactions were defined as feed extending to the margo plicatus after ≥24 hours of fasting. Clinical, diagnostic and outcome findings were compared between LGI and CGI. Long-term survival was determined by a questionnaire. RESULTS: Twenty-seven horses had LGI, 44 had CGI. Large intestinal lesions (32/44) were more common than small intestinal lesions (12/44). Concurrent gastric impactions resolved more slowly than LGI (LGI median 2 days, range 0-8; CGI median 4 days, range 1-10; P = .003). Short- (LGI 63%, 17/27; CGI 59%, 26/44; P = .75) and long-term survival (LGI 3.5 ± 1.9 years; CGI 2.3 ± 2.3 years; P = .42) were not significantly different. However, Lone gastric impactions were more likely to experience gastric rupture (LGI 29.6%, 8/27; CGI 11.4%, 5/44; P = .05). Lone gastric impactions were 8.7 times more likely to require dietary changes (LGI 72.7%, 8/11; CGI 25%, 4/16; 95% confidence interval [CI], 1.53-49.22; P = .01). Gastric impactions recurred in 21.7% (LGI, 6/20; CGI, 4/26; P = .23) of affected horses. CONCLUSIONS AND CLINICAL IMPORTANCE: Lone gastric impactions and CGI present similarly with a comparable prognosis, but LGI are more likely to rupture. Long-term dietary changes are often necessary for horses with LGI.

Ultrasonographic Assessment of Small Intestinal Motility Following Hyoscine Butylbromide Administration in Horses: A Pilot Study.

Horses commonly receive hyoscine butylbromide (HB) prior to hospital admission for colic. This could alter the appearance of the small intestine (SI) on ultrasound scan and affect clinical decision making. The aim of this study was to assess the impact of HB on ultrasonographically assessed SI motility and heart rate. Six horses hospitalised for medical colic with no significant abnormalities on baseline abdominal ultrasound examination were included. Ultrasound was performed in three locations (right inguinal, left inguinal and hepatoduodenal window) before and at 1, 5, 15, 30, 45, 60, 90, and 120 minutes after intravenous injection of 0.3 mg/kg HB. Three blinded reviewers assessed SI motility using a subjective grading scale from 1 to 4, one being normal motility and four being no motility. Moderate interindividual and interobserver variability was observed, but none of the included horses developed dilated turgid loops of SI. Hyoscine butylbromide did not significantly reduce SI motility grade in any location (P = .60 left inguinal, P = .16 right inguinal, P = .09 duodenum). Heart rate (mean ± SD) was 33 ± 3 prior to HB injection and peaked at 71.3 ± 9 one-minute postinjection. Heart rate was significantly increased until 45 minutes (48 ± 9) after HB administration (P = .04). The appearance of dilated turgid SI loops common with strangulating intestinal lesions did not appear to develop following HB administration. Hyoscine butylbromide administered shortly before abdominal ultrasound examination would not be expected to affect clinical decision making in horses without small intestinal disease.

Epidemiology of Colic: Current Knowledge and Future Directions.

Epidemiologic studies are essential for the generation of evidence-based, preventive health care strategies. This includes ways to minimize colic risk and assist informed decision making concerning diagnosis, treatment, and likely outcomes. It is important to consider that colic is not a simple "disease" but is a syndrome of abdominal pain that encompasses multiple different disease processes, and which is multifactorial in nature. This review focuses on prevention and diagnosis of colic, including specific forms of colic, communications with owners/carers concerning colic risk and management, and areas of future research.

Assessment and comparison of microcirculation and macrocirculation in horses undergoing emergency exploratory celiotomy versus elective surgical procedures.

OBJECTIVE: To assess oral buccal microcirculation by hand-held videomicroscopy in horses during colic surgery, comparing microcirculation values with macrocirculatory parameters and with those of healthy elective surgical horses. STUDY DESIGN: Clinical prospective study. ANIMALS: Client-owned horses (nine in the colic group; 11 in the elective group). METHODS: In the colic group, buccal mucosal side stream dark-field microscopy (DFM) videos, cardiac output (CO), mean arterial pressure (MAP), and lactate were obtained at three timepoints under general anesthesia (30, 90, and 150 min after induction). Video analysis was used to determine total vessel density, proportion of perfused vessels, perfused vessel density, and heterogeneity index. Dark-field microscopy videos, MAP, and lactate were obtained at a single timepoint under general anesthesia (45 min after induction) in the elective group. RESULTS: There were no differences in microcirculatory parameters between colic and elective horses, nor was there a difference across timepoints in the colic group. There was a weak negative correlation between microvascular parameters and CO (rho = -0.23). CONCLUSION: The colic group did not have decreased microcirculation in comparison with the healthy elective group. Dark-field microscopy did not correlate well with macrocirculatory parameters in the colic group. IMPACT: Dark-field microscopy may not be a sensitive enough indicator to detect differences in microcirculation between colic and elective groups. The lack of difference in microcirculation may be due to sample size, probe location, or variation in disease severity.

Ingesta-associated choledocholithiasis in horses: 2 cases and literature review.

Equine ingesta-associated choledocholithiasis is a rare cause of morbidity and mortality. We describe here the clinical, gross, histologic, and microbiologic features of this condition in 2 horses and compare the features to 2 previous cases. Case 1 was a 4-y-old Thoroughbred mare with colic. Case 2 was an 18-y-old American Paint Horse mare with colic, chronic weight loss, and inappropriate mentation. Both had elevated biochemical markers of hepatocellular injury and cholestasis and were euthanized given a poor prognosis. Case 1 had a well-formed 5-cm choledocholith surrounding a piece of hay, and had chronic neutrophilic cholangiohepatitis, bridging fibrosis, and extrahepatic obstruction. Case 2 had an ill-formed choledocholith with occasional hay fragments, wood stick, and twigs, and had regionally extensive hepatocellular necrosis with mild neutrophilic cholangiohepatitis and bridging fibrosis. Enterococcus casseliflavus and Escherichia coli were isolated in both cases; Clostridium spp. were also isolated from case 2. All 4 reported cases had increased activity of cholestatic enzymes, hyperbilirubinemia, portal inflammation, and bridging fibrosis. Colic, pyrexia, leukocytosis with neutrophilia, and elevated hepatocellular enzyme activity were documented in 3 cases. Foreign material in all 4 cases was plant origin (choledochophytolithiasis), including hay (n = 2), sticks/twigs (n = 2), and grass awns (n = 1). Ingesta-associated choledocholithiasis may be considered as a cause of colic, pyrexia, and elevated cholestatic biomarkers in horses.

Role of Laparoscopy in Diagnosis and Management of Equine Colic.

Laparoscopy can be valuable in the diagnosis and treatment of specific types of colic in horses. Most commonly, it is used for horses with chronic recurrent colic for further diagnosis, such as by taking biopsies or to perform treatment. Laparoscopy is also often used for prevention of colic, for example, by closing the nephrosplenic space or epiploic foramen. There are fewer indications for laparoscopy in acute colic, though in some cases the technique can be useful for diagnosis, after which the procedure is converted to a hand-assisted laparoscopy. However, manipulation of the intestine is limited compared with an open laparotomy.