Detection of fibrin deposits in horse tissues by immunohistochemistry

BACKGROUND: Histochemical and immunohistochemical techniques have been used to detect fibrin deposits in different tissues in humans and experimental animal models with disseminated intravascular coagulation (DIC). Fibrin deposits also have been observed in horses with severe ischemic and inflammatory disorders by histochemical stainings (phosphotungstic acid hematoxylin [PTAH]). HYPOTHESIS: Immunohistochemical (IHC) methods can be used to accurately detect fibrin deposits in horses at risk of DIC. ANIMALS: Tissue-organ samples collected on postmortem examination from 87 horses with severe inflammatory and ischemic gastrointestinal disorders. In addition, tissue samples from 13 horses with colic and colonic obstructions or displacements and from 13 slaughter horses were used as controls. METHODS: Tissue samples (kidney, lung, and liver) were stained with PTAH and IHC for blinded histologic examination and comparison. A fibrin score (grades 0 to 4) was established for each tissue sample and for each horse for both techniques. RESULTS: When the IHC method was used, fibrin deposition was observed in 47.1% of the horses with colic with a poor prognosis, compared with 41.4% with PTAH. An agreement of 70% was achieved when both methods were compared, and the lung was confirmed as the most affected organ. Almost none of the colic and slaughter control horses had fibrin deposits in their tissues. CONCLUSIONS AND CLINICAL IMPORTANCE: IHC technique for fibrin antigens was very effective in the detection and identification of fibrin deposits in equine tissues and may be a reliable technique for the postmortem diagnosis of DIC.     

Disseminated Intravascular Coagulation Associated with Colic in 23 Horses (1984–1989)

Disseminated intravascular coagulation (DIC) secondary to colic was diagnosed in 23 horses. Each horse was categorized retrospectively as to the cause of the colic based on surgical and/or necropsy findings: group 1 consisted of 14 horses with compromised intestine that required resection and anastomosis; group 2 consisted of 3 horses with nonstrangulating intestinal displacement and/or impactions; and group 3 consisted of 6 horses with colic associated with enteritis and/or colitis. Horses were considered to be affected with DIC if at least three of five hemostatic parameters were significantly abnormal: decreased antithrombin III (AT III) values, increased level of fibrin degradation products (FDP), thrombocytopenia, prolonged activated partial thromboplastin time, and prolonged prothrombin time. The most consistent hemostatic abnormalities were decreased AT III activity, increased FDP titers, and thrombocytopenia. Clotting times were more variable and did not always correlate with the presence of excessive hemorrhage. Excessive hemorrhage was present during surgery in seven horses and occurred within 1 to 12 hours after surgery in nine other horses. In addition to treatment of the primary disease, 19 horses received treatment for DIC consisting of heparin and/or plasma or fresh whole blood transfusions. Heparin alone was used in 12 horses. Heparin, in addition to fresh whole blood transfusions or fresh plasma, was administered to four horses. Three horses were treated with plasma alone. Four other horses were not treated specifically for the DIC. Eight horses (34%) survived the acute coagulopathy. Although a greater proportion of the surviving horses received heparin therapy (87.5%; 7/8) than did those that died (60%; 9/15), the difference was not statistically significant (P = 0.345).(ABSTRACT TRUNCATED AT 250 WORDS)     

Association of admission plasma D-dimer concentration with diagnosis and outcome in horses with colic

Background: Coagulopathies detected in horses with gastrointestinal problems seem to be associated with poor outcome. Plasma D‐Dimer concentration is a sensitive test for assessing coagulopathies. Hypothesis: Plasma D‐Dimer concentration tested on admission is related to diagnosis and outcome in horses with colic. Animals: Four hundred and ninety three horses referred for evaluation of abdominal pain. Methods: Prospective observational clinical study. Horses were grouped according to diagnosis (medical and surgical intestinal obstructions, ischemic disorders with and without intestinal resection, enteritis, peritonitis), outcome (survivors, nonsurvivors), and number of coagulopathies (normal profile, 1 or 2 coagulopathies, subclinical disseminated intravascular coagulation [DIC]). Blood samples were collected on admission and plasma D‐Dimer concentration, clotting times (PT and aPTT), and antithrombin activity were determined. Positive likelihood ratios (LR+) were calculated for evaluation of D‐Dimer cut‐off values, which were later tested in a logistic regression model. Results: Horses with enteritis or peritonitis had significantly (P < .001) higher plasma D‐Dimer concentrations and more severe coagulopathies on admission than horses with other diagnoses. Nonsurvivors also had significantly (P < .001) higher plasma D‐Dimer concentrations at presentation than did survivors, and those horses with subclinical DIC on presentation had an odds ratio (OR) 8.6 (95% confidence interval [CI], 3.3–22.5, P < .001) for nonsurvival. Finally, D‐Dimer concentrations >4,000 ng/mL had a LR+ of 5.9 and an OR 8.8 (95% CI, 4.5–17.1, P < .001) for nonsurvival. Conclusion and Clinical Importance: Plasma D‐Dimer concentration measured on admission can be used to facilitate diagnosis and outcome prediction in horses with colic. A potential cut‐off value for nonsurvival was found at approximately 4,000 ng/mL.     

Concentrations of serum amyloid A and lipopolysaccharide-binding protein in horses with colic

OBJECTIVE: To determine concentrations of 2 acute-phase proteins (serum amyloid A [SAA] and lipopolysaccharide-binding protein [LBP]) in serum samples obtained from horses with colic and identify relationships among these acute-phase proteins and clinical data. ANIMALS: 765 horses with naturally developing gastrointestinal tract diseases characterized by colic (ie, clinical signs indicative of abdominal pain) and 79 healthy control horses; all horses were examined at 2 university teaching hospitals. PROCEDURE: Serum concentrations of SAA and LBP were determined by immunoturbidometric and dot-blot assays, respectively. RESULTS: SAA and LBP concentrations were determined for 718 and 765 horses with colic, respectively. Concentrations of SAA were significantly higher in nonsurvivors than in survivors, and horses with enteritis or colitis and conditions characterized by chronic inflammation (eg, abdominal abscesses, peritonitis, or rectal tears) had SAA concentrations significantly greater than those for horses with other conditions. Serum concentrations of LBP did not correlate with outcome, disease process, or portion of the gastrointestinal tract affected. CONCLUSIONS AND CLINICAL RELEVANCE: Circulating concentrations of SAA were significantly higher at admission in horses with colic attributable to conditions having a primary inflammatory cause (eg, enteritis, colitis, peritonitis, or abdominal abscesses) and were higher in horses that failed to survive the episode of colic, compared with concentrations in horses that survived. Serum concentrations of LBP did not correlate with survival. Analysis of these findings suggests that evaluation of SAA concentrations may be of use in identifying horses with colic attributable to diseases that have inflammation as a primary component of pathogenesis.     

Peritoneal d-Dimer Concentration for Assessing Peritoneal Fibrinolytic Activity in Horses with Colic

Background: Plasma d -dimer concentration is a useful marker to assess systemic coagulation and fibrinolytic activities in humans, dogs, and horses. Peritoneal fibrinolytic activity increases in horses with colic, especially in horses with endotoxin in the peritoneal fluid.
Hypothesis/Objectives: Peritoneal d -dimer concentration can be used to assess peritoneal fibrinolytic activity in horses with severe gastrointestinal (GI) disorders and altered peritoneal fluid.
Animals: Two hundred and twenty-one colic horses and 15 control horses.
Methods: Prospective observational clinical study. Blood and peritoneal fluid were collected on admission. Horses were grouped according to diagnosis, peritoneal fluid analysis, and outcome. Peritoneal d -dimer concentration was determined, together with peritoneal tissue-plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) activities. Plasma d -dimer concentration also was measured.
Results: Peritoneal d -dimer concentration was significantly higher in all colic groups compared with controls, and in horses with enteritis, peritonitis, and ischemic disorders compared with horses with large intestinal obstructions. Peritoneal d -dimer concentration was significantly higher in horses with altered peritoneal fluid (modified transudate and exudate) compared with horses with normal peritoneal fluid analysis. Plasma d -dimer concentration also was significantly higher in the peritonitis group, and in horses with altered peritoneal fluid analysis. Peritoneal and plasma d -dimer concentrations also were significantly higher in nonsurvivors. Peritoneal d -dimer concentration was significantly correlated with decreased peritoneal t-PA activity and increased peritoneal PAI-1 activity.
Conclusions and Clinical Importance: Peritoneal d -dimer concentration is markedly higher in severe GI disorders, and it can be used to assess peritoneal fibrinolytic activity in horses with colic.     

Peritoneal concentrations of transforming growth factor beta in horses with colic

Reasons for performing the study: In man, peritoneal transforming growth factor beta (TGF‐β) is associated with peritoneal diseases and subsequent adhesion formation. No studies on plasma and peritoneal TGF‐β concentrations in horses with colic are available. Objectives: 1) To determine both plasma and peritoneal TGF‐β₁ and TGF‐β₃ concentrations in horses with different types of colic (not previously subjected to abdominal surgery); 2) to compare these concentrations according to the type of peritoneal fluid (transudate, modified transudate and exudate); and 3) to compare and correlate plasma and peritoneal concentrations of TGF‐β₁ and TGF‐β₃ and the types of peritoneal fluid according to the colic group and outcome. Methods: Peritoneal fluid and plasma samples from 78 horses with colic and 8 healthy horses were obtained. Patients were classified according to diagnosis (obstructions, enteritis, ischaemic disorders and peritonitis), peritoneal fluid analysis (transudate, modified transudate and exudate), and outcome (survivors and nonsurvivors). Plasma and peritoneal TGF‐β₁ and TGF‐β₃ concentrations were determined by ELISA. Data were analysed by parametric and nonparametric tests. P≤0.05 was considered as statistically significant. Results: Concentrations of peritoneal fluid TGF‐β₁ were significantly (P = 0.01) higher in horses with peritonitis in comparison with all other colic groups and controls. Horses with ischaemic lesions had significantly (P = 0.01) higher concentrations of peritoneal TGF‐β₁ in comparison with controls and the group of horses with obstructions. Peritoneal TGF‐β₁ concentration also was significantly (P = 0.01) higher in exudates in comparison with transudates. Peritoneal TGF‐β₁ and TGF‐β₃ concentrations and plasma TGF‐β₁ concentration were significantly increased in nonsurvivors compared to survivors (P = 0.001, P = 0.004 and P = 0.05, respectively). Conclusions: Peritoneal TGF‐β₁ concentration was higher in horses with severe gastrointestinal diseases (ischaemic intestinal lesions and peritonitis), in horses with an altered peritoneal fluid (exudate), and in nonsurvivors. Potential relevance: Peritoneal TGF‐β concentration increases in horses with severe gastrointestinal disease as an anti‐inflammatory response.     

Evaluation of the effects of the opioid agonist morphine on gastrointestinal tract function in horses

OBJECTIVE: To evaluate the effects of morphine administration for 6 days on gastrointestinal tract function in healthy adult horses. ANIMALS: 5 horses. PROCEDURES: Horses were randomly allocated into 2 groups in a crossover study. Horses in the treatment group received morphine sulfate at a dosage of 0.5 mg/kg, IV, every 12 hours for 6 days. Horses in the control group received saline (0.9% NaCl) solution at a dosage of 10 mL, IV, every 12 hours for 6 days. Variables assessed included defecation frequency, weight of feces produced, intestinal transit time (evaluated by use of barium-filled spheres and radiographic detection in feces), fecal moisture content, borborygmus score, and signs of CNS excitement and colic. RESULTS: Administration of morphine resulted in gastrointestinal tract dysfunction for 6 hours after each injection. During those 6 hours, mean +/- SD defecation frequency decreased from 3.1 +/- 1 bowel movements in control horses to 0.9 +/- 0.5 bowel movements in treated horses, weight of feces decreased from 4.1 +/- 0.7 kg to 1.1 +/- 0.7 kg, fecal moisture content decreased from 76 +/- 2.7% to 73.5 +/- 2.9%, and borborygmus score decreased from 13.2 +/- 2.9 to 6.3 +/- 3.9. Mean gastrointestinal transit time was also increased, compared with transit times in control horses. CONCLUSIONS AND CLINICAL RELEVANCE: Morphine administered at 0.5 mg/kg twice daily decreased propulsive motility and moisture content in the gastrointestinal tract lumen. These effects may predispose treated horses to development of ileus and constipation.     

Estimate of the national incidence of and operation-level risk factors for colic among horses in the United States, spring 1998 to spring 1999.

OBJECTIVE: To estimate the national incidence of, operation-level risk factors for, and annual economic impact of colic among horses in the United States during 1998 and 1999. DESIGN: Epidemiologic survey. ANIMALS: 21,820 horses on 1,026 horse operations in 28 states. PROCEDURES: Horses were monitored for colic for 1 year, and results were recorded in a log that was collected quarterly. Operation-level data were collected via 4 on-site personal interviews. Associations between colic and independent variables adjusted for size of operation were determined. RESULTS: Annual national incidence of colic in the US horse population was estimated to be 4.2 colic events/100 horses per year. Case fatality rate was 11%, and 1.4% of colic events resulted in surgery. Annual cost of colic in the United States was estimated to be $115,300,000. CONCLUSIONS AND CLINICAL RELEVANCE: The national impact of equine colic is substantial because of the high case fatality rate.     

Fibrin deposits and organ failure in newborn foals with severe septicemia

Background: Septicemia in human neonates frequently is complicated by activation of the coagulation system, disseminated intravascular coagulation (DIC) and multiple organ failure syndrome, which may contribute to high mortality. In adult horses with DIC, the lung has been the organ most frequently affected by fibrin deposits. In addition, in vivo studies suggest that hemostatic mechanisms may be immature in foals <1‐day old. Hypothesis: Newborn foals with severe septicemia have fibrin deposits in their tissues independently of their age, and these fibrin deposits are associated with organ failure. Animals: Thirty‐two septic and 4 nonseptic newborn foals euthanized for poor prognosis. Methods: Tissue samples (kidney, lung, and liver) collected on postmortem examination were stained with phosphotungstic acid hematoxylin (PTAH) and immunohistochemistry (IHC) for blind histologic examination. A fibrin score (grades 0–4) was established for each tissue sample and for each foal. Medical records were reviewed for assessing clinical evidence of organ failure during hospitalization. Results: Fibrin deposits were found in most septic foals (28/32 when using IHC and 21/32 when using PTAH), independently of the age of the foal. The lung was the most affected tissue (97% of the septic foals). Additionally, organ failure was diagnosed in 18/32 septic foals (8 with respiratory failure, 14 with renal failure), although a statistical association with severe fibrin deposition was not identified. Conclusions and Clinical Importance: Nonsurviving septic foals have fibrin deposits in their tissues, a finding consistent with capillary microthrombosis and DIC.     

Evaluation of latex agglutination kits for detection of fibrin(ogen) degradation products and D-dimer in healthy horses and horses with severe colic

Background: Fibrin(ogen) degradation products (FDPs) and D‐dimer are sensitive indicators of excessive fibrinolysis due to disseminated intravascular coagulation (DIC) in dogs. To the authors' knowledge, latex‐agglutination–based plasma FDP and D‐dimer assays have not been validated for use in horses. Objectives: To determine: 1) sensitivity and specificity of latex‐agglutination serum and plasma FDP and D‐dimer assays for diagnosis of DIC; and 2) their prognostic value in horses with severe colic. Methods: At hospital admission and 24 hours later, blood was collected from 30 healthy horses and 20 horses with severe colic. Horses fulfilling predefined laboratory criteria of DIC were enrolled, and their data were subcategorized by survival for analysis. Platelet counts were determined and coagulation panel testing was performed. Serum and plasma FDP concentrations were measured using separate latex agglutination kits. Plasma D‐dimer concentration was measured using 3 latex agglutination kits and a card immunofiltration test. Test sensitivity and specificity results were determined for healthy horses and those with colic. Median test values were compared between colic survivors and nonsurvivors to evaluate the prognostic usefulness of all tests. Results: Performance characteristics varied among assays and kit suppliers. The FDP assays had low sensitivity (<40%), whereas the most accurate D‐dimer kit had 50% sensitivity and 97% specificity. High D‐dimer concentration was the third most common hemostatic abnormality in horses with colic. Median antithrombin (AT) activity was significantly lower and activated partial thromboplastin time (aPTT) was significantly longer in nonsurvivors than survivors. Conclusions: Commercial latex‐agglutination D‐dimer assays might prove useful as adjunctive tests for the diagnosis of DIC in horses with severe colic; however FDP assays are invalid for this purpose. Low AT activity and prolonged aPTT at admission are associated with a poor prognosis in this patient population.     

Clinicopathologic evidence of disseminated intravascular coagulation in horses with acute colitis

OBJECTIVE: To detect subclinical disseminated intravascular coagulation (DIC) in horses with colitis and to determine any association between the diagnosis of subclinical DIC and outcome or occurrence of complications in horses with colitis. DESIGN: Prospective study. ANIMALS: 37 horses admitted to a veterinary teaching hospital for treatment of acute colitis. PROCEDURE: Coagulation profiles were obtained on each horse 0, 24, and 48 hours after admission. Six tests were performed: platelet count, plasma fibrinogen concentration, prothrombin time, activated partial thromboplastin time, antithrombin activity, and serum fibrin degradation products concentration. RESULTS: A clinicopathologic diagnosis of subclinical DIC was made if 3 of the 6 tests had abnormal results at any 1 sample period. No horse had clinical signs of DIC at the time of sampling. Twelve of 37 (32%) horses met the criteria for diagnosis of subclinical DIC within a 1-year period. Outcome was defined as survival or nonsurvival. Five of 12 horses with subclinical DIC and 2 of 25 horses without subclinical DIC did not survive. Crude odds ratio analysis revealed a horse with acute colitis was 8 times as likely to die or be euthanatized if a diagnosis of subclinical DIC was made. CONCLUSIONS AND CLINICAL RELEVANCE: Clinicopathologic evidence of DIC is common and is significantly associated with a poor outcome in horses with acute colitis. Treatment of subclinical DIC may influence outcome in horses with acute colitis.     

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

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

Antigen-specific antibodies in cerebrospinal fluid after intramuscular injection of ovalbumin in horses

Eighteen normal horses were assigned to 1 of 3 treatment groups to investigate the effects of IM or intrathecal (IT) administration of ovalbumin on serum and cerebrospinal fluid (CSF) antibody production. Horses of group 1 were injected intramuscularly with ovalbumin and adjuvant, while horses in treatment groups 2 and 3 received ovalbumin intrathecally or intravenously, followed by IM injection as in group 1. Serum and CSF antibody titers were tested in group I every 30 days for 4 months, while serum and CSF were collected in group 2 and 3 horses at postvaccination day 60. Horses of group 1 (IM) developed a serum antibody titer that peaked at postadministration day 60 (1:24,320 +/- 7,680) (mean +/- I SEM). Anti-ovalbumin antibodies were detected in CSF, and titers paralleled that of the serum, although at a much lower concentration (peak, 1:166 +/- 87). Horses of groups 2 and 3 developed significantly (P = .02) lower serum titers (1:720 and 1:2,067, respectively), but the difference in CSF titers did not achieve statistical significance (P = .06). The results confirm that antigen-specific antibody can be found in the CSF of horses in which antigen is not administered intrathecally. This may affect the interpretation of CSF analysis in diseases such as equine protozoal myeloencephalitis. Further, the findings suggest that IT injection of the soluble antigen ovalbumin induces a state of antigenic tolerance in the horse. The clinical significance of this finding remains unknown at this time.     

Cortisol Circadian Rhythm Ratio: A Simple Method to Detect Stressed Horses at Higher Risk of Colic?

With the hypothesis that police horses with abnormal cortisol circadian rhythm (CCR) had more chance to develop colic, the aim of this study was to determine the CCR ratio in horses subjected to different housing and work conditions and to associate abnormal CCR ratio with incidence of colic. A total of 116 police horses belonging to four different groups were studied. In all, 31 were full-time stabled and performed urban patrolling activity, 27 were full-time stabled and performed equine therapy and sports activities, 25 were part-time stabled and performed urban patrolling, and 33 animals were kept full-time on pasture and did not perform any kind of work activity. Venous blood samples were collected between 6 and 7 am and also 8 hours later, and cortisol concentrations were determined by radioimmunoassay to calculate the CCR ratio. Annual colic incidences (6 months before and after the day on which CCR ratio was determined) were assessed by examining individual medical files. The overall incidence of abnormal CCR ratio (<0.30) was 63.3%, and 107 cases of colic were reported for this population with a mean incidence of 0.92 colic/horse/yr. Horses with abnormal CCR had 2.3 times more chance to have colic (95% CI: 1.07 to 5.28, P = .03) when compared with those with normal CCR. In conclusion, high incidence of abnormal CCR ratio indicates that police horses were under stressful conditions. Horses with abnormal CCR ratios were more prone to suffer colic episodes, indicating that CCR ratio determination could perhaps be useful in detecting horses at risk of colic.     

Mean platelet component as an indicator of platelet activation in foals and adult horses

BACKGROUND: Mean platelet component (MPC) is a new platelet variable, measured by modern commercial complete blood count analyzers, that is reduced during platelet activation in humans and small animals. HYPOTHESIS: MPC decreases in horses with clinical conditions that cause platelet activation and disseminated intravascular coagulation (DIC). ANIMALS: We obtained 418 CBCs from 100 sick and 20 healthy neonates and 178 sick and 45 sound adult horses. Sick neonates were classified into septic and nonseptic, and DIC and non-DIC groups. Adults were grouped by diagnoses (systemic inflammatory disorders, gastrointestinal problems, and thrombocytopenia). METHODS: MPC together with platelet count, mean platelet volume, platelet distribution width, and platelet component distribution width were measured with a commercial analyzer and compared between the different disease and control groups in neonates and in adults. RESULTS: MPC values were significantly lower in the septic and nonseptic neonates (24.0 +/- 3.5 g/dL and 26.6 +/- 2.6 g/dL, respectively) than in the control group (28.1 +/- 1.7 g/dL). Neonates with DIC had the lowest MPC values (23.8 +/- 6.3 g/dL). MPC values in adult horses were significantly lower in the inflammatory (23.5 +/- 4.7 g/dL), gastrointestinal obstruction (23.0 +/- 5.0 g/dL), enteritis (23.6 +/- 4.6 g/dL), ischemic (23.9 +/- 5.1 g/dL), and thrombocytopenia (20.2 +/- 5.7 g/dL) groups when compared with control horses (26.2 +/- 3.5 g/dL). Other platelet variables were not different between the control and the disease groups. CONCLUSION AND CLINICAL IMPORTANCE: MPC might be a useful variable for quickly and easily detecting platelet activation in sick neonates and adult horses.     

Plasma endotoxin in horses presented to an equine referral hospital: correlation to selected clinical parameters and outcomes

Reasons for performing study: Endotoxaemia is frequently presumed on the basis of clinical signs in horses with colic. Objective: Measurements of plasma endotoxin (LPS) are rarely made in clinical cases and there is little information on the correlations between this variable, clinical variables and outcomes. Objectives: To measure LPS levels in plasma of horses presented to the Philip Leverhulme Equine Hospital on admission and daily for up to 4 days and to relate LPS levels to selected clinical parameters, such as heart rate and packed cell volume, and outcomes. Methods: Blood samples were collected and stored at ‐20°C prior to assay of the plasma using a validated kinetic chromogenic Limulus amoebocyte lysate (LAL) assay. Clinical parameters and outcome variables were collected from hospital records. Associations were determined by Chi‐squared test and logistic regression analysis. Results: Daily blood samples were collected from 234 horses. LPS was detected in 26.5% of the study population and in 29% of those horses presented for colic. Horses providing samples with detectable LPS were more likely to die whilst in the hospital than those that did not (P = 0.045). Horses presenting with colic were more likely to have detectable LPS in their plasma than noncolic cases (P = 0.037), although LPS was detected in the plasma of 8 out of 42 noncolic horses. A horse that did not meet the study definition of clinical endotoxaemia was 10 times less likely to provide a positive LPS sample (OR 0.10, 95% CI: 0.05–0.22). Conclusions: The proportion of horses providing samples with detectable LPS was similar to other studies. Potential relevance: LPS was detected in the minority of horses presented with colic. Increased levels of LPS positively correlated with packed cell volume and with risk of mortality in colic cases.     

Congenital retrosternal (Morgagni) diaphragmatic hernias in three horses

CASE DESCRIPTION: 3 Horses were examined and treated because of sudden onset of signs of abdominal pain. CLINICAL FINDINGS: All horses had a retrosternal (Morgagni) hernia involving the right side of the diaphragm. In each horse, the large colon was incarcerated in a right muscular defect in the diaphragm with a large hernial sac. TREATMENT AND OUTCOME: Definitive surgical repair of the hernia was not performed during the initial celiotomy. The hernia was repaired with mesh herniorrhaphy, but without resection of the hernia sac in 2 horses. For 1 horse, conservative management was applied. In the 2 horses treated with surgical correction, no major postoperative complications developed, and all 3 horses have been free of signs of abdominal pain. CLINICAL RELEVANCE: Horses with retrosternal hernias involving the diaphragm can develop clinical signs of intermittent obstruction of the large colon and chronic colic. In horses, retrosternal diaphragmatic hernias appear to develop exclusively in the right ventral aspect of the diaphragm and could represent an embryologic defect of diaphragm formation. Affected horses can be successfully treated with mesh herniorrhaphy or, in some instances, with conservative management.     

Heel bulb lacerations in horses: 101 cases (1988-1994)

OBJECTIVE: To determine clinical history, structures involved, treatment, and outcome of lacerations of the heel bulb and proximal phalangeal region (pastern) in horses. DESIGN: Retrospective study. ANIMALS: 101 horses. PROCEDURES: Medical records of horses with lacerations of the heel bulb and pastern were reviewed, and follow-up information was obtained. RESULTS: 75 horses were Quarter Horses. Most horses were not treated with antimicrobial drugs prior to referral. Mean +/- SD time from injury to referral was 24 +/- 45 hours (range, 1 to 168 hours). Lacerations were most frequently caused by contact with wire or metal objects. In 17 horses, lacerations involved synovial structures; the distal interphalangeal joint was most commonly affected. One horse was euthanatized after initial examination. Wound treatment consisted of cleansing, lavage, debridement, lavage of affected synovial structures, suturing of fresh wounds, and application of a foot bandage or cast. Fifty-six horses were treated with systemically administered antimicrobial drugs. Follow-up information was collected for 61 horses. Fifty-one horses returned to their intended use and had no further complications; 10 horses had complications associated with the wound, and of those horses, 5 were euthanatized and 1 horse died from an unrelated cause. Horses with lacerations that involved synovial structures had worse outcomes than horses with lacerations that did not involve synovial structures. CONCLUSIONS AND CLINICAL RELEVANCE: Horses that sustain heel bulb lacerations can successfully return to their intended use. Involvement of the distal interphalangeal joint is associated with poor prognosis.     

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

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

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

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