Blood lactate concentrations in ponies and miniature horses with gastrointestinal disease

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.

Early Identification of Intestinal Strangulation: Why It Is Important and How to Make an Early Diagnosis

Horses with colic caused by intestinal strangulation can have an excellent outcome with early surgical correction of the obstruction. The expense associated with surgery is typically less with early lesion correction. The challenge is making an early diagnosis of intestinal strangulation. Although for some horses with a strangulating obstruction, the need for surgery is made based on severe colic signs or lack of response to analgesia, in other horses, it is less obvious. Signalment, history, and meticulous physical examination, combined with some targeted diagnostic procedures can help with early diagnosis of intestinal strangulation. Improving the outcome of these horses requires diligence and a team-based approach from the owner or caregiver, primary care veterinarian, and specialists.

Serum amyloid A does not predict non-survival in hospitalised adult horses with acute colitis

BACKGROUND

Predicting non-survival in horses with acute colitis improves early decision making. Therefore, this study aimed to determine the prognostic value of serum amyloid A (SAA) and other clinicopathological and clinical variables in adult horses with acute colitis.

METHODS

Clinical variables, SAA and other blood biomarkers, including plasma L-lactate (lactate), were assessed in 176 horses with acute colitis. A multivariate model for the prediction of non-survival was constructed. Icelandic horses were analysed separately.

RESULTS

Admission SAA was similar in survivors (median 548 mg/L; range 0-5453 mg/L) and non-survivors (396 mg/L; 0-5294) (p = 0.43). A model for non-survival included year of admission, lactate, heart rate, age and colic duration of more than 24 hours. Icelandic horses had a relative risk of 2.9 (95% confidence interval = 2.2-3.8) for acute colitis compared to other breeds. Lactate in Icelandic horses was higher than that in other breeds in both survivors (4.0 mmol/L, range 1.0-12.7 vs. 2.0, 0.7-12.5) and non-survivors (10.0, 1.5-26 vs. 5.4, 0.8-22) (p < 0.001).

LIMITATIONS

The prognostic value of repeated measurements of SAA could not be assessed in this study, as 71% of the non-surviving horses died within a day of admission.

CONCLUSION

Admission SAA did not predict non-survival. Breed needs consideration when lactate is evaluated as a predictor for non-survival in horses with colitis.

Differentiating Strongylus vulgaris-associated, non-strangulating intestinal infarctions from idiopathic peritonitis and acute colitis in horses

BACKGROUND

Horses with non-strangulating intestinal infarction (NSII) are often misdiagnosed with idiopathic peritonitis or acute colitis. Early diagnosis is essential to ensure early surgical intervention and improve survival.

METHODS

Clinical and laboratory data from horses admitted to the University of Copenhagen Large Animal Teaching Hospital with NSII, idiopathic peritonitis or acute colitis between 2009 and 2018 were used for univariate comparisons and a multivariable logistic regression model for prediction of NSII.

RESULTS

Two hundred and thirty-one horses were included. A multivariable model for the prediction of NSII included gastric reflux (more than 5 L) (odds ratio [OR] 8.7; 95% confidence interval [CI] 2.1-36.2), abnormal findings palpated per rectum (intestinal dilatations/impactions [OR 4.43; 95% CI 1.43-13.38], colon displacements [OR 23.16; 95% CI 5.26-101.97] or intestinal mass [OR 179.7; 95% CI 23.5-1375.5]), white blood cell count (OR 1.2; 95% CI 1.1-1.4), packed cell volume (OR 0.9; 95% CI 0.8-0.9), age (OR 0.9; 95% CI 0.8-1.0) and heart rate (OR 1.1; 95% CI 1.0-1.1). The model had a low false positive rate (5%), but a high false negative rate (50%).

LIMITATIONS

Due to the retrospective nature of the study, sample collection was inconsistent, resulting in missing values.

CONCLUSION

The model had some capability in predicting NSII. However, the high risk of false negatives means that exploratory laparotomy should be considered in horses with peritonitis of unknown aetiology in areas where Strongylus vulgaris is prevalent and occurrence of idiopathic peritonitis is low.

Evaluation of Eosinopenia as a SIRS Biomarker in Critically Ill Horses

Systemic inflammatory response syndrome (SIRS) is a very common finding in critically ill patients. To accurately identify patients with SIRS and those who need intensive care, several markers have been evaluated, including cortisol, WBC or lactate. It is widely known that a stress leukogram includes eosinopenia as one of its main markers (neutrophilia, eosinopenia, lymphopenia and mild monocytes). It is known that cortisol concentration in plasma is the main stress biomarker and is strongly correlated with the severity of disease in horses. However, it is not possible to measure this parameter routinely in clinical conditions. Hence, in this study it was hypothesized that the eosinophil count could be a reliable parameter to identify critically ill horses. Horses included in this study were divided into three groups: Group A (sick horses received at the Emergency Unit which did not fulfil the criteria for SIRS), Group B (horses that meet two or more criteria for inclusion in the definition of SIRS) and a control group of healthy horses. In this study, horses with SIRS showed lower eosinophil counts than healthy horses. Moreover, non-surviving horses exhibited lower eosinophil counts than survivors. Eosinopenia could be used to identify horses with SIRS and can be useful as a prognostic marker.

Influence of endocrine disease on l-lactate concentrations in blood of ponies

Background

Blood l‐lactate concentrations are higher in people with developing or established diabetes mellitus and insulin resistance.

Objectives

To investigate whether blood l‐lactate concentrations are positively correlated with measures of insulin dysregulation (ID) or increased autumnal ACTH concentrations in ponies.

Animals

Systemically healthy client‐owned ponies (n = 101).

Methods

Prospective case‐control study. Blood samples were obtained from 101 clinically healthy ponies. Breed, weight, height, and subjective and objective measures of body condition were recorded. Blood l‐lactate, glucose, triglyceride, total adiponectin, and ACTH concentrations were measured and an oral sugar test (OST) was carried out. Correlations between blood l‐lactate and variables of endocrine health were determined.

Results

Using a seasonal cutoff point of ACTH concentrations ≥47 pg/mL, 55 ponies had increased autumnal ACTH concentrations and 45 did not. Using a basal insulin concentration of >50 μiU/mL, 42 ponies were diagnosed with ID and 58 were not. Using a 60 minutes after OST cutoff point of >45 μiU/mL, 57 ponies had ID and 37 did not. Blood l‐lactate concentrations were significantly lower in obese (average body condition score ≥ 7/9) compared to nonobese ponies (0.6 mmol/L; range, 0.0‐1.9 mmol/L vs 0.8 mmol/L; range, 0.3‐2.7 mmol/L; P = .01). No other significant correlations were detected. No differences were detected between ponies with and without increased autumnal ACTH concentrations (0.7 mmol/L; range, 0.0‐2.7 mmol/L vs 0.7 mmol/L; range, 0.3‐1.8 mmol/L; P = .84) and with and without ID (0.7 mmol/L; range, 0.3‐2.7 mmol/L vs 0.8 mmol/L; range, 0.0‐1.6 mmol/L; P = .63).

Conclusions and Clinical Importance

Results do not support an effect of endocrine status on l‐lactate concentrations in blood of ponies.

Variations in haematological and biochemical parameters in healthy ponies

Background

Breed specific reference ranges for selected blood parameters are recommended for proper interpretation of blood tests, but there are only few reports dealing with ponies. The purpose of this study was to investigate if blood parameters differ among ponies’ classes and to check if general normal values for equine species are applicable to ponies.

Results

All, except total protein concentration, biochemical parameter significantly (p < 0.05) differed among ponies’ classes. The most pronounced difference was noted in blood lactate concentrations, higher (p < 0.001) in the smallest ponies (class A). In all groups of ponies muscle enzymes (aspartate aminotransferase and creatine kinase) and urea were high when compared to normal values for equine species, but triglycerides and creatinine were low. Blood lactate concentration was high in comparison with normal values for horses only in class A ponies’.

Conclusions

In healthy ponies, blood lactate concentration significantly differs between height classes. Normal values for equine species should not be directly applied to interpret the lactate, triglycerides, aspartate aminotransferase and creatine kinase values in ponies.

Correlation between l-lactate and glucose concentrations and body condition score in healthy horses and ponies

Background

Blood l‐lactate and glucose concentrations were higher in ponies with gastrointestinal disease than in horses, possibly because of differences in body condition (BC).

Objectives

To investigate whether l‐lactate and glucose concentrations correlate with BC and differ between healthy horses and ponies.

Animals

Systemically healthy client‐owned ponies (n = 101) and horses (n = 51).

Methods

Prospective observational study. Breed, weight, height, and subjective and objective measures of BC were recorded and l‐lactate and glucose concentrations were measured. Correlations between l‐lactate and glucose concentrations and BC were established. The association between l‐lactate concentrations, equid type (pony or horse), BC, age, and glucose concentrations was investigated using a multivariable model.

Results

Weak but significant (P = .001) negative correlations were detected between l‐lactate concentration and average BC score (r = −0.29), heart girth:height ratio (r = −0.27), and age (r = −0.27). Glucose concentrations were significantly (P < .001) positively correlated with neck length:heart girth ratio (r = 0.37) and heart girth:height ratio (r = 0.31). l‐lactate and glucose concentrations were weakly correlated (r = 0.15; P = .04). In the final multivariable model, age (−0.02 ± 0.006; P = .001) and heart girth:height ratio (−1.74 ± 0.53; P = .001) were significantly associated with the natural logarithm of l‐lactate concentration (Lnl‐Lactate). This represents a 2% decrease in l‐lactate concentration per year increase in age and 10% decrease in l‐lactate concentration per 0.06 unit increase in heart girth:height ratio.

Conclusions and Clinical Importance

In healthy horses and ponies, age and BC significantly influence l‐lactate concentrations.

Retrospective evaluation of the association between admission blood glucose and l-lactate concentrations in ponies and horses with gastrointestinal disease (2008-2016): 545 cases

OBJECTIVES

A recent study described increased l-lactate concentrations in ponies with gastrointestinal disease compared to horses, but blood glucose (BG) concentrations were not considered. The study tested the hypothesis that BG and l-lactate concentrations are correlated in horses and ponies with gastrointestinal disease and that BG concentrations, not equid type (pony vs horse), are an independent predictor of L-lactate concentrations. It was further hypothesized that equid type was an independent predictor of BG concentrations.

DESIGN

Retrospective study 2008-2016.

SETTING

University teaching hospital.

ANIMALS

Admission data from 545 animals (384 horses and 161 ponies) with gastrointestinal disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data collected included signalment, clinicopathological findings on admission, and nature and location of the gastrointestinal lesion (strangulating vs non-strangulating and large vs small intestinal lesion). The association between admission blood l-lactate concentrations, equid type (pony or horse) and BG concentrations was investigated in a multivariable model. Admission l-lactate and BG concentrations were strongly correlated (n = 522; r = 0.63; P < 0.001). Ponies had significantly higher l-lactate (2.7 mmol/L (0.5-18.0 mmol/L) vs 1.4 mmol/L (0.3-19 mmol/L); P < 0.001) and BG concentrations than horses (8.4 mmol/L (4.2-24.4 mmol/L); 151 mg/dL (76-439 mg/dL) vs 6.9 mmol/L (3.4-26.8 mmol/L); 124 mg/dL (61-482 mg/dL); P < 0.001). In the multivariable analysis, l-lactate concentrations were significantly and positively associated with admission BG concentrations in all animals and also with equid type. For each millimole per liter (18 mg/dL) increase in BG, l-lactate concentrations increased by 7.9% (5.9, 9.9); P < 0.001. In comparison to ponies, l-lactate concentrations were decreased by 27.7% (37.4, 16.5); P < 0.001 in horses. Admission BG concentrations were significantly and positively associated with l-lactate concentrations in all animals. For each millimole per liter increase in l-lactate concentration, BG concentration increased by 6.2% (4.7, 7.6; P < 0.001). Admission BG concentrations were not associated with equid type.

CONCLUSION

Admission BG concentrations and equid type are independent predictors of blood l-lactate concentrations in equids with gastrointestinal disease, but their relationship requires further investigation.

Advances in Diagnostics and Treatments in Horses with Acute Colic and Postoperative Ileus

Differentiating between medical and surgical causes of colic is one of the primary goals of the colic workup, because early surgical intervention improves prognosis in horses requiring surgery. Despite the increasing availability of advanced diagnostics (hematologic analyses, abdominal ultrasound imaging, etc), the most accurate indicators of the need for surgery remain the presence of moderate to severe signs of abdominal pain, recurrence of pain after appropriate analgesic therapy, and the absence of intestinal borborygmi. Investigation of novel biomarkers, which may help to differentiate surgical lesions from those that can be managed medically, continues to be an active area of research.

The clinical value of whole blood point-of-care biomarkers in large animal emergency and critical care medicine

OBJECTIVE

To summarize the current medical literature and provide a clinical perspective of whole blood point-of-care (POC) biomarkers in large animal emergency and critical care practice.

DATA SOURCES

Original studies, reviews, and textbook chapters in the human and veterinary medical fields.

SUMMARY

POC biomarkers are tests used to monitor normal or disease processes at or near the patient. In both human and veterinary medicine these tools are playing an increasingly important role in the management of critical diseases. The most important whole blood POC biomarkers available for veterinary practitioners include l-lactate, cardiac troponin I, serum amyloid A, triglyceride, creatinine, and glucose, although many other tests are available or on the horizon.

CONCLUSION

Whole blood POC biomarkers enable clinicians to provide improved management of critical diseases in large animals. These tools are especially useful for establishing a diagnosis, guiding therapy, and estimating disease risk and prognosis.

Blood lactate measurement and interpretation in critically ill equine adults and neonates

Admission blood lactate concentration is widely used as a prognostic indicator in equine medicine and can be a useful indicator of disease severity but typically fails to completely discriminate survivors from nonsurvivors. Increased admission lactate concentrations in adult horses typically return to normal within 12 to 24 hours. Lactate concentrations in neonatal foals are higher than adult concentrations for the first 24 to 72 hours of life. Serial measures reflecting both the magnitude and duration of hyperlactatemia might enable more accurate prognostication and provide insight into disease pathogenesis and could be a valuable therapeutic guide.

Evaluation of the colic in horses: decision for referral

This article presents an overview of key factors that should alert the practitioner toward referral of a colic patient to a facility capable of surgical exploration or intensive medical management. Discussion includes a review of important aspects of colic history, signalment, physical examination findings, and diagnostic test results that indicate that a more serious medical or surgical condition exists, and advanced therapy is necessary.