Topic:Clinical Pathology
Clinical pathology in horses involves the study and analysis of biological samples to diagnose and monitor diseases and health conditions. This discipline encompasses various laboratory tests and procedures that assess the physiological and biochemical status of equines. Common analyses include hematology, biochemistry, urinalysis, and cytology, each providing insights into different aspects of equine health. Hematology evaluates blood components, such as red and white blood cells and platelets, to identify conditions like anemia or infection. Biochemistry tests measure enzymes, electrolytes, and metabolites to assess organ function and metabolic status. Urinalysis examines urine samples for indicators of renal function and systemic diseases. Cytology involves the microscopic examination of cells from tissues or fluids to detect abnormalities. This page aggregates peer-reviewed research studies and scholarly articles that explore the methodologies, applications, and diagnostic value of clinical pathology in equine medicine.
Influence of Obesity on Histological Tissue Structure of the Cardiovascular System in Horses. It has been well established that obesity in horses can have a negative impact on their health, including endocrine disturbances. In humans, it is well known that obesity leads to structural and functional changes of the cardiovascular system. The aim of the study was to assess the impact of obesity on the histological structure of the myocardial tissue, as well as great and peripheral arteries in horses. The heart, arteries (aorta, pulmonary artery and palmar arteries) specimens from 7 horses with normal BCS (4-5/9) and 12 extremely obese (BCS 9/9) draft slaughter horses were obtained for his...
Imaging of the Urinary Tract. This article provides a comprehensive review of imaging techniques used to evaluate the equine urinary tract. This overview includes officially recognized modalities and new applications reported in the most current literature. Technical aspects and indications for use of endoscopy and ultrasonography are highlighted. Normal endoscopic and ultrasonographic appearance of the upper and lower urinary tract is described, with characterization of common abnormalities found in patients with hematuria, stranguria, and renal failure. Visual examples of several pathologic conditions from clinical cases...
Urinary Tract Disorders of Foals. Urinary disease in the neonatal period can occur with primary congenital renal defects or as a secondary consequence of birth trauma, ischemic injury, nephrotoxic medications, or systemic illness. This article reviews the clinical evaluation of the urinary system in foals and highlights diagnostic and therapeutic features of the most commonly encountered urinary disorders of the equine neonatal patient.
Discolored Urine in Horses and Foals. This article describes the most common causes of urine discoloration. The review includes a description of the most common disorders causing hematuria, highlighting clinical presentation, treatments, and pathophysiology. Causes of hemoglobinuria and myoglobinuria together with their mechanisms of renal injury are also reviewed.
Paroxysmal Atrial Fibrillation in Horses: Pathophysiology, Diagnostics and Clinical Aspects. Atrial fibrillation (AF) is the most common arrhythmia in horses causing poor performance. As in humans, the condition can be intermittent in nature, known as paroxysmal atrial fibrillation (pAF). This review covers the literature relating to pAF in horses and includes references to the human literature to compare pathophysiology, clinical presentation, diagnostic tools and treatment. The arrhythmia is diagnosed by auscultation and electrocardiography (ECG), and clinical signs can vary from sudden loss of racing performance to reduced fitness or no signs at all. If left untreated, pAF may prom...
Acute Kidney Injury and Renal Failure in Horses. Nephrotoxic and hemodynamically mediated disorders are the most common causes of acute renal failure (ARF) in horses and foals. Leptospira spp. is the most common infectious cause of ARF. Initial treatments for ARF include elimination of nephrotoxic drugs, correction of predisposing disorders, and fluid therapy to promote diuresis. Horses and foals with polyuric ARF often have a good prognosis, while those with oliguric or anuric ARF have a guarded to poor prognosis. When fluid therapy is unsuccessful in improving urine production, various drugs treatments have been used in an attempt to incre...
Metabolic Disorders Associated with Renal Disease in Horses. This article overviews metabolic disorders associated with renal disease. Included is a discussion of the pathophysiology, clinical signs, and treatment of hyperchloremic metabolic acidosis associated with renal tubular acidosis. Conditions affecting the central nervous system including uremic encephalopathy and hyponatremic encephalopathy secondary to renal disease are presented. Finally, a discussion of the unique features of calcium and phosphorus homeostasis in horses is provided with special emphasis on a recently described syndrome of calcinosis and calciphylaxis of unknown etiology.
Full-thickness endotracheal tube defect resulting in an anaesthetic circuit leak. Loss of endotracheal tube (ETT) integrity secondary to dental damage is reported in the human literature. Objective: To describe this problem in equine anaesthesia. Methods: Case report. Conclusions: An 18-year-old Standardbred gelding presented out of hours with colic signs. Findings on clinical examination and pain refractory to analgesia meant that exploratory laparotomy was elected for. Prior to general anaesthesia (GA) leak testing of the anaesthetic machine was performed and the pilot balloon of the endotracheal tube (ETT) was inflated to confirm cuff integrity. Intermittent-positive pre...
Diagnostic characteristics of refractometry cut-off points for the estimation of immunoglobulin G concentration in mare colostrum. Feeding foals with poor quality colostrum predisposes them to failure of passive transfer (FPT). FPT is a major risk factor for neonatal infections. Objective: To assess the optimal cut-offs for the optical (OR) and digital (DR) refractometer and determine their accuracy for poor quality colostrum diagnosis. Methods: A diagnostic validation study. Methods: Eighty-one colostrum samples and sera were collected from broodmares and their neonatal foals, respectively. Colostral and serum IgG concentrations were measured by radial immunodiffusion (RID), DR and OR. Correlation coefficients were calcu...
Metabolomics in clinical and forensic toxicology, sports anti-doping and veterinary residues. Metabolomics is a multidisciplinary field providing workflows for complementary approaches to conventional analytical determinations. It allows for the study of metabolically related groups of compounds or even the study of novel pathways within the biological system. The procedural stages of metabolomics; experimental design, sample preparation, analytical determinations, data processing and statistical analysis, compound identification and validation strategies are explored in this review. The selected approach will depend on the type of study being conducted. Experimental design influences ...
Intratracheal oxygen administration increases FIO2 and PaO2 compared with intranasal administration in healthy, standing horses. To evaluate the efficacy of 2 different oxygen delivery strategies-intranasal and tracheal insufflation-on the inspired fraction of oxygen (FIO2) in standing horses and to determine the time needed for arterial oxygen partial pressure (PaO2) equilibration. Methods: 6 healthy adult horses. Methods: In this blinded, randomized crossover design study, horses were randomly assigned to receive oxygen via nasal cannula (group N) or transcutaneous tracheal catheter (group T). After placement of venous and arterial catheters, FIO2 was measured through a catheter placed into the distal portion of the t...
Retrospective analysis of post-mortem findings in Thoroughbreds aged from birth to 18 months presented to a UK pathology laboratory. Enhanced understanding of reasons for, and timings of, mortality in Thoroughbreds prior to entering race training is warranted to provide insight into this population's health status. The aims of this study were to describe pathologies diagnosed at post-mortem (PM) examination in Thoroughbreds aged from birth to 18 months and investigate associations between age and pathology. Reports from a pathology laboratory in Newmarket, UK, were used to identify eligible cases examined between January 2006 and December 2020. Reported pathologies were extracted and categorised where appropriate. Comorbidi...
Immunohistochemical staining of immunoglobulin G in healthy equine, canine, and feline corneas. Establishing an immunohistochemical approach for semi-quantitative assessment of the presence of immunoglobulin G (IgG) in equine, canine, and feline corneas. Methods: Healthy corneas of horses, dogs, and cats, euthanized because of a fatal disease or an unrecoverable trauma unrelated to and without a history of ophthalmic disease were formalin-fixed, paraffin-embedded, and determined to be pathomorphologically healthy by light microscopy. Automated immunohistochemistry was performed using primary antibodies against IgG, biotin-conjugated secondary antibodies, and streptavidin-peroxidase, as w...
Assessment of Skin and Mucosa at the Equine Oral Commissures to Assess Pathology from Bit Wear: The Oral Commissure Assessment Protocol (OCA) for Analysis and Categorisation of Oral Commissures. This study addresses the presence and location of natural pigmentation, potentially pathological changes in pigment, interruptions of the natural lining (scars), roughness, and erosions/contusion (bruising) in and around the corners of the lips of 206 horses presented to a veterinarian for routine preventative dental treatment. After sedation, photographs were taken and later evaluated for the presence of lesions. During the photographic analysis, the Oral Commissure Assessment (OCA) protocol was developed to map precisely the areas of skin and mucosa around the corners of the lips, and the pr...
Effect of perfusate volume on amikacin concentrations after saphenous intravenous regional limb perfusion in standing, sedated horses. To determine the influence of perfusate volume on synovial fluid amikacin concentrations in the joints of the hind limb after standing saphenous intravenous regional limb perfusion (IVRLP). Methods: Randomized crossover design. Methods: Six adult horses. Methods: Saphenous IVRLP was performed in 6 standing horses with 1 g of amikacin diluted with 0.9% NaCl to volumes of 10 ml, 60 ml, and 120 ml. Samples of synovial fluid from the tarsocrural, metatarsophalangeal, and hind limb distal interphalangeal joints were collected at 15 and 30 min after perfusate administration. Concentrations ...
What Is Your Diagnosis? In collaboration with the American College of Veterinary Radiology.
An Exploratory Study on Vectorcardiographic Identification of the Site of Origin of Focally Induced Premature Depolarizations in Horses, Part II: The Ventricles. In human cardiology, the anatomical origin of ventricular premature depolarizations (VPDs) is determined by the characteristics of a 12-lead electrocardiogram (ECG). Former studies in horses had contradictory results regarding the diagnostic value of the 12-lead ECG and vectorcardiography (VCG), which results were attributed to the different cardiac conduction system in this species. The objective of this study was to determine if the anatomical origin of pacing-induced VPDs could be differentiated in horses based upon VCG characteristics. A 12-lead ECG was recorded in seven horses under gener...
An Analysis of Risk Factors for a Fracture or Luxation in Recovery From General Anesthesia in Horses: A Single Centre Study☆. Catastrophic fractures or luxations (FoL) sustained during recovery from general anesthesia are a significant cause of mortality during equine anesthesia. There is a lack of evidence regarding potential risk factors for a FoL occurring in the immediate anesthetic recovery period. A single center, retrospective, case-matched study was performed to identify risk factors for sustaining a catastrophic FoL during recovery from general anesthesia. Clinical data were obtained for horses which sustained a catastrophic FoL when recovering from general anesthesia from January 2011 to June 2020 in a sing...
Validation of a dedicated positron emission tomography scanner for imaging of the distal limb of standing horses. A positron emission tomography (PET) scanner, with an openable ring of detectors, was specifically designed to image the distal limb of standing horses. The goals of this prospective, preclinical, experimental, methods comparison study were to validate the safety of the scanner, assess image quality, and optimize scanning protocols. Six research horses were imaged three times (twice standing, once anesthetized) and six horses in active race training were imaged once under standing sedation. Multiple scans of both front fetlocks were obtained with different scan durations and axial fields of vi...
Comparison of Flunixin Meglumine, Meloxicam and Ketoprofen on Mild Visceral Post-Operative Pain in Horses. The analgesic efficacy of meloxicam and ketoprofen against equine visceral pain is unclear. The aim of this study was to compare the analgesic efficacy of meloxicam (M) and ketoprofen (K) to flunixin meglumine (F) following inguinal castration. Horses undergoing inguinal castration under general anesthesia were randomly assigned F (1.1 mg/kg), M (0.6 mg/kg) or K (2.2 mg/kg) intravenously two hours pre-operatively and 24 h later. A pain score (out of 31) was recorded blindly by a senior clinician and veterinary student before NSAIDs administration (T0), and after the first (T1) and second (T2) ...
A Descriptive Study of the Clinical Presentation, Management, and Outcome of Horses with Acute Soft Tissue Trauma of the Tarsus and the Association with Synovial Involvement. The tarsus is one of the most common areas of traumatic injury with associated synovial involvement (SI) in horses. The aim of this retrospective study was to describe the clinical presentation, diagnostic procedures, management (emphasizing the type, duration, and route of antimicrobial administration), and outcome of cases with acute soft tissue trauma to the tarsal region. The presenting clinical features, the results of diagnostic modalities, and the initial response to therapy were assessed for their usefulness to predict SI. Medical records of 72 cases were included and SI was diagnosed ...
Analysis of peripheral blood chemiluminescence in horses. The aim of this study was to analyze the chemiluminescence (CL) of peripheral blood in clinically healthy horses of different sexes and ages. The tests were carried out on 119 half- -breed horses, representing various forms of use (66 recreational horses and 53 sport horses). The test material was peripheral blood, which was collected under resting conditions, i.e. before physical activity related to the use of these animals. In the blood samples, spontaneous and stimulated CL with zymosan and phorbol myristate acetate were determined. It has been found that regular training effort increases t...
Use of biochemical and protein profiles of seminal plasma to prediction of semen quality and fertility in stallions. The identification of various substances in seminal plasma has opened the way to study their functionality. It was aimed to identify the electrophoretic protein profile (EPP) and biochemical parameters (BP) of seminal plasma (SP) as predictors of semen quality and fertility in stallion. Forty-six ejaculates from 7 fertile stallions, aged between 6-26 years, were collected from May to July and 117 mares were used to obtain fertility data. For each ejaculate, volume, sperm motility, concentration were determined and seminal plasma samples were collected to perform one- -dimensional electrophores...
Effect of Ageratina adenophora on hepatic and pulmonic pathological lesions in horses. The effect of Ageratina adenophora on pathological characteristics of the liver and lungs as well as serum biochemical parameters in horses were investigated. Ten horses without ingestion history of Ageratina adenophora were classified into the control group, and 10 poisoned but survived horses with 3 months ingestion history were set as the case group. Results showed that serum AST, ALT, ALP, magnesium and phosphorus were elevated significantly, while creatinine was decreased remarkably. Hematoxylin and eosin staining of liver tissues showed diffuse swelling or destruction of hepatocytes, nar...
Tumor Cell Plasticity in Equine Papillomavirus-Positive Versus-Negative Squamous Cell Carcinoma of the Head and Neck. Squamous cell carcinoma of the head and neck (HNSCC) is a common malignant tumor in humans and animals. In humans, papillomavirus (PV)-induced HNSCCs have a better prognosis than papillomavirus-unrelated HNSCCs. The ability of tumor cells to switch from epithelial to mesenchymal, endothelial, or therapy-resistant stem-cell-like phenotypes promotes disease progression and metastasis. In equine HNSCC, PV-association and tumor cell phenotype switching are poorly understood. We screened 49 equine HNSCCs for equine PV (EcPV) type 2, 3 and 5 infection. Subsequently, PV-positive versus -negative lesi...
Arthroscopic findings and long-term outcomes in 76 sport horses with meniscal injuries (2008-2018). To report the findings and long-term outcome of 76 sport horses with meniscal injury. Methods: Retrospective case series. Methods: Seventy-six horses with 93 meniscal injuries in 85 stifles. Methods: Medical records of sport horses diagnosed with meniscal injury during arthroscopy were reviewed. Owner follow up was obtained via telephone interview ≥1.5 years postoperatively. Preoperative and intraoperative findings, and postoperative treatments, were analyzed for potential association with return to athletic performance. Results: The medial meniscus was involved in 82.8% of cases, with gra...
Clostridial Diseases of Horses: A Review. The clostridial diseases of horses can be divided into three major groups: enteric/enterotoxic, histotoxic, and neurotoxic. The main enteric/enterotoxic diseases include those produced by Clostridium perfringens type C and Clostridioides difficile, both of which are characterized by enterocolitis. The main histotoxic diseases are gas gangrene, Tyzzer disease, and infectious necrotic hepatitis. Gas gangrene is produced by one or more of the following microorganisms: C. perfringens type A, Clostridium septicum, Paeniclostridium sordellii, and Clostridium novyi type A, and it is characterized by ...
Studies on Age-Related Changes in Equine Cheek Teeth Angulation and Dental Drift. Cheek teeth (second through fourth premolars and first through third molars) diastema is a common and painful equine disorder caused by the absence of effective tight interdental contact between these teeth. Limited objective information is available on the angulation of equine cheek teeth that control dental drift or on mesial or distal equine cheek teeth drift that should normally prevent this disorder. Objective: To measure the angulation of the mesial and distal cheek teeth in horses of different ages, quantify age-related cheek teeth mesial and distal dental drift, and measure the cheek t...
Activated platelets and platelet-leukocyte aggregates in the equine systemic inflammatory response syndrome. In humans, activated platelets contribute to sepsis complications and to multiple organ failure. In our prospective analytical study of cases of the equine systemic inflammatory response syndrome (SIRS), we adapted a standard human protocol for the measurement of activated platelets and platelet-leukocyte aggregates (PLAs) in equine platelet-leukocyte-rich plasma (PLRP) by flow cytometry, and we investigated the hypothesis that activated platelets and PLAs are increased in clinical cases of SIRS. We included 17 adult horses and ponies fulfilling at least 2 SIRS criteria, and 10 healthy equids ...