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.
Evaluation of 2 ELISAs to determine Borrelia burgdorferi seropositivity in horses over a 12-month period. The blacklegged tick (), which transmits , the causative agent of Lyme disease, has undergone rapid range expansion in Ontario. In horses, Lyme disease remains an enigmatic disease, with limited understanding of the pathogenesis and many issues pertaining to selection and interpretation of laboratory tests. We evaluated seropositivity in naturally exposed horses over a 12-mo period and compared paired samples with 2 common serologic tests. Serum samples were collected in 2017, ~1 y after initial testing, from a cohort of 22 horses that were seropositive in a 2016 seroprevalence study. Sampl...
Determination of correlation of proximal sesamoid bone osteoarthritis with high-speed furlong exercise and catastrophic sesamoid bone fracture in Thoroughbred racehorses. To examine whether proximal sesamoid bone (PSB) articular cartilage and bone osteoarthritic changes or palmar osteochondral disease (POD) scores were associated with exercise history and catastrophic PSB fracture in Thoroughbred racehorses. Methods: PSBs from 16 Thoroughbred racehorses (8 with and 8 without PSB fracture). Methods: Exercise history was collected, and total career high-speed furlongs was used as the measure of total exercise per horse. At necropsy, medial and lateral condyles of the third metacarpus from each forelimb were assigned a POD score, followed by imaging with micro-CT ...
Pharmacokinetics of mycophenolate mofetil following single-dose intravenous and single- and multiple-dose oral administration and clinicopathologic effects of mycophenolate mofetil following long-term oral administration in healthy horses. To characterize the pharmacokinetics of mycophenolate mofetil (MMF) following single-dose IV or PO administration, characterize the pharmacokinetics of MMF following long-term PO administration, and describe the clinicopathologic effects of long-term MMF administration in horses. Methods: 12 healthy adult horses. Methods: In phase 1, 6 horses received a single IV (2.5 mg/kg) or PO (5 mg/kg) dose of MMF in a randomized balanced crossover assessment (≥ 2-week interval between administrations). In phase 2, 6 other horses received MMF for 60 days (5 mg/kg, PO, q 24 h for 30 days and then 5 mg/kg...
Evaluation of the in vitro effects of local anesthetics on equine chondrocytes and fibroblast-like synoviocytes. To investigate the in vitro effects of clinically relevant concentrations of the local anesthetics (LAs) bupivacaine, lidocaine, lidocaine with preservative (LP), mepivacaine, and ropivacaine on equine chondrocyte and fibroblast-like synoviocyte (FLS) viability. Methods: Chondrocytes and FLSs of the metacarpophalangeal joints of 4 healthy adult horses. Methods: Viability of chondrocytes and FLSs was determined with 3 assays: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH), and trypan blue (TB) exclusion (only FLS). Viability was assessed after 30...
Clinical, pathologic, and epidemiologic features of nocardioform placentitis in the mare. Placentitis is the leading cause of infectious abortion in the horse and contributes to roughly 19% of all abortions in the United States. A type of placental infection, nocardioform placentitis (NP) is associated with gram-positive branching actinomycetes localized within the ventral body of the feto-maternal interface to create a lymphoplasmacytic mucoid lesion. While the etiology of this disease is poorly described, this placental infection continues to cause episodic abortions in addition to weak and/or growth retarded neonates. The goal of the present study was to perform a comprehensive ...
Renal Resistive Index as A Potential Indicator of Acute Kidney Injury in Horses. Reliable and simple tests are constantly being sought to enable the quick detection of acute kidney injury in humans and animals. Diagnosis of subclinical AKI in horses, mainly in field practice, is difficult. An ultrasound scan is a routine test performed when kidney disease is suspected. The aim of the study was to establish the value of the renal resistive index (RRI) in intrarenal arteries in horses with clinical AKI and compare it to that of healthy horses. The second goal was to determine whether potentially nephrotoxic agents can influence RRI. The kidney ultrasonography examination was...
Effect of Aerosolised Salbutamol Administration on Arterial Potassium Concentration in Anaesthetised Horses. Aerosolized salbutamol has been associated with hypokalemia in horses undergoing colic surgery. The objective of this study was to evaluate the effect of aerosolized salbutamol on arterial potassium concentration ([K +]) in healthy anaesthetized horses undergoing elective surgery. Anesthetic records were reviewed from healthy adult horses undergoing elective surgery over a 3-year period with two complete sets of arterial electrolyte (sodium [Na +], potassium [K +], chloride [Cl -], calcium [Ca 2+]) concentration measurements. Records were excluded if intra-operative electrolyte supplementation...
Three Manual Noncommercial Methods to Prepare Equine Platelet-Rich Plasma. In light of PRP's increasing popularity in veterinary practice, this study aimed to compare three manual methods to prepare and cool equine PRP. The blood of 18 clinically healthy mares was collected via venipuncture in a blood transfusion bag (method 1), blood tubes (method 2), and a syringe (method 3). In method 1, samples were double centrifuged; method 2 involved one centrifugation, and in method 3 the syringe was kept in an upright position to sediment for 4 h. After processing with three methods, PRP and platelet-poor plasma (PPP) were extracted and assessed for red (RBC) and white blood...
Development of a constant pressure perfused ex vivo model of the equine larynx. Distal axonopathy is seen in a broad range of species including equine patients. In horses, this degenerative disorder of the recurrent laryngeal nerve is described as recurrent laryngeal neuropathy (RLN). The dysfunctional innervation of the cricoarytenoideus dorsalis muscle (CAD) leads to a loss of performance in affected horses. In general, ex vivo models of the larynx are rare and for equine patients, just one short report is available. To allow for testing new therapy approaches in an isolated organ model, we examined equine larynges in a constant pressure perfused setup. In order to chec...
A Pilot Randomised Clinical Trial Comparing a Short-Term Perioperative Prophylaxis Regimen to a Long-Term Standard Protocol in Equine Colic Surgery. For surgical interventions classified as clean or clean-contaminated, including laparotomy, guidelines in human and veterinary medicine recommend a short-term perioperative antibiotic prophylaxis (PAP). In equine colic surgery, however, PAP commonly exceeds 24 h. Objective: The aim of this study was to compare a single-shot to a 5-day lasting PAP considering surgical site infections (SSI) and other adverse effects probably associated with the particular antimicrobial regimen. Methods: The study was designed as a randomised non-inferiority pilot study including horses subjected to colic surgery...
Evaluation of Serum and Urine Neutrophil Gelatinase-associated Lipocalin and Cystatin C as Biomarkers of Acute Kidney Injury in Horses. Diagnosis of acute kidney injury (AKI) in horses is difficult at the subclinical stage, due to nonspecific clinical signs. The aim of this study was to evaluate the concentrations of selected serum and urinary biomarkers in healthy horses, horses at risk of AKI, and those with clinical AKI. Methods: Thirty healthy horses, 30 horses at risk of AKI and 11 horses with clinical AKI and azotaemia were included in the study. Serum and urinary neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C were measured using commercially available enzyme immunoassay tests. Results: The median and (...
The use of electrical impedance tomography (EIT) to evaluate pulse rate in anaesthetised horses. Electrical impedance tomography (EIT) provides clinically useful lung images; however, it would be an advantage to extract additional cardiovascular information from the data. The aim of this study was to evaluate if cardiac-related changes measured by EIT can be used to measure pulse rate (PR) under physiological as well as high and low blood pressure states in anaesthetised horses. Electrical impedance tomography data and PR from seven horses anaesthetised in dorsal recumbency were recorded over 1 min during mechanical ventilation and 1 min of apnoea. Data were collected at four measurement ...
Dentigerous Equine Teratoma in a Stallion: Surgical Management and Clinicopathology. Teratoma is a rare germ cell testicular cancer composed of cells that are not normally present in the site where it originates. These tumors are rarely described in horses, where they may develop due to cryptorchidism. Teratomas consist of cells originating from different germinal layers, arising from germinal multi-potential cells with differentiation defects, and can simultaneously contain several tissues from two or more embryonic layers. Testicular teratomas are described in horses, cats, dogs, wild boars, bulls, and humans. In the rare descriptions found in literature of testicular terato...
Investigation of synovial fluid lubricants and inflammatory cytokines in the horse: a comparison of recombinant equine interleukin 1 beta-induced synovitis and joint lavage models. Lameness is a debilitating condition in equine athletes that leads to more performance limitation and loss of use than any other medical condition. There are a limited number of non-terminal experimental models that can be used to study early inflammatory and synovial fluid biophysical changes that occur in the equine joint. Here, we compare the well-established carpal IL-1β-induced synovitis model to a tarsal intra-articular lavage model, focusing on serial changes in synovial fluid inflammatory cytokines/chemokines and the synovial fluid lubricating molecules lubricin/proteoglycan 4 and hya...
Effect of topical cyclopentolate alone or combined with phenylephrine in healthy horses. Evaluate the effect of repeated doses of topical 1% cyclopentolate hydrochloride alone and in combination with topical 2.5% phenylephrine on pupil diameter (PD), tear production (STT-1), intraocular pressure (IOP), digestive function (gut motility and feces production), and heart rate (HR). Methods: Six healthy mares. Methods: In a prospective, randomized, controlled, and crossover design study, the left eye of six healthy mares was administered 0.2 mL of cyclopentolate alone and in combination with 0.2 mL of phenylephrine. The drugs were administered 3 times a day for 1 day, twice a day fo...
Long-term detection of clodronate in equine plasma by liquid chromatography-tandem mass spectrometry. Clodronate is a non-nitrogen-containing bisphosphonate drug approved in equine veterinary medicine. Clodronate is prohibited for use in competition horses; therefore, to set up an appropriate control, detection times and screening limits are required. The quantitative method in plasma consisted of addition of chloromethylene diphosphonic acid as internal standard. Automated sample preparation comprised a solid phase extraction with weak anion exchange properties on microplate. After methylation of the residue with trimethyl orthoacetate, analysis was conducted by high-performance liquid chroma...
Dual-contrast computed tomography enables detection of equine posttraumatic osteoarthritis in vitro. To prevent the progression of posttraumatic osteoarthritis, assessment of cartilage composition is critical for effective treatment planning. Posttraumatic changes include proteoglycan (PG) loss and elevated water content. Quantitative dual-energy computed tomography (QDECT) provides a means to diagnose these changes. Here, we determine the potential of QDECT to evaluate tissue quality surrounding cartilage lesions in an equine model, hypothesizing that QDECT allows detection of posttraumatic degeneration by providing quantitative information on PG and water contents based on the partitions of...
Hand-Held Point-of-Care Ultrasound: A New Tool for Veterinary Student Self-Driven Learning in the Time of COVID-19. The coronavirus pandemic abruptly halted all in-person clerkships, or clinical rotations, for clinical veterinary students across the United States. Online clerkships in radiology offered the opportunity to expand the student's ability to interpret medical images but did not allow for the development of physical hands-on imaging skills recognized as core competencies in veterinary medicine. The present report highlights the value of providing veterinary students with a smartphone-associated Butterfly iQ point-of-care ultrasound during a 3-week self-driven virtual clerkship. During the virtual ...
Use of Electrical Impedance Tomography (EIT) to Estimate Tidal Volume in Anaesthetized Horses Undergoing Elective Surgery. This study explores the application of electric impedance tomography (EIT) to estimate tidal volume (VT) by measuring impedance change per breath (∆Z). Seventeen healthy horses were anaesthetised and mechanically ventilated for elective procedures requiring dorsal recumbency. Spirometric VT (VT) and ∆Z were recorded periodically; up to six times throughout anaesthesia. Part 1 assessed these variables at incremental delivered VT of 10, 12 and 15 mL/kg. Part 2 estimated VT (VT) in litres from ∆Z at three additional measurement points using a line of best fit obtained from Part 1. During pa...
Outbreak of equine coronavirus infection among riding horses in Tokyo, Japan. In 2020, an outbreak of equine coronavirus (ECoV) infection occurred among 41 horses at a riding stable in Tokyo, Japan. This stable had 16 Thoroughbreds and 25 horses of other breeds, including Andalusians, ponies and miniature horses. Fifteen horses (37 %) showed mild clinical signs such as fever, lethargy, anorexia and diarrhoea, and they recovered within 3 days of onset. A virus neutralization test showed that all 41 horses were infected with ECoV, signifying that 26 horses (63 %) were subclinical. The results suggest that subclinical horses played an important role as spreaders. A genome ...
Serum and cerebrospinal fluid phosphorylated neurofilament heavy protein concentrations in equine neurodegenerative diseases. Currently, there is little information regarding the concentrations of phosphorylated neurofilament heavy protein (pNfH) in the serum and cerebrospinal fluid (CSF) of horses with neurodegenerative diseases. Specifically, pNfH concentrations have not yet been evaluated in horses with equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM). Objective: To determine pNfH concentrations using a commercial enzyme-linked immunosorbent assay (ELISA) in serum and CSF from control horses and horses with eNAD/EDM, cervical vertebral compressive myelopathy (CVCM) and Shivers. Metho...
Training related risk factors for exercise induced pulmonary haemorrhage in British National Hunt racehorses. Exercise induced pulmonary haemorrhage (EIPH) is an important condition of horses performing high intensity exercise, with reported prevalence among racehorses of up to 95%, based on the detection of blood on tracheobronchoscopy. Previously identified risk factors include age, sex, season, race type, years spent in racing and lower airway inflammation. Objective: To estimate the prevalence of EIPH in British National Hunt racehorses as indicated by two outcome measures: presence of tracheal blood on tracheobronchoscopy, and presence of moderate-large (significant) proportions of haemosideropha...
Risk factors for laminitis and nonsurvival in acute colitis: Retrospective study of 85 hospitalized horses (2011-2019). Acute colitis is a serious cause of morbidity and death in horses. Recent studies have compared clinical features of coronavirus and salmonellosis, but no study has compared clinical features of enteric salmonellosis, coronavirus, and neorickettsiosis. Objective: To identify risk factors for laminitis and nonsurvival to discharge in horses with enteric salmonellosis, coronavirus, or neorickettsiosis. Methods: Eighty-five horses hospitalized for acute colitis from 2011 to 2019. Methods: Retrospective case series. Medical record review (2011-2019) of adult (≥2 years) horses with colitis. Pri...
Development of a 3′:5′ digital PCR assay to determine horse mRNA integrity. Accurate tools to measure RNA integrity are essential to obtain reliable gene expression data. The reverse transcription quantitative PCR (RT-qPCR) based 3':5' assay permits a direct determination of messenger RNA (mRNA) integrity. However, the use of standard curves and the possible effect of PCR inhibitors make this method cumbersome and prone to variation, especially in small samples. Here we developed a triplex digital PCR (dPCR) 3':5' assay for assessing RNA integrity in equine samples as rapid and simple alternative to RT-qPCR. This dPCR assay not only provides a straight forward analysi...
Tandem Mass Tag (TMT) Proteomic Analysis of Saliva in Horses with Acute Abdominal Disease. The aim of this study was to investigate the changes in the salivary proteome in horses with acute abdominal disease (AAD) using a tandem mass tags (TMT)-based proteomic approach. The saliva samples from eight horses with AAD were compared with six healthy horses in the proteomic study. Additionally, saliva samples from eight horses with AAD and eight controls were used to validate lactoferrin (LF) in saliva. The TMT analysis quantified 118 proteins. Of these, 17 differed significantly between horses with AAD and the healthy controls, 11 being downregulated and 6 upregulated. Our results showe...
Outcomes Following Transcorneal Diode Laser Ablation of Uveal Cysts: 48 Horses (2006-2020). Uveal cysts can lead to undesirable behaviors and poor performance in horses. Transcorneal laser ablation has been proposed as a safe and effective treatment for uveal cysts suspected of causing behavioral changes but outcomes have been reported in only a small number of horses. In this retrospective study, records were identified for horses who had undergone transcorneal cyst ablation using a diode laser. Information was collected regarding signalment, behavioral or performance issues reported prior to the procedure, and complications. Owners were contacted to provide follow-up information re...
Evaluation of transpalpebral ultrasonographic measurement of optic nerve sheath diameter for indirect assessment of intracranial pressure in anesthetized and standing healthy adult horses. To determine whether an association exists between direct intracranial pressure (ICP) measurement and ultrasonographic measurement of optic nerve sheath diameter (ONSD) in anesthetized and standing horses. Methods: Cross-sectional study performed on a convenience sample of healthy adult horses. Methods: University teaching hospital. Methods: Eight adult horses donated to the University. Enrolled horses were free of abnormalities on physical examination, CBC, neurological evaluation, and ophthalmological examination. Results: Horses were anesthetized in lateral recumbency for placement of an IC...
Biochemical and hematologic changes in whole blood from Brazilian horses stored in citrate-phosphate-dextrose-adenine pouches for up to 28 days. Anaerobic cellular metabolism causes a series of structural and physiologic changes during storage that could compromise post-transfusion viability, reducing the safety of using blood stored for an extended period. Objective: We aimed to follow the biochemical and hematologic alterations of equine blood stored in plastic bags containing citrate-phosphate-dextrose-adenine (CPDA-1) for up to 28 days. Methods: Whole blood samples (450 mL) were collected from 20 Brazilian Saddle horses into CPDA-1 pouches and stored between 2°C and 6°C in a blood bank. On days 0, 7, 14, 21, and 28 of storage, ...
Bacterial meningitis after dental extraction in a 17-year-old horse. Dental extractions in horses may result in bacteremia, which can lead to systemic complications. Bacterial meningitis following oral cheek tooth extractions in a 17-year-old Thoroughbred gelding is described in this report. The bacterial meningitis was confirmed by histopathology. The gelding was presented for evaluation of intermittent fever, loose feces, and mild colic signs which started 5 days after cheek tooth extraction. This case illustrates a rare complication associated with oral tooth extraction in a horse and highlights the unusual presenting features of meningitis. Key clinical mes...
Inflammatory response of miniature horses subjected to open and half-closed orchiectomy techniques. This study aimed to evaluate the inflammatory response of miniature horses subjected to open and half-closed orchiectomy by physical examination, blood cell count, peritoneal fluid evaluation, total plasma protein, fibrinogen, and serum amyloid A (SAA) concentrations. Methods: Thirteen male healthy miniature horses were divided into two groups, according to the surgical approach: half-closed technique (HCT) and open technique (OT). The HCT group was subjected to ligation of the spermatic cord followed by its sharp incision, and closure of the vaginal tunic, and the OT group was only submitted ...