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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.
Effects of furosemide and pentoxifylline on blood flow properties in horses. The effects of furosemide and pentoxifylline on blood flow properties in horses were investigated. Hematologic and rheologic changes were examined in 4 horses before and 3 minutes after administration of epinephrine (1 mg, IV). The next day, hemorheologic changes were determined before and 3 hours after administration of furosemide (1 mg/kg of body weight, IM), and after administration of epinephrine at the sampling at 3 hours. Hematologic and rheologic changes were evaluated weekly in 3 horses given pentoxifylline (8.5 mg/kg, q 12 h, PO) for 28 days. In addition, hemorheologic responses to ep...
Adverse drug reactions: report of the Australian Veterinary Association Adverse Drug Reaction Subcommittee, 1992. Fifty-nine reports of suspected adverse drug reactions (ADRs) were received by the Adverse Drug Reaction Subcommittee of the Australian Veterinary Association from February 1991-March 1992 inclusive. The number of reports received/number of animals involved per species was: dogs (23/24); cats (20/30); horses (4/4); cattle (7/10); sheep (3/745); poultry (1/580); pigs (1/8). Of these, 38 (64%) were classified as definite ADRs and 9 (15%) as probable ADRs. In 10 (17%) reports an ADR could not be substantiated or there was insufficient information available to make a decision. Two reports involved...
Primary pulmonary neoplasm in a horse. A 16-year-old Thoroughbred gelding was evaluated for respiratory disease and found to have a primary lung tumor on postmortem examination. A tentative antemortem diagnosis was made on the basis of results of radiography and cytologic examination of a needle aspirate guided by ultrasonography. A histologic diagnosis of bronchioalveolar adenocarcinoma was made. Thoracic neoplasia is rare in horses. The most frequently reported primary pulmonary tumor is the granular cell tumor.
Prognostic indicators for horses with duodenitis-proximal jejunitis. 75 horses (1985-1989). The medical records of 75 horses with duodenitis-proximal jejunitis (DPJ) were reviewed. Ages, physical parameters, laboratory values, and treatment data were compared between horses surviving DPJ and horses not surviving DPJ (Table 1). Fifty of 75 horses (66.6%) survived. Sixty-six horses (88.0%) were managed with medical treatment alone and nine horses (12.0%) were managed with medical treatment plus surgical intervention. Using a logistic regression model, the association of each of the 19 physical and laboratory parameters with death was evaluated retrospectively in the 75 horses. Three pa...
[Comparison of IgG determination in foals using commercially available rapid tests]. The three tests (EQUI Z-Test, AGLUTINADE FOAL IMMUNITY, CITE Foal IgG-Test) were evaluated for their accuracy and usefulness in the field. Single radial immunodiffusion was used as reference method. All tests were easily and rapid to perform and results were obtained within a few minutes. It was easy to get the results of the CITE Foal IgG-Test, but use of the EQUI Z-Test and the FOAL AGLUTINADE IMMUNITY-Test needed some practice to get correct results. Results obtained by the CITE Foal IgG-Test correlated to single radial immunodiffusion in 94%, those obtained by FOAL AGLUTINADE IMMUNITY-Test...
Safety of ceftiofur sodium administered intramuscularly in horses. Ceftiofur sodium, a broad-spectrum cephalosporin antibiotic, was evaluated for safe use in horses. Male or female horses were allotted to groups and were given either saline solution (control), or 2.2, 6.6, or 11 mg of an aqueous solution of ceftiofur sodium/kg of body weight/d, IM, for 30 or 31 days. These dosages are expressed in terms of the ceftiofur free acid, and represent 1 to 5 times the proposed therapeutic dosage (2.2 mg/kg/d) administered for 3 times the maximal recommended duration of 10 days. Some of the horses were euthanatized and necropsied on day 31 or 32. The other horses wer...
Effects of hypoxia and azotaemia on the pharmacokinetics of amikacin in neonatal foals. The effects of hypoxia and azotaemia on the pharmacokinetics of amikacin were evaluated in 20 full-term neonatal critically ill foals which required 24-h supportive care, antibiotics and dextrose-supplemented polyionic fluids given intravenously, nasal insufflation with oxygen and nutritional supplementation. There was no association between sepsis score or survival and pharmacokinetic parameters. Concurrent hypoxia and azotaemia were associated with significantly decreased clearance and increased peak and trough serum concentrations of amikacin; however, peaks or troughs did not exceed toxic ...
Mesothelioma in horses. Pleural mesothelioma and pericardial mesothelioma with spread to the pleural cavity were diagnosed in 2 horses. Clinical signs included respiratory distress, depression and pleural pain. The affected body cavities contained copious, serous effusions containing very large neoplastic mesothelial cells with densely-staining cytoplasm, hyperchromic nuclei and prominent, often multiple, nucleoli. Ultrastructurally, the neoplastic cells appeared as solid aggregates, with profuse microvillous borders and neolumen formation. Cytological examination, together with confirmative ancillary diagnostic test...
Animal immunodeficiency viruses. Feline immunodeficiency virus (FIV) has morphological, physical and biochemical characteristics similar to human immunodeficiency virus (HIV), the cause of AIDS in man. However, it is antigenically and genetically distinct from HIV; an antigenic relatedness with equine infectious anaemia virus has been demonstrated. FIV has been molecularly cloned and sequenced. Diagnostic tests are commercially available and attempts at preparing inactivated, subunit and molecularly engineered vaccines are being made in different laboratories. During FIV infection a transient primary illness can be recognized...
Primary meningeal lymphoma in a horse. Primary meningeal lymphoma was diagnosed in an 18-year-old Morgan gelding. The horse was examined because of a 3-day history of progressive ataxia and weakness. The gait abnormalities were worse on the left side, and the pelvic limbs were more affected than the thoracic limbs. Additional findings included signs of depression, miosis of the left pupil, ptosis of the left upper eyelid, and areas of muscle atrophy on the left side of the neck and over the dorsal aspect of the left scapula. Inflammatory changes were evident in the CSF. At necropsy, there was diffuse and irregular thickening of the...
Microvascular permeability changes in ischemia/reperfusion injury in the ascending colon of horses. The normal microvascular permeability of the ascending colon in horses and the microvascular permeability of that segment after ischemia and reperfusion were investigated. Microvascular permeability was estimated by the ratio of lymphatic protein to plasma protein concentration (Cl/Cp) at high lymph flow rates in 8 adult horses in 2 equal groups: normal and ischemic (2-hour period). Lymphatic flow rates and lymph and plasma protein concentrations were determined. Intestinal biopsy specimens were obtained at the end of each experiment. Flow independent values were selected and compared by one-w...
Postanesthetic recumbency associated with hyperkalemic periodic paralysis in a quarter horse. Anesthesia and surgery in a Quarter Horse affected with hyperkalemic periodic paralysis resulted in euthanasia after 7 days of postoperative recumbency. Initial recovery was uneventful after extensive sinus surgery, but within 2 hours, the horse had severe muscle weakness. Plasma electrolyte concentrations were within the normal range during the period of recumbency. There was no clinical or laboratory evidence of severe muscle damage. Despite treatment with acetazolamide, isoproterenol, and intensive nursing, the horse was unable to stand for more than a few seconds and developed severe decub...
Evaluation of an automated system for hemoglobin measurement in animals. In veterinary medicine, PCV determined by centrifugation of blood in a microhematocrit tube is the most common clinical test used to initially assess and monitor anemic and polycythemic animals. In contrast, blood hemoglobin (Hb) concentration, rather than PCV, is generally determined in human patients. One automated system photometrically measures blood Hb concentration after conversion of Hb to azide methemoglobin without dilution and was found to be a simple and accurate instrument for use in human medicine. We evaluated the system for its accuracy in measuring blood Hb concentration in ani...
Effects of pentoxifylline on equine neutrophil function and flow properties. Pentoxifylline has been reported to improve peripheral vascular circulation by altering the flow properties of blood. To determine if the hemorrheological effects of pentoxifylline were mediated by alterations in neutrophil function and/or flow properties, we evaluated the drug's effects on equine neutrophils in vitro. Pentoxifylline, at a concentration of 1 x 10(-1) M, but not at concentrations of 1 x 10(-6) M to 1 x 10(-2) M, markedly suppressed neutrophil superoxide production, zymosan phagocytosis and adherence to nylon wool. Pentoxifylline failed to improve neutrophil filterability throug...
Seroprevalence of antibodies to Borrelia burgdorferi in a population of horses in central Texas. Four hundred sixty-nine serum samples were obtained from horses admitted to the internal medicine service of the Texas Veterinary Medical Center between Jan 1 and Dec 31, 1990. Serum samples were tested by ELISA for antibody to Borrelia burgdorferi. Of these 469 samples, 1 (0.2%) was repeatedly seropositive for the organism by ELISA. Confirmatory testing by protein immunoblot was negative. The observed seroprevalence was 0%; the upper bound of the 95% confidence interval was 0.6%. These findings indicate the evidence of infection with B burgdorferi is presently uncommon in horses in central Te...
Acetylsalicylic acid and blood coagulation in the horse. Equine blood may contain salicylic acid (SA) taken up as free acid or represents the metabolite of acetylsalicylic acid (ASA). To obtain information of SA in race horses we screened blood samples of trotting-horses routinely drawn to be analyzed for doping substances. The individual values determined followed a Gaussian distribution displaying a geometric mean of 19 ng SA per ml serum. A probit analysis revealed linear relationship (r = 0.995). Additional studies examined the antithrombotic efficacy of ASA in the horse. An oral dose of 300 mg ASA considerably elevated the bleeding time for mor...
Evaluation of clinical signs of disease, bronchoalveolar and tracheal wash analysis, and arterial blood gas tensions in 13 horses with chronic obstructive pulmonary disease treated with prednisone, methyl sulfonmethane, and clenbuterol hydrochloride. We evaluated the efficacy of 3 treatments for chronic obstructive pulmonary disease in horses: prednisone (400 mg/horse, PO, daily; n = 7), methyl sulfonmethane (10 g/horse, PO, q 12 h; n = 6), and clenbuterol hydrochloride (0.4 mg/horse, PO, q 12 h; n = 7). A fourth group acted as controls (n = 6) and was not treated. The treatment period lasted 10 days. Each horse was a member of 2 different groups for 10 days, separated by an 18-day interval of no treatment. All horses were housed together in an outdoor pen without bedding. Horses were fed alfalfa/grass hay mix ad libitum from a large feede...
Pharmacokinetics of metronidazole and its concentration in body fluids and endometrial tissues of mares. Serum concentrations of metronidazole were determined in 6 healthy adult mares after a single IV injection of metronidazole (15 mg/kg of body weight). The mean elimination rate (K) was 0.23 h-1, and the mean elimination half-life (t1/2) was 3.1 hours. The apparent volume of distribution at steady state was 0.69 L/kg, and the clearance was 168 ml/h/kg. Each mare was then given a loading dose (15 mg/kg) of metronidazole at time 0, followed by 4 maintenance doses (7.5 mg/kg, q 6 h) by nasogastric tube. Metronidazole concentrations were measured in serial samples of serum, synovia, peritoneal flui...
C3 fixed in vivo to cornea from horses inoculated with Leptospira interrogans. C3 was detected bound in vivo to the opaque cornea of horses inoculated with killed Leptospira interrogans. Employing epithelial corneal cells isolated from a monolayer in tissue culture, we proved that C3 is fixed in vitro to the intact cell surface after incubation with a fresh equine anti-Leptospira serum. These findings, in addition to the infiltration of cornea with neutrophils and lymphocytes, may explain the mechanisms of tissue damage in recurrent uveitis of horses with leptospirosis.
Effect of hypertonic and isotonic saline solutions on plasma constituents of conscious horses. Blood constituents and vascular volume indices were determined in 5 standing horses by use of 2-period crossover experimental design. Horses were either administered hypertonic (2,400 mosm/kg of body weight, i.v.) or isotonic (300 mosm/kg, i.v.) saline solution. Each solution was administered at a dosage of 5 ml/kg (infusion rate, 80 ml/min). Samples for determination of PCV, plasma volume, blood volume, plasma osmolality, total amount of plasma protein and plasma concentrations of protein, Na, K, and Cl were collected at 0 hour (baseline, before fluid infusion) and 0.5 hour (at the end of flu...
Sarcocystis neurona-associated ataxia in horses in Brazil. Sarcocystis neurona-like schizonts were found in sections of brain and spinal cord of two ataxic horses from Brazil. The diagnosis was supported by staining with anti-Sarcocystis serum in an immunohistochemical test. One of the affected horses was born in Argentina and raised in Brazil, and the other horse was born and raised in Brazil.
Furosemide-induced electrolyte depletion associated with echinocytosis in horses. Echinocytes have been incriminated in the pathogenesis of exertional diseases in horses. To evaluate the hypothesis that echinocytes are dehydrated erythrocytes, we decreased blood sodium and potassium concentrations in 4 horses by administering furosemide (1.0 mg/kg of body weight, q 12 h) for 2 days and we monitored CBC, serum and erythrocyte sodium and potassium concentrations, and echinocyte numbers. Serum sodium concentration decreased progressively over the 48 hours of furosemide administration, then returned to near baseline concentration at 168 hours. A statistically significant decrea...
Effects of ketamine infusion on halothane minimal alveolar concentration in horses. Eight adult horses were used in a study to determine ketamine's ability to reduce halothane requirement. To obtain steady-state plasma concentrations of 0.5, 1.0, 2.0, 4.0, and 8.0 micrograms/ml, loading doses and constant infusions for ketamine were calculated for each horse on the basis of data from other studies in which the pharmacokinetic properties of ketamine were investigated. Blood samples for determination of plasma ketamine concentrations were collected periodically during each experiment. Plasma ketamine concentrations were determined by capillary gas chromatography/mass spectromet...
[Electrophoretic studies of serum protein fractions in horses with laminitis]. The spectrum of serum proteins was evaluated in 46 horses affected with spontaneous laminitis and correlations between the severity of the disease and changes of the protein pattern were analyzed. The investigation was made in two groups; group A consisted of 21 horses of various breeds (warmblood, thoroughbred, standardbred) and group B of 25 ponys. Each group was subdivided according to the severity of the disease, using the OBEL-grade (OG) classification system. Serum proteins were separated by different one- and two-dimensional electrophoretic methods. Sera analysed by cellulose acetate el...
Autonomic neurone degeneration in equine dysautonomia (grass sickness). Histological investigations were undertaken on four sympathetic autonomic ganglia and on the myenteric and sub-mucosal plexuses of the jejunum in healthy animals, in naturally occurring cases of acute, sub-acute and chronic equine dysautonomia and in ponies in which neuronal damage had been induced by the injection of acute grass sickness sera. The degree of neuronal damage is related to the type of dysautonomia. The coeliac-mesenteric ganglion reacts differently from other ganglia and is less severely damaged in cases of short duration. Extensive experimentally induced damage to the coeliac-m...
[Respiratory support techniques in foals in a newborn intensive care unit for large animals]. Various techniques for support and control of respiration in neonatal foals are described. It is crucial to evaluate respiration through frequent arterial blood gas analysis. Details for blood sampling from the metatarsal arteries and interpretation of results are provided. Typical diseases in newborn foals, which cause hypoxemia and/or hypercapnia and can be indications for respiratory support are apnea, hypopnea, pulmonary atelectasis, surfactant deficiency, meconium-, fetal fluid- and milk aspiration, maladjustment syndrome, cardiovascular abnormalities, anemia, airway obstruction, compromi...
Effect of the somatostatin analogue octreotide on gastric fluid pH in ponies. The effect of the somatostatin analogue, octreotide, on gastric fluid pH was investigated in 4 ponies. Gastric fluid pH was determined after SC administration of octreotide or physiologic saline solution (control). A baseline sample of fluid was obtained, the agent was given, and 8 additional samples were collected hourly. Administration of octreotide at all dosages tested (0.1, 0.5, 1.0, and 5.0 micrograms/kg of body weight) increased gastric pH to > 5.0. Baseline values were consistently 4.0 for 2.4 +/- 1.2, 4.8 +/- 0.8, 5.7 +/- 1.3, and 5.4 +/- 2.6 (mean +/- SD) continuous hours, respec...
