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Topic:Pathology
Pathology in horses involves the study of diseases and abnormalities affecting equine health, encompassing a range of conditions that can impact various systems within the horse's body. This field examines the causes, mechanisms, and effects of diseases, as well as the structural and functional changes they induce in equine tissues and organs. Common pathological conditions in horses include laminitis, colic, equine infectious anemia, and respiratory disorders. Understanding these diseases involves evaluating clinical signs, diagnostic methods, and treatment options. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, pathogenesis, and clinical implications of pathological conditions in horses.
Spontaneous vascular mineralization in the brain of horses. Cerebral vascular mineralization was found in 12 (60%) of 20 3- to 10-year-old healthy horses collected at an abattoir. It was variable in degree and occurred mostly in the pallidal arteries showing two types of lesions; small globoid bodies along capillaries, and amorphous deposits in the wall of arterioles, small- or medium-sized arteries and veins. Both types were strongly positive for periodic acid-Schiff reaction, and weakly positive for von Kossa's and Berlin blue stains. Elemental analysis of the deposit revealed the presence of large amounts of aluminum, moderate amounts of phosphorus,...
Three cases of carcinoid in the equine nasal cavity and maxillary sinuses: histologic and immunohistochemical features. Three cases of carcinoid tumor in horses are described. The tumors originated from the maxillary sinuses and the retrobulbar region and caused exophthalmos. Histologically, they had a characteristic endocrine pattern and were argyrophilic with the Grimelius stain. All tumors contained reactivity for neuron-specific enolase and synaptophysin. Two of three tumors were reactive for both bovine and porcine chromogranin A. These immunohistochemical results confirm the neuroendocrine nature of these tumors. Neuroendocrine cells could not be detected in the nasal mucosa and maxillary sinuses of a nor...
Congenital cleft vertebral centrum and intra- and extraspinal cyst in a foal. A midsagittal centrum cleft of T5-6, malformation and fusion of T3-7, intra- and extraspinal cyst, and myelodysplasia were found in a 3-month-old female Arabian foal that had experienced posterior ataxia since birth. Based on studies in other species, ecto-endodermal adhesions early in embryogenesis leading to formation of an enterogenous cyst is the most probable pathogenesis.
Pyrrole detection and the pathologic progression of Cynoglossum officinale (houndstongue) poisoning in horses. Houndstongue (Cynoglossum officinale), a noxious weed that contains pyrrolizidine alkaloids (PAs), infests pastures and fields in the western United States and Europe. The purpose of this study was to develop techniques to better diagnose PA poisoning and describe the progression of gross and microscopic lesions caused by houndstongue intoxication. Six horses were gavaged daily with a suspension of houndstongue containing 5 or 15 mg/kg total PA for 14 days. Two horses were treated similarly with ground alfalfa as controls. Liver biopsy samples and serum biochemical and hematologic values were ...
Acute post-treatment enterocolitis in 13 horses treated in a Norwegian surgical ward. Case histories, results of laboratory analyses, treatment regimens and outcome are described for 13 horses that developed acute enterocolitis after various surgical treatments. Twelve of the 13 horses had been cast in lateral recumbency, and 10 of those 12 had received general anesthesia. Eleven horses had been treated with antimicrobial drugs. Most horses (11) developed diarrhea 2 days after initiation of treatment, with a variation from 1 to 5 days. The most apparent symptoms were fever, up to 40.5 degrees C, elevated heart rate, discoloration of mucous membranes, and diarrhea. Dehydration, ...
Recent acute and subacute mycotoxicoses recognized in France. Successful investigation and prevention of mycotoxic problems requires close collaboration between scientists from several disciplines ranging from agronomists and technologists required during production of food and feeds, to toxicologists and pathologists examining the effects of mycotoxins on animals and man. Zootoxic metabolites following fungal infection result from four general mechanisms: (i) secondary fungal metabolism (mycotoxins, eg, aflatoxins); (ii) bioconversion of vegetal compounds (eg, dicoumarol); (iii) plant reactions (phytoalexins, eg, coumestrol); and (iv) plant-fungus assoc...
[A horse with chronic eosinophilic enteritis]. A three-year-old pregnant Dutch Warmblood mare was referred to the Department of Large Animal Medicine and Nutrition, Faculty of Veterinary Medicine, because of weight loss for 1 month. The main clinical features were (beside weight loss) moderate ventral oedema, enlarged mesenteric lymph nodes, and uniform thickening of the wall of the jejunum. Haematological evaluation revealed leukocytosis (15.9 G.l-1 with 18% lymphocytes and 1% eosinophils) and a decreased total serum protein and albumin concentration (35 g.l-1 and 36.3% albumin). At necropsy transmural eosinophilic enteritis was found in ...
Hematology and hemostasis in the horse: normal functions and common abnormalities. In diseased animals, laboratory evaluations of erythrocytes, leukocytes, and hemostasis provide important information that contributes to either narrowing the list of potential diagnoses or to determining a specific diagnosis. To adequately interpret the results of these evaluations, normal erythrocyte and leukocyte kinetics and normal hemostatic function must be understood. In addition, knowledge of common diseases resulting in abnormalities of these laboratory tests and of typical changes in these tests caused by these diseases is vital. This article has reviewed normal erythrocyte and leuko...
Transphyseal vessel involvement in repair of metaphyseal retained cartilage. A foal with retained cartilage in the distal metaphysis of the right and left radii and third metacarpal bones had abnormal physeal vasculature. In areas where cartilage was retained, vessels crossed the physis, and branched at the physeal-metaphyseal junction or at the site of retained cartilage. Vessels appeared to be involved in re-initiation of endochondral ossification and in the repair reponse to the presence of retained cartilage. In areas where the physis was radiographically and histologically normal, no vessels crossed the physis. A function of transphyseal vessels may be as a reserv...
Necropsy survey of metacarpal fusion in the horse. Paired metacarpi obtained at necropsy from 100 horses ranging in age from term fetus to 35 years were examined to estimate the prevalence and sites of metacarpal fusion. Metacarpal fusion was seen in 192 of 200 metacarpi, and 78% of all horses 2 years or older had 2 or more fusions. Fusion of the second metacarpal bone to the third metacarpal bone was significantly (P < 0.001) more common than was fusion of the fourth to the third metacarpal bone. Fusions appeared for the most part in pairs and were bilaterally symmetric. Rooney-Prickett type-A carpometacarpal joint configurations (in which...
Histologic appearance of axial osteochondral fragments from the proximoplantar/proximopalmar aspect of the proximal phalanx in horses. Osteochondral fragments from the axial proximoplantar/proximopalmar region of the proximal phalanx were removed from 38 joints in 30 horses. Ninety-three percent of the horses were Standardbreds, and 28 of the 30 had a low-grade lameness. All but 1 of the horses had hind limb involvement. A total of 43 fragments were removed. Most (71%) of the fragments involved the medial aspect of the joint and had to be dissected from a covering of synovial tissue. Histologically, the circumference of most fragments consisted of a transition zone at the attachment of the joint capsule, a region of nonarticu...
Abortion in a mare associated with Corynebacterium pseudotuberculosis infection. No abstract available
Equine colonic lipomatosis. No abstract available
[Fertility in mares after disturbed or undisturbed puerperium; evidence from clinical, microbiologic and hormone analysis]. Because of the mare's ability to conceive very soon post partum a thoroughly performed control of the puerperal period is of particular importance. In addition to cytological and histological examinations of the uterus, rectal palpation and vaginoscopic inspection as well as microbiological examinations of uterine swabs and the evaluation of the mare's hormonal status during the puerperal period provide useful information which can be used either prognostically or to initiate a specific therapy. 55 mares were examined on days 3, 6 and 9 post partum. Rectal palpation, vaginoscopic inspection, m...
Ependymoma of the neurohypophysis and hypernatremia in a horse. A 2-year-old Standardbred gelding was examined because of prolapse of the third eyelid; myoclonus of the muscles of the head, neck, and forelimbs; and persistent tail swishing. The horse had a high plasma sodium concentration but was not drinking water. The hypernatremia could not be corrected by means of IV administration of fluids, and the horse became worse and, 6 days later, died. At necropsy, a tumor was found to be compressing the neurohypophysis and the area in the brain in which the thirst centers are believed to be located. It is believed that hypernatremia in this horse was a result ...
Equine melanocytic tumors: a retrospective study of 53 horses (1988 to 1991). A study of 57 cutaneous melanocytic tumors from 53 horses revealed 4 distinct clinical syndromes: melanocytic nevus, dermal melanoma, dermal melanomatosis, and anaplastic malignant melanoma. Melanocytic nevus and anaplastic melanoma each had histopathologic features that distinguished them from dermal melanoma and dermal melanomatosis. Dermal melanoma and dermal melanomatosis were histologically similar but could be differentiated by their clinical features. Melanocytic nevi were diagnosed in 29 horses with an average age of 5 years; they were solitary, superficial masses that occurred in both...
Aseptic tenosynovitis of the digital flexor tendon sheath, fetlock and pastern annular ligament constriction. The anatomy of the digital flexor tendon sheath and related tendons and ligaments is described. Diagnosis and management of acute tenosynovitis and long-term tenosynovitis and associated tendon injuries are discussed, as well as the syndrome of stenosis of the fetlock canal (or fetlock annular ligament constriction) and palmar annular ligament constriction. Desmitis of the palmar annular ligament is also described.
Paraneoplastic bullous stomatitis in a horse. An adult horse with a 2-month history of anorexia, ataxia, and oral blisters had developed these clinical signs just prior to the appearance and growth of a cervical mass. Bullous stomatitis was characterized histologically as subepidermal clefting. Clinical signs were unresponsive to treatment with antibiotics or corticosteroids; however, surgical removal of the mass coincided with remission of all signs. Histologic findings of the mass were consistent with hemangiosarcoma. Results of indirect immunofluorescence and immunoprecipitation on frozen serum from the horse were characteristic of par...
Age-related morphometrical changes of arteries of uterine wall in mares. To investigate the morphological changes of uterine wall arteries associated with the progression of age in Thoroughbred broodmares, uterine wall arteries from 13 mares, aged 2 to 31 years, were studied by routine histomorphometry. The ratio of intimal thickness to external diameter increased due to hyperplasia of elastic fibers and was significantly correlated with age (r = 0.95, P < 0.001). The ratio of medial thickness to external diameter decreased and was also significantly correlated with age (r = -0.84, P < 0.001). Using electron microscopy, it was determined that the cross-sectional ar...
Needle aspiration lung biopsy: reevaluation of the blood patch technique in an equine model. To reexamine the blood patch technique in a laboratory model of lung biopsy free of confounding clinical variables. Methods: An equine model of lung biopsy was developed with an excised lobe connected to an insufflation bulb and pressure monitor. Patched and control unpatched punctures were made in the lung surface, and the pressure within the lung was raised to the maximum achievable. Whether air leakage from the puncture sites could be induced was determined and, if so, at what pressure it occurred. Results: At statistical analysis with the Kaplan-Meier test and the Cox proportional hazards ...
Presence of CD4+ and CD8+ T cells and expression of MHC class I and MHC class II antigen in horses with Borna disease virus-induced encephalitis. Tissues from 9 horses and 1 donkey suffering from natural Borna disease were investigated immunomorphologically. Lymphocytic inflammatory reactions and increased expressions of MHC class I and class II antigen were found in the brain as well as in the trigeminal and olfactory system. Perivascular inflammatory infiltrates were dominated by CD4+ T cells, whereas the majority of CD8+ T cells were disseminated intraparenchymally. No evidence of inflammation was found in the retina. Borna disease virus proteins and nucleic acids were present in the hippocampus, thalamus and medulla oblongata in all...
Serotonin-containing cells in the horse gastrointestinal tract. The presence and distribution of serotonin-containing cells in the gastroenteric tract of horses have been investigated. The enterochromaffin (EC) cells have been identified using immunostaining procedures at both light and electron microscopic level. The EC cells were very numerous in the pyloric gland region, were only few in the duodenum but were absolutely lacking from the more distal portions of the intestine.
Mural blood flow distribution in the large colon of horses during low-flow ischemia and reperfusion. Six horses were subjected to 3 hours of low-flow ischemia and 3 hours of reperfusion of the large colon. After induction of anesthesia, the large colon was exteriorized through a ventral midline celiotomy. Colonic blood flow was measured continuously, using Doppler ultrasonic flow probes placed on the colonic arteries supplying the dorsal and ventral colons and was allowed to stabilize for 15 to 30 minutes after instrumentation. Low-flow ischemia was induced by reducing colonic arterial blood flow to 20% of baseline (BL) flow. Colonic mucosal, seromuscular, and full-thickness blood flow were d...
Equine herpesvirus 2 in pulmonary macrophages of horses. In a search of viral agents in pulmonary macrophages of horses with chronic pulmonary disease, equine herpesvirus 2 was found to be unique. In 8 of 9 horses with chronic pulmonary disease, antigens of equine herpesvirus 2 were detected by indirect immunofluorescence staining of scattered foamy macrophages immediately after harvesting by bronchoalveolar lavage and fractionation on metrizamide gradients. In a healthy horse, antigens were not found. After 1 week of cultivation of bronchoalveolar lavage cells from a second group of 9 horses with chronic pulmonary disease, viral antigens were detec...
