Dermoid cysts formation is a complication of wound pinch grafting in a horse: A case report.

OBJECTIVES: To describe dermoid cyst formation as an uncommon complication of the pinch grafting technique in horses. STUDY DESIGN: Case report. ANIMAL: A 8 year old Arabian gelding. METHODS: Clinical presentation, imaging, treatment, and histopathology records were reviewed. The horse originally presented due to delayed healing of a laceration to the distal aspect of the metatarsus. The wound was treated initially with debridement and it was allowed to fill with healthy granulation tissue prior to pinch grafting. Two months after grafting, the horse started to show self-mutilation behavior targeting the wound site. Ultrasonographic examination revealed the presence of cystic lesions in the subcutaneous tissue in the wound bed and adjacent to the long digital extensor tendon. RESULTS: Treatment involved surgical excision of the cysts, which resulted in a resolution of the self-mutilation episodes. The specimens were submitted for histopathological investigation, which revealed findings compatible with dermoid cyst formation, suspected to be secondary to the skin-grafting procedure. CONCLUSION: Dermoid cysts formation should be considered as a potential differential diagnosis for skin graft complications in horses.

Snake Envenomation.

Snakebite envenomation (SBE) in horses can have devastating outcomes. Tissue damage, cardiotoxicity, coagulopathy, and neurotoxicity can be concerns with SBE. Understanding the actions of venom components is important in developing a successful treatment plan. Antivenom is the mainstay of treatment. Long-term deleterious effects can occur including cardiac dysfunction and lameness.

Cantharidin.

Cantharidin is the toxic component of blister beetles of the genus Epicauta. Cantharidin is a potent vesicant which causes blisters, erosions, and ulcerations in the gastrointestinal and urinary tracts, and can cause myocardial necrosis. Blister beetles are found over most of North America and specifically contaminate alfalfa at harvest. History of alfalfa feeding, with colic, dysuria, hypocalcemia, and hypomagnesemia are suggestive of blister beetle toxicosis. Myocardial damage causes increased serum cardiac troponin 1. Tentative diagnosis can be made by finding the beetles in feed or ingesta. Definitive diagnosis requires detection of cantharidin in urine or gastric contents. Treatment involves ending exposure, decreasing absorption, controlling pain, using gastroprotectants, and fluids and electrolyte replacement. Prognosis is guarded to poor.

A nonsense variant in Rap Guanine Nucleotide Exchange Factor 5 (RAPGEF5) is associated with equine familial isolated hypoparathyroidism in Thoroughbred foals.

Idiopathic hypocalcemia in Thoroughbred (TB) foals causes tetany and seizures and is invariably fatal. Based upon the similarity of this disease with human familial hypoparathyroidism and occurrence only in the TB breed, we conducted a genetic investigation on two affected TB foals. Familial hypoparathyroidism was identified, and pedigree analysis suggested an autosomal recessive (AR) mode of inheritance. We performed whole-genome sequencing of the two foals, their unaffected dams and four unaffected, unrelated TB horses. Both homozygosity mapping and an association analysis were used to prioritize potential genetic variants. Of the 2,808 variants that significantly associated with the phenotype using an AR mode of inheritance (P<0.02) and located within a region of homozygosity, 1,507 (54%) were located in a 9.7 Mb region on chr4 (44.9-54.6 Mb). Within this region, a nonsense variant (RAPGEF5 c.2624C>A,p.Ser875*) was significantly associated with the hypoparathyroid phenotype (Pallelic = 0.008). Affected foals were homozygous for the variant, with two additional affected foals subsequently confirmed in 2019. Necropsies of all affected foals failed to identify any histologically normal parathyroid glands. Because the nonsense mutation in RAPGEF5 was near the C-terminal end of the protein, the impact on protein function was unclear. Therefore, we tested the variant in our Xenopus overexpression model and demonstrated RAPGEF5 loss-of-function. This RAPGEF5 variant represents the first genetic variant for hypoparathyroidism identified in any domestic animal species.

Overview of the causes of abortion in horses, their follow-up and management.

Abortions in horses represent an important health and economic challenge for equine industry. Primary causes of abortion are divided in non-infectious and infectious. Non-infectious causes include abnormalities of foetal appendices (umbilical cord and placenta essentially), abnormalities of gestation, maternal and foetal origins. Infectious abortions are caused in almost cases by bacterial infections, followed by viruses, fungi and parasites. New abortive pathogens (as Leptospira, Neospora caninum, Coxiella burnetii, Chlamydophila abortus, and) have been confirmed in equines by comparison already known for their abortive properties in human or in other species. Despite an increasing number of autopsies and continuous improvements in diagnostic tools, in management and surveillance, 20%-40% of the causes of equine abortion remain unknown depending on the country. To increase the likelihood of a definitive diagnosis in cases of abortion and stillbirth in horses, new diagnostic approaches are needed.

A review of investigated risk factors for developing equine recurrent uveitis.

Equine recurrent uveitis (ERU) is an ocular inflammatory disease that can be difficult to manage clinically. As such, it is the leading cause of bilateral blindness for horses. ERU is suspected to have a complex autoimmune etiology with both environmental and genetic risk factors contributing to onset and disease progression in some or all cases. Work in recent years has aimed at unraveling the primary triggers, such as infectious agents and inherited breed-specific risk factors, for disease onset, persistence, and progression. This review has aimed at encompassing those factors that have been associated, implicated, or substantiated as contributors to ERU, as well as identifying areas for which additional knowledge is needed to better understand risk for disease onset and progression. A greater understanding of the risk factors for ERU will enable earlier detection and better prognosis through prevention and new therapeutics.

Pyogenic granuloma of the cornea in a pony: Uncommon complication of corneal wound healing.

A 6-year-old miniature Shetland pony mare was referred for evaluation of a left corneal mass, which developed from the healing tissue of a corneal traumatic ulceration that had occurred 4 weeks previously. On gross examination, a spherical, smooth-surfaced, and pink-colored lesion of about 1 cm in diameter was protruding from the left palpebral fissure. Ophthalmic examination revealed that it was attached to the scar tissue of the cornea, and that one corpora nigra was adherent to the posterior face of corneal wounded area, without sign of uveitis. The remainder of the ophthalmic examination was unremarkable. The mass was excised, and cryotherapy was used as an adjunctive therapy. Histopathology of the resected mass was consistent with a pyogenic granuloma on the basis of radially oriented proliferating capillaries, embedded in immature granulation tissue containing an infiltrate of neutrophils, plasma cells and eosinophils. There were no histological features of malignancy. 2 months after surgery, the ventral part of the fibrotic corneal scar was slightly raised by a pink tissue, suggesting possible recurrence of the initial lesion. A second cryotherapy was performed over the leukoma area. No recurrence has been noted for a follow-up period of more than 25 months. Pyogenic granuloma is a benign proliferative fibrovascular response that typically develops after trauma or surgery. Corneal involvement is rare in humans, and to the authors' knowledge has never been documented in veterinary ophthalmology.

Effects of intra-articular injection of an acellular equine liquid amniotic allograft in healthy equine joints.

OBJECTIVE: Evaluate effects of acellular equine liquid amnion allograft (ELAA) injected into healthy equine joints. STUDY DESIGN: Randomized, blinded, controlled experiment. ANIMALS: Eight healthy adult horses. METHODS: One intercarpal joint (ICJ) of each horse was randomly assigned to be injected with 1.5 ml of ELAA (treatment) while the contralateral ICJ was injected with 1.5 ml of 0.9% NaCl (control). Subjective lameness evaluation, force plate analysis, and synovial fluid analysis, including interleukin-1 receptor antagonist (IL-1ra) analysis, were performed before (day 0) and at days 1, 3, 5, and 10. Synovial fluid analysis was also performed on days 20 and 30. RESULTS: No difference in subjective lameness (P = .75) and no decrease in peak vertical force or vertical impulse were seen in any limb on any day. Total nucleated cell count (TNCC) was increased in treatment joints on days 1 (P = .0007; T: 6039 cells/µl, C: 240 cells/µl) and 3 (P < .0001; T: 1119 cells/µl, C: 240 cells/µl). Log-10 transformed values for IL-1ra were higher in treated joints on days 1 (P = .0005; T: 3553.7 pg/ml, C: 1890.1 pg/ml) and 3 (P = .01; T: 2283.2 pg/ml, C: 1250.7 pg/ml). CONCLUSION: Injection of ELAA into the ICJ caused an increase in synovial fluid TNCC in comparison with saline control but no lameness was observed. There was increased IL-1ra on days 1 and 3 after ELAA injection. CLINICAL SIGNIFICANCE: Intra-articular injection of ELAA into healthy equine joints results in no significant safety concerns. The observed increase in IL-1ra may provide beneficial effects in inflamed joints.

Environmental risk factors for UV-induced cutaneous neoplasia in horses: A GIS approach.

Objective: Ultraviolet light (UV) is a risk factor for the development of cutaneous neoplasia in many mammalian species. This study evaluated UV exposure as a risk factor of concern for the development of cutaneous neoplasia in equine species due to the significant UV exposure that may accrue over their lifetimes. Animals and samples: Neoplastic biopsy specimens from 3272 horses that were submitted over a 10-year period to the Colorado State University Diagnostic Medicine Center and to the University of Saskatchewan Western College of Veterinary Medicine and Prairie Diagnostic Services were evaluated. Procedure: This retrospective study assessed the spatial relationships between altitude, latitude, longitude, and UV maximum value and the probability of UV-induced cutaneous neoplasia. Results: Cases from areas at high altitude proved to have a higher prevalence of UV-induced cutaneous neoplasia than those from areas at lower elevations. A multivariable regression analysis demonstrated that altitude was the only factor significantly and positively associated with the diagnosis of UV-induced neoplasia. Conclusion and clinical relevance: Evidence of cutaneous neoplasia in horses and environmental factors that influence the degree of UV exposure in a geographic location may aid in diagnosis and suggest preventive measures from UV overexposure.

Facteurs de risque environnementaux des néoplasies cutanées induites par les UV chez le cheval : une approche SIG. Objectif: La lumière ultraviolette (UV) est un facteur de risque pour le développement de néoplasies cutanées chez de nombreuses espèces de mammifères. Cette étude a évalué l'exposition aux UV en tant que facteur de risque préoccupant pour le développement de néoplasies cutanées chez les équidés en raison de l'exposition importante aux UV qui peut s'accumuler au cours de leur vie. Animaux et échantillons: Des échantillons de biopsie néoplasique de 3272 chevaux qui ont été soumis sur une période de 10 ans au Colorado State University Diagnostic Medicine Center et au University of Saskatchewan Western College of Veterinary Medicine and Prairie Diagnostic Services ont été évalués. Procédure: Cette étude rétrospective a évalué les relations spatiales entre l'altitude, la latitude, la longitude et la valeur maximale des UV et la probabilité de néoplasie cutanée induite par les UV. Résultats: Les cas des régions de haute altitude se sont avérés avoir une prévalence plus élevée de néoplasie cutanée induite par les UV que ceux des régions de basse altitude. Une analyse de régression multivariée a démontré que l'altitude était le seul facteur significativement et positivement associé au diagnostic de néoplasie induite par les UV. Conclusion et pertinence clinique: Les preuves de néoplasie cutanée chez les chevaux et les facteurs environnementaux qui influencent le degré d'exposition aux UV dans un lieu géographique peuvent aider au diagnostic et suggérer des mesures préventives contre la surexposition aux UV.(Traduit par Dr Serge Messier).

Infectious Causes of Equine Placentitis and Abortion.

A variety of infectious agents including viral, bacterial, and fungal organisms can cause equine abortion and placentitis. Knowledge of normal anatomy and the common pattern distribution of different infectious agents will assist the practitioner in evaluating the fetus and/or placenta, collecting appropriate samples for further testing, and in some cases, forming a presumptive diagnosis. In all cases, it is recommended to confirm the diagnosis with molecular, serologic, or microbiological testing. If a causative agent can be identified, then appropriate biosecurity and vaccination measures can be instituted on the farm.

Current Topics in Medical Colic.

The list of medical causes of acute or chronic colic in horses is extensive. The purpose of this article is to review 4 medical causes of equine colic with a focus on newer trends in treatment. The 4 topics selected include gastric impaction, gastric glandular disease, colon displacement, and inflammatory bowel disease.

Neonates and Periparturient Mares: Tips and Tricks for Diagnosis and Management.

Colic is a common presenting complaint in foals. Unfortunately, evaluation of foals with colic can be difficult due to the common clinical presentation of acute abdominal pain attributable to a wide variety of disorders and a broad range of etiologies. Similar to foals, colic is one of the most common diseases of pregnant and periparturient mares. Several conditions are unique or occur more commonly in broodmares. This article reviews the most commonly encountered types of colic events in neonatal foals and periparturient mares, how to correctly diagnose these conditions, as well as details concerning appropriate medical management and/or surgical intervention.

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.

Repeat Celiotomy-Current Status.

Repeat celiotomy can be lifesaving in horses with a surgically treatable postoperative obstruction, although guidelines for its use are lacking, except for uncontrollable postoperative pain. Overdiagnosis of ileus as the cause of postoperative obstruction could delay a second surgery so the disease progresses beyond a manageable level of severity. Although many horses respond favorably to repeat celiotomy, complications can be severe and life threatening, such as incisional infection and adhesions. Repeat celiotomy does not seem to exacerbate postoperative ileus, despite additional surgical manipulation. An important benefit of repeat celiotomy is termination of hopeless cases, thereby reducing cost and suffering.

Recurrent Colic: Diagnosis, Management, and Expectations.

Most recurrent episodes of non-specific colic are self-limiting, and the results of clinical examinations are unremarkable. Differentiating these cases from serious diseases can be difficult, but repeated evaluations are warranted. Horses presenting with very frequent bouts of colic are more likely to have serious diseases and a higher mortality rate compared to horses presenting with less frequent bouts of transient colic. Horses with recurrent bouts of prolonged colic are more likely to have motility issues or partial intestinal obstruction. Non-gastrointestinal diseases can also cause recurrent bouts of pain ("false colic"). Adhesions are common causes of colic following abdominal surgery.

Demographic, morphologic, hormonal and metabolic factors associated with the rate of improvement from equine hyperinsulinaemia-associated laminitis.

BACKGROUND: Although several studies have investigated factors associated with the onset and occurrence of hyperinsulinaemia-associated laminitis (HAL), few have examined the factors associated with the rate of improvement during recovery from an acute bout of the disease. This observational study sought to discover if a range of demographic, morphologic, hormonal and metabolic variables are associated with the improvement rate from HAL in 37 naturally-occurring cases identified by 16 clinics across Germany. Each case was evaluated for laminitis severity on the day of inclusion in the trial (d 0), then after 4, 9, 14, 25 and 42 d. The horses were managed according to best clinical practice including restricting exercise and prescribing a diet of hay-only, for a minimum of 9 d. Blood samples were also collected during each evaluation, except on d 9, and analysed for glucose, insulin, ACTH and leptin. RESULTS: Based on individual clinical laminitis scores plotted against time, most horses improved markedly within 2 weeks, with a 'fast group' (n = 27) having a median (interquartile range) score on a 12-point scale of 0 (0-2) by d 14. However, there was a clear disparity within the total cohort, as ~ 1 in 4 horses demonstrated much slower improvement, with a median score of 5 (4-7) by d 14, or a marked relapse thereafter ('slow group', n = 10). Horses in the slow improvement group were younger (12.5 (8.8-16.3) vs 17 (14-24) yr; P = 0.008), but were not more likely to be heavier, male, very fat, to have presented with a previous history of laminitis or elevated ACTH concentrations, or to be receiving pergolide treatment. Of the hormonal and metabolic parameters measured, glucose and insulin concentrations were within the normal range following transition to the hay-only diet, but were higher in the group that failed to improve quickly, with a small but significant difference being evident on d 4, 14 and 25 for glucose (11 to 16%; P < 0.05), and a larger difference for insulin on d 14 and 25 (51 to 55%; P < 0.05). There was no difference between the groups in ACTH or leptin concentrations throughout the study. The main limitations of this study were the small number of slow-improvement horses and an inability to control or measure certain variables, such as feed quality. CONCLUSIONS: Young age and a modest increase in blood glucose and insulin concentrations are associated with delayed laminitis improvement.

Standing laparoscopy combined with a conventional inguinal approach to treat extended septic funiculitis in 12 horses.

OBJECTIVE: To describe a 2-step surgical procedure combining standing laparoscopy with a conventional inguinal approach to treat deep intra-abdominal funiculitis (extended septic funiculitis) after castration. STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: Twelve client-owned horses. METHODS: Medical records of horses treated for extended septic funiculitis with the 2-step surgical procedure were reviewed. Data collected included the initial castration technique, number of surgical interventions for septic funiculitis prior to presentation, clinical signs, diagnostic and surgical procedure, and short-term and long-term survival. RESULTS: Complete resection of the infected spermatic cord was achieved without intraoperative complications. Intra-abdominal adhesions were documented in 6 horses, involving the ascending colon (4 cases) and descending colon (2 cases). Postoperatively, minor incisional swelling (2/12) and emphysema (3/12) at the laparoscopic portals were observed. All horses survived to discharge. At 3 months, wounds had completely healed without complications. No recurrence of signs was recorded at long-term follow up (4-36 months after discharge). CONCLUSION: In cases of extended septic funiculitis, complete resection of the infected spermatic cord can be safely performed using a laparoscopic-assisted surgical approach, reducing postoperative complications and risk of recurrence of infection.

Percutaneous doxycycline sclerotherapy in a horse with a mandibular aneurysmal bone cyst.

OBJECTIVE: To describe the use and outcome of sclerotherapy with intralesional doxycycline foam in a horse with a mandibular aneurysmal bone cyst. STUDY DESIGN: Case report. ANIMALS: Client-owned 1 year old Standardbred filly. METHODS: The horse presented for progressive mandibular swelling. A 10 mg/mL doxycycline foam was prepared for intralesional injection. Three doses were injected into the lesion under computed tomographic guidance at 6 and 15 weeks after initial treatment. Volume reduction was monitored after each treatment with 3D volumetric rendering and region of interest segmentation using commercially available software. RESULTS: The volume of the lesion decreased from 458.7455 cm3 before treatment, to 363.3101 cm3 at 6 weeks, 273.5855 cm3 at 15 weeks, and 247.2316 cm3 6 months later, resulting in a total reduction of 54% of the initial volume. Bone formation was noted in the lesion. No adverse effects related to doxycycline foam injections were noted. The mandibular swelling was resolved after treatment. CONCLUSION: Intralesional doxycycline sclerotherapy was shown to be efficacious in reducing the volume of the aneurysmal bone cyst in the horse presented in this report. There was complete resolution of mandibular swelling with no side effects related to the intralesional injections.

Fragment size is associated with post-operative complications following elective arthroscopy of the tibiotarsal joint of horses.

The objective of this retrospective study was to determine the occurrence of joint-related complications after elective arthroscopy of the tibiotarsal joint (TTJ) in 329 horses, and the association with specific clinical parameters. Data were collected from medical records of horses undergoing elective tibiotarsal joint arthroscopy for fragment removal. Exact conditional univariate regression was used to determine significant risk factors for joint-related post-operative complications. Of 485 joints, 2 (0.4%) developed surgical site infection, 4 (0.8%) developed septic arthritis, 1 (0.2%) developed synovial fistula. There was a significantly increased odds of having septic arthritis as height and length of the distal intermediate ridge of the tibia (DIRT) lesion increased. The median height and length of the DIRT fragments in affected cases was 13.5 mm and 18.0 mm, respectively. For each unit (1 mm) increase in height, there was a 42% increase in the risk of septic arthritis occurrence (P = 0.0042), and a 15% increase for each unit increase in length (P = 0.035). Horses were significantly less likely to develop septic arthritis when suture smaller than USP 0 was used. Horses with larger osteochondritis dissecans lesions of the DIRT region have an increased risk of developing septic arthritis following fragment removal.

La taille des fragments est associée à des complications postopératoires après arthroscopie élective de l'articulation tibiotarsienne des chevaux. L'objectif de cette étude rétrospective était de déterminer la fréquence de complications articulaires après arthroscopie élective de l'articulation tibiotarsienne (TTJ) chez 329 chevaux, et l'association avec des paramètres cliniques spécifiques. Les données ont été recueillies à partir des dossiers médicaux de chevaux subissant une arthroscopie élective de l'articulation tibiotarsienne pour l'élimination de fragments. Une régression univariée conditionnelle exacte a été utilisée pour déterminer les facteurs de risque significatifs de complications postopératoires liées aux articulations.Sur 485 articulations, deux (0,4 %) ont développé une infection du site opératoire, quatre (0,8 %) une arthrite septique, et une (0,2 %) une fistule synoviale. Il y avait une probabilité significativement accrue d'avoir une arthrite septique à mesure que la hauteur et la longueur de la lésion de la crête intermédiaire distale du tibia (DIRT) augmentaient. La hauteur et la longueur médianes des fragments DIRT dans les cas affectés étaient respectivement de 13,5 mm et de 18,0 mm. Pour chaque unité (1 mm) d'augmentation de hauteur, il y avait une augmentation de 42 % du risque de survenue d'arthrite septique (P = 0,0042); et une augmentation de 15 % pour chaque augmentation unitaire de longueur (P = 0,035). Les chevaux étaient significativement moins susceptibles de développer une arthrite septique lorsqu'une suture plus petite que USP 0 était utilisée.Les chevaux présentant des lésions d'ostéochondrite disséquante plus importantes de la région DIRT ont un risque accru de développer une arthrite septique après le retrait des fragments.(Traduit par Dr Serge Messier).

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.