Endocarditis in six horses

Six horses (five males) aged three months to fourteen years had endocarditis at necropsy. Two of the horses had a clinical diagnosis of valvular endocarditis with negative blood cultures. Single or complex valvular involvement was present in five horses. One horse had non-infectious thrombi associated only with the chordae tendineae. Mitral valves were affected in four horses, and aortic semilunar valves were affected in two. Infarcts had occurred in the kidneys and the myocardium of four horses. Bacteria were isolated postmortem from the valvular vegetations of two horses; Candida parapsilosis was isolated and demonstrated morphologically in a third horse.     

Comparison of endoscopic,necropsy and histology scoring of equine gastric ulcers

Equine gastric ulcer syndrome (EGUS) represents a major health problem in performance horses. Much debate exists regarding endoscopic gastric ulcer scoring systems and their ability accurately to predict severity or depth of gastric ulcers. The purpose of this study was to evaluate the ability of an endoscopist to count gastric ulcers and predict gastric ulcer severity or depth using 2 endoscopic scoring systems and compare them to the same gastric ulcers see on necropsy and histopathology. Endoscopic examination of the stomach was performed under general anaesthesia on 23 mixed breed yearling horses, after feed was withheld for 24 h. Gastric ulcers were scored using 2 systems, number/severity-scoring (N/S) and practitioner simplified (PS) systems. After endoscopy, the horses were subjected to euthanasia and the stomach mucosa examined blindly and scored again at necropsy using above scoring systems. Representative gastric ulcers were then placed in 10% formalin and processed routinely for histopathology. The gastric ulcers were scored using a histopathology system (HSS) based on ulcer depth. Number scores in the N/S scoring system and PS on endoscopic and necropsy examinations were compared using Friedman 2 way analysis of variance. Where significant differences between variables were found a post hoc analysis was conducted using a Tukey's Studentised range (HSD) test. Severity scores using the N/S (ENGS) and PS scores recorded for the stomach via endoscopy and scores from HSS were evaluated for significant association using a Mantel-Haenszel Chi-square and Pearson moment correlation coefficient analysis. Significance was P < 0.05. All horses had gastric ulcers in the nonglandular mucosa via endoscopic examination and at necropsy examination. Mean nonglandular ulcer number (ENGN) score was significantly (P = 0.0024) lower on endoscopic examination compared to the score at necropsy (NNGN); whereas PS scores were not significantly different on endoscopy when compared to necropsy examination. A significant but weak association was found between ENGS and HSS (3.89, P = 0.048; r = 0.453, P = 0.045) and no correlation was found between PS and HSS (1.2, P = 0.272; r = 0.117; P = 0.622). Only 1/23 horses had glandular ulcers observed via endoscopic examination whereas, 6/23 horses had glandular ulcers at necropsy and on histopathology. The prevalence of EGUS is high in stalled yearling horses. The endoscopist may underestimate the number of gastric ulcers and may not be able accurately to predict the severity or depth of those ulcers present in the nonglandular equine stomach. Furthermore, the endoscopist may miss glandular gastric ulcers.     

Putative uremic encephalopathy in horses: five cases (1978-1998)

OBJECTIVE: To determine historical, physical examination, clinicopathologic, and postmortem findings in horses with putative uremic encephalopathy. Design-Retrospective study. Animals-5 horses with renal failure and neurologic disease not attributable to abnormalities in any other organ system. PROCEDURE: Medical records from 1978 to 1998 were examined for horses with renal disease and neurologic signs not attributable to primary neurologic, hepatic, or other diseases. Signalment, history, physical examination findings, clinicopathologic data, renal ultrasonographic findings, and postmortem data were reviewed. RESULTS: Of 332 horses with renal disease, 5 met selection criteria. Historical findings, physical examination findings, clinicopathologic data, ultrasonographic data, and postmortem findings were consistent with chronic renal failure. Swollen astrocytes were detected in all 4 horses examined at necropsy. CONCLUSIONS AND CLINICAL RELEVANCE: A single criterion was not determined to be pathognomonic for uremic encephalopathy in horses. Uremic encephalopathy should be considered as a differential diagnosis in horses with evidence of chronic renal failure and encephalopathic neurologic sign not attributable to other causes. Astrocyte swelling, which was common to all 4 horses examined at necropsy, may serve as a microscopic indicator of uremic encephalopathy in horses.     

Surgical repair of radial carpal bone fractures in two racehorses

A 3-year-old Standardbred gelding (Case 1) and a 2-year-old Thoroughbred gelding (Case 2) were referred for surgical evaluation of a left radial carpal bone (RCB) fracture, sustained during training. Clinical findings at the time of initial examination included a palpable effusion within the left middle carpal joint in both horses and marked signs of pain and reduced range of motion on flexion of the affected carpus. In both horses, the RCB fracture was evident on the following radiographic views of the carpus: dorsolateral–palmaromedial oblique (30° off lateromedial) and flexed lateromedial. An additional loose wedge-shaped osteochondral fragment at the proximal articular surface of the RCB could be seen in Case 2. Both horses underwent surgical reduction and repair of the fracture between 1 and 2 days following the initial injury, which consisted of arthroscopic removal of any intra-articular osteochondral fragments, and arthroscopic assisted-interfragmentary compression via a standard dorsomedial and dorsolateral approach to the antebrachiocarpal joint (ACJ) and middle carpal joints (MCJ). The two horses returned to function as racehorses, 6 months (Case 1) and 16 months (Case 2) after surgery. The RCB is a relatively uncommon site for large carpal fractures in horses. The clinical presentation and findings from this report were similar to that of third carpal bone (C3) slab fractures, confirming that surgical repair is indicated in selected cases of RCB fractures.     

Eyeworms (Thelazia lacrymalis) in one- to four-year-old Thoroughbreds at necropsy in Kentucky (1984 to 1985)

From Mar 1, 1984, to Feb 28, 1985, both eyes from 189 one- to four-year-old Thoroughbreds (88 males, 90 females, and 11 geldings) in Kentucky were examined at necropsy for eyeworms. Thelazia lacrymalis was recovered from 45% of 1-year-old horses, 26% of 2-year-old horses, 45% of 3-year-old horses, and 50% of 4-year-old horses; overall, 43% of 1- to 4-year old horses were infected. Prevalence of eyeworms in horses in the present study was comparable with that in horses of similar ages examined at necropsy in Kentucky in 2 previous studies (1975 to 1976 and in 1979), except for the lower percentage of infected 2-year-old Thoroughbreds in the present study.     

Postanesthetic hind limb adductor myopathy in five horses

Five horses that underwent prolonged anesthesia (greater than 3 hours) in dorsal recumbency for a surgical procedure were unable to stand after recovery and were euthanatized. A provisional diagnosis of postanesthetic myopathy was confirmed at necropsy in all 5 horses. However, distribution of affected muscles in these horses was atypical, because there was bilateral hind limb adductor muscle involvement.     

Severe renal hemorrhage caused by pyelonephritis in 7 horses: clinical and ultrasonographic evaluation

Case records of 7 horses diagnosed with pyelonephritis were reviewed to determine common features that might aid in diagnosis, treatment, and prognosis of this disease. All 7 horses had been admitted for evaluation of hematuria. During cystoscopy of 5 horses, hemorrhage was observed from one or both ureters. Renal biopsy of 1 horse, laboratory analysis of ureteral discharge of 2 horses, and renal ultrasonography of all horses indicated that pyelonephritis was the cause of hemorrhage. Sonographic renal changes included decreased length, increased echogenicity, abnormal outline, loss of corticomedullary distinction, pyelectasia, and focal hypoechoic or hyperechoic cortical defects. Renal hemorrhage in all horses eventually resolved but recurred in 4 of 5 horses that were followed long-term.     

ULTRASOUND LOCALIZATION AND GUIDANCE FOR RENAL BIOPSY IN THE HORSE

Real-time ultrasonography was used to assist percutaneous renal biopsies in seven normal horses. Ultrasound (US) guidance and blind biopsy following US localization were compared. Ten biopsies (seven right kidney and three left kidney) were performed. A transverse approach to the lateral border of the right kidney through the 17th intercostal space was favored, with the needle angle being approximately perpendicular to the body wall. Both biopsy techniques were effective, but blind biopsy following US localization was favored as it was easily performed by one operator without the need for specialized biopsy equipment. The spleen had a variable location and its penetration with the biopsy needle was necessary to obtain two left kidney biopsies. Macroscopic and microscopic hematuria was observed postbiopsy in one and four horses, respectively, out of six horses examined. Perirenal hemorrhage was a prominent finding on necropsy in five of six horses euthanized.     

Onchocerca spp: frequency in Thoroughbreds at necropsy in Kentucky

Examination of the ligamentum nuchae for Onchocerca spp was completed in 523 Thoroughbreds (1 to 29 years old) at necropsy in Kentucky during a 13-month period (1984 to 1985). Onchocerca spp were found in 306 (59%) of the horses. Frequencies of this parasite were 3%, 17%, 40%, 43%, and 42% in 1-, 2-, 3-, 4-, and 5-year-old horses, respectively. For 6- to 29-year-old horses, frequency varied from 71% to 100%, except for 26-year-old horses (50%); 87% of the 304 horses examined in the 6- to 29-year-old age groups was infected. The suspensory ligaments and flexor tendons from fetlocks (thoracic limb only) of 100 Thoroughbreds (3 to 24 years old) were examined at necropsy during a 4-month period (1984) for Onchocerca spp. Infected horses were not found.     

Coccidioidomycosis in Przewalski's horses (Equus przewalskii).

Coccidioidomycosis is a rare, often subclinical infection in domestic animals caused by the fungus Coccidioides immitis. Because of an apparent high incidence of coccidioidomycosis in Przewalski's horses (Equus przewalskii) housed at a single facility, necropsy records and biomaterials from animals that died between 1984 and 2000 were reviewed (n = 30, 15 males, 15 females). Coccidioidomycosis was the leading cause of death (33%) in this population with lesions in the lungs and tracheobronchial lymph nodes of all animals and variable involvement of the skeletal muscle, heart, kidney, liver, skin, brain, spinal cord, spleen, as well as other regional lymph nodes. At the time of death, affected horses tended to be younger than unaffected animals, were from multiple lineages, and males were over represented. During the same time period, no other exotic equids (n = 76) housed at the same facility were diagnosed with coccidioidomycosis, suggesting that environmental factors are not the sole cause of the high incidence in E. przewalskii. Numbers of the lymphocyte subsets (CD3, CD4, CD5, CD8, CD21+ cells) quantified by flow cytometry were similar between Przewalski's horses and domestic horses (Equus caballus). Although responses of lymphocyte blastogenesis assays were similar between Przewalski's (n = 5) and domestic horses (n = 5) in response to the T cell mitogen concanavalin A, lymphocytes from two of the Przewalski's horses failed to proliferate in response to Coccidioides. One of these horses had systemic disease and the second developed coccidioidomycosis 2 yr later. These results suggest that the immune system of some Przewalski's horses fails to respond appropriately to Coccidioides.     

Acute renal disease from Leptospira interrogans in three yearlings from the same farm

Renal dysfunction due to leptospirosis has been reported infrequently in the horse. The animals in this case presentation developed an acute and persistent febrile illness that could have been attributed to a number of infectious diseases. Upon numerous subsequent clinical evaluations, detection of renal dysfunction narrowed the list of differential diagnoses. This Case Report describes 3 horses with acute renal disease from Leptospira interrogans. Pyrexia was the initial clinical sign and was refractory to antimicrobial therapy. Once azotaemia developed, leptospirosis was diagnosed as the origin of the renal dysfunction. Treatment included i.v. crystalloid fluids, diuretics, anti‐inflammatory medication, antibiotics, pentoxifylline and polysulphated glucosaminoglycan. Additionally, one of these 3 horses required a continuous infusion of vasopressors to resolve the azotaemia. Pyrexia resolved within 48 h of treatment initiation for leptospirosis. The azotaemia resolved completely after 3 months (Case 1), 3 weeks (Case 2) and 5 days (Case 3).     

INJURY OF THE COLLATERAL LIGAMENTS OF THE DISTAL INTERPHALANGEAL JOINT DIAGNOSED BY MAGNETIC RESONANCE

We describe the clinical, imaging, and necropsy findings of two horses with severe injury of the collateral ligaments of the distal interphalangeal (DIP) joint diagnosed using magnetic resonance (MR) imaging. In MR images it was possible to examine the collateral ligaments of the DIP joint from the origin at the middle phalanx to the insertion on the distal phalanx. Both horses in this report had abnormal high signal intensity within the collateral ligaments of the DIP joint, and one horse had abnormal high signal intensity within the bone of the distal phalanx on short tau inversion recovery (STIR) and T2-weighted imaging sequences. High signal intensity on STIR and T2-weighted images represents abnormal fluid accumulation indicative of inflammation, within ligament, tendon, or bone on these imaging sequences. Abnormalities were confirmed on necropsy in both horses. Injury of the collateral ligaments of the DIP joint should be considered as a source of pain in horses with lameness localized to the foot.     

Comparison of the Diagnostic Value of Ultrasonography and Standing Radiography for Pelvic–Femoral Disorders in Horses

Objective— To assess agreement between ultrasonography (transcutaneous and transrectal) and standing radiography in horses with fractures in the pelvic region and disorders of the coxofemoral joint.
Study Design— Case series.
Animals— Warmblood horses (n=23) and 2 ponies.
Methods— Medical records (1999–2008) of equids with pelvic or coxofemoral disorders that had pelvic radiography and ultrasonography were retrieved and results of both techniques compared.
Results— Radiography and ultrasonography each identified equal numbers of fractures of the tuber coxa (n=4), ilial shaft (2), ischium (3), femoral neck (2), and osteoarthritis/osis of the coxofemoral joint (6). Fractures of the ilial wing (4) were only identified by ultrasonography not by standing radiography. Of 9 acetabular fractures, 3 were identified on radiographs only, 5 were identified with both modalities. One pubic fracture was identified using ultrasonography and radiography. One acetabular and 1 pubic fracture were only diagnosed on necropsy.
Conclusions— We found reasonable agreement (73%; 24/33) between ultrasonography and standing radiography for diagnosis of pelvic–femoral disorders. Ultrasonography was more useful for ilial wing fractures and radiography for acetabular fractures.
Clinical Relevance— Ultrasonography is a rapid, safe imaging technique for detecting disorders of the pelvic region with a high diagnostic yield and is a preferred initial approach in horses with severe hindlimb lameness.     

Diaphragmatic hernia in horses: 44 cases (1986–2006)

Objectives – To present a case series of horses diagnosed with diaphragmatic hernia, and to determine the significance of (1) historical information, examination findings, and laboratory data; and (2) exploratory laparotomy or necropsy findings on short- and long-term outcome.
Setting – University Referral Hospital.
Design – Retrospective study.
Animals – Forty-four horses/foals admitted between 1986 and 2006 with a diagnosis of diaphragmatic hernia made either at exploratory laparotomy or necropsy.
Interventions – None.
Measurements and Main Results – Information from the medical records included history, clinical examination findings at presentation, and findings of exploratory laparotomy or necropsy. Logistic regression or the Fisher exact test was used to determine factors associated with survival. Outcome was defined as survival to discharge (short-term survival), and long-term survival was defined as horses alive at least 1-year post surgery. Of the 44 horses, 18 died or were euthanized before surgery. Twenty-six were taken to surgery, 17 were euthanized. Nine horses recovered from anesthesia, 7 of which survived to hospital discharge. Of these, 5 were alive at long-term follow-up. Survival was significantly associated with the age of the horse (≤2 y old) at presentation, presence of normal peritoneal fluid at presentation, amount of compromised viscera at surgery (<50% small intestine), and the size (<10 cm) and location (ventral) of the diaphragmatic tear.
Conclusion – This study confirms that size and location of the lesion do play a significant role in prognosis. And, although the prognosis for horses with diaphragmatic hernia is poor, if horses have operable lesions there is a fair prognosis for long-term survival.     

Lack of associations between ultrasonographic appearance of parenchymal lesions of the canine liver and histological diagnosis

Objective: To assess if there are any ultrasonographic features that may enable tentative diagnosis of hepatic parenchymal disease. Methods: Records of 371 dogs that had abdominal ultrasonography and abnormal liver on biopsy or necropsy were reviewed. Results: Histological diagnoses were hepatitis (n=77), nodular hyperplasia (n=47), vacuolar change (n=45), fibrosis (n=32), primary hepatic carcinoma (n=30), lymphoma (n=28), metastatic neoplasia (n=27), necrosis (n=21), lipidosis (n=17), haemangiosarcoma (n=13), round cell tumour (n=9), hepatocellular adenoma (n=8), degenerative change (n=6), steroid hepatopathy (n=7) and extramedullary haematopoiesis (n=4). The most prevalent ultrasonographic features were multifocal lesions (63% livers with haemangiosarcoma and 43% livers with hepatocellular carcinoma), diffuse lesions (71% livers with steroid hepatopathy, 44% livers with fibrosis and 40% livers with vacuolar hepatopathy), hyperechoic lesions (71% livers with steroid hepatopathy, 41% livers with lipidosis and 38% livers with fibrosis), heterogeneous lesions (62% livers with haemangiosarcoma), hepatomegaly (43% livers with steroid hepatopathy) and peritoneal fluid (62% livers with haemangiosarcoma). Target lesions were associated with malignancy in 67% instances. Marked variability in ultrasonographic appearance of lesions was observed for all diagnoses, and no statistically significant associations between ultrasonographic appearance and diagnosis were found. Clinical Significance: Histological examination remains essential for diagnosis of canine hepatic disease.     

Equine Mandibular Fibrosarcoma in Two Horses: Clinical,Diagnostic, and Therapeutic Considerations

A 25 year old Arabian gelding (case 1) presented for a large mandibular swelling involving the caudal aspect of the left horizontal mandible and a 14 year old Quarter Horse gelding (case 2) presented for a soft tissue swelling on the labial mucosa adjacent to 304. Both horses were bright and alert on presentation. Computed tomography allowed for further characterization regarding the extent of bone penetration within the lesions. This facilitated surgical planning and resection in Case 2. Histopathology of both masses diagnosed fibrosarcomas. Case 1 was humanely euthanized due to the severity of bone involvement and the grave prognosis. Case 2 underwent a left subtotal rostral hemimandibulectomy that proved to be successful in complete resection of the fibrosarcoma with a comfortable and cosmetic post-operative outcome. Surgeries that were once deemed radical should be considered for the treatment of neoplastic masses involving the soft tissues and bony structures of the oral cavity. With the aid of computed tomography, assessment of tumor penetration into deeper tissues can be achieved, thus facilitating complete surgical excision.     

Clinical and haematological features of haemangiosarcoma in dogs

Canine haemangiosarcoma was studied retrospectively in 31 cases recorded among 2,871 dogs presented for necropsy (1.08%). The German Shepherd breed was more frequently represented than other breeds. Affected dogs were older than 5 years (mean 9.1 years). Nineteen were males. Presenting signs often included episodic lethargy and weakness, with depression, anorexia and mucosal pallor. Spleen and lungs were the most frequently affected sites. Haematological findings in 9 dogs with splenic or hepatic haemangiosarcoma included a mild to moderate normochromic anaemia, neutrophilia, thrombocytopaenia, poikilocytosis and increased target cells. Acanthocytes occurred in 90% of cases, schizocytes in 80% and keratocytes and metarubyricytes in 70%. Fibrin split products were increased in 2 of the 3 cases in which they were measured. The changes in erythrocyte morphology are considered to be useful diagnostic features of canine haemangiosarcoma.     

Injuries and outcome of three horses hospitalised in the aftermath of Hurricane Isaac

This case series describes 3 horses rescued from flooded areas, hospitalised and treated at the Louisiana State University Veterinary Teaching Hospital in the wake of Hurricane Isaac. The purpose of the paper is to familiarise practitioners with the injuries that may be found in flood‐afflicted horses and livestock. Case 1 presented with a degloving injury of the right hindlimb. The gelding developed neurological signs and was subjected to euthanasia; necropsy was consistent with Salmonella sepsis and disseminated mycosis due to Candida krusei, the first case reported in a horse. Case 2 presented with dermatitis attributable to chemical exposure and pneumonia and was subjected to euthanasia due to severe bilateral laminitis. Case 3 sustained a degloving injury of the left hindlimb and was subjected to euthanasia due to intractable pain. This case series illustrates the need for preparation and evacuation to avoid life‐threatening injuries in equids and livestock caused by hurricanes and their aftermath.     

Metastatic pattern in dogs with splenic haemangiosarcoma: Clinical implications

A retrospective study was undertaken to characterise the biological behaviour of splenic haemangiosarcoma (HSA) in dogs. Metastatic pattern data for 25 dogs with splenic HSA that were presented for clinical signs relating to splenic lesions (eg, abdominal mass and, or, haemoperitoneum) and had undergone necropsy were analysed. Six of 25 dogs with splenic HSA that were presented for abdominal mass/haemoperitoneum had right atrial HSA. Fifteen of 19 (79 per cent dogs) with splenic HSA associated with abdominal mass/hemoperitoneum without right atrial involvement had disease confined to the peritoneal cavity. The most common metastatic sites in these dogs were liver, omentum and mesentery. Extraperitoneal metastases were seen in four of 19 (21 per cent) dogs without right atrial involvement. Analysis of signalment data of dogs in this series and the literature revealed no differences between dogs with disease confined to the peritoneal cavity and dogs with extraperitoneal metastases. The subjectivity of primary site designation, importance of ante mortem identification of individuals with concurrent right atrial involvement, and need for more aggressive therapy directed at intraperitoneal metastases are discussed.     

Upper respiratory signs associated with Anaplasma phagocytophilum infection in two horses

An adult Quarter Horse gelding (Case 1) was evaluated for tachypnoea and acute dysphagia. A 20-year-old Quarter Horse gelding (Case 2) was evaluated for respiratory stertor and severe, acute swelling of the head in the submandibular region. A physical examination, complete blood count, blood chemistry, upper airway endoscopy, and peripheral blood Anaplasma phagocytophilum polymerase chain reaction were completed for both horses. Both horses tested positive for A. phagocytophilum. The upper airway endoscopy for Case 1 revealed a feed contaminated pharynx, absent swallowing reflex, and left laryngeal hemiplagia. The upper airway endoscopy for Case 2 revealed severe diffuse pharyngeal swelling occluding the airway. Due to increased respiratory effort in Case 2, a tracheotomy was performed. In both horses, treatment consisted of intravenous oxytetracycline 6.6 mg/kg bwt i.v. q. 24 h for 2–3 days followed by minocycline 4 mg/kg bwt per os q. 12 h for 10–14 days. Both horses made full recoveries.