Imogen C. Johns

Hemangiosarcoma in 11 Young Horses

Hemangiosarcoma is a rare neoplasm of horses and hemangiosarcoma in young horses might behave differently than in mature horses. The purpose of this study was to identify the characteristics of hemangiosarcoma occurring in horses < or = 3 years of age. Medical records from 1982 to 2004 were searched for horses < or = 3 years of age with a histopathologic diagnosis of hemangiosarcoma. Eleven records were identified. Thoroughbred and Thoroughbred crosses predominated. Age ranged from 9 days to 3 years. All horses presented with cutaneous or leg swellings or joint effusion. Physical examination findings included tachycardia, fever, and depression. Laboratory abnormalities included anemia (5/11), hyperfibrinogenemia (4/11), hypofibrinogenemia (3/11), thrombocytopenia (2/11), and neutrophilic leukocytosis (1/11). Ultrasonographic and radiographic evaluation was not diagnostic in any case. Antemortem histopathologic diagnosis was obtained in 10 cases. Six of 11 horses were euthanized. Surgical resection was performed in 5 horses, 2 of which were later euthanized. Diagnosis was confirmed histologically at postmortem examination in all euthanized horses. Two cases resolved spontaneously. Early histopathologic diagnosis may allow cure if the mass is localized and amenable to surgical resection. In cases where the horse is medically stable, and masses are not interfering with quality of life, a period of observation may be warranted.

Comparison of flunixin meglumine and meloxicam for post operative management of horses with strangulating small intestinal lesions

REASONS FOR PERFORMING STUDY Ex vivo evidence suggests that cyclo-oxygenase (COX) 2-preferential inhibitor nonsteroidal anti-inflammatory drugs (NSAIDs), such as meloxicam, have a less detrimental effect on intestinal healing than flunixin meglumine (FM). Whether this translates to a beneficial effect in horses with naturally occurring strangulating small intestinal (SSI) lesions is unknown. OBJECTIVES To compare the clinical outcome of horses with naturally occurring SSI lesions treated with meloxicam or FM. STUDY DESIGN Randomised prospective study. METHODS Cases presenting to the Royal Veterinary College Equine Referral Hospital and Bell Equine Veterinary Clinic during 2010 and 2011 in which an SSI lesion was identified at exploratory laparotomy were eligible for inclusion. Horses received either 1.1 mg/kg bwt FM or 0.6 mg/kg bwt meloxicam i.v. q. 12 h. Clinical outcomes and clinical and laboratory parameters associated with endotoxaemia were compared between groups. RESULTS Sixty cases were enrolled, 32 horses received FM and 28 received meloxicam. There was no difference in signalment, physical examination or surgical factors between groups. The overall survival to discharge was 81%; there was no difference in survival (P = 0.14) or incidence of post operative ileus (P = 0.25) between groups. There was no significant difference between the plasma lipopolysaccharide (LPS) concentrations at 0 h (P = 0.18) or 48 h (P = 0.60); however, there was a significant difference between neutrophil count at 48 h (P<0.05) and at 96 h (P<0.01) with significantly greater cell numbers in horses receiving meloxicam compared with FM. Blinded pain score evaluation showed that more horses receiving meloxicam showed gross signs of pain than those treated with FM (P = 0.04). CONCLUSIONS Nonsteroidal anti-inflammatory drug choice did not affect major clinical outcomes in horses with SSI lesions but had some effects on signs of pain. This study provides no evidence to recommend one NSAID treatment above another based on survival or the incidence of ileus; however, evaluation of a larger number of cases is required.

Conjunctival bacterial and fungal flora in healthy horses in the UK.

OBJECTIVES To describe the bacterial and fungal flora of the normal conjunctiva of horses in the UK; to determine the effect of horse age, sex, geographic location, and housing on this flora; and to determine the most appropriate antimicrobial drug(s) for prophylactic treatment of corneal ulcers. ANIMAL STUDIED A total of 60 adult healthy horses were studied. PROCEDURE Swabs of the conjunctiva were obtained from 60 horses housed in two locations within the UK. Specimens were cultured for aerobic bacteria and fungi, and sensitivity against six ophthalmic antimicrobials assessed. The effect of age, sex, location and housing on the frequency of microbial isolation was evaluated. RESULTS Fifty-four bacterial isolates, representing thirteen genera of bacteria were cultured from 31 (52%) horses. The most frequently isolated bacterial species was Acinetobacter sp (17/32 horses). The majority of isolates (28/54: 52%) were gram-positive. Three genera of fungi (Mucor, Absidia and Aspergillus spp) were isolated from eight (13%) horses. There was no significant effect of geographic location, sex, age or housing on frequency of microbial isolation. Horses from which gram-negative bacteria were isolated were significantly older than horses from which gram-positive bacteria were isolated. High efficacy (greater than 90% of isolates sensitive in vitro) was displayed by chloramphenicol, gentamicin and tetracycline. CONCLUSIONS The microbial species isolated are comparable with studies performed in other countries, although the frequency of Acinetobacter isolation was higher which may reflect a geographic difference. The topical antimicrobials gentamicin and chloramphenicol are appropriate first line antimicrobials for empirical treatment of corneal ulcers in the UK.

Coagulation Abnormalities and Complications after Percutaneous Liver Biopsy in Horses

BACKGROUND Liver biopsy is useful in the diagnosis of liver disease in horses. However, bleeding is the major complication. Liver dysfunction can result in abnormalities in coagulation, although there is no definitive association between risk of hemorrhage after biopsy and coagulopathy in humans. Frequency of coagulopathies in horses with liver disease and the nature and frequency of complications after liver biopsy are not reported. HYPOTHESIS/OBJECTIVES To determine whether there is an association between coagulopathy and hemorrhage after liver biopsy in horses. ANIMALS Horses with suspected liver disease from which a liver biopsy had been obtained. METHODS Retrospective study. Variables indicative of coagulation were recorded. The frequency and nature of complications after biopsy were assessed using clinical and hematologic data. The association between abnormal coagulation variables and complications was assessed. RESULTS Seventy biopsies were obtained from 66 horses. At least 1 coagulation profile abnormality was identified in 58% of the 43 horses with histopathologically confirmed liver disease. Complications were observed in 4/32 monitored horses (33 biopsies). Three horses had a decrease in the packed cell volume suggestive of subclinical bleeding, and 1 horse developed a diaphragmatic hematoma. There was no association between coagulation profile abnormality and complications. CONCLUSION AND CLINICAL IMPORTANCE Abnormalities of coagulation are common in horses with liver disease. Liver biopsy appears to be a safe procedure in the horse. An abnormal coagulation profile is not clearly associated with an increased risk of complications after biopsy.

Blood culture status in mature horses with diarrhoea: a possible association with survival

REASONS FOR PERFORMING STUDY The incidence and implications of positive blood cultures in mature horses with diarrhoea is unknown. The diagnosis of bacteraemia may alter treatment and prognosis. HYPOTHESIS The proportion of horses with diarrhoea that are blood culture positive is higher than previously assumed and a positive blood culture has a negative impact on survival. METHODS Blood cultures were taken at admission and 24 h after admission from 31 mature horses with diarrhoea. RESULTS Nine (29%) horses were blood culture positive within 24 h of admission. Organisms isolated included Corynebacterium spp. (n = 6), Streptococcus spp. (n = 2), Pantoea agglomerans (n = 1), Gram-negative rod (n = 1), Bacillus spp. (n = 1) and yeast (n = 1). Horses with positive blood cultures were significantly less likely to survive. Prior treatment with antimicrobial drugs had no significant effect on blood culture status. Horses with positive blood cultures had a significantly higher heart rate, packed cell volume (PCV) and plasma potassium concentration at admission, and a higher PCV and lower total plasma protein concentration 24 h after admission. CONCLUSIONS Positive blood cultures occur more frequently than previously reported, and may have a negative impact on survival in horses with diarrhoea. POTENTIAL RELEVANCE Results of blood cultures may be useful in formulating a prognosis for horses with diarrhoea. Further research is required to determine the effect of antimicrobial treatment on outcome.

Antimicrobial resistance in faecal Escherichia coli isolates from horses treated with antimicrobials: A longitudinal study in hospitalised and non-hospitalised horses

The objective of this study was to examine the emergence and persistence of antimicrobial resistant faecal Escherichia coli in horses treated with antimicrobial drugs in a hospital and community setting. Faecal samples were collected from hospitalised (n=56) and non-hospitalised (n=14) horses treated with antimicrobials, and 10 non-treated hospitalised controls. Samples were obtained pre-treatment and 5 days later in all horses, and 2 weeks and 2 months after treatment in treated horses. Susceptibility to 15 antimicrobials was tested via disc diffusion on up to 3 E. coli isolates per sample. Phenotypic extended spectrum beta-lactamase (ESBL) production was identified via a combination disc method, and ESBL-encoding sequences identified by PCR. A resistant E. coli isolate was identified in 138/228 (60.5%) samples. The proportion of resistant samples was not significantly different between hospitalised and non-hospitalised treated horses. The odds of a sample containing a resistant isolate increased significantly at day 5 in treated horses, but not in controls. Two weeks following treatment, the odds of resistance in non-hospitalised horses returned to pre-treatment levels, but remained significantly above pre-treatment levels in hospital-treated horses, returning to base-line 2 months after treatment. Seven samples (17 isolates) were positive for ESBL production. The genes bla(CTX-M) and bla(TEM) were identified in 12/17 isolates, with bla(SHV) in 4/17. Antimicrobial administration to horses in hospital and community settings is associated with an increased but transient risk of faecal shedding of antimicrobial-resistant E. coli. The high prevalence of resistant isolates suggests that methods to minimise their potential spread should be considered.

Presumed immune-mediated hemolytic anemia in two foals with Rhodococcus equi infection.

OBJECTIVE To describe the clinical presentation, case management, and outcome in 2 foals with Rhodococcus equi infection associated with presumptive severe immune-mediated hemolytic anemia. SERIES SUMMARY Two foals diagnosed with R. equi pneumonia on the basis of tracheal wash cultures, thoracic radiographs, and thoracic ultrasonography were concurrently diagnosed with hemolytic anemia. Both foals required whole blood transfusions, and were treated with the antimicrobial combination of rifampin and a macrolide (eg, clarithromycin, erythromycin, or azithromycin). Dexamethasone was used to prevent further hemolysis in both foals, and to treat acute lung injury/acute respiratory distress syndrome in 1 of the foals. Both foals survived, and required prolonged antimicrobial therapy. NEW OR UNIQUE INFORMATION PROVIDED Although extra-pulmonary disorders are commonly diagnosed in foals infected with R. equi, hemolytic anemia is rarely described. Dexamethasone is considered the treatment of choice for immune-mediated hemolytic anemia, but may be contra-indicated in foals with severe bacterial infections. In these foals, a relatively low dose and short duration of dexamethasone was utilized in an attempt to minimize immune suppression, although early discontinuation in 1 foal precipitated a second hemolytic crisis.

Management of Rhodococcus equi pneumonia in foals

License. The full terms of the License are available at http://creativecommons.org/licenses/by-nc/3.0/. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. Permissions beyond the scope of the License are administered by Dove Medical Press Limited. Information on how to request permission may be found at: http://www.dovepress.com/permissions.php Veterinary Medicine: Research and Reports 2013:4 49–59 Veterinary Medicine: Research and Reports Dovepress

Bacteroides sp as a cause of anaerobic keratitis in a pony

Summary This Case Report describes anaerobic infection of the conjunctiva and cornea in a pony. A 13-year-old pony was admitted for evaluation following suspected ocular trauma. Bacterial conjunctivitis and keratitis were diagnosed based on clinical appearance of the eye and cytological evaluation of a corneal scraping. The pony responded poorly to topical therapy, and enucleation was performed. Culture of the corneal scraping yielded Corynebacterium sp. and Bacteroides sp. Anaerobic keratitis and conjunctivitis is uncommonly reported in horses, but should be suspected when there is a history of ocular trauma or skin disease, or when a malodorous ocular discharge is identified.

Ultrasonographically visible hepatic location in clinically normal horses

OBJECTIVE Ultrasound is widely used for evaluating horses with suspected liver dysfunction. Although a change in size is considered suggestive of pathology, no clear guidelines exist to define the hepatic ultrasonographically visible locations (HUVL) in horses. The aim of the study was to describe the HUVL in normal horses and determine whether this is altered by signalment, height, weight and body condition score (BCS). DESIGN Prospective observational study. PROCEDURE Bilateral ultrasonographic evaluation was performed in 58 clinically normal horses with no history of hepatic disease. The most cranial/caudal intercostal spaces (ICS), total number of ICS in which the liver was visualised and the ventral extent of the liver were recorded. RESULTS Liver was visualised on the right in 56/58 horses (97%), the left in 41/58 (71%) and on both sides in 39/58 (67%). The most cranial ICS was 5 (right) or 4 (left) and the most caudal was 16 (right) or 11 (left). Liver was visualised in ICS 0-11 (right) and ICS 0-5 (left). Liver was not visualised ventral to the costochondral junction. There was no significant effect of sex, breed, height, weight or BCS on HUVL. Liver was visible in significantly fewer ICS on the right in horses aged 24 years and older (median ICS 3.5) compared with younger horses (median ICS 7; P = 0.016). CONCLUSION These findings suggest that the liver should be consistently visualised on the right side, but absence of ultrasonographically visible liver on the left is unlikely to be clinically relevant. Liver dimensions may be decreased in older horses.