Does temporomandibular joint pathology affect performance in an equine athlete?

Temporomandibular joint (TMJ) pathology is a rarely reported cause of decreased performance among equine athletes or at least seldom recognised. This case report describes the work‐up of a high level dressage horse with decreased performance. Temporomandibular joint pathology was suspected based on computed tomography (CT) and the horse responded very well to joint treatment.     

Contrast radiography in the equine orthopaedic case

Routine contrast radiography has a valuable role in equine orthopaedics, providing additional information to standard radiography. However, ultrasonography provides additional information with respect to soft tissue pathology not appreciable when using contrast radiography alone, particularly in the investigation of synovial sepsis, ligament and tendon pathology, and osteochondral defects. The benefits of contrast media in more advanced imaging modalities such as computed tomography are just being recognised clinically.     

Metastatic cancer of unknown primary in 21 dogs

The aim of this retrospective study was to describe clinical features, treatment and outcome of 21 dogs with metastatic cancer of unknown primary (MCUP), a biopsy‐proven malignancy being diagnosed at a metastatic stage, in which the anatomical origin of the primary tumour cannot be detected. All dogs underwent total‐body computed tomography. Signalment, type and duration of clinical signs, metastasis site, pathology results, treatment and outcome were recorded. Carcinoma was the most common diagnosis (57.1%), followed by sarcoma, melanoma and mast cell tumour. The median number of disease sites per dog was 2, with bones, lymph nodes, lungs and spleen being the most frequent metastatic locations. The median survival for all dogs was 30 days. Overall, a primary site was not identified in 20 (95.2%) dogs. MCUP encompasses a variety of different pathologic entities and harbours a poor prognosis.     

Optimizing treatment of DNA methyltransferase inhibitor RG108 on porcine fibroblasts for somatic cell nuclear transfer

Aberration in DNA methylation is believed to be one of the major causes of abnormal gene expression and inefficiency of somatic cell nuclear transfer (SCNT). RG108, a non‐nucleoside DNA methyltransferase (DNMT) inhibitor, has been reported to facilitate somatic nuclear reprogramming and improved blastocyst formation. The aim of this study was to investigate interaction effect of RG108 treatment time (24–72 hr) and concentrations (0.05–50 µM) on donor cells, and further to optimize the treatment for porcine SCNT. Our results showed that RG108 treatment resulted in time‐dependent decrease of genome‐wide DNA methylation on foetal fibroblasts, which only happened after 72‐hr treatment in our experiments, and no interaction effect between treatment time and concentration. Remarkable decrease of methylation in imprinted gene H19 and increased apoptosis was observed in 5 and 50 µM RG108‐treated cells. Furthermore, the blastocyst rates of SCNT embryos were increased as the fibroblasts treated with RG108 at 5 and 50 µM, and additional treatment during cultivation of SCNT embryos would not provide any advantage for blastocyst formation. In conclusion, the RG108 treatment of 72 hr and 5 μM would be optimized time and concentration for porcine foetal fibroblasts to improve the SCNT embryonic development. In addition, combined treatment of RG108 on donor cells and SCNT embryos would not be beneficial for embryonic development.     

Computed tomography assisted repair of a central tarsal bone slab fracture in a horse

A 13‐year‐old Quarter Horse gelding was presented for repair of a central tarsal bone fracture. Radiographs showed a single large nondisplaced sagittal slab fracture; however, computed tomography (CT) revealed an additional small, displaced central tarsal bone fragment. The complex fracture was repaired, under the same anaesthetic period as the CT examination, using the CT hard copies images, intraoperative fluoroscopy and radiographs. The horse recovered well and after rehabilitation showed no residual lameness at work. Computed tomography was instrumental in achieving precise screw placement and successful fracture repair.     

Eosinophilic pulmonary granulomatosis in a young dog with prolonged remission after treatment

A two‐year‐old Jack Russell terrier was presented for evaluation of chronic cough and exercise intolerance. Previous treatment with antibiotics and glucocorticoids had only partially ameliorated the clinical signs. During investigation, hypoxaemia, peripheral eosinophilia and an eosinophilic bronchoalveolar lavage fluid were noted. Thoracic radiographs revealed two ovoid clearly delineated soft‐tissue opacities, one in the caudal segment of the left cranial lung lobe (diameter 26 mm) and the other in the right cranial lung lobe (diameter 20 mm). These findings were verified by computed tomography, which identified an additional smaller lesion (diameter 16 mm) dorsally in the right caudal lobe. Ultrasound‐guided fine‐needle aspiration samples confirmed the diagnosis of eosinophilic pulmonary granulomatosis and treatment with prednisolone and azathioprine was initiated. Within 1 month, granulomas were no longer detectable radiographically. All medication was discontinued after 7 months and currently, after 2·5 years, the dog remains free of clinical signs. To the authors’ knowledge this is the first case report to describe prolonged remission from idiopathic canine eosinophilic pulmonary granulomatosis.     

USE OF RADIOGRAPHY IN COMBINATION WITH COMPUTED TOMOGRAPHY FOR THE ASSESSMENT OF NONCARDIAC THORACIC DISEASE IN THE DOG AND CAT

Computed tomography (CT) of the thorax was performed in 28 dogs and five cats and findings were compared with previous thoracic radiographs. The sample population included all animals that had thoracic radiographs and a CT study within 5 days of each other, where the complete imaging studies were available for review. Thoracic radiographs were considered indeterminate in 31 patients and CT examinations were done to acquire additional information. The presence of additional information from CT relating to presence of pathology, location of pathology, extent of pathology, and involvement of mediastinal structures was recorded. Whether there was a change in diagnosis based on the CT findings was also recorded. In only 4/33 animals (all dogs) did CT fail to provide any new information for the parameters evaluated when compared with survey thoracic radiographs. Additional information about the pathology that was present was gained by CT in 5/5 cats and 21/ 28 dogs. New information on compartmental location of pathology was seen in 4/5 cats and 19/28 dogs. New information on pathology extent was noted in 5/5 cats and 20/28 dogs. Additional information regarding involvement of mediastinal structures was obtained in 2/5 cats and 10/28 dogs. A change in diagnosis was made in 3/5 cats and 13/28 dogs. In conclusion, CT is a valuable tool for evaluating intrathoracic disease. CT provides additional cross-sectional anatomic information that can aid in anatomic localization and evaluation of the extent of the pathology in question.     

Microsporidial keratopathy in two dogs

A microsporidial keratopathy is described in two dogs. Both dogs presented with a unilateral stromal keratopathy characterized by multifocal coalescing opacities, and the diagnosis was made on histopathologic examination of keratectomy specimens. Transmission electron microscopy (TEM) on formalin‐fixed, paraffin‐embedded corneal tissue was performed in one dog, and the morphologic features were consistent with Nosema species infection. Both dogs were initially diagnosed and treated by superficial keratectomy. One dog received additional antifungal medication and underwent a penetrating keratoplasty following local recurrence two years later. No other systemic lesions attributable to the microsporidial infection were identified clinically. The clinical and diagnostic pathology findings, treatment, and follow‐up are discussed.     

Safety evaluation of orally administered afoxolaner and milbemycin oxime in eight‐week‐old dogs

The safety profile of afoxolaner (an isoxazoline molecule) when combined with milbemycin oxime (a macrocyclic lactone) was evaluated according to the regulatory requirements when administered six times orally in a soft chewable formulation at a dose of at least 1×, 3×, or 5× the maximum exposure dose in 8‐week‐old Beagle dogs. Thirty‐two healthy puppies (16 males and 16 females) were enrolled and allocated randomly to one of four treatment groups. Three doses were administered at 28‐day intervals (Days 0, 28, and 56), followed by three additional doses administered with 14‐day intervals (Days 84, 98, and 112). The study ended on Day 126. Treatment groups were as follows: Group 1: untreated, sham‐dosed control; Group 2: afoxolaner/milbemycin oxime chews administered at a dose of at least 5 and 1 mg/kg, respectively (1×); Group 3: afoxolaner/milbemycin oxime chews administered at a dose of at least 15 and 3 mg/kg, respectively (3); and Group 4: afoxolaner/milbemycin oxime chews administered at a dose of at least 25 and 5 mg/kg, respectively (5×). All dogs were examined for general health twice a day beginning on Day ‐14. Physical examinations, and blood collections for clinical pathology analysis and afoxolaner and milbemycin oxime plasma concentrations, were performed throughout the study. No afoxolaner/milbemycin oxime treatment‐related changes were observed in growth, physical variables, clinical pathology variables, or tissues examined histologically. No clinically relevant or statistically significant health abnormalities related to the administration of afoxolaner/milbemycin oxime were observed. No signs of macrocyclic lactone sensitivity were observed at any time during the study. Vomiting and diarrhea were observed sporadically across all groups including the controls. Based upon the results of this study, afoxolaner/milbemycin oxime soft chewables were shown to be safe when administered repeatedly at up to 5× the maximum exposure dose in dogs as young as 8 weeks of age.     

Temporary regression of locally invasive polypoid rhinosinusitis in a dog after photodynamic therapy

A 5‐year‐old male cross‐breed dog with chronic rhinosinusitis was presented. Computed tomography (CT) revealed opacities consistent with soft tissue or fluid in the left nasal cavity and frontal sinus. A diagnosis of chronic rhinosinusitis with myxomatous polyps was based on the histology of biopsy samples, so prednisolone treatment was administered for 1 month. Although the clinical signs slightly improved, no changes were observed on the CT images. At 8 months after the initial presentation, the dog was treated with antivascular photodynamic therapy (PDT) using benzoporphyrin derivative monoacid ring A and, 11 days later, CT revealed remarkably decreased soft tissue opacity; the facial swelling and sneezing also resolved. Three additional sessions of PDT were performed at 114, 210, and 303 days after the first PDT because of recurrence of clinical signs. The disease was well controlled for approximately 10 months by antivascular PDT.     

Safety of a benazepril and pimobendan combination tablet in adult healthy dogs

The objective of the study was to investigate the safety of a combination tablet of benazepril and pimobendan, Fortekor PLUS^®, in a randomized, blinded, parallel‐group design study in healthy adult beagle dogs. The test article, Fortekor PLUS^® tablets, was administered orally twice daily for 6 months at one, two, and four times the highest recommended dosage of 0.5 mg/kg benazepril hydrochloride/0.25 mg/kg pimobendan (four males and four females per group). An additional control group was sham‐dosed. Fortekor PLUS^® did not induce any treatment‐related effects on body weight, food consumption, neurological, ophthalmologic or physical assessments over the 6‐month treatment period. The test article was possibly associated with an increased frequency of occasional vomiting. Fortekor PLUS^® was associated with small, but significant, increases in heart rate and reductions in PR and QT intervals, which were assessed by electrocardiography. These effects were most probably related to reflex tachycardia secondary to reduced systemic blood pressure. Statistically significant changes in some clinical pathology variables were noted after test article administration, but were considered to be of no clinical relevance as values remained within reference ranges and/or were not dose‐dependent. No treatment‐related macroscopic or microscopic findings were observed. In conclusion, Fortekor PLUS^® tablets were well tolerated in healthy adult dogs when administered at one, two, and four times the highest recommended dosage for 6 months.     

Trends in veterinary cancer imaging

With the recent advances in diagnostic imaging technology, cancer imaging in veterinary medicine has become more specific for disease diagnosis, more accurate for determining tumour margins and more sensitive for detecting metastatic disease. Ultrasound provides highly detailed images of parenchymal masses and infiltrative lesions while providing a means for aspiration or biopsy using real‐time image guidance. Computed tomography and magnetic resonance‐imaging techniques provide exquisite anatomical resolution that improves diagnostic accuracy, provides an accurate means of radiation or surgical treatment planning and a quantitative means for monitoring response to therapy. In addition to traditional anatomic imaging, new techniques are being developed for estimating functional parameters such as tumour perfusion, cell metabolism and gene expression. While conventional planar scintigraphy has been available for some time, newer nuclear imaging modalities such as positron emission tomography promise to further improve the accuracy of initial tumour diagnosis and staging and determination of response to therapy. Although many of these functional techniques are not yet clinically available, it is highly likely that some will be integrated into routine clinical practice in the near future.     

18F‐FDG‐PET/CT as adjunctive diagnostic modalities in canine fever of unknown origin

Fever of unknown origin (FUO) is a persistent or recurrent fever for which the underlying source has not been identified despite diagnostic investigation. In people, ¹⁸F‐fluoro‐2‐deoxyglucose positron emission tomography (¹⁸F‐FDG‐PET) alone or in combination with computed tomography (CT) is often beneficial in detecting the source of fever when other diagnostics have failed. Veterinary reports describing use of these modalities in animals with fever of unknown origin are currently lacking. Aims of this retrospective case series were to describe ¹⁸F‐FDG‐PET or ¹⁸F‐FDG‐PET/CT findings in a group of dogs with fever of unknown origin. Dogs presenting to a single center between April 2012 and August 2015 were included. A total of four dogs met inclusion criteria and underwent either positron emission tomography (n = 2) or positron emission tomography/CT (n = 2) as a part of their diagnostic investigation. All subjects underwent extensive diagnostic testing prior to ¹⁸F‐FDG‐PET/CT. Initial diagnostic evaluation failed to identify either a cause of fever or an anatomic location of disease in these four dogs. In each dog, positron emission tomography or positron emission tomography/CT was either able to localize or rule out the presence of focal lesion thereby allowing for directed sampling and/or informed disease treatment. Follow up ¹⁸F‐FDG‐PET/CT scans performed in two patients showed improvement of observed abnormalities (n = 1) or detected recurrence of disease allowing for repeated treatment before clinical signs recurred (n = 1). Fever resolved after specific treatment in each dog. Findings from the current study supported the use of positron emission tomography or positron emission tomography/CT as adjunctive imaging modalities for diagnosis and gauging response to therapy in dogs with fever of unknown origin.     

Single-phase bone scintigraphy in dogs with obscure lameness

Objectives : To evaluate the diagnostic merits of scintigraphy in dogs with clinically obscure lameness origin. Methods : In 43 dogs, the scintigraphic findings were compared with the results of subsequent radiological, computed tomography and/or arthroscopic findings and/or additional neurological examination. Results : In all dogs, focal increased uptake was found in one or more joints or bones. The presence of associated pathology was confirmed by radiography, computed tomography and/or arthroscopy of the limb region of interest. Additional neurological examination was performed when indicated. In cases of elbow pathology, unilateral involvement of the elbow was confirmed with computed tomography/arthroscopy in 14 cases, while bilateral increased uptake could not be confirmed with radiography or computed tomography in three cases. Three dogs showed an increased activity in one joint on the bone scan, while computed tomography, arthroscopy or radiography revealed bilateral joint disease. Generalised mild increased radionuclide uptake in all joints and bones was observed in the lame limb in 15 forelimbs and five hindlimbs. Generalised prominent uptake of an entire limb was noted in three cases suffering from neurological disease. Clinical Significance : Scintigraphy may provide information on areas of increased radionuclide uptake, thereby aiding in the localisation of obscure lameness. Generalised mild increased uptake of radionuclide in all joints and bones in the lame limb may occur in the older dog. The generalised prominent uptake, seen in three cases with neurological disease, may resemble reflex sympathetic dystrophy syndrome seen in human beings.     

Arthroscopic treatment for cervical articular process joint osteochondrosis in a Thoroughbred horse

A yearling Thoroughbred colt was presented for investigation of neck stiffness and episodes of intermittent neck pain without neurological signs. Osteochondrosis (OCD) of the cervical articular process joints (APJs) was diagnosed with the aid of radiography and computed tomography. An articular osteochondral fragment of the left fourth caudal cervical articular process was removed arthroscopically following a cut down approach to the joint capsule of the affected APJ. Surgical removal resulted in resolution of clinical signs at 4 weeks. However, subsequently the horse was markedly ataxic 6 weeks post surgery after being found cast in its stable. Cervical stenotic myelopathy was considered the most likely cause based on clinical and radiographic signs and the horse was subjected to euthanasia due to a poor prognosis for racing. Post‐mortem examination identified atypical cartilage within several cervical APJs with histological changes consistent with OCD. This case report supports OCD of the APJs as a cause of neck pain and confirms the clinical practicality and short‐term effectiveness of arthroscopic fragment removal. Surgical treatment for cervical OCD should be considered in horses without neurological signs, although case selection is important and the underlying pathology remains a risk factor for the development of subsequent neurological signs.     

Computed tomographic contrast tenography of the digital flexor tendon sheath of the equine hindlimb

Pre‐surgical investigation of digital flexor tendon sheath pathology remains challenging with current standard imaging techniques. The aim of this prospective, anatomical, pilot study was to describe the anatomy of the equine hind limb digital flexor tendon sheath using a combination of computed tomography (CT) and computed tomographic contrast tenography in clinically normal cadaver limbs. Ten pairs of hind limbs with no external abnormalities were examined from the level of the tarsometatarsal joint distally. Limbs initially underwent non‐contrast CT examination using 120 kVp, 300 mAs, and 1.5 mm slice thickness. Sixty millilitres of ioversol iodinated contrast media and saline (final concentration 100 mg/ml) were injected using a basilar sesamoidean approach. The computed tomographic contrast tenography examination was then repeated, before dissection of the specimens to compare gross and imaging findings. The combined CT and computed tomographic contrast tenography examinations provided excellent anatomical detail of intra‐thecal structures. The borders of the superficial and deep digital flexor tendons, and the manica flexoria were consistently identifiable in all limbs. Detailed anatomy including that of the mesotenons, two of which are previously undescribed, and the plantar annular ligament were also consistently identifiable. Dissection of all 10 pairs of limbs revealed there to be no pathology, in accordance with the imaging findings. In conclusion, the combination of CT and computed tomographic contrast tenography may be useful adjunctive diagnostic techniques to define digital flexor tendon sheath pathology prior to surgical exploration in horses.     

Computed tomographic findings in a Bluetick Coonhound with a longitudinal thoracic tracheal tear

A 9‐year‐old intact male Bluetick Coonhound presented for progressive subcutaneous emphysema of 5 days’ duration due to a suspected tracheal tear. Cervical computed tomography (CT) and thoracic CT were performed after failure to identify the tracheal tear with tracheoscopy. A longitudinal tracheal tear was identified starting 4.3 cm cranial to the tracheal bifurcation and extending caudally over a distance of 3.6 cm. Severe pneumomediastinum, subcutaneous emphysema, and retroperitoneal gas were also present. A follow‐up CT 7 days postoperatively confirmed the successful repair of the tear with partial resolution of the presurgical secondary pathology and the patient recovered uneventfully.     

Idiopathic haemarthrosis in eight horses

Objectives To review eight horses diagnosed with idiopathic haemarthrosis and to describe the intra‐articular use of yttrium‐90 (⁹⁰Y) and methylprednisolone acetate (MPA) in recurrent haemarthrosis cases. Design Retrospective case series. Method The medical records, diagnostic images, histopathology and outcome of all horses diagnosed with idiopathic haemarthrosis between 1998 and 2010 were reviewed. Results Four Thoroughbred racehorses with haemarthrosis of the antebrachiocarpal joint had severe acute lameness (median, grade 4) and marked joint effusion after high‐speed exercise. Another four horses (2 Thoroughbred racehorses, 1 Standardbred racehorse, 1 Warmblood) had haemarthrosis of the tarsocrural joint and presented with mild, intermittent lameness (median, grade 1) and marked, persistent joint effusion. Six of the eight horses had recurrent haemarthrosis prior to treatment. Radiographic and nuclear scintigraphic examinations did not identify bone pathology. Diagnostic arthroscopy (7 cases) identified grossly hypertrophied yellow/brown discoloured synovium. Synovial histopathology of these cases revealed chronic synovial hyperplasia with severe haemosiderosis and granulomatous inflammatory reaction of varying severity. All horses underwent rest, bandaging and phenylbutazone administration. Two horses had subtotal mechanical synovectomy, four horses had intra‐articular administration of ⁹⁰Y and MPA, and one horse underwent both treatments. Seven cases returned to their previous use (median time, 7 months). Haemarthrosis recurred in three horses, two of which had received the ⁹⁰Y and MPA treatment. Conclusion Idiopathic haemarthrosis should be considered a differential for acute and recurrent joint related lameness and effusion. Recurrence appears not uncommon and the use of intra‐articular ⁹⁰Y and MPA in conjunction with a conservative management treatment protocol warrants further evaluation.     

The Utrecht Score: A novel histopathological scoring system to assess the prognosis of dogs with cortisol‐secreting adrenocortical tumours

A cortisol‐secreting adrenocortical tumour (ACT) is the cause of naturally occurring canine hypercortisolism in approximately 15% to 20% of cases. The differentiation between an adrenocortical adenoma and carcinoma is usually based on histopathology. However, histopathological parameters have never been linked to the dogs' survival. Moreover, in human medicine the inter‐observer variability of some histopathological parameters that are used for ACTs is high. The objective of this study was to establish a reliable and easy‐to‐use histopathological scoring system for cortisol‐secreting ACTs that can assess the prognosis of dogs after adrenalectomy. Cortisol‐secreting ACTs of 50 dogs, collected between 2002 and 2015, were included in this study. Twenty histopathological features were assessed by one veterinary pathologist and one resident in veterinary pathology. In addition, the Ki67 proliferation index was assessed by two observers. Only parameters with intra‐ and inter‐observer agreement scores (intra‐class correlation or Cohen's kappa coefficient) of ≥0.40 were included in survival analyses. Use of multivariate forward stepwise regression analysis with associated hazard ratios led us to a scoring system which we call the Utrecht score: the Ki67 proliferation index, +4 if more than 33% of the tumour cells have clear/vacuolated cytoplasm and + 3 if necrosis is present. Using cut‐off values of 6 and 11, we could distinguish three groups that had significantly shorter survival times with increasing Utrecht scores. We conclude that the Utrecht score can be used to assess the prognosis of dogs with cortisol‐secreting ACTs after adrenalectomy, which can help to select high‐risk dogs that might benefit from adjuvant treatment or additional monitoring.