Progressing a scoring scheme for intervertebral disc calcification screening in Dachshund dogs

Intervertebral disc disease (IVDD) is a major health problem in Dachshunds. Of all the dog breeds they have the highest incidence of IVDD, owing to their chrondrodystrophy and subsequent accelerated intervertebral disc (IVD) degeneration. Degenerated IVDs are predisposed to herniation, resulting in spinal cord injury and commonly paralysis. Late-stage IVD degeneration can include dystrophic calcification, and this calcification may be detected on spinal radiographs (radiographically detectable intervertebral disc calcification [RDIDC]). IVDD and RDIDC are highly heritable in Dachshunds, with RDIDC scores at young adult age being a strong predictor of clinical IVDD occurrence later in life. A screening program was developed whereby potential breeding candidates undergo spinal radiography and scoring for RDIDC, with the aim of reducing the incidence of IVDD through selective breeding. Despite the existence of a large body of literature around IVDD in Dachshunds, including a solid scientific basis for the development of the radiographic screening tool, several deficiencies and areas for ongoing research were identified and guided this project. Widespread global awareness and application of the screening program was lacking. Therefore, an extensive appraisal of the literature was performed resulting in the paper ‘Radiographic scoring for intervertebral disc calcification in the Dachshund’, which is available in the Veterinary Journal. For a test to be useful it must be precise, and the scorer variability (precision) for RDIDC scoring had not been evaluated. Accordingly, the within-scorer (repeatability) and between-scorer (reproducibility) variability of RDIDC scoring was estimated using five scorers with varying levels of prior experience, both at the individual IVD level and at the whole dog level for breeding classification purposes. Overall, RDIDC scoring was found to be highly consistent within scorers, with increased precision achieved by scorers with greater experience. However, unique individual scorer patterns were identified as a factor. These results supported the ongoing use of the screening program, and were published in Preventive Veterinary Medicine. Investigation of the utility of alternate diagnostic imaging modalities, namely computed tomography (CT) and magnetic resonance imaging (MRI), for scoring IVD calcification in Dachshunds had not previously been undertaken. The first step in evaluating these modalities for potential use was to assess scorer agreement for CT and MRI, and compare these results with radiography (i.e. RDIDC scoring). Supporting the results of prior work, radiography was identified as a highly precise test with repeatability and reproducibility estimates that were greater than for CT and MRI, likely attributable to scorer familiarity with the modality and RDIDC scoring. Again, increased scorer experience corresponded with greater RDIDC scoring precision. Despite these findings, CT identified substantially higher overall numbers of IVD calcifications than the other modalities, and further analysis of this data to examine the accuracy of the various modalities is warranted. Despite the work achieved through this project, ongoing research is needed. Additional experiments are planned, including analysis of the potential effect of instruction and training on RDIDC scorer subjectivity, and an epidemiological study of the Australian Dachshund population.Thesis (MPhil) -- University of Adelaide, School of Animal & Veterinary Sciences, 201

A new fossil species of Clypeaster (Echinoidea) from Malaysian Borneo and an overview of the Central Indo-Pacific echinoid fossil record

A complete, but fractured and crushed, echinoid corona from early to middle Miocene of Sarawak, Malaysia, is described as a new species, Clypeaster sarawakensis nov. sp. Although similar to modern C. rarispinus, the new species shows a distinct set of characters including petal length, periproct position and gut coiling. The discovery of a new Clypeaster, a genus characterised by a high preservation potential, illustrates that little is known about echinoid evolution and diversification in the Central Indo-Pacific, which features as a biodiversity hotspot since the Oligocene. Besides describing Clypeaster sarawakensis, we also compiled the known Central Indo-Pacific echinoid fossil record and used it to examine the Cenozoic diversity of echinoids. The overall diversity throughout the Cenozoic, and especially the rapid diversity increase at the Oligocene–Miocene boundary, corresponds to diversity trends observed in other taxa from the region

What is your diagnosis?

Alana J. Rosenblatt, Sarah J. Zito, Natalie S. Webste

Concurrent spinal epidural empyema and endocarditis in a dog

A 9-year-old neutered male Rhodesian ridgeback cross dog was evaluated for progressive non-ambulatory paraparesis, fever, and leukocytosis. The dog was diagnosed with spinal epidural empyema (SEE) and infectious endocarditis (IE) of the mitral valve based on the findings of contrast-enhanced computed tomography (CT), CT myelography, echocardiography, and bacterial culture. The report herein describes the clinical presentation, CT findings, clinical and surgical management of this case, together with the electrocardiography, and echocardiography findings. To the authors' knowledge, this is the first reported case of spinal epidural empyema likely to be caused by infectious endocarditis of the mitral valve in a dog

Radiographic scoring for intervertebral disc calcification in the Dachshund

Intervertebral disc disease is a common, painful and debilitating neurological condition of dogs, causing substantial morbidity and mortality. The Dachshund is particularly susceptible to this disorder. The goal of this article is not to duplicate previously published reviews on canine intervertebral disc degeneration and degenerative diseases. Rather, the aims are threefold: (1) to reflect on selected clinical and pathophysiological aspects of intervertebral disc degeneration and disc disease that are pertinent to the Dachshund breed; (2) to review a radiographic spinal scoring scheme developed to reduce the prevalence of intervertebral disc disease in Dachshunds; and (3) to suggest further areas of research to improve upon the currently established scoring scheme in an attempt to address this breed's greatest health problem

T2-Weighted magnetic resonance imaging measurements of optic nerve sheath diameter in dogs with and without presumed intracranial hypertension

Intracranial hypertension is a cause of cerebral ischemia and neurologic deficits in dogs. Goals of this retrospective study were to test interobserver agreement for MRI measurements of optic nerve sheath diameter and associations between optic nerve sheath diameter, signalment data, and presumed intracranial hypertension status in a cohort of dogs. A veterinary radiologist interpreted scans of 100 dogs and dogs were assigned to groups based on presence or absence of at least two MRI characteristics of presumed intracranial hypertension. Two observers who were unaware of group status independently measured optic nerve diameter from transverse T2-weighted sequences. Mean optic nerve sheath diameter for all dogs was 3 mm (1-4 mm). The mean difference between observers was 0.3 mm (limits of agreement, -0.4 and 1.0 mm). There was no correlation between optic nerve sheath diameter and age for either observer (r = -0.06 to 0.00) but a moderate positive correlation was observed between optic nerve sheath diameter and body weight for both observers (r = 0.70-0.76). The 22 dogs with presumed intracranial hypertension weighed less than the 78 dogs without (P = 0.02) and were more often female (P = 0.04). Dogs with presumed intracranial hypertension had a larger ratio of optic nerve sheath diameter to body weight for each observer-side pair (P = 0.01-0.04) than dogs without. Findings indicated that the ratio of MRI optic nerve sheath diameter relative to body weight may be a repeatable predictor of intracranial hypertension in dogs

Diagnosis and treatment of mesenteric volvulus in a red kangaroo (Macropus rufus)

Case Description-An 8-year-old male red kangaroo (Macropus rufus) was evaluated with a 2-week history of vomiting and anorexia. Four days prior, the patient became refractory to medical management. The kangaroo was admitted for diagnostic testing and treatment including whole body CT, blood work, and emergency laparotomy.Clinical Findings-CT findings of a severely enlarged stomach, splenic displacement, and a whirl sign were indicative of mesenteric volvulus with gastric dilatation-volvulus (GDV). Contrast enhancement of abdominal viscera suggested intact arterial blood supply; however, compression of the caudal vena cava and portal vein indicated venous obstruction. Results of preoperative blood work suggested biliary stasis without evidence of inflammation. Additionally, a tooth root abscess was diagnosed on the basis of results of CT.Treatment and Outcome-Exploratory laparotomy confirmed the diagnosis of mesenteric volvulus and GDV. The volvuli were corrected by clockwise derotation, and a gastropexy was performed. Tissue samples were obtained from the spleen and liver for evaluation. The kangaroo recovered from surgery, and the abscessed tooth was extracted 6 days later. Eight days after initial evaluation, the kangaroo was discharged.Clinical Relevance-In the present report, the CT whirl sign was used to diagnose volvulus of the abdominal viscera, which suggests that this diagnostic indicator has utility in veterinary patients. Mesenteric volvulus with GDV was successfully treated in a nondomestic species. The tooth root abscess, a common condition in macropods, may explain the historic episodes of anorexia reported by the owner and may have contributed to the development of mesenteric volvulus and GDV in this kangaroo

Imaging diagnosis-meningoencephalitis secondary to suppurative rhinitis and meningoencephalocele infection in a dog

Nasal encephaloceles (meningoceles or meningoencephaloceles) are rare and not reported to be infected or coupled with a facial deformity in dogs. This report describes an older dog with acute worsening of seizures due to suppurative meningoencephalitis with coexisting suppurative rhinitis and infection of a meningoencephalocele. Additionally, the dog had a facial deformity for at least 5 years. The results of necropsy, computed tomography, and postmortem magnetic resonance imaging are compared. The development of nasal encephaloceles is discussed, including the potential role of early trauma, and whether separation of neural ectoderm from the surface ectoderm is part of the pathogenesis

Rhinosinusitis in an Australian mare caused by Flavodon flavus, a recently recognized invasive fungal pathogen of the horse

We describe herein the clinical, endoscopic, computed tomography (CT), pathologic, and microbiologic features of an infection caused by an under-recognized fungal pathogen, Flavodon flavus, in a 25-y-old Australian Quarter Horse. The horse had a unilateral obstructive nasal mass, resulting in stertor and dyspnea. On endoscopy, the mass was tan, multinodular, and completely obstructed the nasal passage. CT analysis revealed a large, soft tissue–attenuating and partially mineralized mass in the right nasal passage and dorsal-conchofrontal sinus, expanding into adjacent paranasal sinuses with associated bone lysis and rhinosinusitis. Histopathology of the mass on 2 occasions revealed suppurative inflammation initially, and pyogranulomatous inflammation subsequently. The inflammatory reaction surrounded numerous spherical fungal structures (~60–80 µm diameter) that stained positively on periodic acid–Schiff and Grocott methenamine silver stains. PCR for the fungal internal transcribed spacer 1 and 2 regions followed by Sanger sequencing on a cultured isolate identified the agent as F. flavus, which has only been reported previously as pathogenic in one horse in the United States, to our knowledge. Previous reports described this fungus as a nonpathogenic, environmental commensal fungus associated with insects and plants

Precision of spinal radiographs as a screening test for intervertebral disc calcification in Dachshunds

Among dog breeds, the Dachshund has the highest lifetime incidence of intervertebral disc disease (IVDD). Intervertebral disc (IVD) calcification is an indicator of severe degeneration that predisposes to disc herniation. IVDD is heritable in Dachshunds, and in some countries, breeding candidates are screened to reduce IVDD occurrence by selecting dogs according to their score of radiographically detectable intervertebral disc calcification (RDIDC) and excluding dogs with ≥5 RDIDCs from breeding. This study evaluated the precision of scoring spinal radiographs for IVD calcification and subsequent classification of Dachshund dogs for breeding based on their RDIDC score. Digital radiographs of the spine were obtained in 19 clinically healthy, young adult Dachshunds, and scored for RDIDC independently by five scorers with varying levels of experience, three times each. Within scorer (repeatability) and between scorer (reproducibility) variability was estimated both at the individual IVD level and at the whole dog level for breeding classification purposes.At the IVD level, some degree of scorer effect was supported by the pairwise repeatability (92.3%; 95% CI: 88.8-94.7%) being marginally higher than the reproducibility (89.2%; 95% CI: 85.7-91.8%). Scorer-specific patterns confirmed the presence of scorer subjectivity. Repeatability significantly increased with scorer experience but the reproducibility did not. RDIDC scoring repeatability and reproducibility substantially decreased at the cervicothoracic spine region, likely due to anatomical superimpositions. At the dog level, a breeding classification could be repeated by the same scorer for 83.6% (95% CI: 73.8-90.2%) of the dogs, and was reproduced between two scorers for 80.2% (95% CI: 66.6-89.1%) of the dogs. The repeatability of breeding classification also seemed to increase with scorer experience but not the reproducibility. Overall, RDIDC scoring revealed some degree of inconsistency explained by scorer subjectivity and inexperience, and anatomical superimpositions. Scorer training and experience is strongly recommended to improve test precision and ensure appropriate classification of Dachshunds for breeding