Inner ear fluid‐attenuated inversion recovery MRI signal intensity in dogs with vestibular disease

The inner ear contains endolymph and perilymph. The second is comparable and in continuity with the cerebrospinal fluid (CSF) so it is expected to suppress in fluid‐attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) if normal. Even though inner ear FLAIR abnormalities have been extensively described in humans with inner ear disease, its diagnostic value in dogs is yet to be proven. The goal of this retrospective cohort study was to investigate the diagnostic utility of FLAIR MRI in dogs with vestibular disease. A review of medical records identified 101 dogs that had brain MRI performed because of vestibular signs. Based on the final diagnosis, patients were allocated to three groups: otitis media/interna, idiopathic vestibular disease, and central vestibular disease. Additionally, a control group (n = 73) included dogs with normal MRI and without vestibular signs. Inner ears were delineated using a region of interest, and signal intensity was measured in FLAIR and T2‐weighted images. The percentages of suppression in FLAIR were calculated and compared between affected and unaffected sides of each individual and between groups using a general linear mixed model. Correlation between suppression and CSF cell count and protein concentration was assessed. Affected inner ears in dogs with otitis media/interna had decreased suppression in FLAIR compared to the unaffected side (P < .001), and all other groups (P < .01). No significant correlation was detected between CSF results and suppression. These results show the diagnostic value of FLAIR in otitis media/interna due to lack of suppression in the affected inner ear.     

Assessment of biomarkers influencing treatment success on small intestinal lymphoma in dogs

This study aimed to determine a reliable therapeutic biomarker for localized small intestinal lymphoma (SIL) in dogs based on clinical and histopathological features. We retrospectively investigated 84 dogs with localized SIL, including 36 dogs receiving surgery and 48 dogs receiving chemotherapy. The dogs receiving surgery were divided into two subgroups: 18 dogs (group 1) with overall survival (OS) <120 days (median OS) and 18 dogs (group 2) with OS ≥120 days. Correspondingly, the dogs receiving chemotherapy were divided into 24 dogs (group 3) with OS <98 days (median OS) and 24 dogs (group 4) with OS ≥98 days. Clinical, haematological, histopathological and immunohistochemical analyses were comparatively evaluated among the four subgroups. There was no significant difference in OS between the surgery and chemotherapy groups. In dogs receiving surgery, the rate of Ki67‐positive cells was significantly increased in group 1 compared to group 2 and showed no significant difference between groups 3 and 4. In dogs receiving chemotherapy, the rate of O6‐methylguanine‐DNA methyltransferase (MGMT) was significantly higher in group 3 than in group 4 and showed no significant difference between groups 1 and 2. Additionally, our data showed that OS in dogs with higher Ki67 expression might be significantly increased by chemotherapy than by surgery, that of those with higher MGMT expression might be significantly increased by surgery than by chemotherapy, and Ki67 and MGMT were independent of each other. Indices of Ki67 and MGMT are suggested therapeutic biomarkers to determine the optimal first‐line treatment for localized SIL in dogs.     

Comparison of different bronchial closure techniques following pneumonectomy in dogs

The comparison of the histologic healing and bronchopleural fistula (BPF) complications encountered with three different BS closure techniques (manual suture, stapler and manual suture plus tissue flab) after pneumonectomy in dogs was investigated for a one-month period. The dogs were separated into two groups: group I (GI) (n = 9) and group II (GII) (n = 9). Right and left pneumonectomies were performed on the animals in GI and GII, respectively. Each group was further divided into three subgroups according to BS closure technique: subgroup I (SGI) (n = 3), manual suture; subgroup II (SGII) (n = 3), stapler; and subgroup III (SGIII) (n = 3), manual suture plus tissue flab. The dogs were sacrificed after one month of observation, and the bronchial stumps were removed for histological examination. The complications observed during a one-month period following pneumonectomy in nine dogs (n = 9) were: BPF (n = 5), peri-operative cardiac arrest (n = 1), post-operative respiratory arrest (n = 1), post-operative cardiac failure (n = 1) and cardio-pulmonary failure (n = 1). Histological healing was classified as complete or incomplete healing. Histological healing and BPF complications in the subgroups were analyzed statistically. There was no significant difference in histological healing between SGI and SGIII (p = 1.00; p > 0.05), nor between SGII and SGIII (p = 1.00; p > 0.05). Similarly, no significant difference was observed between the subgroups in terms of BPF (p = 0.945; p > 0.05). The results of the statistical analysis indicated that manual suture, stapler or manual suture plus tissue flab could be alternative methods for BS closure following pneumonectomy in dogs.     

Timing of left heart base descent in dogs with dilated cardiomyopathy and normal dogs.

The identification and assessment of myocardial failure in canine idiopathic dilated cardiomyopathy (DCM) is achieved using a variety of two-dimensional and Doppler echocardiographic techniques. More recently, the availability of tissue Doppler imaging (TDI) has raised the potential for development of new ways of more accurately identifying a disease phenotype. Nevertheless, TDI has not been universally adapted to veterinary clinical cardiology primarily because of the lack of information on its utility in diagnosis. We assessed the application of timing of left heart base descent using TDI in the identification of differences between DCM and normal dogs. The times from the onset of the QRS complex on a simultaneously recorded electrocardiograph to the onset (Q--S'), peak (Q--peak S'), and end (Q--end S') of the systolic velocity peak were measured in the interventricular septum (IVS) and the left ventricular free wall. The duration of S' was also calculated. The Q--S' (FW), Q--end S' (FW), and duration S' (FW) were correlated with ejection fraction in the diseased group (P < 0.05). In addition, Q--S', Q--peak S', Q--end S', and the peak S' velocity were prolonged in the diseased dogs at both the free wall and in the IVS (P < 0.01). The duration of S' was unaffected by disease status. These findings provide insight into the electromechanical uncoupling that occurs in canine DCM and identifies new TDI parameters that can be added to the range of Doppler and echocardiographic parameters used for detecting myocardial failure in the dog.     

The echocardiographic effects of romifidine in dogs with and without prior or concurrent administration of glycopyrrolate

Objective To determine the cardiopulmonary response to romifidine (RO) in the dog with or without prior or concurrent administration of glycopyrrolate. Study Design Randomized, cross‐over experimental study. Animals Six (three male, three female) cross‐bred dogs weighing 23 ± 2.4 kg. Methods Two‐dimensional guided M‐mode echocardiography was performed in conscious dogs simultaneously with measurement of systolic arterial blood pressure (SBP) and heart rate (HR). Dimensions of the left ventricle (LVID), interventricular septum (IVS), and left ventricular free wall (LVFW) were obtained in systole (S) and diastole (D). Amplitude of motion (Amp) of the IVS and LVFW were also measured. From these, measures of wall stress (WS) and fractional shortening (FS) of the left ventricle were derived. Baseline echocardiographic measurements were recorded, following which one of the five treatments was administered. Glycopyrrolate (G) 0.01 mg kg^?1, or saline (S) 0.5 mL, was administered IM as pre‐medication (Gp or Sp), or G was administered concurrently (Gc) with romifidine (RO). Treatments were: T₁, Sp + RO (40 μg kg^?1); T₂, Gp + RO (40 μg kg^?1); T₃, Sp + RO (120 μg kg^?1); T₄, Gp + RO (120 μg kg^?1); and T₅, Sp + Gc +RO (120 μg kg^?1). Romifidine or RO + Gc was administered SC 20 minutes after pre‐medication (time 0), and further measurements were taken 10, 20, 30, 60, and 90 minutes after RO. Results Echocardiographic indices of cardiac systolic function (LVID‐S, FS, Amp‐LVFW) and HR were decreased in RO‐sedated dogs (p < 0.0001) . The magnitude of change in cardiac indices was least with low‐dose RO. At most sampling times, high‐dose RO produced significantly more alteration in cardiac indices. Systolic blood pressure increased in all treatment groups, with the greatest increases in those groups receiving G. Glycopyrrolate significantly increased HR; however, cardiac indices were further reduced. Wall stress significantly increased, with a more dramatic increase in groups receiving G. Conclusions Indices of LV systolic function were reduced in RO‐sedated dogs in a dose‐related manner. Glycopyrrolate further reduced these indices and dramatically increased measurements of wall stress in dogs sedated with RO. Clinical relevance Use of low‐dose RO minimizes cardiac dysfunction; however, it should still be used cautiously in dogs with cardiomyopathy or heart failure. The routine use of G is not recommended to alleviate the bradycardia associated with RO in conscious dogs.     

A simple specimen preparation method for histopathological evaluation of vestibular organs

Vestibular organs consist of the maculae staticae, which are located in both the utricle and saccule, as well as the semicircular ducts and their ampullas. There have been no reports on specimen preparation methods for vestibular organs, including maculae staticae or semicircular ducts. In this study, we investigated highly reproducible methods of preparing vestibular organ specimens for histopathological examinations. We established a method that allows researchers to observe the utricle and saccule, including otoliths, the ampulla of a semicircular duct, and parts of semicircular ducts. This highly reproducible method is useful for histopathological analysis of mice with symptoms of abnormal equilibrium caused by medical toxicity and genetic modification.     

Safety and tolerability of 0.1% tacrolimus solution applied to the external ear canals of atopic beagle dogs without otitis

Tacrolimus is a nonsteroidal alternative to treat noninfectious otitis externa (OE) in people. This 21‐day study investigated whether twice daily application (0.2 mL/dose) of sterile olive oil based 0.1% tacrolimus suspension in ears of atopic beagle dogs without OE was associated with adverse local reactions, development of OE, change in otic cytology, vestibular dysfunction, or hearing loss detected by brainstem auditory evoked response (BAER). The study was randomized, double‐blinded, and placebo‐controlled. Twenty‐two dogs matched for age and sex were randomized to tacrolimus or vehicle control treatment groups. Two investigators independently evaluated dogs for signs of adverse effects including OE the first 4 days of treatment, then every 3 days. A logistic regression model was fit for each investigator’s clinical scores (SAS, 9.2, 2008). Time (P = 0.0032) and group (P = 0.0167) were always significant for OE. Inter‐observer reliability of clinical scores was strong, measured using Kappa coefficients and proportion of agreement. All nine exclusions (7/10 control‐ and 2/12 tacrolimus‐treated dogs) were excluded for yeast OE. Inter‐observer agreement to exclude was 100%. All dogs not excluded had normal BAER assessments before treatment, weekly during treatment, and after 21 days of treatment. None showed vestibular abnormalities at these times. Tacrolimus blood concentrations (Abbott IMx Tacrolimus II) were below detection limits (3 ng/mL) at baseline and after 21 days of treatment. Results suggest otic application of olive oil based tacrolimus suspension to canine ears with intact tympanic membranes is unlikely to result in hearing loss or vestibular dysfunction but yeast OE is a possible risk.     

Signs consistent with syringobulbia may be detected in dogs undergoing MRI

Syringobulbia is a pathologic condition characterized by one or more fluid‐filled cavities within the brainstem. This retrospective case series describes observations in eight dogs with syringobulbia diagnosed during MRI. All dogs were adult, small‐breed dogs with concurrent syringomyelia and neurologic deficits localized to sites rostral to the spinal cord, which cannot be explained by syringomyelia (eg, six dogs had vestibular signs). On MRI, the fluid‐filled cavities had signal intensity characteristics like cerebrospinal fluid, were in the medulla oblongata, and were solitary in each dog. Initially, the shape of the cavity was a slit in five dogs and bulbous in two dogs. Magnetic resonance imaging was repeated in five dogs (6‐55 months of age). One dog had progression of syringobulbia from slit‐like to bulbous, and four dogs had unchanged slit‐like syringobulbia. One dog developed slit‐like syringobulbia after cranioplasty. A variety of medical and surgical treatments were performed with improvement of some but not all clinical signs. One dog died following surgery due to cardiopulmonary failure and the other seven dogs were alive at least 1 year after the initial diagnosis, which was the least time of follow‐up. One surviving dog developed a unilateral hypoglossal nerve deficit 2 months after the initial diagnosis and megaesophagus 14 months later. In conclusion, detecting a fluid‐filled cavity in the medulla oblongata consistent with syringobulbia is possible in dogs undergoing MRI. The cavity is likely acquired, slit‐like or bulbous, progressive, or static, and might be associated with breed size and neurologic signs localized to the medulla oblongata.     

Examination of hemostatic parameters to detect hypercoagulability in dogs with severe protein‐losing nephropathy

Objective – To identify hemostatic abnormalities in dogs with protein‐losing nephropathies (PLN) that represent risk factors for pathologic thrombosis. Design – Cross‐sectional observational study of client‐owned dogs with PLN, nonprotein losing renal failure (RF), and systemic illness (SI) exclusive of primary renal disease. Setting – Urban University Referral Center. Animals – A total of 29 dogs (n=11 PLN, n=7 RF, n=11 SI) were enrolled between January 2001 and July 2002. Samples were also collected from 20 clinically normal dogs to serve as hemostasis assay controls. Interventions – None. Hemostasis Testing – Citrate anticoagulated blood was collected for point‐of‐care testing with a viscoelastic monitor (thromboelastograph [TEG]) and citrate plasma was prepared for coagulation screening tests and specific assay of the following hemostatic proteins: antiplasmin, antithrombin, D‐dimer, Factor VIII, fibrinogen, plasminogen, protein C, and von Willebrand factor. Results – Dogs with PLN and RF demonstrated TEG abnormalities consistent with hypercoagulability (eg, short clotting time, high clot amplitude) and both groups had significantly lower antithrombin than the SI group. The PLN dogs had significantly higher protein C than either the RF or SI group. Hyperfibrinogenemia was a consistent finding among all 3 disease groups, and the coagulation index a measure of hypercoagulability derived from TEG parameters, directly correlated with fibrinogen values of all study dogs. Conclusions – Hemostatic abnormalities consistent with systemic hypercoagulability are common in dogs with RF and PLN, however, no prothrombotic factors unique to PLN were identified in our study. The thrombotic tendency of PLN may therefore involve parameters we did not directly assess such as platelet reactivity, fibrinolysis, perturbations in blood flow, and/or endothelial dysfunction. High protein C is a novel finding in PLN dogs of unknown clinical relevance.     

Results of cystometry and urethral pressure profilometry in dogs sedated with medetomidine or xylazine

OBJECTIVE: To compare effects of medetomidine and xylazine hydrochloride on results of cystometry and micturition reflexes in healthy dogs and results of urethral pressure profilometry (UPP) in sedated and conscious dogs. ANIMALS: 20 dogs. PROCEDURES: Urodynamic testing was performed 6 times in each dog (3 times after administration of xylazine [1 mg/kg of body weight, IV] and 3 times after administration of medetomidine (30 microg/kg, IM). Before each episode of sedation, UPP was performed. Heart and respiratory rates and indirect blood pressures were recorded prior to and 5, 10, 20, and 30 minutes after injection of sedative. Cystometry measurements included threshold volume, threshold pressure, and tonus limb. The UPP measurements included maximal urethral closure pressure (MUCP), functional profile length, and, in male dogs, plateau pressure. RESULTS: Mean MUCP was decreased markedly in xylazine- and medetomidine-sedated dogs. Xylazine and medetomidine also decreased plateau pressure in male dogs. The MUCP measurements were consistent among days for conscious and xylazine-sedated dogs but were inconsistent for medetomidine-sedated female dogs. The proportion of valid cystometry measurements was greater for xylazine (39 of 60) than for medetomidine (27 of 60). Cystometry was considered invalid when bladder pressure reached 30 cm H2O without initiation of a micturition reflex. CONCLUSIONS AND CLINICAL RELEVANCE: Medetomidine and xylazine have similar effects on measurement of UPP and cystometry. Medetomidine was less consistent among days for UPP in female dogs and produced fewer valid cystometry tests, compared with xylazine. For urodynamic evaluations, medetomidine administered IM cannot be substituted for xylazine administered IV.     

Computed tomographic characteristics of pneumolabyrinth in a French bulldog with otitis media and externa

A four‐year‐old female French bulldog was presented for evaluation of acute, left‐sided peripheral vestibular syndrome. Computed tomographic (CT) examination of the head revealed the presence of air within the left cochlea and vestibule, consistent with pneumolabyrinth. This was concurrent with ipsilateral otitis media and externa. Pneumolabyrinth is an uncommon finding in humans and is most frequently due to head trauma and temporal bone fracture. This is the first report describing pneumolabyrinth in a dog, apparently of nontraumatic origin in this case.     

Cytological comparison of fine-needle aspirates of liver and spleen of normal dogs and of dogs with cutaneous mast cell tumours and an ultrasonographically normal appearing liver and spleen

Staging of dogs with cutaneous mast cell tumours (MCTs) is an important diagnostic step. Aspiration of the liver and the spleen is often part of routine staging. This study cytologically compared mast cell numbers in fine‐needle aspirates of liver and spleen of clinically normal unaffected dogs with those of dogs with cutaneous MCT and an ultrasonographically normal appearing liver and spleen. The unaffected dogs (n = 32) were selected from humane society dogs, and the affected dogs (n = 51) were selected from hospital cases. There were no statistically significant differences in each of the parameters evaluated for the liver aspirates. For splenic aspirates, affected dogs showed significantly more mast cells per cluster (P = 0.04) and more isolated mast cells per slide (P = 0.03) compared with unaffected dogs. However, no clinically important difference existed between the unaffected and affected dogs; thus, routine aspiration of an ultrasonographically normal appearing liver and spleen of dogs with cutaneous MCT does not appear to be a clinically useful staging tool.     

Treatment of hydrocephalus with ventriculoperitoneal shunting in twelve dogs

Objective: To report use of ventriculoperitoneal shunt in dogs for management of hydrocephalus for which no cause could be identified. Study Design: Case series. Animals: Dogs with hydrocephalus (n=12). Methods: Medical records (June 2003–June 2009) were reviewed to determine preoperative clinical findings, initial postoperative, and long‐term outcome. Additional follow‐up information was obtained from owners and referring veterinarians. Results: All dogs had signs of forebrain dysfunction, 7 had vestibular signs and 3 had signs of spinal pain. Postoperative complications included pain (n=4), undershunting because of shunt kinking (n=1) and seizures (n=1). Initial improvement occurred in all dogs and was sustained in 9 dogs, 1 of which required revision surgery. Conclusions: Sustained clinical improvement can be achieved in hydrocephalus with no active underlying cause by use of ventriculoperitoneal shunting.     

Radiocardiography in dogs with atrial fibrillation

Summary

In 54 of 99 dogs with atrial fibrillation heart function was examined scintigraphically. Data on the ejection fraction (EF), end‐diastolic volume (EDV) and regurgitation fraction (RF) are presented. Of these animals 37 had a seriously decreased EF (< 30%) with a more or less normal RF value, whereas a smaller group (17) had a moderately decreased EF (but ≥ 30%) and a seriously increased RF value. In both groups the EDV was increased.     

Effects of feeding a high omega‐3 fatty acids diet in dogs with naturally occurring osteoarthritis

The aim of this randomized, placebo‐controlled and double‐blinded trial was to compare the effect of a veterinary therapeutic diet (VTD) rich in omega‐3 fatty acids (omega‐3) from fish origin to a regular diet used as control (CTR) over a period of 13 weeks in dogs afflicted by naturally occurring osteoarthritis (OA). Thirty privately owned dogs were selected. Dogs had lameness confirmed by an orthopaedic examination, had stifle/hip OA and had locomotor disability based on the peak of the vertically oriented ground reaction force (PVF) measured using a force platform. At Baseline, all owners were asked to determine 2–5 activities of daily living that were the most impaired. Activities were scores (0–4) in accordance with severity using case‐specific outcome measures (CSOM). The PVF was also measured. Dogs (15/group) were then randomly assigned to receive either the CTR or the VTD. The CSOM was completed twice weekly. The recording of PVF was repeated at Week 7 and 13. The VTD‐fed dogs showed a significantly higher PVF at Week 7 (p < 0.001) and at Week 13 (p < 0.001) when compared to Baseline. From Baseline to Week 13, VTD‐fed dogs had a mean (± SD) change in PVF recording of 3.5 ± 6.8% of body weight (%BW) compared with 0.5 ± 6.1%BW (p = 0.211) in CTR‐fed dogs. This change in primary outcome was consistent with an effect size of 0.5. Conversely, dogs fed the CTR did not show significant change in PVF measurements. At the end of the study, the CSOM was significantly decreased (p = 0.047) only in VTD fed dogs. In lame OA dogs, a VTD that contains high level of omega‐3 from fish origin improved the locomotor disability and the performance in activities of daily living. Such nutritional approach appears interesting for the management of OA.     

Serial haemostatic monitoring of dogs with multicentric lymphoma

Lymphoma is the most common haematopoietic malignancy in dogs and it has been associated with hypercoagulability and subsequent thromboembolism. The objectives of this study were to serially characterize the haemostatic status of dogs with multicentric lymphoma. Thromboelastography, thrombin–antithrombin complex concentration and routine haematology and coagulation panels were measured. Twenty‐seven dogs were included in the study and 15 completed the study in remission. At presentation, 81% (22/27) of dogs with multicentric lymphoma had altered haemostatic profiles consistent with hypercoagulability. Laboratory evidence of hypercoagulability did not resolve during treatment or for up to 1 month following attainment of clinical remission. Accelerated rate of clot formation at the time of chemotherapeutic protocol completion was associated with decreased survival time. We concluded that dogs with multicentric lymphoma were frequently hypercoagulable from presentation through 4 weeks after the completion of chemotherapy. Increased angle and shortened K in dogs that have successfully completed their chemotherapeutic protocol may be associated with shorter survival times.     

Saccadic oscillations in 4 dogs and 1 cat

Disorders affecting the control of saccadic eye movements result in involuntary saccadic oscillations and are widely reported in human medicine. Information regarding the occurrence and potential importance of saccadic oscillations in veterinary medicine is currently limited. The clinical histories of three dogs and one cat displaying involuntary eye movements consistent with opsoclonus are presented, with final diagnoses including idiopathic generalized tremor syndrome and neuronal ceroid lipofuscinosis (NCL). A dog with eye movements closely resembling macrosaccadic oscillations is also presented, for which a final diagnosis of NCL was made. All animals had clinical signs of cerebellar disease. As in human medicine, recognition of these forms of involuntary eye movement might suggest a cerebellar neuroanatomic localization. Opsoclonus and macrosaccadic oscillations are forms of involuntary saccadic eye movement that are both unrecognized and under‐reported in veterinary medicine.     

Computed tomographic findings in three dogs naturally infected with Crenosoma vulpis

Crenosoma vulpis is a nematode lungworm found in wild and domestic canids in some parts of North America and Europe. Reported radiographic findings are nonspecific and consist of a combination of bronchial and interstitial changes of variable severity. This retrospective, case series study aimed to describe thoracic computed tomographic (CT) findings for a group of dogs with confirmed crenosomosis. Selection criteria were presentation with a chronic cough during the period of January 2016 to February 2017, evaluation by thoracic CT, and final diagnosis of C. vulpis infection based on bronchoscopic findings, bronchoalveolar lavage fluid analysis, and quantitative polymerase chain reaction. Medical records and CT images were retrieved and reviewed by a board‐certified veterinary internist, a veterinary internal medicine resident, two board‐certified veterinary radiologists, and a veterinary radiology intern, and findings were recorded. Three dogs met inclusion criteria. Thoracic CT findings for all dogs included the following: diffuse bronchial wall thickening, multifocal peribronchial ground glass attenuation, consolidation of the pulmonary parenchyma, and cylindrical bronchiectasis. In two dogs, the bronchial wall thickening was irregular to nodular, which was consistent with the bronchoscopic findings. Two dogs showed pulmonary parenchymal bands. Thoracic computed tomographic changes in dogs with C. vulpis are consistent with those seen on thoracic radiographs and crenosomosis should be considered in dogs with these findings.