Corpus Callosal Abnormalities in Dogs

Background

Corpus callosal abnormalities (CCA) in dogs have been only sporadically reported and are poorly characterized.

Hypothesis/Objectives

To describe the clinical presentation and magnetic resonance imaging (MRI) characteristics of dogs with CCA.

Animals

Fifteen client‐owned dogs.

Methods

Retrospective study. Records of the contributing institutions were reviewed to identify dogs diagnosed with malformations affecting the corpus callosum (CC); cases in which the CCA was thought to be secondary were excluded.

Results

The most represented breeds were Staffordshire Bull Terriers (5/15) and Miniature Schnauzers (3/15; n = 3, 20%) and the mean age at time of presentation of 19 months (range 3–81 months). The clinical signs most commonly reported were adipsia/hypodipsia with associated hypernatremia (12/15), tremors (6/15), and seizures (6/15). Review of the MR images revealed that 10 dogs had absence of the rostral CC and hypoplasia of the caudal portion, 4 dogs had a diffusely hypoplastic and dysplastic CC, and 1 dog had a diffusely hypoplastic CC. In 14 cases, there was abnormal cortical development with fusion of the ventral frontal lobes and part of the diencephalon, indicating lobar holoprosencephaly.

Conclusions and Clinical Importance

Previous literature has mainly associated CCA with adipsia and only 12 of 15 dogs in the current series demonstrated this abnormality. There are different degrees of the malformation but in 10 dogs the rostral portion of the CC is most severely affected. Fourteen dogs have simultaneous fusion of the midline structures rostral to the CC; this region has several structures involved in thirst regulation and might explain this derangement.     

Hemostatic Abnormalities in Dogs With Hemangiosarcoma

The hemostasis profiles of 24 dogs with histologically confirmed hemangiosarcoma were prospectively evaluated. Microangiopathic hemolysis was defined as the presence of schistocytes; disseminated intravascular coagulation was defined as 1) thrombocytopenia, 2) fibrin(ogen) degradation products greater than 10 micrograms/mL, 3) prolongation of one or more coagulation times (activated partial thromboplastin time or one-stage prothrombin time) by greater than 25% of the control, 4) fragmented red blood cells (greater than or equal to 1+ based on a semiquantitative grading scale), and 5) fibrinogen less than or equal to 80 mg/dL. Three of the five criteria listed above had to be met for disseminated intravascular coagulation to be diagnosed. Fifty percent of the dogs were considered to have disseminated intravascular coagulation at presentation. Thrombocytopenia was present in 75% of the dogs and was the most common abnormality. The mean platelet count was 137,800/microL. Twenty-five percent of the dogs died as a result of the hemostatic abnormalities. Only 12% of the dogs had microangiopathic hemolysis without other evidence of disseminated intravascular coagulation. Hemostatic abnormalities are present in many dogs with hemangiosarcoma at the initial clinical presentation and represent an important clinical finding.     

Meta‐Analyses of Factors Associated with Leptospirosis in Domestic Dogs

Factors related with leptospirosis in domestic dogs have been reported worldwide. The aims of this study were to identify factors associated with this disease described in different observational studies and to combine the coinciding factors in at least four studies using meta‐analyses, to obtain a pooled odds ratio (OR) as measure of infection risk. A literature search was performed in electronic databases, electronic databases of specific journals and search engines to find studies published in English, Spanish and Portuguese available from January 1960 to January 2015. Two hundred and eighteen factors were identified in 31 publications including cross‐sectional and case–control studies. Finally, independent meta‐analyses were performed with six different variables, which included between 4 and 8 articles. The pooled OR indicated that the variables ‘mixed‐breed dogs’, ‘flooding occurrence in the habitat of the dog’ and ‘working dogs’ were risk factors for leptospirosis, while ‘being a dog less than 1 year old’ was a protective factor; however, all these associations were not statistically significant. Otherwise, the variables ‘male dog’ and ‘urban dog’ were statistically significant risk factors for infection. This study highlights the need for more formal studies on the epidemiology of canine leptospirosis. Nevertheless, the study revealed that some risk factors for infection coincided in different observational studies. These factors could be considered to raise suspicion about the disease, especially when there is a history of exposure to the bacteria.     

Interreader agreement of radiographic left atrial enlargement in dogs and comparison to echocardiographic left atrial assessment

Introduction

Assessing left atrial (LA) size is an integral part of the cardiac evaluation in dogs. Left atrial size is routinely evaluated by thoracic radiographs or echocardiography.

犬、猫钩端螺旋体病的流行病学调查

为了解钩端螺旋体病在犬、猫体内的感染情况,2011年,在北京地区建立了20个宠物疫病监测点,随机收集了犬、猫血清及尿液样本396份,进行犬、猫钩端螺旋体病的流行病学调查。调查结果为显微镜凝集试验检测犬、猫血清共计200份,抗体阳性的样品共有106份,阳性率为53%,其中猫血清为阳性的样品有20份,阳性率为27.8%;犬血清为阳性的样品有86份,阳性率为67.2%。RT-PCR检测犬、猫尿液共计196份,阳性的样品共有54份,阳性率为27.6%,其中猫尿样21份,阳性样品4份,阳性率为19%;犬尿样175份,阳性样品50份,阳性率为28.6%。     

Pulmonary Thromboembolism in Dogs

Pulmonary thromboembolism (PTE) is an infrequently diagnosed complication of many systemic diseases including heartworm disease, glomerulopathy leading to the nephrotic syndrome, immune-mediated hemolytic anemia, hyperadrenocorticism, pancreatitis, neoplasia, and sepsis. Acute, unexplained dyspnea in a patient with minimal abnormalities on thoracic radiographs should prompt consideration of this diagnosis. Confirmation requires ventilation-perfusion radionuclide scanning or selective pulmonary angiography. Treatment includes cage rest, anticoagulant therapy with heparin and warfarin, correction of the underlying disorder, and supportive care. Clinicians should be prepared to treat hemorrhage associated with anticoagulant therapy. Recombinant tissue plasminogen activator may prove useful as a thrombolytic in the treatment of animals suffering massive PTE, but is, at present, expensive.     

Unilateral and Bilateral Brainstem Auditory-Evoked Response Abnormalities in 900 Dalmatian Dogs

In a survey of 900 Dalmatian dogs, brainstem auditory-evoked responses (BAER) and clinical observations were used to determine the incidence and sex distribution of bilateral and unilateral BAER abnormalities and their association with heterochromia iridis (HI). To assess the efficacy of BAER testing in guiding breeding programs, data from 749 dogs (subgroup A), considered to be a sample of the population at large, were compared with data from a subgroup (subgroup B; n = 151) in which selection of breeding stock had been based on BAER testing from the beginning of the 4-year survey. Brainstem auditory-evoked responses were elicited by applying click stimuli unilaterally, while applying a white noise masking sound to the contralateral ear. Under these conditions, BAER were either normal, unilaterally absent, or bilaterally absent. Dogs with bilaterally absent BAER were clinically deaf; dogs with unilaterally absent BAER were not clinically deaf but appeared dependent on their BAER-normal ears for their auditory-cued behavior. Dogs with unilaterally absent BAER often were misidentified as normal by uninformed observers. Among the 900 dogs, 648 (72.0%) were normal, 189 (21.0%) had unilateral absence of BAER, and 63 (7.0%) had bilateral absence of BAER or were clinically deaf and assumed to have bilaterally absent BAER (n = 4). Total incidence in the population sampled was assumed to be higher, because some bilaterally affected dogs that would have been members of subgroup A undoubtedly did not come to our attention. Among females, 24.0% were unilaterally abnormal and 8.2% were bilaterally abnormal whereas, among males, 17.8% were unilaterally abnormal and 5.7% were bilaterally abnormal.(ABSTRACT TRUNCATED AT 250 WORDS)     

Abnormalities of Serum Magnesium in Critically III Dogs: Incidence and Implications

Serum magnesium (Mg) is an infrequnetly measured electrolyte in small animal patients. Currently, little is known about the prevalence and significance of abnormalities in serum Mg in animals. Therefore, a prospective study was performed to examine the incidence and clinical implications of abnormalities in serum Mg levels in critically ill dogs.
Serum Mg and other electrolytes were measured in 93 normal dogs housed at the Purina Pet Care Center and in 48 ill dogs admitted to a small animal critical care unit. The normal reference range for canine serum Mg was determined to be 1.89 – 2.51 mg/dl. Based on this range, 54% of the critically ill dogs were hypomagnesemic (< 1.89 mg/dl) and 13% were hypermagnesemic (> 2.51 mg/dl). Of the electrolytes measured in these patients, serum Mg had the highest prevalence of abnormal values. Hypomagnesemic patients had a significantly higher incidence of concurrent hypokalemia and hyponatremia (p < 0.05), as well as a longer length of hospitalization (p < 0.05) than their normomagnesemic counterparts. Hypermagnesemic patients were 2.6 times more likely not to survive their illness when compared to patients with normal serum Mg levels.
Abnormalities in serum Mg appear to be common in critically ill dogs. These patients commonly have other concurrent electrolyte abnormalities. Since serum Mg is not routinely measured, the presence of hypokalemia or hyponatremia should alert the clinician to the possibility of coexisting hypomagnesemia. The clinical implications of hypomagnesemia and hypermagnesemia in ill dogs appear to involve prolonged hospitalization and increased mortality, respectively: however, the exact etiology remains undetermined.     

Serum Cardiac Troponin I Concentration in Dogs with Precapillary and Postcapillary Pulmonary Hypertension

Background: Pulmonary hypertension (PH) is a disease condition leading to right-sided cardiac hypertrophy and, eventually, right-sided heart failure. Cardiac troponin I (cTnI) is a circulating biomarker of cardiac damage.
Hypothesis: Myocardial damage can occur in dogs with precapillary and postcapillary PH.
Animals: One hundred and thirty-three dogs were examined: 26 healthy controls, 42 dogs with mitral valve disease (MVD) without PH, 48 dogs with pulmonary hypertension associated with mitral valve disease (PH-MVD), and 17 dogs with precapillary PH.
Methods: Prospective, observational study. Serum cTnI concentration was measured with a commercially available immunoassay and results were compared between groups.
Results: Median cTnI was 0.10 ng/mL (range 0.10–0.17 ng/mL) in healthy dogs. Compared with the healthy population, median serum cTnI concentration was increased in dogs with precapillary PH (0.25 ng/mL; range 0.10–1.9 ng/mL; P < .001) and in dogs with PH-MVD (0.21 ng/mL; range 0.10–2.10 ng/mL; P < .001). Median serum cTnI concentration of dogs with MVD (0.12 ng/mL; range 0.10–1.00 ng/mL) was not significantly different compared with control group and dogs with PH-MVD. In dogs with MVD and PH-MVD, only the subgroup with decompensated PH-MVD had significantly higher cTnI concentration compared with dogs with compensated MVD and PH-MVD. Serum cTnI concentration showed significant modest positive correlations with the calculated pulmonary artery systolic pressure in dogs with PH and some echocardiographic indices in dogs with MVD and PH-MVD.
Conclusions and Clinical Importance: Serum cTnI is high in dogs with either precapillary and postcapillary PH. Myocardial damage in dogs with postcapillary PH is likely the consequence of increased severity of MVD.