Medullary Position at the Craniocervical Junction in Mature Cavalier King Charles Spaniels: Relationship with Neurologic Signs and Syringomyelia

Background

Medullary elevation (ie, medullary kinking) at the craniocervical junction (CCJ) is reported in dogs with Chiari‐like malformations (CM), but its diagnostic criteria and clinical relevance are unclear.

Objective

To describe the position of the medulla at the CCJ in mature cavalier King Charles spaniels (CKCS), and evaluate its relationship with clinical status and the presence of syringomyelia.

Animals

Thirty‐six CKCS, 5–12 years of age, including 16 asymptomatic dogs.

Methods

Dogs were assigned a neurologic grade; magnetic resonance imaging (MRI) of the CCJ then was performed. The presence of a CM and syringomyelia was recorded and syringomyelia severity was quantified. Medullary position was quantified using the medullary kinking index, the elevation angle and obex position relative to the foramen magnum. The relationship between medullary position measures and presence and severity of neurologic signs and syringomyelia was investigated.

Results

Chiari‐like malformation was found in 33 dogs; 26 of them had syringomyelia. Mean medullary kinking index was 46.4% (SD, 10.3), elevation angle was 132° (SD, 12) and obex position was 3.5 mm (SD, 0.8). A higher medullary kinking index was associated with the presence of neurologic signs (P = .0368). Obex position was associated with the presence (P = .0018) and severity of syringomyelia (P = .0164).

Conclusions and clinical importance

There is a significant association between medullary elevation and clinical signs, whereas more caudal brainstem positions appear related to the presence of syringomyelia.     

Chiari‐Like Malformation and Syringomyelia in American Brussels Griffon Dogs

Background

Although Chiari‐like malformation (CM) and syringomyelia (SM) have been described in many small breed dogs, the prevalence and clinical manifestations of this complex have not been documented in a large cohort of American Brussels Griffon (ABG) dogs.

Objectives

To characterize the clinical and magnetic resonance imaging (MRI) features of CM and SM in the ABG breed.

Animals

Eighty‐four American Kennel Club registered ABG dogs were recruited.

Methods

Prospective study. Complete histories and neurologic examinations were obtained before MRI. Images were blindly reviewed and calculations were made by using OsiriX. All analyses were performed by Student''s t‐test, Spearman''s correlation, ANOVA, and chi‐square test where appropriate.

Results

Chiari‐like malformation and SM were present in 65% and 52% of dogs, respectively. Twenty‐eight percent of dogs had neurologic deficits and 20% had neck pain. Mean central canal (CC) transverse height was 2.5 mm with a mean length of 3.6 cervical vertebrae. Neurologic deficits were significantly associated with a larger syrinx (P = .04, P = .08) and syrinx size increased with age (P = .027). SM was associated with a smaller craniocervical junction (CCJ) height (P = .04) and larger ventricles (P = .0001; P < .001).

Conclusions and Clinical Importance

Syringomyelia and CM are prevalent in American Brussels Griffon dogs. Syrinx size is associated with neurologic deficits, CM, larger ventricles, a smaller craniocervical junction height, neurologic deficits, and cerebellar herniation. Fifty‐two percent of dogs with a SM were clinically normal.     

Association of Vitamin D Status and Clinical Outcome in Dogs with a Chronic Enteropathy

Background

Dogs with a chronic enteropathy (CE) have a lower vitamin D status, than do healthy dogs. Vitamin D status has been associated with a negative clinical outcome in humans with inflammatory bowel disease.

Objectives

To examine the relationship between serum 25 hydroxyvitamin D (25(OH)D) concentrations at diagnosis and clinical outcome in dogs with a CE.

Animals

Forty‐one dogs diagnosed with CE admitted to the Royal Dick School of Veterinary Studies, Hospital for Small Animals between 2007 and 2013.

Methods

Retrospective review. Serum 25(OH)D concentrations were compared between dogs which were alive at follow up or had died because of non‐CE‐related reasons (survivors) and dogs which died or were euthanized due to their CE (non‐survivors). A binary logistic regression analysis was performed to determine significant predictors of death in dogs with CE.

Results

Serum concentrations of 25(OH)D at the time a CE was diagnosed were significantly lower in nonsurvivors (n = 15) (median nonsurvivors 4.36 ng/mL, interquartile range 1.6–17.0 ng/mL), median survivors (n = 26) (24.9 ng/mL interquartile range 15.63–39.45 ng/mL, P < .001). Serum 25(OH)D concentration was a significant predictor of death in dogs with CE (odds ratio 1.08 [95% CI 1.02–1.18)]).

Conclusions

Serum 25(OH)D concentrations at diagnosis are predictive of outcome in dogs with CE. The role of vitamin D in the initiation and outcome of chronic enteropathies in dogs is deserving of further study.     

Low‐Field Magnetic Resonance Imaging and Multislice Computed Tomography for the Detection of Cervical Syringomyelia in Dogs

Background

Syringomyelia (SM) is defined as the presence of fluid‐containing cavities within the parenchyma of the spinal cord. Sagittal magnetic resonance (MR) images have been described as the preferred technique for visualizing SM in dogs and humans.

Objective

To investigate whether computed tomography (CT) can be used to diagnose SM.

Animals

Thirty‐two client‐owned dogs referred for investigation of the cervical spine on magnetic resonance imaging (MRI) and CT.

Methods

Two reviewers retrospectively analyzed sagittal and transverse T1‐weighted spin echo (T1WSE) MR images and CT images from each dog for the presence of SM and, if SM was present, the width (mm, syrinx width [SW]) was measured. The results were analyzed statistically.

Results

For the presence of SM there was a moderate interobserver agreement for MR (81%, κ = 0.54) and almost perfect agreement for CT (94%, κ = 0.87). There was a moderate intramodality agreement for both observers (observer 1 81%, κ = 0.59; observer 2 81%, κ = 0.57). For measurement of SW the repeatability was the best on the midsagittal T1WSE images (95% repeatability coefficient <0.52 mm) and the reproducibility was the best on midsagittal images in both modalities (95% limits of agreement −0.55–0.45; P = 0.002).

Conclusion and Clinical Importance

Both techniques can be used to detect SM. Midsagittal MR and CT images are best used for measuring SW. Computed tomography can be used as a diagnostic tool for SM when MRI is not available, but CT cannot replace MRI as the standard screening technique for the detection of SM in Cavalier King Charles Spaniel for breeding purposes.     

Prevalence of Chiari‐like Malformations in Clinically Unaffected Dogs

Background

The importance of Chiari‐like malformation (CM) in the generation of clinical signs or the formation of syringomyelia in dogs is incompletely understood, partly because the prevalence of various CM definitions in unaffected dogs is unknown.

Hypothesis/Objectives

The aims were: to estimate the prevalence of CM in dogs asymptomatic for CM or syringomyelia, according to 3 currently used definitions; and, to investigate the effect of brachycephaly and head position during magnetic resonance (MR) imaging on estimates of the prevalence of CM.

Animals

One ninety‐nine client‐owned dogs without apparent signs of CM or syringomyelia.

Methods

Blinded, retrospective analysis. Archived MR images were analyzed for evidence of cerebellar indentation and impaction into or herniation through the foramen magnum. Logistic regression analysis was used to investigate the relationship of CM diagnosis with head position and the cranial index (a measure of brachycephaly).

Results

In 185 non‐Cavalier King Charles Spaniel (CKCS) dogs, indentation was identified in 44% (95% CI, 47–51%) and impaction in 22% (95% CI, 16–28%). No asymptomatic, non‐CKCS dogs showed herniation. Regression analysis showed a significant increase in the odds of indentation and impaction in an extended head position and as the cranial index increased (became more brachycephalic).

Conclusions and Clinical Importance

The high prevalence of cerebellar indentation and impaction suggests that they may be normal anatomical variations and therefore unsuitable as definitions of CM. We suggest that future research into CM in dogs should define cases and controls more strictly so that overlap between normal and abnormal animals is minimized.     

Low‐Field MRI and Multislice CT for the Detection of Cerebellar (Foramen Magnum) Herniation in Cavalier King Charles Spaniels

Background

Cavalier King Charles Spaniels (CKCS) have a high prevalence of Chiari‐like malformation (CM). Herniation of the cerebellum into the foramen magnum is a key diagnostic feature for CM. Midsagittal MR images are the preferred technique for visualizing cerebellar herniation (CH).

Objective

To investigate whether CT can be used to diagnose CH.

Animals

Fifteen client‐owned CKCS dogs referred for investigation of the brain and cranial cervical spine on MRI and CT.

Methods

Two reviewers retrospectively analyzed midsagittal T1WSE and T2WSE MR images and midsagittal pre‐ and postcontrast 2D multiplanar reformatted CT images from each dog for the presence of CH. And, if present, the length (mm, CHL) of the herniation was measured. The results were analyzed statistically.

Results

There was no significant difference between the different observers and techniques for the detection of CH and measurement of CHL. Overall, the CHL was longer on the CT images.

Conclusion and Clinical Importance

Both techniques are useful for detecting CH and measuring CHL. Because CHL does not have a known direct impact on the clinical presentation of CM, CT can be used as a diagnostic tool in a routine clinical practice for CM in CKCS when MRI is not available. We emphasize that MRI is the standard screening technique in CKCS for breeding purposes to detect the presence of CM and SM and, at the current time, CT cannot replace MRI.     

Prevalence and Heritability of Symptomatic Syringomyelia in Cavalier King Charles Spaniels and Long‐term Outcome in Symptomatic and Asymptomatic Littermates

Background

Syringomyelia (SM) is common in the Cavalier King Charles Spaniel (CKCS). Dogs with syringes express clinical signs or might be clinically silent.

Objectives

To investigate the prevalence and heritability of symptomatic SM, the association between clinical signs and magnetic resonance imaging (MRI) findings, and long‐term outcome.

Animals

All CKCS registered in the Danish Kennel Club in 2001 (n = 240).

Methods

A cross‐sectional questionnaire‐based prevalence study validated by telephone interviews and clinically investigated clinical signs of SM. Dogs were 6 years at the time of investigation. A prospective observational litter study including clinical investigations, MRI and 5‐year follow‐up of symptomatic and asymptomatic siblings. Heritability was estimated based on the scale of liability in the study population and litter cohort.

Results

The cross‐sectional study estimated a prevalence of symptomatic SM at 15.4% in the population. Thirteen symptomatic and 9 asymptomatic siblings participated in the litter study. Spinal cord syringes were confirmed in 21 of 22 littermates (95%). Syrinx diameter and mean syrinx : spinal cord ratio were significantly correlated with clinical signs (P < .01). Estimated heritability of symptomatic SM was 0.81. Symptomatic SM motivated euthanasia in 20%. Dogs with syringes, which expressed no clinical signs at the age of 6, remained asymptomatic in 14/15 cases (93%).

Conclusions and Clinical Importance

The prevalence of symptomatic SM is high and genetics have a high impact on clinical disease expression. Further investigations of factors influencing the outbreak threshold of clinical signs of SM are desirable.     

Serum Cortisol Concentrations in Dogs with Pituitary‐Dependent Hyperadrenocorticism and Atypical Hyperadrenocorticism

Background

Atypical hyperadrenocorticism (AHAC) is considered when dogs have clinical signs of hypercortisolemia with normal hyperadrenocorticism screening tests.

Hypothesis/Objectives

To compare cortisol concentrations and adrenal gland size among dogs with pituitary‐dependent hyperadrenocorticism (PDH), atypical hyperadrenocorticism (AHAC), and healthy controls.

Animals

Ten healthy dogs, 7 dogs with PDH, and 8 dogs with AHAC.

Method

Dogs were prospectively enrolled between November 2011 and January 2013. Dogs were diagnosed with PDH or AHAC based on clinical signs and positive screening test results (PDH) or abnormal extended adrenal hormone panel results (AHAC). Transverse adrenal gland measurements were obtained by abdominal ultrasound. Hourly mean cortisol (9 samplings), sum of hourly cortisol measurements and adrenal gland sizes were compared among the 3 groups.

Results

Hourly (control, 1.4 ± 0.6 μg/dL; AHAC, 2.9 ± 1.3; PDH, 4.3 ± 1.5) (mean, SD) and sum (control, 11.3 ± 3.3; AHAC, 23.2 ± 7.7; PDH, 34.7 ± 9.9) cortisol concentrations differed significantly between the controls and AHAC (P < .01) and PDH (P < .01) groups. Hourly (P < .01) but not sum (P = .27) cortisol concentrations differed between AHAC and PDH dogs. Average transverse adrenal gland diameter of control dogs (5.3 ± 1.2 mm) was significantly less than dogs with PDH (6.4 ± 1.4; P = .02) and AHAC (7.2 ± 1.5; P < .01); adrenal gland diameter did not differ (P = .18) between dogs with AHAC and PDH.

Conclusions and Clinical Importance

Serum cortisol concentrations in dogs with AHAC were increased compared to controls but less than dogs with PDH, while adrenal gland diameter was similar between dogs with AHAC and PDH. These findings suggest cortisol excess could contribute to the pathophysiology of AHAC.     

Prevalence and Prognostic Importance of Pulmonary Hypertension in Dogs with Myxomatous Mitral Valve Disease

Background

Pulmonary hypertension (PH) is common in dogs with myxomatous mitral valve disease (MMVD) but its effect on clinical outcome has not been investigated.

Hypothesis/objectives

The presence of PH worsens the outcome in dogs with MMVD. To compare survival times of dogs with MMVD and PH to those without PH.

Animals

Two hundred and twelve client‐owned dogs.

Methods

Case review study. Medical records of dogs diagnosed with ACVIM stage B2 and C MMVD between January 2010 and December 2011 were retrospectively reviewed. Long‐term outcome was determined by telephone interview or from the medical record. End of the observation period was March 2013. PH was identified if tricuspid regurgitation peak velocity was >3 m/s.

Results

Two hundred and twelve were identified. Eighty‐three dogs (39%) had PH. PH was more commonly identified in stage C compared to B2 (P < .0001). One hundred and five (49.5%) dogs died during the observation period. Median survival time for the entire study population was 567 days (95% CI 512–743). Stage C (P = .003), the presence of PH (P = .009), left atrial to aortic root ratio (LA/Ao) >1.7 (P = .0002), normalized left‐ventricular end‐diastolic diameter (LVEDn) >1.73 (P = .048), and tricuspid regurgitation pressure gradient (TRPG) >55 mmHg (P = .009) were associated with worse outcomes in the univariate analyses. The presence of TRPG >55 mmHg (HR 1.8 95% CI 1–2.9; P = .05) and LA/Ao > 1.7 (HR 2 95% CI 1.2–3.4; P = .01) remained significant predictors of worse outcome in the multivariate analysis.

Conclusions and Clinical Importance

In dogs with MMVD, moderate to severe PH worsens outcome.     

Effect of Chronic Administration of Phenobarbital,or Bromide,on Pharmacokinetics of Levetiracetam in Dogs with Epilepsy

Background

Levetiracetam (LEV) is a common add‐on antiepileptic drug (AED) in dogs with refractory seizures. Concurrent phenobarbital administration alters the disposition of LEV in healthy dogs.

Hypothesis/Objectives

To evaluate the pharmacokinetics of LEV in dogs with epilepsy when administered concurrently with conventional AEDs.

Animals

Eighteen client‐owned dogs on maintenance treatment with LEV and phenobarbital (PB group, n = 6), LEV and bromide (BR group, n = 6) or LEV, phenobarbital and bromide (PB–BR group, n = 6).

Methods

Prospective pharmacokinetic study. Blood samples were collected at 0, 1, 2, 4, and 6 hours after LEV administration. Plasma LEV concentrations were determined by high‐pressure liquid chromatography. To account for dose differences among dogs, LEV concentrations were normalized to the mean study dose (26.4 mg/kg). Pharmacokinetic analysis was performed on adjusted concentrations, using a noncompartmental method, and area‐under‐the‐curve (AUC) calculated to the last measured time point.

Results

Compared to the PB and PB–BR groups, the BR group had significantly higher peak concentration (C _max) (73.4 ± 24.0 versus 37.5 ± 13.7 and 26.5 ± 8.96 μg/mL, respectively, P < .001) and AUC (329 ± 114 versus 140 ± 64.7 and 98.7 ± 42.2 h*μg/mL, respectively, P < .001), and significantly lower clearance (CL/F) (71.8 ± 22.1 versus 187 ± 81.9 and 269 ± 127 mL/h/kg, respectively, P = .028).

Conclusions and Clinical Importance

Concurrent administration of PB alone or in combination with bromide increases LEV clearance in epileptic dogs compared to concurrent administration of bromide alone. Dosage increases might be indicated when utilizing LEV as add‐on treatment with phenobarbital in dogs.     

Biopterin Status in Dogs with Myxomatous Mitral Valve Disease is Associated with Disease Severity and Cardiovascular Risk Factors

Background

Endothelial dysfunction (ED) has been suggested to be associated with myxomatous mitral valve disease (MMVD) in dogs. Tetrahydrobiopterin (BH4) is an important cofactor for production of the endothelium‐derived vasodilator nitric oxide (NO). Under conditions of oxidative stress, BH4 is oxidized to the biologically inactive form dihydrobiopterin (BH2). Thus, plasma concentrations of BH2 and BH4 may reflect ED and oxidative stress.

Objective

To determine plasma concentrations of BH2 and BH4 in dogs with different degrees of MMVD.

Animals

Eighty‐four privately owned dogs grouped according to ACVIM guidelines (37 healthy control dogs including 13 Beagles and 24 Cavalier King Charles Spaniels [CKCSs], 33 CKCSs with MMVD of differing severity including 18 CKCSs [group B1] and 15 CKCSs [group B2], and 14 dogs of different breeds with clinical signs of congestive heart failure [CHF] because of MMVD [group C]).

Methods

Dogs underwent clinical examination including echocardiography. Plasma concentrations of BH2 and BH4 were measured using high‐performance liquid chromatography with fluorescence detection.

Results

Higher plasma BH4 and BH2 concentrations were found with dogs in CHF compared with all other groups (control, B1 and B2; P ≤ .001). Females had higher concentrations of BH4 and BH4/BH2 (P ≤ .0003). BH4/BH2 was found to decrease with age (P < .0001). Cardiovascular risk factors in humans such as passive smoking (P ≤ .01) and increased body weight (P ≤ .009) were associated with lower BH4 concentrations.

Conclusions and Clinical Importance

Age, sex, body weight, passive smoking, and cardiac status are associated with plasma biopterin concentration in dogs. Additional studies should clarify the clinical implications of the findings.     

Behavioral Abnormalities in Lagotto Romagnolo Dogs with a History of Benign Familial Juvenile Epilepsy: A Long‐Term Follow‐Up Study

Background

Lagotto Romagnolo (LR) dogs with benign juvenile epilepsy syndrome often experience spontaneous remission of seizures. The long‐term outcome in these dogs currently is unknown. In humans, behavioral and psychiatric comorbidities have been reported in pediatric and adult‐onset epilepsies.

Hypothesis/Objectives

The objectives of this study were to investigate possible neurobehavioral comorbidities in LR with a history of benign familial juvenile epilepsy (BFJE) and to assess the occurrence of seizures after the remission of seizures in puppyhood.

Animals

A total of 25 LR with a history of BFJE and 91 control dogs of the same breed.

Methods

Owners of the LR dogs in the BFJE and control groups completed an online questionnaire about each dog''s activity, impulsivity, and inattention. Principal component analysis (PCA) served to extract behavioral factors from the data. We then compared the scores of these factors between the 2 groups in a retrospective case–control study. We also interviewed all dog owners in the BFJE group by telephone to inquire specifically about possible seizures or other neurological problems after remission of seizures as a puppy.

Results

Lagotto Romagnolo dogs with BFJE showed significantly higher scores on the factors Inattention and Excitability/Impulsivity than did the control group (P = .003; P = .021, respectively). Only 1 of the 25 BFJE LR exhibited seizures after remission of epilepsy in puppyhood.

Conclusions and Clinical Importance

Although the long‐term seizure outcome in BFJE LR seems to be good, the dogs exhibit behavioral abnormalities resembling attention deficit hyperactivity disorder (ADHD) in humans, thus suggesting neurobehavioral comorbidities with epilepsy.     

Estimating the Sensitivity and Specificity of Real‐Time Quantitative PCR of Fecal Samples for Diagnosis of Rhodococcus equi Pneumonia in Foals

Background

Real‐time, quantitative PCR (qPCR) methods for detecting Rhodococcus equi in feces have been developed as a noninvasive, rapid diagnostic test for R. equi pneumonia, but have not been evaluated in a large population of foals.

Objective

The objective of this study was to evaluate the clinical utility of fecal PCR as a diagnostic test for R. equi pneumonia in foals using receiver operating characteristic (ROC) methods.

Animals

186 foals born in 2011 at an R. equi‐endemic ranch in Texas.

Methods

Fecal samples were collected at the time of onset of clinical signs for pneumonic foals (n = 31). Foals with pneumonia were matched by age and birth date to healthy (n = 31) and subclinical (n = 124) control foals; fecal samples were collected from these controls. DNA was extracted from feces using commercial kits and concentration of virulent R. equi in feces was determined by qPCR.

Results

Concentration of R. equi in feces differed significantly (P < .05) among groups. The area under the ROC curve for fecal qPCR for diagnosis of R. equi pneumonia was 89% (95% CI, 83–99), with a sensitivity of 94% and specificity of 72%.

Conclusions and Clinical Importance

qPCR of feces can be useful as an alternative to tracheobronchial aspiration for the diagnosis of R. equi in foals with clinical signs of pneumonia. Caution should be used in extrapolating results of this study to other populations because fecal concentration of R. equi might vary by geographic location or management practices.     

Incidence,Timing, and Risk Factors of Azathioprine Hepatotoxicosis in Dogs

Background

The use of azathioprine (AZA) in dogs is limited by the development of hepatotoxicosis and cytopenias.

Hypothesis and Objectives

To characterize the observed incidence, timing, and risk factors for AZA hepatotoxicosis in dogs treated clinically, and to determine the relationship between the development of hepatotoxicosis and cytopenias.

Animals

Fifty‐two dogs treated with AZA with clinical and biochemical follow‐up, with a subset of 34 dogs available for determination of changes in liver enzyme activities in serum.

Methods

Retrospective medical record review, from January 2009 through December 2013.

Results

Hepatotoxicosis (as defined by a >2‐fold increase in serum ALT) was observed in 5 of 34 dogs (15%) within a median onset of 14 days (range, 13–22 days). Dogs had a median 9‐fold increase in ALT and 8‐fold increase in ALP, which stabilized or resolved with drug discontinuation or dose reduction. German shepherds were significantly over‐represented (3 of 5 dogs with hepatotoxicosis; P = .0017). Thrombocytopenia or neutropenia were seen in 4 of 48 dogs with CBC follow‐up (8% of dogs), but occurred significantly later in treatment (median onset, 53 days; range 45–196 days) compared to hepatotoxicosis (P = .016).

Conclusions and Clinical Importance

These results support the routine monitoring of liver enzymes during the first 1–4 weeks of AZA treatment in dogs, with continued monitoring of the CBC. Additional studies are warranted to characterize the apparently higher risk of AZA hepatotoxicosis in German shepherds.     

Relationship between lean body mass and serum renal biomarkers in healthy dogs

Background

Symmetric dimethylarginine (SDMA) is an accurate and precise biomarker for estimating glomerular filtration rate (GFR) in humans and cats. Serum creatinine (sCr) also correlates with GFR, but has limitations as a biomarker of renal function because nonrenal factors can influence its concentration.

Hypothesis

Differences in lean body mass (LBM) influence sCr, but not serum SDMA concentrations.

Animals

Forty‐one healthy Beagles, mean age 9.9 years (range: 3.1–14.8 years), were studied over a 6 month period.

Methods

Serum biomarkers of renal function were measured prospectively at baseline, and 1, 3, and 6 months. SDMA concentrations were measured by liquid chromatography‐mass spectroscopy and sCr concentrations by enzymatic colorimetry. Body composition was determined by dual energy x‐ray absorptiometry.

Results

LBM (P < .001) and age (P = .006) were significant explanatory variables for sCr concentration (R ²  = 0.38), but not SDMA concentration. Time on food was the only significant explanatory variable for SDMA concentration (R ²  = 0.49). SDMA concentrations decreased across time (P < .001). LBM was affected by sex (males > females; P = .02). Mature adult dogs (<8 years) had greater LBM compared with geriatric dogs (≥8 years; P < .001).

Conclusion and Clinical Importance

sCr concentrations, but not SDMA concentrations, are influenced by LBM, which limits sCr utility as a biomarker for monitoring renal function in dogs with decreased LBM. Reductions in LBM can lower sCr concentration and overestimate GFR. SDMA concentrations, but not sCr concentrations were influenced by time on food. SDMA could have clinical advantages over sCr in monitoring response to nutritional interventions.     

Vitamin D Status in Different Stages of Disease Severity in Dogs with Chronic Valvular Heart Disease

Background

In humans with heart disease, vitamin D deficiency is associated with disease progression and a poor prognosis. A recent study showed that serum 25‐hydroxyvitamin D [25(OH)D] concentration, the hallmark of vitamin D status, was lower in dogs with heart failure than in normal dogs, and a low concentration was associated with poor outcome in dogs with heart failure.

Objectives

To elucidate the vitamin D status of dogs with chronic valvular heart disease (CVHD) at different stages of disease severity.

Animals

Forty‐three client‐owned dogs with CVHD.

Methods

In this cross‐sectional study, dogs were divided into 3 groups (14 dogs in Stage B1, 17 dogs in Stage B2, and 12 dogs in Stage C/D) according to ACVIM guidelines. Dogs underwent clinical examination including echocardiography. Serum 25(OH)D concentrations were measured in each dog.

Results

Serum 25(OH)D concentration was significantly lower in Stage B2 (median, 33.2 nmol/L; range, 4.9–171.7 nmol/L) and C/D (13.1 nmol/L; 4.9–58.1 nmol/L) than in Stage B1 (52.5 nmol/L; 33.5–178.0 nmol/L) and was not significantly different between Stage B2 and Stage C/D. Among clinical variables, there were significant negative correlations between 25(OH)D concentration and both left atrial‐to‐aortic root ratio and left ventricular end‐diastolic diameter normalized for body weight.

Conclusions and Clinical Importance

These results indicate that vitamin D status is associated with the degree of cardiac remodeling, and the serum 25(OH)D concentration begins to decrease before the onset of heart failure in dogs with CVHD.     

Sound Pressure Levels in 2 Veterinary Intensive Care Units

Background

Intensive care units (ICUs) in human hospitals are consistently noisy environments with sound levels sufficient to substantially decrease sleep quality. Sound levels in veterinary ICUs have not been studied previously, but environmental sound has been shown to alter activity in healthy dogs.

Hypothesis

Veterinary ICUs, like those in human medicine, will exceed international guidelines for hospital noise.

Animals

NA.

Methods

Prospective, observational study performed consecutively and simultaneously over 4 weeks in 2 veterinary ICUs. Conventional A‐weighted sound pressure levels (equivalent continuous level [a reflection of average sound], the sound level that is exceeded 90% of the recording period time [reflective of background noise], and maximum sound levels) were continuously recorded and the number of spikes in sound >80 dBA were manually counted.

Results

Noise levels were comparable to ICUs in human hospitals. The equivalent continuous sound level was higher in ICU1 than in ICU2 at every time point compared, with greatest differences observed on week day (ICU1, 60.1 ± 3.7 dBA; ICU2, 55.9 ± 2.5 dBA, P < .001) and weekend nights (ICU1, 59.9 ± 2.4 dBA; ICU2, 53.4 ± 1.7 dBA, P < .0001) reflecting a 50% difference in loudness. Similar patterns were observed for the maximum and background noise levels. The number of sound spikes was up to 4 times higher in ICU1 (162.3 ± 84.9 spikes) than in ICU2 (40.4 ± 12.2 spikes, P = .001).

Conclusions and Clinical Importance

These findings show that sound in veterinary ICUs is loud enough to potentially disrupt sleep in critically ill veterinary patients.     

Comparative Analysis of mRNA Expression of Surface Antigens between Histiocytic and Nonhistiocytic Sarcoma in Dogs

Background

Definitive diagnosis of histiocytic sarcoma (HS) in dogs is relatively difficult by conventional histopathological examination because objective features of HS are not well defined.

Hypothesis

Quantitative analysis of mRNA expression of selected cellular surface antigens (SAs) specific to HS in dogs can facilitate objective and rapid diagnosis.

Animals

Dogs with HS (n = 30) and dogs without HS (n = 36), including those with other forms of lymphoma (n = 4), inflammatory diseases (n = 6), and other malignant neoplasias (n = 26).

Methods

Retrospective clinical observational study. Specimens were collected by excisional biopsy, needle core biopsy, or fine needle aspiration. To determine HS detection efficacy, mRNA expression levels of selected SAs specific to HS in dogs, including MHC class IIα, CD11b, CD11c, and CD86, were quantitatively analyzed using real‐time quantitative polymerase chain reaction.

Results

Each SA mRNA expression level was significantly higher in HS dogs than in non‐HS dogs (P = .0082). Cutoff values for discriminating between HS and non‐HS dogs based on these expression levels were calculated on the basis of receiver‐operating characteristic analysis. Accuracy of the cutoff values, including MHC class IIα, CD11b, CD11c, and CD86, was 87.9, 86.4, 86.4, and 84.8%, respectively.

Conclusions and Clinical Importance

Our results suggest that quantitative analysis of mRNA expression of the selected SAs could be an adjunctive diagnostic technique with high diagnostic accuracy for HS in dogs. Substantial investigation is required for exclusion of diseases with similar cell types of origin to lymphoma.     

Plasma Vitamin D Metabolites and C‐Reactive Protein in Stage‐Stop Racing Endurance Sled Dogs

Background

Dogs are a unique model for examining the effects of exercise on vitamin D status because of their lack of vitamin D synthesis by UV exposure. In addition, the inflammatory response may be associated with hypovitaminosis D.

Objectives

To investigate the effects of several days of endurance exercise on plasma vitamin D (25‐(OH)D₃, 24,25‐(OH)D₃ and 1,25(OH)D₃) and serum C‐reactive protein (CRP) concentrations in stage‐stop racing sled dogs.

Animals

12 racing sled dogs and 8 control dogs.

Methods

Blood was collected before the race and immediately after racing on days 2 and 8. Plasma vitamin D metabolites and serum CRP concentrations were measured.

Results

Racing dogs showed a significant increase in 25(OH)D₃ on day 2 (P = .027) and day 8 of the race (P < .001), whereas no increases were observed in control dogs. The plasma concentration of 24,25(OH)D₃ showed a significant increase by day 8 (P < .001). There were no significant changes in 1,25(OH) D₃ concentrations across all time points and groups. Racing dogs had significantly increased CRP concentrations by day 2 (39.3 ± 30.1 μg/mL; P < .001).

Conclusions and Clinical Importance

Increases in vitamin D metabolites as well as increases in CRP concentrations were observed in racing sled dogs. This finding was contrary to the hypothesis that decreases in vitamin D status in athletes may be related to the acute phase inflammatory response during exercise. In addition, the increased 24,25(OH)D₃ concentrations compared to what is observed in other species suggests metabolic variations in dogs that lead to enhanced disposal of vitamin D.     

Effect of Screening Abdominal Ultrasound Examination on the Decision to Pursue Advanced Diagnostic Tests and Treatment in Dogs with Neurologic Disease

Background

Abdominal ultrasound examinations (AUS) are commonly performed before advanced neurodiagnostics to screen for diseases that might affect diagnostic plans and prognosis.

Objectives

Describe the type and frequency of abnormalities found by AUS in dogs presenting with a neurological condition, identify risk factors associated with abnormalities, and evaluate treatment decisions based on findings.

Animals

Seven hundred and fifty‐nine hospitalized dogs.

Methods

Retrospective study. Medical records of dogs presented from 2007 to 2009 for neurologic disease were searched for signalment, neuroanatomic localization, and AUS findings. Whether dogs had advanced neurodiagnostics and treatment was analyzed.

Results

Fifty‐eight percent of dogs had abnormal findings on AUS. Probability of abnormalities increased with age (P < 0.001). Nondachshund breeds had higher probability of abnormal AUS than dachshunds (odds ratio [OR] = 1.87). Eleven percent of dogs did not have advanced neurodiagnostics and in 1.3%, this was because of abnormal AUS. Dogs with ultrasonographic abnormalities were less likely than dogs without to have advanced neurodiagnostics (OR = 0.3 [95% confidence interval [CI]: 0.17, 0.52]), however, the probability of performing advanced diagnostics was high regardless of normal (OR = 0.95 [95% CI: 0.92, 0.97]) or abnormal (OR = 0.85 [95% CI: 0.81, 0.88]) AUS. Treatment was more often pursued in small dogs and less often in dogs with brain disease.

Conclusions and Clinical Importance

Findings from screening AUS had a small negative effect on the likelihood of pursuing advanced neurodiagnostics. Although it should be included in the extracranial diagnostic workup in dogs with significant history or physical examination abnormalities, AUS is considered a low‐yield diagnostic test in young dogs and dachshunds.