Agreement of Serum Spec cPL with the 1,2‐o‐Dilauryl‐Rac‐Glycero Glutaric Acid‐(6′‐methylresorufin) Ester (DGGR) Lipase Assay and with Pancreatic Ultrasonography in Dogs with Suspected Pancreatitis

Background

Spec cPL is the most sensitive and specific test for diagnosing pancreatitis in dogs. Its results have not been compared to those of the 1,2‐o‐dilauryl‐rac‐glycero‐3‐glutaric acid‐(6′‐methylresorufin) ester (DGGR) lipase assay or those of abdominal ultrasonography.

Objectives

To investigate agreement of Spec cPL with DGGR lipase activity and pancreatic ultrasonography in dogs with suspected pancreatitis.

Animals

One hundred and forty‐two dogs.

Methods

DGGR lipase activity (reference range, 24–108 U/L) and Spec cPL were measured using the same sample. The time interval between ultrasonography and lipase determinations was <24 hours. The agreement of the 2 lipase assays at different cutoffs and the agreement between pancreatic ultrasonography and the 2 tests were assessed using Cohen''s kappa coefficient (κ).

Results

DGGR lipase (>108, >216 U/L) and Spec cPL (>200 μg/L) had κ values of 0.79 (95% confidence interval [CI], 0.69–0.9) and 0.70 (CI, 0.58–0.82). DGGR lipase (>108, >216 U/L) and Spec cPL (>400 μg/L) had κ values of 0.55 (CI, 0.43–0.67) and κ of 0.80 (CI, 0.71–0.9). An ultrasonographic diagnosis of pancreatitis and DGGR lipase (>108, >216 U/L) had κ values of 0.29 (CI, 0.14–0.44) and 0.35 (CI, 0.18–0.52). Ultrasonographically diagnosed pancreatitis and Spec cPL (>200, >400 μg/L) had κ values of 0.25 (CI, 0.08–0.41) and 0.27 (CI, 0.09–0.45).

Conclusions and Clinical Importance

Although both lipase assays showed high agreement, agreement between ultrasonography and lipase assays results was only fair. Because lipase results are deemed more accurate, ultrasonography results should be interpreted carefully.     

Changes in Serum and Urine SAA Concentrations and Qualitative and Quantitative Proteinuria in Abyssinian Cats with Familial Amyloidosis: A Five‐year Longitudinal Study (2009–2014)

Background

Diagnosis of familial amyloidosis (FA) in Abyssinian cats usually is made on postmortem examination.

Hypothesis/Objectives

Sequential analysis of serum SAA (sSAA), urinary SAA (uSAA), urinary protein:creatinine (UPC) ratio, or sodium‐dodecylsulfate agarose gel electrophoresis (SDS‐AGE) may facilitate early identification of cats with FA.

Animals

Twenty‐three Abyssinian cats belonging to cattery A or B (low and high prevalence of FA, respectively).

Methods

Prospective longitudinal study using 109 blood and 100 urine samples collected over 4‐year period every 4 months, if possible, or more frequently in case of illness. Cats that died during study were necropsied. Health status of live cats was checked 5 years after enrollment. Serum amyloid A (sSAA) and urinary SAA (uSAA) were measured using ELISA kit. The UPC ratio and SDS‐AGE also was performed.

Results

Familial amyloidosis was not identified in cattery A, whereas 7/14 cats from cattery B had FA. Serum amyloid A concentrations were not significantly different between cats in catteries A and B or between cats with or without FA, despite frequent peaks in cats from cattery B. Conversely, uSAA was significantly higher in cattery B, especially in the terminal phases of FA. Proteinuria occasionally was found in cats from both catteries, especially in those with FA. Urine protein electrophoresis identified mixed proteinuria only in cats with FA.

Conclusions and Clinical Importance

Serum amyloid A and UPC ratio are not helpful for early identification of Abyssinian cats with FA. Conversely, increases in uSAA with or without mixed proteinuria may be found before onset of clinical signs in cats with FA.     

Clinical Presentation and Outcome of Cats with Circumcaval Ureters Associated with a Ureteral Obstruction

Background

Circumcaval ureters (CU) are a rare embryological malformation resulting in ventral displacement of the caudal vena cava, which crosses the ureter, potentially causing a ureteral stricture.

Objectives

To evaluate cats with obstructed CU(s) and report the presenting signs, diagnostics, treatment(s), and outcomes. Cats with obstructed CU(s) were compared to ureterally obstructed cats without CU(s).

Animals

193 cats; 22 circumcaval obstructed (Group 1); 106 non‐circumcaval obstructed (Group 2); 65 non‐obstructed necropsy cases (Group 3).

Methods

Retrospective study, review of medical records for cats treated for benign ureteral obstructions from AMC and University of Pennsylvania between 2009 and 2013. Inclusion criteria: surgical treatment of benign ureteral obstruction, complete medical record including radiographic, ultrasonographic, biochemistry, and surgical findings.

Results

Seventeen percent (22/128) of obstructed cats had a CU (80% right‐sided) compared to 14% (9/65) non‐obstructed necropsy cats (89% right‐sided). Clinical presentation, radiographic findings, and creatinine were not statistically different between Groups 1 and 2. Strictures were a statistically more common (40%) cause of ureteral obstruction in Group 1 compared to Group 2 (17%) (P = .01). The MST for Groups 1 and 2 after ureteral decompression was 923 and 762 days, respectively (P = .62), with the MST for death secondary to kidney disease in both groups being >1,442 days. Re‐obstruction was the most common complication in Group 1 (24%) occurring more commonly in ureters of cats treated with a ureteral stent(s) (44%) compared to the subcutaneous ureteral bypass (SUB) device (8%) (P = .01).

Conclusions and Clinical Importance

Ureteral obstructions in cats with a CU(s) have a similar outcome to those cats with a ureteral obstruction and normal ureteral anatomy. Long‐term prognosis is good for benign ureteral obstructions treated with a double pigtail stent or a SUB device. The SUB device re‐obstructed less commonly than the ureteral stent, especially when a ureteral stricture was present.     

Evaluation and Diagnostic Potential of Serum Ghrelin in Feline Hypersomatotropism and Diabetes Mellitus

Background

Ghrelin is a growth hormone secretagogue. It is a potent regulator of energy homeostasis. Ghrelin concentration is down‐regulated in humans with hypersomatotropism (HS) and increases after successful treatment. Additionally, ghrelin secretion seems impaired in human diabetes mellitus (DM).

Hypothesis

Serum ghrelin concentration is down‐regulated in cats with HS‐induced DM (HSDM) compared to healthy control cats or cats with DM unrelated to HS and increases after radiotherapy.

Animals

Cats with DM (n = 20) and with HSDM (n = 32), 13 of which underwent radiotherapy (RT‐group); age‐matched controls (n = 20).

Methods

Retrospective cross‐sectional study. Analytical performance of a serum total ghrelin ELISA was assessed and validated for use in cats. Differences in serum ghrelin, fructosamine, IGF‐1 and insulin were evaluated.

Results

Ghrelin was significantly higher (P < .001) in control cats (mean ± SD: 12.9 ± 6.8 ng/mL) compared to HSDM‐ (7.9 ± 3.3 ng/mL) and DM‐cats (6.7 ± 2.3 ng/mL), although not different between the HSDM‐ and DM‐cats. After RT ghrelin increased significantly (P = .003) in HSDM‐cats undergoing RT (from 6.6 ± 1.9 ng/mL to 9.0 ± 2.2 ng/mL) and the after RT ghrelin concentrations of HSDM cats were no longer significantly different from the serum ghrelin concentration of control cats. Serum IGF‐1 did not significantly change in HSDM‐cats after RT, despite significant decreases in fructosamine and insulin dose.

Conclusion and Clinical Importance

Ghrelin appears suppressed in cats with DM and HSDM, although increases after RT in HSDM, suggesting possible presence of a direct or indirect negative feedback system between growth hormone and ghrelin. Serum ghrelin might therefore represent a marker of treatment effect.     

Pasireotide for the Medical Management of Feline Hypersomatotropism

Background

Feline hypersomatotropism (HST) is a cause of diabetes mellitus in cats. Pasireotide is a novel multireceptor ligand somatostatin analog that improves biochemical control of humans with HST.

Hypothesis/Objectives

Pasireotide improves biochemical control of HST and diabetes mellitus in cats.

Animals

Hypersomatotropism was diagnosed in diabetic cats with serum insulin‐like growth factor‐1 (IGF‐1) concentration >1,000 ng/mL by radioimmunoassay and pituitary enlargement.

Methods

Insulin‐like growth factor 1 was measured and glycemic control assessed using a 12‐hour blood glucose curve on days 1 and 5. On days 2, 3, and 4, cats received 0.03 mg/kg pasireotide SC q12h. IGF‐1, insulin dose, and estimated insulin sensitivity (product of the area under the blood glucose curve [BGC] and insulin dose) were compared pre‐ and post treatment. Paired t‐tests or Wilcoxon signed rank tests were employed for comparison where appropriate; a linear mixed model was created to compare BGC results.

Results

Insulin‐like growth factor 1 decreased in all 12 cats that completed the study (median [range] day 1: 2,000 ng/mL [1,051–2,000] and day 5: 1,105 ng/mL [380–1,727], P = .002, Wilcoxon signed rank test). Insulin dose was lower on day 5 than on day 1 (mean reduction 1.3 [0–2.7] units/kg/injection, P = .003, paired t‐test). The product of insulin dose and area under the BGC was lower on day 5 than day 1 (difference of means: 1,912; SD, 1523; u × mg/dL × hours, P = .001; paired t‐test). No clinically relevant adverse effects were encountered.

Conclusions

Short‐acting pasireotide rapidly decreased IGF‐1 in cats with HST and insulin‐dependent diabetes. The decrease in IGF‐1 was associated with increased insulin sensitivity.     

Clinical Characterization of Epilepsy of Unknown Cause in Cats

Background

The diagnosis of feline epilepsy of unknown cause (EUC) requires a thorough diagnostic evaluation, otherwise the prevalence of EUC could be overestimated.

Hypothesis

Feline EUC is a clinically defined disease entity, which differs from feline hippocampal necrosis by the absence of magnetic resonance imaging (MRI) signal alteration of the hippocampus. The objectives of this study were (1) to evaluate the prevalence of EUC in a hospital population of cats by applying well‐defined inclusion criteria, and (2) to describe the clinical course of EUC.

Animals

Eighty‐one cats with recurrent seizures.

Methods

Retrospective study—medical records were reviewed for cats presented for evaluation of recurrent seizures (2005–2010). Inclusion criteria were a defined diagnosis based on laboratory data, and either MRI or histopathology. Final outcome was confirmed by telephone interview with the owner. Magnetic resonance images were reviewed to evaluate hippocampal morphology and signal alterations.

Results

Epilepsy of unknown cause was diagnosed in 22% of cats with epilepsy. Physical, neurologic, and laboratory examinations, and either 1.5 T MRI and cerebrospinal fluid analysis or postmortem examination failed to identify an underlying cause. Cats with EUC had a higher survival rate (P < .05) and seizure remission occurred frequently (44.4%).

Conclusion and Clinical Importance

A detailed clinical evaluation and diagnostic imaging with MRI is recommended in any cat with recurrent seizures. The prognosis of cats with normal MRI findings and a clinical diagnosis of EUC are good. Standardized imaging guidelines should be established to assess the hippocampus in cats.     

Risk Factors and Outcomes in Cats with Acquired Myasthenia Gravis (2001–2012)

Background

Acquired myasthenia gravis (MG) in cats most commonly causes generalized weakness without megaesophagus and is more often associated with a cranial mediastinal mass, compared to dogs.

Hypothesis/Objectives

To extend the clinical findings described in the report of 2000 on MG in cats (J Am Vet Med Assoc 215:55–57).

Animals

Two hundred and thirty‐five cats with MG.

Methods

Retrospective case study to evaluate the long‐term outcome and incidence of spontaneous remission in myasthenic cats. Information including signalment, clinical presentation, presence of and type of cranial mediastinal mass, treatment including surgical versus medical, survival time, and outcome including spontaneous remissions was collected and analyzed in cats diagnosed at the Comparative Neuromuscular Laboratory, University of California San Diego by detection of acetylcholine receptor antibody titers >0.3 nmol/L by immunoprecipitation radioimmunosassay.

Results

Acquired MG in cats is associated with a euthanasia rate of 58%. Abyssinian and Somali cats had an increased incidence of MG compared to mixed breed cats or cats of other breeds. A cranial mediastinal mass, most commonly thymoma, was observed in 52% of the cats, which is higher than in the previous report. Spontaneous remission is not a characteristic of MG in cats.

Conclusions and clinical importance

Myasthenia gravis in cats is a chronic disease associated with a high incidence of a cranial mediastinal mass. Spontaneous remission is not common and clinicians should warn owners of the necessity for long‐term treatment. The clinical outcome with a cranial mediastinal mass did not differ between surgical or medical treatment.     

Computed Tomographic Angiography under Sedation in the Diagnosis of Suspected Canine Pancreatitis: A Pilot Study

Background

Computed tomography (CT) is highly accurate for diagnosing pancreatitis in humans. The diagnosis of pancreatitis in dogs is based on clinical signs, laboratory findings, and ultrasonographic (US) changes. There are, however, inherent limitations in relying on laboratory and ultrasound findings for the clinical diagnosis of pancreatitis in dogs.

Hypothesis/Objectives

We hypothesized that CT angiography would be a rapid and reliable method to confirm pancreatitis in dogs compared to ultrasonography. The aim was to describe the CT characteristics and compare them to ultrasound findings and correlate the CT appearance to the severity of the patients'' clinical course.

Animals

A prospective pilot case series; 10 dogs with pancreatitis were enrolled if the history, clinical signs, laboratory, and ultrasonographic findings were indicative of pancreatitis.

Methods

A 3‐phase angiographic CT was performed under sedation. Afterward, each dog had US‐guided aspirates of the pancreas collected and blood drawn for cPLi assay. Images were evaluated for portion of visible pancreas, pancreatic size and margin, pancreatic parenchyma, presence of peripancreatic changes and contrast enhancement pattern. The results were compared with outcome.

Results

An enlarged, homogeneously to heterogeneously attenuating and contrast‐enhancing pancreas with ill‐defined borders was identified in all dogs. CT identified more features characterizing pancreatic abnormalities compared to US. Thrombi were found in 3/10 dogs. Three dogs with heterogeneous contrast enhancement had an overall poorer outcome than those with homogenous enhancement.

Conclusions and Clinical Importance

CT angiography under sedation was used in dogs to confirm clinically suspected pancreatitis and identified clinically relevant and potentially prognostic features of pancreatitis in dogs.     

Evaluation of Thyroid‐Stimulating Hormone,Total Thyroxine,and Free Thyroxine Concentrations in Hyperthyroid Cats Receiving Methimazole Treatment

Background

Iatrogenic hypothyroidism (IH) after treatment of hyperthyroidism can impair renal function. No study compared the efficacy of measurement of serum free thyroxine by equilibrium dialysis (fT4ed) or thyroid‐stimulating hormone (TSH) concentrations for monitoring cats receiving methimazole.

Objectives

To (1) compare the ability of total T4 and fT4ed concentrations in conjunction with TSH to define thyroid function in hyperthyroid cats receiving methimazole, (2) determine the prevalence of IH in cats receiving methimazole, and (3) examine the relationship between thyroid axis hormones and serum creatinine concentration.

Animals

One hundred and twenty‐five serum samples from hyperthyroid cats receiving methimazole and total T4 concentrations ≤3.9 μg/dL.

Methods

Total T4, fT4ed, and TSH concentrations were measured to evaluate thyroid status and serum creatinine concentration was measured to assess renal function. A low total T4 or fT4ed concentration in combination with an increased TSH concentration defined IH.

Results

Forty‐one cats (33%) had increased TSH concentrations. Of cats with total T4 and fT4ed concentrations below the reference range, 68% and 73%, respectively, had TSH concentrations above the reference range. Only 18% of cats with a normal TSH concentration had an increased serum creatinine concentrations as compared to 39% of those with increased TSH concentrations (P < .001).

Conclusions

Free T4ed does not identify more cats with potential IH as compared to total T4. The IH prevalence was approximately 20%. Measurement of TSH may be more helpful in indicating that azotemia, if present, is at least in part related to IH. Investigation is needed to define TSH assay utility in identifying possible subclinical IH.     

Incidence of Diabetes Mellitus in Insured Swedish Cats in Relation to Age,Breed and Sex

Background

Diabetes mellitus (DM) is a common endocrinopathy in cats. Most affected cats suffer from a type of diabetes similar to type 2 diabetes in humans. An increasing prevalence has been described in cats, as in humans, related to obesity and other lifestyle factors.

Objectives

To describe the incidence of DM in insured Swedish cats and the association of DM with demographic risk factors, such as age, breed and sex.

Animals

A cohort of 504,688 individual cats accounting for 1,229,699 cat‐years at risk (CYAR) insured by a Swedish insurance company from 2009 to 2013.

Methods

We used reimbursed insurance claims for the diagnosis of DM. Overall incidence rates and incidence rates stratified on year, age, breed, and sex were estimated.

Results

The overall incidence rate of DM in the cohort was 11.6 cases (95% confidence interval [CI], 11.0–12.2) per 10,000 CYAR. Male cats had twice as high incidence rate (15.4; 95% CI, 14.4–16.4) as females (7.6; 95% CI, 6.9–8.3). Domestic cats were at higher risk compared to purebred cats. A significant association with breed was seen, with the Burmese, Russian Blue, Norwegian Forest cat, and Abyssinian breeds at a higher risk compared to other cats. No sex predisposition was found among Burmese cats. Several breeds with a lower risk of DM were identified.

Conclusions and clinical importance

Our results verify that the Burmese breed is at increased risk of developing DM. We also identified several previously unreported breeds with increased or decreased risk of DM.     

Acute Effects of Ivabradine on Dynamic Obstruction of the Left Ventricular Outflow Tract in Cats with Preclinical Hypertrophic Cardiomyopathy

Background

Ivabradine is a negative chronotropic drug with minimal effects on central hemodynamics. Its effect on dynamic obstruction of the left ventricular outflow tract (LVOT) in cats with hypertrophic cardiomyopathy (HCM) remains unknown.

Hypothesis/Objectives

Ivabradine reduces dynamic obstruction of the LVOT in cats with HCM.

Animals

Twenty‐eight client‐owned cats with preclinical HCM and dynamic LVOT obstruction.

Methods

Randomized, double‐blind, active‐control single dose study. Cats received a single dose of either ivabradine (0.3 mg/kg PO) or atenolol (2 mg/kg PO). Heart rate, echocardiographic variables, and systolic blood pressure (SBP) were recorded before and 3 hours after drug administration. Statistical comparisons were made using ANCOVA.

Results

Peak velocity in the LVOT was significantly decreased compared to baseline for both drugs; however, the effect was more prominent with atenolol (mean reduction 2.53 m/s; 95% CI 2.07–3.13 m/s) compared to ivabradine (mean reduction 0.32 m/s; 95% CI −0.04 to 0.71 m/s; P < .0001). Echocardiographic indices of systolic function were largely unchanged by ivabradine, but significantly reduced by atenolol.

Conclusions and Clinical Importance

A single dose of ivabradine decreases dynamic LVOT obstruction in cats with HCM, but the clinical effect is negligible and inferior compared to that achieved by atenolol.     

Survival Time of Cross‐Match Incompatible Red Blood Cells in Adult Horses

Background

There is a markedly reduced half‐life of transfused RBCs when donor and recipient cats or humans are cross‐match incompatible. Only 10–20% of horses have naturally occurring alloantibodies. Therefore, cross‐match testing before blood transfusion is not always performed.

Hypothesis

Cross‐match incompatibility predicts shortened RBC survival time as compared to that of compatible or autologous blood.

Animals

Twenty healthy adult horses.

Methods

Prospective trial. Blood type, anti‐RBC antibody screen (before and 1 month after transfusion) and major and minor cross‐match determined 10 donor‐recipient pairs. Two pairs were cross‐match compatible, the remainder incompatible. Donor blood (4 L) was collected into citrate phosphate dextrose adenine‐1, labeled with NHS‐biotin, and transfused into recipients. Samples were collected at 1 hour and 1, 2, 3, 5, 7, 14, 21, 28, and 35 days after transfusion, and biotinylated RBCs were detected by flow cytometry. Horses were monitored for transfusion reaction during transfusion and daily for 5 days.

Results

Cross‐match incompatibility was significantly associated with decreased RBC survival time (P < .001). The half‐life of transfused incompatible (cross‐match >1+) allogenic equine RBCs was 4.7 (95% CI, 3.2–6.2) days versus 33.5 (24–43) days for compatible pairings. Cross‐match incompatibility was associated with acute febrile transfusion reaction (P = .0083). At day 30, only 1 horse had developed novel anti‐RBC antibodies.

Conclusions and Clinical Importance

Cross‐match incompatibility was predictive of febrile transfusion reaction and shortened transfused RBC survival, but did not result in production of anti‐RBC antibodies at 30 days. Cross‐match testing before transfusion is recommended.     

Relationship Between Degenerative Joint Disease,Pain, and Bartonella spp. Seroreactivity in Domesticated Cats

Background

Recently, a potential association was identified between Bartonella exposure and arthritides in mammalian species other than cats.

Hypothesis/Objectives

We hypothesized that Bartonella exposure is associated with more severe degenerative joint disease (DJD) and a greater burden of DJD‐associated pain in client‐owned cats.

Animals

Ninety‐four client‐owned cats (6 months to 20 years old), ranging from clinically unaffected to severely lame because of DJD.

Methods

Using physical examination and radiography, pain and radiographic scores were assigned to each part of the bony skeleton. Sera were tested for Bartonella henselae, B. koehlerae, and B. vinsonii subsp. berkhoffii (genotypes I, II, and III) antibodies using immunofluorescence antibody assays. Variables were categorized and logistic regression used to explore associations.

Results

Seropositivity to Bartonella was identified in 33 (35.1%) cats. After multivariate analysis controlling for age, total DJD score (OR, 0.51; 95% CI, 0.26–0.97; P = .042), appendicular pain score (OR, 0.33; 95% CI, 0.17–0.65; P = .0011), and total pain score (OR, 0.35; 95% CI, 0.17–0.72; P = .0045) were significantly inversely associated with Bartonella seroreactivity status, indicating that cats with higher DJD and pain scores were less likely to be Bartonella seropositive.

Conclusions and Clinical Importance

Based upon this preliminary study, Bartonella spp. seropositivity was associated with decreased severity of DJD and decreased DJD‐associated pain in cats. Additional studies are needed to verify these findings, and if verified, to explore potential mechanisms.     

Plasma and Erythrocyte Glutathione Peroxidase Activity,Serum Selenium Concentration,and Plasma Total Antioxidant Capacity in Cats with IRIS Stages I–IV Chronic Kidney Disease

Background

Serum selenium concentrations and the activity of plasma glutathione peroxidase (GPx) decrease with the progression of chronic kidney disease (CKD) in human patients. Selenium is considered a limiting factor for plasma GPx synthesis. Plasma total antioxidant capacity (TAC) is decreased in CKD cats in comparison to healthy cats.

Hypothesis

Serum selenium concentrations and plasma and erythrocyte GPx activity in cats with CKD are lower than in healthy cats. Serum selenium concentrations, the activity of enzymes, and plasma TAC progressively decrease with the progression of kidney disease according to IRIS (International Renal Interest Society) classification.

Animals

Twenty‐six client‐owned cats in IRIS stages I–IV of CKD were compared with 19 client‐owned healthy cats.

Methods

A CBC, serum biochemical profile, urinalysis, plasma and erythrocyte GPx activity, serum selenium concentration, and plasma TAC were measured in each cat.

Results

Cats in IRIS stage IV CKD had a significantly higher (P = .025) activity of plasma GPx (23.44 ± 6.28 U/mL) than cats in the control group (17.51 ± 3.75 U/mL). There were no significant differences in erythrocyte GPx, serum selenium concentration, and plasma TAC, either among IRIS stages I–IV CKD cats or between CKD cats and healthy cats.

Conclusions and Clinical Importance

Erythrocyte GPx activity, serum selenium concentration, and plasma TAC do not change in CKD cats compared with healthy cats. Selenium is not a limiting factor in feline CKD. Increased plasma GPx activity in cats with stage IV CKD suggests induction of antioxidant defense mechanisms. Antioxidant defense systems might not be exhausted in CKD in cats.     

Effect of Feeding an Iodine‐Restricted Diet in Cats with Spontaneous Hyperthyroidism

Background

Exclusive feeding of an iodine‐restricted diet has been proposed as a method for controlling clinical manifestations of hyperthyroidism in hyperthyroid cats.

Objectives

To determine the effect of feeding an iodine‐restricted diet on TT4 concentrations and clinical signs in cats with spontaneous hyperthyroidism.

Animals

Forty‐nine client‐owned cats with spontaneous hyperthyroidism.

Methods

Retrospective case series. Hyperthyroid cats were exclusively fed a commercially available iodine‐restricted diet. Clinical response was assessed by change in weight and heart rate and serum TT4, blood urea nitrogen (BUN), and creatinine concentrations at various times during dietary management (21–60 days, 60–180 days).

Results

Serum TT4 normalized in 20/48 cats (42%) and 39/47 cats (83%) at 21–60 days and 61–180 days, respectively. Cats in which the TT4 concentrations were still above reference range at 21–60 days had a significantly higher starting TT4 than those that normalized their TT4 levels during the same time period (P = .038). Body weight did not significantly increase (P = .34) nor heart rate decrease (P = .64) during the study. There was a significant decrease in serum creatinine (P = .028). Cats in the low reference range for serum TT4 concentrations did not have a significant increase in body weight (P = .41) nor creatinine (P = .54) when compared to those with high reference range.

Conclusions and Clinical Importance

Restricted‐iodine diets were effective at maintaining serum TT4 concentrations within reference ranges for a majority of cats with spontaneous hyperthyroidism over 1 year, although not all clinical signs of hyperthyroidism improved.     

Evaluation of Serum Thyroid‐Stimulating Hormone Concentration as a Diagnostic Test for Hyperthyroidism in Cats

Background

In humans, measurement of serum thyroid‐stimulating hormone (TSH) concentration is commonly used as a first‐line discriminatory test of thyroid function. Recent reports indicate that canine TSH (cTSH) assays can be used to measure feline TSH and results can help diagnose or exclude hyperthyroidism.

Objectives

To investigate the usefulness of cTSH measurements as a diagnostic test for cats with hyperthyroidism.

Animals

Nine hundred and seventeen cats with untreated hyperthyroidism, 32 euthyroid cats suspected of having hyperthyroidism, and 131 clinically normal cats.

Methods

Prospective study. Cats referred to the Animal Endocrine Clinic for suspected hyperthyroidism were evaluated with serum T₄, T₃, free T₄ (fT ₄), and TSH concentrations. Thyroid scintigraphy was used as the gold standard to confirm or exclude hyperthyroidism.

Results

Median serum TSH concentration in the hyperthyroid cats (<0.03 ng/mL) was significantly (P < .001) lower than concentrations in clinically normal cats (0.05 ng/mL) or euthyroid cats with suspected thyroid disease (0.06 ng/mL). Only 18 (2.0%) hyperthyroid cats had measurable TSH concentrations (≥0.03 ng/mL), whereas 114 (69.9%) of the 163 euthyroid cats had detectable concentrations. Combining serum TSH with T₄ or fT ₄ concentrations lowered the test sensitivity of TSH from 98.0 to 97.0%, but markedly increased overall test specificity (from 69.9 to 98.8%).

Conclusions and Clinical Importance

Serum TSH concentrations are suppressed in 98% of hyperthyroid cats, but concentrations are measurable in a few cats with mild‐to‐moderate hyperthyroidism. Measurement of serum TSH represents a highly sensitive but poorly specific test for diagnosis of hyperthyroidism and is best measured in combination with T₄ and fT ₄.     

Multiple Hypersensitivities Including Recurrent Airway Obstruction,Insect Bite Hypersensitivity,and Urticaria in 2 Warmblood Horse Populations

Background

Multiple hypersensitivities (MHS) have been described in humans, cats, and dogs, but not horses.

Hypotheses

Horses suffering from recurrent airway obstruction (RAO), insect bite hypersensitivity (IBH), or urticaria (URT) will have an increased risk of also being affected by another one of these hypersensitivities. This predisposition for MHS also will be associated with decreased shedding of strongylid eggs in feces and with a single nucleotide polymorphism (SNP BIEC2‐224511), previously shown to be associated with RAO.

Animals

The first population (P1) included 119 randomly sampled horses representative of the Swiss sporthorse population; the replication population (P2) included 210 RAO‐affected Warmblood horses and 264 RAO‐unaffected controls. All horses were Warmbloods, 14 years or older.

Methods

Associations between disease phenotypes (RAO, IBH, URT, MHS) fecal egg counts, the SNP BIEC2‐224511 as well as management and environmental factors were investigated.

Results

In P1, RAO‐affected horses had a 13.1 times higher odds ratio (OR) of also suffering from IBH (P = .004). In P2, the respective OR was 7.4 (P = .002) and IBH‐affected horses also showed a 7.1 times increased OR of concomitantly suffering from URT (P < .001). IBH, URT, and MHS phenotypes were significantly associated with the absence of nematode eggs in the feces.

Conclusions and Clinical Importance

This is the first report of MHS in horses. Specifically, an increased risk for IBH should be expected in RAO‐affected horses.     

Relationship between Plasma Fibroblast Growth Factor‐23 Concentration and Survival Time in Cats with Chronic Kidney Disease

Background

Fibroblast growth factor‐23 (FGF‐23) and parathyroid hormone (PTH) are commonly increased in cats with azotemic chronic kidney disease (CKD). Both are predictors of survival time in human patients, but these relationships have not previously been examined in the cat.

Objectives

To investigate the relationship between plasma FGF‐23 and PTH concentrations at diagnosis of CKD in cats with survival time and with disease progression over 12 months.

Animals

214 azotemic, client‐owned cats (≥9 years).

Methods

Retrospective study: Biochemical and urinary variables at diagnosis of azotemic CKD, including plasma FGF‐23 and PTH concentrations were assessed as predictors of survival time (all‐cause mortality) using Cox regression, and as predictors of CKD progression over 12 months using logistic regression.

Results

In the final multivariable Cox regression model, survival was negatively associated with plasma creatinine (P = .002) and FGF‐23 concentrations (P = .014), urine protein‐to‐creatinine ratio (P < .001) and age (P < .001). Survival was positively associated with PCV (P = .004). In the final multivariable logistic regression model, independent predictors of CKD progression included logFGF‐23 and age. Neither plasma phosphate nor PTH was found to be an independent predictor of survival time or of CKD progression.

Conclusions and Clinical Importance

Plasma FGF‐23 concentration is a novel prognostic indicator in cats with CKD, independent of other factors including plasma creatinine and phosphate concentrations. Further work is required to assess if FGF‐23 contributes directly to CKD progression, but regardless these findings may make FGF‐23 a useful biomarker for predicting poorer outcomes in cats with CKD.     

Platelet Activation in Cats with Hypertrophic Cardiomyopathy

Background

Cats with hypertrophic cardiomyopathy (HCM) are at risk for development of systemic thromboembolic disease. However, the relationship between platelet activation state and cardiovascular parameters associated with HCM is not well described.

Objectives

To characterize platelet activation by flow cytometric evaluation of platelet P‐selectin and semiquantitative Western blot analysis of soluble platelet‐endothelial cell adhesion molecule‐1 (sPECAM‐1).

Animals

Eight normal healthy cats (controls) owned by staff and students of the School of Veterinary Medicine and 36 cats from the UC Davis Feline HCM Research Laboratory were studied.

Methods

Platelet‐rich plasma (PRP) was used for all flow cytometry studies. Platelet surface CD41 and P‐selectin expression were evaluated before and after ADP stimulation. sPECAM‐1 expression was evaluated by Western blot analysis of platelet‐poor plasma that had been stabilized with aprotinin. Standard echocardiographic studies were performed.

Results

Resting platelets from cats with severe HCM had increased P‐selectin expression compared to controls, and expressed higher surface density of P‐selectin reflected by their increased mean fluorescence intensities (MFI). Stimulation with ADP also resulted in significantly increased P‐selectin MFI of platelets from cats with severe HCM. Increased P‐selectin expression and MFI correlated with the presence of a heart murmur and end‐systolic cavity obliteration (ESCO). sPECAM‐1 expression from cats with moderate and severe HCM was significantly increased above those of control cats.

Conclusions and Clinical Importance

P‐selectin and sPECAM expression may be useful biomarkers indicating increased platelet activation in cats with HCM.     

Serial Evaluation of Abdominal Fluid and Serum Amino‐terminal pro‐C‐type Natriuretic Peptide in Dogs with Septic Peritonitis

Background

Serum N‐terminal pro‐C‐natriuretic peptide (NT‐proCNP) has shown promise as a diagnostic biomarker for sepsis. Its sensitivity to detect dogs with septic peritonitis (SP) is reportedly low, perhaps attributable to the compartmentalization of NT‐proCNP in the abdominal cavity.

Objectives

To evaluate the use of an ELISA for the measurement of NT‐proCNP in canine abdominal fluid and to describe the peri‐operative pattern of abdominal fluid and serum NT‐proCNP concentrations in dogs with SP.

Animals

Five client‐owned dogs with nonseptic abdominal effusion of varying etiologies and 12 client‐owned dogs with SP undergoing abdominal surgery and placement of a closed‐suction abdominal drain (CSAD). Six dogs were included upon hospital admission; 6 were included the day after surgery.

Methods

Prospective pilot study. A commercially available ELISA kit was analytically validated for use on canine abdominal fluid. The NT‐proCNP concentrations were measured in the abdominal fluid of control dogs, and in serum and abdominal fluid of dogs with SP from admission for CSAD removal.

Results

In dogs with SP, admission abdominal fluid NT‐proCNP concentrations were lower than the concurrent serum concentrations (P = 0.031), and lower than control canine abdominal fluid concentrations (P = 0.015). Postoperatively, abdominal fluid NT‐proCNP concentrations remained lower than serum concentrations (P < 0.050), except on day 4.

Conclusions and Clinical Importance

The ELISA kit was able to measure NT‐proCNP in canine abdominal fluid. In dogs with SP, low serum NT‐proCNP concentrations cannot be explained by abdominal compartmentalization.