Effects of Levothyroxine Administration and Withdrawal on the Hypothalamic-Pituitary-Thyroid Axis in Euthyroid Dogs.

BACKGROUND: Chronic supplementation can suppress the hypothalamic-pituitary-thyroid axis (HPTA) and make it difficult to assess thyroid function after withdrawal of levothyroxine. OBJECTIVES: To determine whether the HPTA is suppressed after levothyroxine administration in euthyroid dogs and the time required for resolution of any suppression. ANIMALS: Twenty-eight healthy euthyroid dogs. METHODS: A prospective, randomized study administering levothyroxine to euthyroid dogs for 8 weeks (group 1) or 16 weeks (group 2). Serum concentrations of total thyroxine (T4 ), free thyroxine (fT4 ) by equilibrium dialysis, thyroid stimulating hormone; thyrotropin (TSH), and 3,5,3'-triiodothyronine (T3 ) were measured every 4 weeks during supplementation and for 16 weeks after levothyroxine was discontinued. RESULTS: Mean serum concentrations of T4 and fT4 were significantly higher (P < .0001) and TSH was lower (P < .0001) in all dogs during levothyroxine administration compared to baseline. Mean serum concentrations of T4 , fT4, and TSH in both groups, beginning 1 week after levothyroxine was discontinued, were significantly different (P < .01) compared to values during levothyroxine administration but not compared to baseline values (P > .3). CONCLUSIONS AND CLINICAL IMPORTANCE: Assessing thyroid function tests 1 week after cessation of levothyroxine at 26 µg/kg once a day for up to 16 weeks will provide an accurate assessment of thyroid function in healthy euthyroid dogs.

Invasive Microsporum canis causing rhinitis and stomatitis in a cat.

Microsporum canis is a pathogenic fungus that typically causes dermatophytosis in cats. This report describes a cat with a Microsporum canis infection causing invasive fungal rhinitis that extended through the hard palate, resulting in adjacent stomatitis. Treatment with itraconazole and terbinafine resolved the infection.

Spontaneous Course of Biliary Sludge Over 12 Months in Dogs with Ultrasonographically Identified Biliary Sludge.

BACKGROUND: Biliary sludge is associated with gallbladder (GB) dysmotility and mucus hypersecretion suggesting a link between biliary sludge and the formation of GB mucoceles (GBM). If biliary sludge progresses to GBM, treatment to reduce the production and progression of sludge is warranted. HYPOTHESIS/OBJECTIVES: The objective of this study was to determine the course of biliary sludge in dogs. ANIMALS: Seventy-seven healthy, client-owned dogs ≥4 years of age screened for biliary sludge; 45 affected dogs identified. METHODS: Prospective, observational design. Serial ultrasound examinations were evaluated at 3, 6, 9, and 12 months to monitor degree of sludge based on proportion of GB filled with sludge (mild [0.01-24.4%], moderate [24.5-49.4%], moderate to severe [49.5-74.4%], severe [74.5-100%]), gravity dependency of sludge, and GB dimensions. RESULTS: After 1 year of follow-up, the degree of sludge was mild (34%), moderate (47%), moderate to severe (13%), severe (3%), or absent (3%). There was no significant difference in median degree of sludge over 1 year (P = .36). There were no significant changes in the gravity dependency of sludge over 1 year. A subset of dogs, 24%, with initial gravity-dependent sludge developed a combination of nondependent and dependent sludge. Dogs had resolved (2%), decreased (19%), static (40%), increased (29%), or recurrent (10%) sludge at the conclusion of the study. CONCLUSIONS AND CLINICAL IMPORTANCE: Biliary sludge was prevalent, affected dogs remained asymptomatic, and it rarely resolves in healthy dogs over a period of 1 year. Some dogs developed nongravity-dependent sludge within 1 year, which might indicate changes in consistency of sludge.

Histopathologic variation between liver lobes in dogs.

BACKGROUND: Biopsy of the liver evaluates a small portion of tissue, with inferences made to the entire organ. The method and number of biopsies obtained are tempered by consideration of the risks and benefits. Recommendations often include biopsy of more than one liver lobe, although the consistency of histopathology among lobes in dogs is unknown. HYPOTHESIS/OBJECTIVES: To describe the distribution of histopathologic abnormalities between liver lobes. We hypothesized that discordant results would be evenly distributed among all liver lobes. ANIMALS: Seventy dogs undergoing necropsy. METHODS: Prospective study. Liver samples were obtained from all lobes. A primary diagnosis was assigned to each liver sample based on the predominant histopathologic abnormality. RESULTS: In this population of dogs, biopsy of at least 2 liver lobes identified the predominant histologic abnormality in 98.6% of the cases. Ten (14%) of the dogs had ≤ 3 lobes in agreement and could not be assigned a predominant diagnosis. The same diagnosis was present in 6/6 lobes in 39 (56.5%) dogs, 5/6 lobes in 10 (14.5%) dogs, 4/6 lobes in 10 (14.5%) dogs, 3/6 lobes in 7 (10.1%) dogs, and 2/6 in 3 (4.3%) dogs. The number of discordant results did not differ between the liver lobes. CONCLUSION AND CLINICAL IMPORTANCE: The likelihood of obtaining a sample that is reflective of the predominant histologic abnormality in the liver is increased when multiple liver lobes are biopsied.

A comparison of liver sampling techniques in dogs.

BACKGROUND: The liver sampling technique in dogs that consistently provides samples adequate for accurate histopathologic interpretation is not known. HYPOTHESIS/OBJECTIVES: To compare histopathologic results of liver samples obtained by punch, cup, and 14 gauge needle to large wedge samples collected at necropsy. ANIMALS: Seventy dogs undergoing necropsy. METHODS: Prospective study. Liver specimens were obtained from the left lateral liver lobe with an 8 mm punch, a 5 mm cup, and a 14 gauge needle. After sample acquisition, two larger tissue samples were collected near the center of the left lateral lobe to be used as a histologic standard for comparison. Histopathologic features and numbers of portal triads in each sample were recorded. RESULTS: The mean number of portal triads obtained by each sampling method were 2.9 in needle samples, 3.4 in cup samples, 12 in punch samples, and 30.7 in the necropsy samples. The diagnoses in 66% of needle samples, 60% of cup samples, and 69% of punch samples were in agreement with the necropsy samples, and these proportions were not significantly different from each other. The corresponding kappa coefficients were 0.59 for needle biopsies, 0.52 for cup biopsies, and 0.62 for punch biopsies. CONCLUSION AND CLINICAL IMPORTANCE: The histopathologic interpretation of a liver sample in the dog is unlikely to vary if the liver biopsy specimen contains at least 3-12 portal triads. However, in comparison large necropsy samples, the accuracy of all tested methods was relatively low.

Longitudinal prevalence of hypertension, proteinuria, and retinopathy in dogs with spontaneous diabetes mellitus.

BACKGROUND: The prevalence and progression of vascular complications of spontaneous diabetes mellitus (DM) in dogs have not been described. OBJECTIVES: To investigate the effects of duration of disease, as estimated by time since DM diagnosis, and glycemic control on prevalence of systemic hypertension, proteinuria, and diabetic retinopathy in dogs with spontaneous DM. ANIMALS: Seventeen client-owned dogs with spontaneous DM. METHODS: Prospective, longitudinal observational study. Dogs with DM of less than 1 year's duration were recruited and evaluated once every 6 months for 24 months. Recorded measures included indirect BP, urine albumin, protein and creatinine concentrations, serial blood glucose and serum fructosamine concentrations, ophthalmic examination, and a standardized behavioral questionnaire. RESULTS: Eleven dogs completed the 2-year follow-up period, during which the highest recorded prevalence of systolic and diastolic hypertension was 55 and 64%, respectively. Prevalence of microalbuminuria and elevated urine protein:creatinine ratio (UPC) ranged up to 73 and 55%, respectively. Prevalence of retinopathy ranged up to 20%. No significant effect of time since DM diagnosis or glycemic control was detected for any of the measures examined. Additionally, no significant associations between BP, urine albumin concentration, UPC and retinopathy were detected. CONCLUSIONS AND CLINICAL RELEVANCE: With the exception of proteinuria, which was substantial in some cases, clinically deleterious diabetic vascular complications were not identified in dogs in this study.

Cardiac biomarkers in hyperthyroid cats.

BACKGROUND: Hyperthyroidism has substantial effects on the circulatory system. The cardiac biomarkers NT-proBNP and troponin I (cTNI) have proven useful in identifying cats with myocardial disease but have not been extensively investigated in hyperthyroidism. HYPOTHESIS: Plasma NT-proBNP and cTNI concentrations are higher in cats with primary myocardial disease than in cats with hyperthyroidism and higher in cats with hyperthyroidism than in healthy control cats. ANIMALS: Twenty-three hyperthyroid cats, 17 cats with subclinical hypertrophic cardiomyopathy (HCM), and 19 euthyroid, normotensive healthy cats ≥8 years of age. Fourteen of the hyperthyroid cats were re-evaluated 3 months after administration of radioiodine ((131)I). METHODS: Complete history, physical examination, complete blood count, serum biochemistries, urinalysis, blood pressure measurement, serum T4 concentration, plasma concentrations of NT-proBNP and cTNI, and echocardiogram were obtained prospectively from each cat. RESULTS: Hyperthyroid cats and cats with HCM had plasma NT-proBNP and cTNI concentrations that were significantly higher than those of healthy cats, but there was no significant difference between hyperthyroid cats and cats with HCM with respect to the concentration of either biomarker. In hyperthyroid cats that were re-evaluated 3 months after (131) I treatment, plasma NT-proBNP and cTNI concentrations as well as ventricular wall thickness had decreased significantly. CONCLUSIONS AND CLINICAL IMPORTANCE: Although there may be a role for NT-proBNP in monitoring the cardiac response to treatment of hyperthyroidism, neither NT-proBNP nor cTNI distinguish hypertrophy associated with hyperthyroidism from primary HCM. Therefore, the thyroid status of older cats should be ascertained before interpreting NT-proBNP and cTNI concentrations.

Ultrasonographic findings of the pancreas in cats with elevated serum pancreatic lipase immunoreactivity.

BACKGROUND: Pancreatitis is a common disease in cats that is difficult to diagnose. HYPOTHESIS/OBJECTIVES: To determine the sensitivity and specificity of ultrasonographic changes of the pancreas with serum feline pancreatic lipase immunoreactivity (fPLI) as the standard for diagnosis of pancreatitis. ANIMALS: 35 cats with clinical signs consistent with pancreatitis with an abdominal ultrasound examination and serum fPLI concentration measured within 3 days of the ultrasound. METHODS: Retrospective study: Pancreatic thickness, pancreatic margination, pancreatic echogenicity, and peripancreatic fat echogenicity were evaluated. Sensitivity and specificity were calculated with an elevated serum fPLI concentration indicative of pancreatitis as the standard for diagnosis. RESULTS: Serum fPLI was elevated and diagnostic for pancreatitis in 19 of 35 cats. The single ultrasound characteristic with the highest sensitivity was hyperechoic peripancreatic fat at 68% (95% confidence interval = 44-87%), indicating a moderate probability that cats with pancreatitis will have this abnormality on ultrasonographic examination. Specificity was >90% for each of increased pancreatic thickness, abnormal pancreatic margin, and hyperechoic peripancreatic fat. The sensitivity and specificity of ultrasound were 84% (95% confidence interval = 60-97%) and 75% (95% confidence interval = 48-93%), respectively, in cats with elevated serum fPLI indicative of pancreatitis. CONCLUSIONS AND CLINICAL IMPORTANCE: The presence of a thick left limb of the pancreas, severely irregular pancreatic margins, and hyperechoic peripancreatic fat in cats with appropriate clinical signs and elevated serum fPLI are highly supportive of pancreatitis.

A comparison of hepatic sonographic features and histopathologic diagnosis in canine liver disease: 138 cases.

BACKGROUND: Ultrasound examination is commonly used in the diagnostic evaluation of liver disease in dogs. HYPOTHESIS/OBJECTIVES: To determine if hepatic sonographic features were predictive of findings on liver histopathology. We hypothesized that there would be a relationship between sonographic features and the category of liver disease based on histologic assessment. ANIMALS: One hundred and thirty-eight dogs in which the liver was evaluated by both abdominal ultrasound examination and histopathologic examination. Twenty-five dogs were included in each of the following categories based on histopathology: normal, degenerative, vascular, inflammatory, and neoplasia. Thirteen dogs had nodular regeneration. METHODS: Retrospective study. Medical records of dogs from 2005 to 2010 were searched for cases in which the liver was evaluated by abdominal ultrasound examination as well as by histopathology. After independent evaluation of ultrasound images, the recorded sonographic features were analyzed to identify abnormalities associated with each histopathologic diagnosis or degree of fibrosis. RESULTS: Sixty-four percent of sonographically unremarkable livers had histologic abnormalities. Both microhepatia and the identification of abnormal vasculature were significantly associated with a histopathologic diagnosis of vascular disease. Hepatic masses were significantly associated with a diagnosis of neoplasia. Dilated common bile duct and thickened gall bladder wall were significantly associated with hepatitis. There were no sonographic findings consistently present with hepatic fibrosis. CONCLUSION AND CLINICAL IMPORTANCE: Although some ultrasonographic findings, including masses, microhepatia, anomalous veins, and biliary changes, are associated with specific histopathologic abnormalities, sonographic findings are inconsistently detected in many disorders. Overall, hepatic ultrasonographic abnormalities have substantial limitations in predicting the underlying disease.

Diagnostic utility of abdominal ultrasonography in dogs with chronic diarrhea.

BACKGROUND: Chronic diarrhea is common in dogs and has many causes. Ultrasonographic descriptions of many gastrointestinal diseases have been published, but the diagnostic utility of ultrasonography in dogs with chronic diarrhea has not been investigated. HYPOTHESIS: Diagnostic utility of abdominal ultrasound will be highest in dogs with GI neoplasia and lowest in those with inflammatory disorders. ANIMALS: 87 pet dogs with chronic diarrhea. METHODS: Prospective study in which medical records were reviewed and contribution of abdominal ultrasound toward making diagnosis was scored. RESULTS: In 57/87 (66%) of dogs, the same diagnosis would have been reached without ultrasonography. In 13/87 (15%) of dogs, the ultrasound examination was vital or beneficial to making the diagnosis. Univariable analysis identified that increased diagnostic utility was associated with weight loss (P = .0086), palpation of an abdominal or rectal mass (P = .0031), diseases that commonly have mass lesions visible on ultrasound examination (P < .0001), and a final diagnosis of GI neoplasia. Multivariable regression indicated that utility of abdominal ultrasonography would be 30 times more likely to be high in dogs in which an abdominal or rectal mass was palpated (odds ratio 30.5, 95% CI 5.5-169.6) (P < .0001) versus dogs without a palpable mass. In 15/87 (17%) of dogs, additional benefits of ultrasonography to case management, independent of the contribution to the diagnosis of diarrhea, were identified. CONCLUSIONS AND CLINICAL IMPORTANCE: Overall, the diagnostic utility of abdominal ultrasonography was low in dogs with chronic diarrhea. Identification of factors associated with high diagnostic utility is an indication to perform abdominal ultrasonography in dogs with chronic diarrhea.

Concentrations of noncortisol adrenal steroids in response to ACTH in dogs with adrenal-dependent hyperadrenocorticism, pituitary-dependent hyperadrenocorticism, and nonadrenal illness.

BACKGROUND: Increases of adrenal hormone concentrations other than cortisol have been reported in dogs with hyperadrenocorticism (HAC). HYPOTHESIS/OBJECTIVES: Measuring noncortisol adrenal hormone concentrations will help identify HAC in dogs. The objective was to determine plasma cortisol, androstenedione, estradiol, progesterone, testosterone, and 17-hydroxyprogesterone concentrations during ACTH stimulation testing of dogs with clinical signs of HAC to ascertain their utility in diagnosis of the disease. ANIMALS: Ninety dogs with clinical findings consistent with HAC had ACTH stimulation tests performed. Results from 29 dogs were excluded from analysis because diagnoses were inconclusive for a variety of reasons. Results from 32 dogs with HAC and 29 dogs with disease other than HAC were analyzed. METHODS: Prospective observational study. Concentrations of adrenocortical hormones were determined before and 1 hour after injecting 5 µg/kg ACTH IM. Diagnoses were determined by response to therapy, histopathology or both. RESULTS: Post-ACTH cortisol (P < .001), progesterone (P = .001), and 17-hydroxyprogesterone (P < .001) concentrations were associated with a diagnosis of HAC. Sensitivity and specificity, respectively, for diagnosing HAC for post-ACTH cortisol were 84 and 59%, progesterone 88 and 55%, and 17-hydroxyprogesterone 91 and 59%, and for post-ACTH cortisol, progesterone and 17-hydroxyprogesterone combined were 88 and 55%. Of 5 dogs with HAC and normal post-ACTH cortisol concentrations, 5 had increased progesterone and 4 had increased 17-hydroxyprogesterone. CONCLUSIONS AND CLINICAL IMPORTANCE: Serum progesterone and 17-hydroxyprogesterone concentrations were useful to diagnose HAC in this study, but were not more sensitive or specific than cortisol concentration.

Reproductive effects of prolonged experimentally induced hypothyroidism in bitches.

BACKGROUND: Hypothyroidism has detrimental effects on reproduction in females of many species. Studies of hypothyroidism in bitches are limited and results conflicting. HYPOTHESIS: Hypothyroidism interferes with reproductive function and health of offspring in bitches. ANIMALS: A total of 9 healthy mixed-breed bitches (control) and 9 mixed breed bitches with hypothyroidism induced by radioactive iodine administration. METHODS: Dogs in both groups were bred 20.9 ± 4.0 and 56 ± 7.6 weeks after radioiodine administration in the hypothyroid group and again after levothyroxine was administered for 37 ± 14 weeks to hypothyroid dogs. Measures of the estrus cycle, fertility, gestation, whelping, and pup health were evaluated at each breeding. Comparisons were made between hypothyroid and control dogs as well as within groups between times. RESULTS: Pregnancy was documented in all dogs in both groups at the 1st breeding, 4/8 and 6/6 untreated hypothyroid and control dogs, respectively, at the 2nd breeding, and 6/6 and 5/6 treated hypothyroid and control dogs, respectively, at the 3rd breeding. Periparturient mortality was higher and birth weight was lower in pups born to untreated hypothyroid dogs compared with control dogs or treated hypothyroid dogs. There was no difference in interestrus interval, gestation duration, breeding behavior, interval between birth of pups, or serum progesterone concentrations at any breeding between or within groups. Resolution of hypothyroidism reversed the detrimental effects of thyroid hormone deficiency on reproduction. CONCLUSIONS AND CLINICAL IMPORTANCE: Hypothyroidism causes reversible periparturient mortality and low birth weight in offspring. Further investigation is necessary to determine if fertility is affected.

The effects of illness on urinary catecholamines and their metabolites in dogs.

BACKGROUND: Urinary catecholamines and metanephrines have been proposed as a diagnostic tool for identifying canine pheochromocytomas, but the effects of critical illness on urine concentrations of catecholamines and metanephrines currently are unknown. OBJECTIVES: To examine the effects of illness on urine concentrations of catecholamines and metanephrines in dogs. ANIMALS: Twenty-five critically ill dogs and 25 healthy age- and sex-matched control dogs. METHODS: Prospective observational study. Urine was collected from healthy and critically ill dogs, and urine concentrations of epinephrine, norepinephrine, metanephrine, and normetanephrine were measured by high-performance liquid chromatography with electrochemical detection. Urinary catecholamine and metanephrine:creatinine ratios were calculated and compared between groups. RESULTS: Urinary epinephrine, norepinephrine, metanephrine, and normetanephrine:creatinine ratios were higher in critically ill dogs when compared with a healthy control population (P=.0009, P<0.0001, P<0.0001, and P<0.0001, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE: Illness has a significant impact on urinary catecholamines and their metabolites in dogs. Further investigation of catecholamine and metanephrine concentrations in dogs with pheochromocytomas is warranted to fully evaluate this test as a diagnostic tool; however, the findings of this study suggest that the results may be difficult to interpret in dogs with concurrent illness.

Diagnostic utility of abdominal ultrasonography in dogs with chronic vomiting.

BACKGROUND: Chronic vomiting is a common problem in dogs that has many causes. Ultrasonographic descriptions of many gastrointestinal (GI) diseases have been published. However, diagnostic utility of ultrasonography in dogs with chronic vomiting has not been investigated. HYPOTHESIS: Diagnostic utility of abdominal ultrasound will be highest in dogs with GI neoplasia and lowest in those with inflammatory disorders. ANIMALS: Eighty-nine pet dogs with chronic vomiting. METHODS: Medical records were reviewed and the contribution of abdominal ultrasound to the clinical diagnosis was subjectively scored. RESULTS: In 68.5% of dogs, the reviewers thought that the same diagnosis would have been reached without performing ultrasonography. In 22.5% of dogs, the ultrasound examination was considered to be vital or beneficial to the diagnosis. Univariable analysis identified that increased diagnostic utility was associated with increasing age, a greater number of vomiting episodes per week, presence of weight loss, a greater percentage of lost body weight, and a final diagnosis of GI lymphoma or gastric adenocarcinoma. However, multivariate analysis only identified increasing age and a final diagnosis of gastric adenocarcinoma or GI lymphoma to be associated with increased diagnostic utility. In 12.4% of dogs, additional benefits of ultrasonography to case management, excluding the contribution to the vomiting problem, were identified. CONCLUSIONS AND CLINICAL IMPORTANCE: The diagnostic utility of abdominal ultrasonography was high in 27% of dogs. The presence of factors that are associated with high diagnostic utility is an indication to perform abdominal ultrasonography in dogs with chronic vomiting.

Canine sterile nodular panniculitis: a retrospective study of 14 cases.

BACKGROUND: Sterile nodular panniculitis (SNP) is an uncommon inflammatory condition of subcutaneous fat that can be idiopathic, but has also been associated with underlying conditions such as pancreatic disease or systemic lupus erythematosus (SLE). The pathogenesis and clinical course of the condition are not well understood. OBJECTIVES: To retrospectively review cases of SNP associated with systemic signs, concurrent disease, or both and characterize the clinical, laboratory, imaging, and histopathologic findings, treatment, and response to treatment. ANIMALS: Fourteen dogs with histologically confirmed SNP diagnosed between 1996 and 2008. METHODS: Retrospective study. RESULTS: Skin lesions were ulcerated or draining nodules in 9 dogs and nonulcerative subcutaneous nodules in 5. Most dogs had systemic signs, such as fever, inappetence, lethargy, and multiple lesions. Common clinicopathologic findings included neutrophilia with or without left shift, increased alkaline phosphatase activity, mild hypoglycemia, hypoalbuminemia, and proteinuria. Concurrent diseases included pancreatic disease, SLE, rheumatoid arthritis, polyarthritis, lymphoplasmacytic colitis, and hepatic disease. Dogs responded to immunosuppressive doses of corticosteroids when administered. Prognosis for recovery was related to the underlying disease process. CONCLUSIONS AND CLINICAL IMPORTANCE: SNP is not a single disease. Rather, it is a cutaneous marker of systemic disease in many cases. After thorough evaluation for concurrent disease and infectious causes, immunosuppressive treatment is often effective.

Effect of experimental hypothyroidism on glomerular filtration rate and plasma creatinine concentration in dogs.

BACKGROUND: Hypothyroidism affects renal function in a manner opposite the effects of hyperthyroidism. OBJECTIVE: To evaluate the effects of experimentally induced hypothyroidism on glomerular filtration rate (GFR) and basal plasma creatinine concentration in dogs. ANIMALS: Sixteen anestrous, female dogs. METHODS: Hypothyroidism was induced by administration of (131)I in 8 dogs, and 8 healthy euthyroid dogs acted as controls. Exogenous plasma creatinine clearance (an estimate of GFR) was measured in all dogs before (control period) and 43-50 weeks after induction of hypothyroidism (posttreatment period). Other pharmacokinetic parameters of creatinine were also determined. RESULTS: No significant difference was observed for basal plasma creatinine concentration and creatinine clearance between control and hypothyroid dogs in the control period. In the posttreatment period, mean + or - SD creatinine clearance in the hypothyroid group (2.13 + or - 0.48 mL/min/kg) was lower (P < .001) than that of the control group (3.20 + or - 0.42 mL/kg/min). Nevertheless, basal plasma creatinine concentrations were not significantly different between the hypothyroid and control groups (0.74 + or - 0.18 versus 0.70 + or - 0.08 mg/dL, respectively) because endogenous production of creatinine was decreased in hypothyroid dogs (22 + or - 3 versus 32 + or - 5 mg/kg/d, P=.001). CONCLUSION AND CLINICAL IMPORTANCE: Hypothyroidism causes a substantial decrease in GFR without altering plasma creatinine concentrations, indicating that GFR evaluation is needed to identify renal dysfunction in such patients.

Idiopathic eosinophilic masses of the gastrointestinal tract in dogs.

BACKGROUND: Eosinophilic inflammation of the gastrointestinal tract of dogs occurs in numerous disorders, typically resulting in diffuse intestinal thickening. Rarely, eosinophilic masses have been reported. OBJECTIVE: Describe a series of dogs with 1 or more idiopathic eosinophilic gastrointestinal masses (IEGM) to better characterize the clinical features, treatment, and prognosis. ANIMALS: Seven dogs with 1 or more gastrointestinal masses composed primarily of eosinophilic infiltrates for which no underlying cause was found. METHODS: Retrospective case series. RESULTS: Rottweilers and purebred, large breed dogs predominated. Dogs were middle-aged and typically had chronic signs of upper or lower gastrointestinal disease. Decreased appetite, vomiting, and evidence of gastrointestinal hemorrhage were present in the majority of cases. An abdominal or rectal mass was frequently noted on physical examination. Common laboratory abnormalities included peripheral eosinophilia, mature neutrophilia, hypoproteinemia, and hypocholesterolemia. The masses were histologically composed of moderate to severe eosinophilic infiltrates, which were often transmural and accompanied by fibrosis. All dogs treated with surgery alone died of complications of their disease. Treatment with corticosteroids and ivermectin improved clinical signs, caused resolution of eosinophilic infiltrates, and prolonged survival in most dogs treated medically. CONCLUSIONS AND CLINICAL IMPORTANCE: These findings suggest that the prognosis for dogs with IEGM may be good when recognized and managed appropriately. When surgery is performed, medical treatment should also be added.

Influence of isoflurane general anesthesia or anesthesia and surgery on thyroid function tests in dogs.

BACKGROUND: Anesthesia and surgery affect thyroid function tests in humans but have not been studied in dogs. HYPOTHESIS: Anesthesia and anesthesia with surgery will affect thyroid function tests in dogs. ANIMALS: Fifteen euthyroid dogs. METHODS: Prospective, controlled, interventional study. Dogs were assigned to one of 3 groups: control, general anesthesia, and general anesthesia plus abdominal exploratory surgery. Dogs in the anesthesia and surgery groups were premedicated with acepromazine and morphine, induced with propofol, and maintained on isoflurane. Samples for measurement of serum thyroxine (T4), free T4 (fT4) by equilibrium dialysis, triiodothyronine (T3), reverse T3 (rT3), and thyroid-stimulating hormone concentrations were collected from each dog immediately before premedication, at multiple times during anesthesia, surgery, 4, 8, 12, 24, 36, and 48 hours after anesthesia, once daily for an additional 5 days, and once 14 days after anesthesia. Sampling was performed at identical times in the control group. RESULTS: Serum T4 decreased significantly from baseline in the surgery and anesthesia groups compared with the control group at 0.33 (P= 0.043) and 1 hour (P= 0.018), and 2 (P= 0.031) and 4 hours (P= 0.037), respectively, then increased significantly in the surgery group compared with the control group at 24 hours (P= 0.005). Serum T3 decreased significantly from baseline in the anesthesia group compared with the control group at 1 hour (P= 0.034). Serum rT3 increased significantly from baseline in the surgery group compared with the control and anesthesia groups at 8 (P= 0.026) and 24 hours (P= 0.0001) and anesthesia group at 8, 12, 24, and 36 hours (P= 0.004, P= 0.016, P= 0.004, and P= 0.014, respectively). Serum fT4 increased significantly from baseline in the surgery group compared to the control at 24 hours (P= 0.006) and at day 7 (P= 0.037) and anesthesia group at 48 hours (P= 0.023). CONCLUSIONS AND CLINICAL IMPORTANCE: Surgery and anesthesia have a significant effect on thyroid function tests in dogs.

Effect of short-term hypothyroidism on reproduction in the bitch.

Hypothyroidism in bitches has been reported to cause a variable interestrus interval, infertility, abortion, and stillbirth. The objective of this study was to evaluate the effect of experimentally induced hypothyroidism in bitches on fertility, pregnancy, parturition, and neonatal health. Eighteen healthy multiparous bitches were used; hypothyroidism was induced (by radioiodine administration) in nine bitches and the remaining nine served as untreated controls. After breeding, bitches were evaluated for pregnancy, fetal resorption, gestation length, litter size, duration and strength of uterine contractions (during parturition), interval between delivery of pups, viability of pups at birth, periparturient survival, and weight of pups at birth through 4 weeks of age. Bitches were bred a median of 19 weeks after induction of hypothyroidism. All bitches became pregnant and delivered term litters. There was no difference in the interestrus interval, litter size, or gestation length between hypothyroid and control bitches. Duration of uterine contractions was longer, but contraction strength was weaker in hypothyroid than control bitches; however, the interval between delivery of pups was not affected. Periparturient puppy mortality was significantly higher in litters from hypothyroid bitches. Viability scores and weight at birth were significantly lower in pups from hypothyroid bitches than controls. There was no difference between groups in pup weight gain during the first 4 weeks, in the interval from birth to the eyes opened, or to the onset of walking. Although hypothyroidism of relatively short duration did not affect fertility, it prolonged parturition and reduced pup survival in the periparturient period.

Absence of urinary tract infection in dogs with experimentally induced hyperadrenocorticism.

Objectives of this study were to determine occurrence of urinary tract infection and describe results of urine analysis and urine culture in dogs with experimentally induced hyperadrenocorticism. Dogs were randomly assigned to receive either hydrocortisone (nine dogs) or placebo (eight dogs) for 49 consecutive days. Before and on day 49 of treatment, evaluation of dogs included physical examination, abdominal ultrasound, urine culture, urinalysis, adrenal function testing, and measurement of urine protein and creatinine and activity of serum alkaline phosphatase. All dogs in the experimental group had clinical and laboratory findings of hyperadrenocorticism. Urine specific gravity was significantly decreased and urine protein-to-creatinine ratio was significantly increased in dogs with hyperadrenocorticism. Urinary tract infection did not occur in any dogs. We conclude that administration of hydrocortisone created a model of hyperadrenocorticism; however, urinary tract infection did not occur. Additional evaluation is needed to determine association between urinary tract infection and hyperadrenocorticism.