Effects of concurrent canine Cushing's syndrome and diabetes Mellitus on insulin requirements, trilostane dose, and survival time.

Trilostane and insulin requirements and survival time of dogs with concurrent naturally-occurring Cushing's syndrome (CS) and diabetes mellitus (DM) has not been fully investigated. This retrospective study evaluated trilostane and insulin doses in dogs with concurrent CS and DM compared to dogs with only CS or DM. Additionally, a survival analysis was performed using a Kaplan-Meier survival curve. Survival time was compared through Log-rank test. Cox proportional regression method was used to screen predictor factors of death in dogs with CS, DM or concurrent CS and DM. A total of 95 dogs were included, 47 dogs had CS, 31 dogs had DM and 17 dogs had concurrent CS and DM. After long-term follow-up, dogs with concurrent CS and DM required higher final median doses of insulin than dogs with DM [0.90 (0.73-1.1) vs 0.67 (0.55-0.73) u/kg/12 h; P = 0,002]. Conversely, the median trilostane requirements in dogs with concurrent CS and DM did not differ from the median trilostane requirements of dogs with CS [1.52 (0.76-2.80) vs 1.64 (1.19-4.95) mg/kg/day; P = 0.283]. No statistical difference was found for the median survival time between dogs with CS and dogs with concurrent CS and DM (1245 vs 892 days; p = 0.152). Although, median survival time of dogs with DM was not reached, it was longer than median survival time of dogs with CS and DM (892 days; P = 0.002). In conclusion, diabetic dogs with concurrent CS need higher insulin doses and have a shorter survival time compared to diabetic dogs without CS.

A mediastinal mass causing Budd-Chiari-like syndrome in a cat.

Background: Budd-Chiari syndrome (BCS) is considered a rare condition in cats that is characterized by the obstruction of the hepatic venous outflow tract from the level of the small hepatic veins to the level of the termination of the inferior vena cava into the right atrium in the absence of cardiac or pericardial disease, or sinusoidal obstruction syndrome. Case description: This report presents a 13-year-old cat with a two-week history of progressive lethargy, inappetence, weight loss, and abdominal distension. Findings/treatment and outcome: The radiological study was consistent with pleural effusion, as well as alveolar and interstitial pulmonary patterns. Ultrasonography confirmed hepatic venin congestion and ascites. Abdominocentesis revealed a modified transudate. A computed tomography (CT) angiography showed a mass at the level of the caudal mediastinum that compressed the caudal vena cava (CVC). Mediastinal lymphoma was considered the most likely differential diagnosis. These findings were interpreted as Budd-Chiari-like syndrome (BCLS) secondary to a mediastinal mass although, unfortunately, no further diagnostic or treatment procedures were accepted by the owners. BCLS is a rare condition in cats, where most of the reported cases occurred as a result of obstruction of the caudal vena cava. In this report, BCLS was caused by a mass located in the caudal mediastinum oppressing the caudal vena cava. Conclusion: This is the first report of BCLS in cats diagnosed by CT angiography, and it shows the value of this technique to define the origin and extent of the mass and to evaluate the presence or absence of metastatic lesions.

Kidney function and glucose metabolism in overweight and obese cats.

Background: In people, obesity and prediabetes mellitus might predispose to chronic kidney disease (CKD).Aims: To assess the association of overweight [Body condition score (BCS) >5] and glucose metabolism alterations, with established or potential markers of CKD. In addition, fructosamine and fasted blood glucose were compared as predictors of early abnormal glucose metabolism.Methods: 54 clinically healthy cats were included in a cross-sectional study comprising 25 neutered males and 29 (28 neutered) females aged 7.2 (5.5-9.4) years. Two potential markers of CKD, namely urinary free active transforming growth factor-ß1-creatinine ratio and urinary retinol binding protein-creatinine ratio were measured along with other parameters to assess CKD. A receiver operating curve was used to identify the best sensitivity and specificity of fructosamine to identify cats with fasting glucose >6.5 mmol/L.Results: No association was found between BCS and markers of CKD. Fructosamine was greater in cats with fasting glucose >6.5 mmol/L compared to those with fasting glucose ≤6.5 mmol/L. A fructosamine concentration ≥250 µmol/L was able to detect cats with hyperglycemia with a sensitivity of 77% and a specificity of 65%. Furthermore, fructosamine was more strongly correlated with fasting glucose than albumin-corrected fructosamine (r = 0.43, p = 0.002 vs r = 0.32, p = 0.026). Cats with higher fructosamine had lower serum symmetric dimethylarginine concentrations.Conclusion: The present study does not suggest an effect of obesity on renal function in domestic cats.Clinical relevance: Fructosamine might be of value for the diagnosis of prediabetes mellitus in cats.

Lactocin AL705 as quorum sensing inhibitor to control Listeria monocytogenes biofilm formation.

AIMS: The control of Listeria monocytogenes biofilm formation using lactocin AL705 bacteriocin at sub-minimum inhibitory concentrations (MICs) through an antiquorum sensing strategy, was preliminarily investigated. METHODS AND RESULTS: The screening for biofilm formation of different Listeria species at 10°C allowed selecting L. monocytogenes FBUNT for its use as biofilm producer. MIC and minimum bactericidal concentration of lactocin AL705 purified extract against the pathogen was determined. Bacteriocin sub-MICs were used to evaluate biofilm reduction. Concentrations between 2·5-20 AU ml-1 of lactocin AL705 produced significant decreases in biofilm formation without affecting the growth of the pathogen after 3 days of incubation. When bacteriocin concentrations (5-20 arbitrary units per millilitre (AU ml-1 )) were investigated as quorum sensing (QS) inhibitors using Vibrio harveyi as reporter strain, a significant reduction in luminescence by lactocin AL705 (20 AU ml-1 ) was observed. Even when L. monocytogenes produced AI-2 like molecules as recognized by the reporter strain, bacteriocins did not interfere with this compound. CONCLUSION: Antilisterial lactocin AL705 used to disrupt QS through a signal molecule inactivation was able to control L. monocytogenes FBUNT biofilm formation. Other molecule(s) different from the AI-2 involved during biofilm formation could be acting as target of the bacteriocin. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of bacteriocins derived from food-grade micro-organisms as a QS inhibition represents an effective strategy to control pathogens as well as an environmentally friendly sanitation method to mitigate postprocessing food contamination.

ISO-based assessment of accuracy and precision of glucose meters in dogs.

BACKGROUND: Portable blood glucose meters (PBGMs) allow easy glucose measurements. As animal-specific PBGMs are not available everywhere, those for humans are widely used. OBJECTIVES: To assess the accuracy and precision of 9 PBGMs in canine whole blood (WB) and plasma, based on the ISO 15197:2013. ANIMALS: Fifty-nine client-owned dogs attending the Veterinary Teaching Hospital. METHODS: Analytical evaluation of 100 blood samples was performed for accuracy and 23 for precision (glucose 29-579 mg/dL) following ISO recommendations. A PBGM was considered accurate if 95% of the measurements were within ±15 mg/dL from the reference when glucose was <100 mg/dL and within ±15% when it was ≥100 mg/dL, and if 99% of them were within zones A and B in error grid analysis (EG). A hexokinase-based analyzer was used as reference. Ninety samples were assessed for hematocrit interferences. RESULTS: Accuracy requirements were not fulfilled by any PBGM in WB (74% of measurements within the limits for the most accurate) and by 1 only in plasma. However, the EG analysis in WB was passed by 6 PBGM and by all in plasma. The most accurate were also the most precise, with coefficients of variation <5% in WB and <3% in plasma. Hematocrit correlated with bias against the reference method in 4 PBGM (r = -0.243 - [-0.371]; P < .021). CONCLUSIONS AND CLINICAL IMPORTANCE: This disparity among PBGM suggests that meters approved for humans need to be evaluated before use in other species.

Long-term survival of dogs with adrenal-dependent hyperadrenocorticism: a comparison between mitotane and twice daily trilostane treatment.

BACKGROUND: Treatment of adrenal-dependent hyperadrenocorticism (ADH) involves either surgical resection of the adrenal tumor or medical therapy. For many years, mitotane has been considered the medical treatment of choice for dogs with ADH. OBJECTIVES: The aim of this study was to determine survival and prognostic factors for dogs with ADH treated with mitotane and trilostane. ANIMALS: Twenty-six dogs with ADH were included in the study. METHODS: Fourteen dogs were treated with mitotane and 12 dogs were treated with trilostane. Medical records were reviewed. Epidemiologic factors, signalment, clinicopathologic abnormalities, endocrine test results, and treatment protocols were evaluated to identify potential predictive factors of overall survival time. RESULTS: Survival times of dogs treated with mitotane (median, 15.6 months) or trilostane (median, 14.0 months) were not significantly different. Using univariate analysis, age and postadrenocorticotropic hormone cortisol concentrations were inversely correlated with survival time. The multivariate model also identified weakness at presentation as a negative prognostic indicator. CONCLUSION AND CLINICAL IMPORTANCE: The type of medical treatment (mitotane versus trilostane) does not influence survival time in dogs with ADH; therefore, trilostane, a drug with less frequent and milder adverse effects, might be used as the primary medical treatment when adrenalectomy cannot be performed.

Evaluation of 2 trilostane protocols for the treatment of canine pituitary-dependent hyperadrenocorticism: twice daily versus once daily.

BACKGROUND: Trilostane is the drug of choice to treat pituitary-dependent hyperadrenocorticism (PDH) in dogs, but there is still controversy about which protocol best controls the clinical signs and results of adrenal functioning test. OBJECTIVES: To compare the efficacy of twice daily (BID) versus once daily (SID) trilostane administration and to compare the safety of both protocols in the treatment of dogs with PDH. ANIMALS: Thirty-two client-owned dogs diagnosed with PDH between 2008 and 2010 and treated with trilostane either BID or SID. METHODS: In this prospective randomized study, 2 trilostane protocols were evaluated on the basis of the owner's perception of clinical signs, on the results of laboratory tests, and on the results of the ACTH stimulation test in dogs with PDH. Dogs were followed up for a period of 1 year. RESULTS: During the study, more dogs in the BID group had complete clinical recovery than in the SID group. However, there was no significant difference in the mean post-ACTH cortisol concentration between groups. Basal cortisol concentration at 6 months was higher in animals treated SID compared with animals treated BID. Mean total daily doses of trilostane used to control PDH, as well as adverse effects observed in the course of the study, in both groups were not statistically different. CONCLUSION AND CLINICAL IMPORTANCE: Adverse effects were mild using either protocol of treatment. Using trilostane BID might increase the number of dogs with a good clinical response compared with using trilostane SID.

Clinical features, outcome and prognostic factors in dogs diagnosed with non-cortisol-secreting adrenal tumours without adrenalectomy: 20 cases (1994-2009).

The aims of this study were to describe the clinical features, the outcome and the prognostic factors of dogs with non-cortisol-secreting adrenal masses without adrenalectomy, and also to provide clinical data that can be useful for making decisions when managing dogs with these types of neoplasms. Medical records from 1994 to 2009 were reviewed and 20 dogs were included in the study. The results showed that mean age at diagnosis for dogs with non-cortisol-secreting adrenal masses was 12 years with no sex predisposition. Most dogs were asymptomatic. The most frequent clinical signs, when present, were lethargy, weakness and hypertension. Radiological evidence of metastases at diagnosis was not frequent. The maximal dorso-ventral thickness of the adrenal mass ranged from 10.0 to 45.0 mm. Right adrenal gland masses were more frequent than left-sided. Hypertension was found to be related to tumour growth during follow-up. The median survival time of dogs with non-cortisol-secreting tumours was 17.8 months. Body weight at diagnosis, tumour size and the presence of metastases at diagnosis were inversely related to survival. In conclusion, survival of dogs with non-cortisol-secreting adrenal tumours without adrenalectomy is relatively high and comparable with that of dogs treated with adrenalectomy. Dogs with metastasis and large adrenal tumours have a poorer prognosis. Hypertension is related to tumour growth, and might be used as an additional tool to assess the potential growing capacity of the tumour.

Comparison of non-selective adrenocorticolysis with mitotane or trilostane for the treatment of dogs with pituitary-dependent hyperadrenocorticism.

Forty-six dogs with pituitary-dependent hyperadrenocorticism were treated with mitotane by the non-selective adrenocorticolysis protocol and 40 were treated twice a day with trilostane. The treatment groups were compared by chi-squared tests, and survival data were analysed using Kaplan-Meier survival plots and a Cox proportional hazard method. The non-selective adrenocorticolysis protocol was very effective (89 per cent), its toxicity was moderate (24 per cent) and there were fewer recurrences (29 per cent) than reported with the classical selective adrenocorticolysis protocol (58 per cent). In a multivariate model, age and bodyweight at diagnosis were significantly negatively correlated with survival time. The median survival time of the dogs treated with trilostane twice a day (900 days) was longer (P=0.05) than that of the dogs treated with mitotane (720 days).

Utilización de indicadores ambientales para la prevención del dengue en la habana vieja / Utilization of environmental indicators for the prevention of dengue in Old Havana

El objetivo del presente trabajo fue probar indicadores ambientales para la prevención del dengue en el municipio La Habana Vieja, en Ciudad de La Habana. Se emplearon 5 indicadores ambientales, para los cuales fue evaluada la disponibilidad, calidad y comparabilidad de los datos en espacio y tiempo. Se realizó un estudio descriptivo durante 12 ciclos de igual número de días cada uno, en 2 etapas de la fase de aseguramiento de la campaña de lucha antivectorial en los años 2002 y 2004, respectivamente. El universo lo constituyeron todas las áreas de salud del municipio en estudio. Para la mayoría de los indicadores los datos estaban disponibles, se encontraron identificadas las principales limitaciones que afectaban su calidad y fueron comparables en espacio y tiempo. El indicador en el que se obtuvieron peores resultados fue el de vertimientos de aguas albañales por más de 7 días. En este municipio las áreas de salud de peor calidad ambiental fueron “Robert Manuel Zulueta”, “Diego Tamayo” y “Ángel Arturo Aballí”

Utilización de indicadores ambientales para la prevención del dengue en la habana vieja / Utilization of environmental indicators for the prevention of dengue in Old Havana

El objetivo del presente trabajo fue probar indicadores ambientales para la prevención del dengue en el municipio La Habana Vieja, en Ciudad de La Habana. Se emplearon 5 indicadores ambientales, para los cuales fue evaluada la disponibilidad, calidad y comparabilidad de los datos en espacio y tiempo. Se realizó un estudio descriptivo durante 12 ciclos de igual número de días cada uno, en 2 etapas de la fase de aseguramiento de la campaña de lucha antivectorial en los años 2002 y 2004, respectivamente. El universo lo constituyeron todas las áreas de salud del municipio en estudio. Para la mayoría de los indicadores los datos estaban disponibles, se encontraron identificadas las principales limitaciones que afectaban su calidad y fueron comparables en espacio y tiempo. El indicador en el que se obtuvieron peores resultados fue el de vertimientos de aguas albañales por más de 7 días. En este municipio las áreas de salud de peor calidad ambiental fueron “Robert Manuel Zulueta”, “Diego Tamayo” y “Ángel Arturo Aballí”(AU)

Use of aminoglutethimide in the treatment of pituitary-dependent hyperadrenocorticism in the dog.

The aim of this study was to evaluate the efficacy and safety of aminoglutethimide in the treatment of dogs with pituitary-dependent hyperadrenocorticism (PDH). Ten dogs were diagnosed with PDH based on clinical and laboratory data, adrenal function tests (adrenocorticotropic hormone [ACTH] stimulation test and urinary cortisol/creatinine ratio [UCCR] combined with a high dose oral dexamethasone suppression test) and ultrasonographic evaluation of the adrenal glands. Aminoglutethimide was administered daily at a dose of 15 mg/kg bodyweight for one month. Median basal cortisol concentration and post-ACTH cortisol concentration one month after treatment were significantly lower than pretreatment values. Complete response was achieved in one dog, and partial response was obtained in three dogs. Severe side effects of anorexia, vomiting and weakness occurred in one dog and medication was withdrawn. Two further dogs developed decompensations of concurrent diseases and medication was stopped in these animals as well. Mild toxicity occurred in four dogs. Moderate to severe elevations in liver enzymes occurred in all dogs. The efficacy of this drug is lower than that observed using mitotane and ketoconazole, and adverse effects limit its use. Aminoglutethimide, using the protocol described, cannot be recommended for long-term management of PDH in the dog.

Serum total thyroxine, total triiodothyronine, free thyroxine, and thyrotropin concentrations in dogs with nonthyroidal disease.

OBJECTIVE: To determine whether nonthyroidal disease of various causes and severity is associated with abnormalities in baseline serum concentrations of total thyroxine (T4), triiodothyronine (T3), free T4, or thyrotropin (thyroid-stimulating hormone [TSH]) in dogs believed to be euthyroid. DESIGN: Case-control study. ANIMALS: 223 dogs with confirmed nonthyroidal diseases and presumptive normal thyroid function, and 150 clinically normal dogs. PROCEDURE: Serum total T4, total T3, free T4, and TSH concentrations were measured in dogs with confirmed nonthyroidal disease. Reference ranges for hormone concentrations were established on the basis of results from 150 clinically normal dogs. RESULTS: In dogs with nonthyroidal disease, median serum concentrations of total T4, total T3, and free T4 were significantly lower than those in clinically normal dogs. Median serum TSH concentration in sick dogs was significantly greater than that of clinically normal dogs. When stratified by severity of disease (ie, mild, moderate, and severe), dogs with severe disease had low serum concentrations of total T4, total T3, or free T4 more commonly than did dogs with mild disease. In contrast, serum TSH concentrations were more likely to remain within the reference range regardless of severity of disease. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that serum total T4, free T4, and total T3 concentrations may be low (ie, in the hypothyroid range) in dogs with moderate to severe nonthyroidal disease. Serum TSH concentrations are more likely to remain within the reference range in sick dogs.

Measurement of serum concentrations of free thyroxine, total thyroxine, and total triiodothyronine in cats with hyperthyroidism and cats with nonthyroidal disease.

OBJECTIVE: To determine the usefulness of measuring serum free thyroxine (T4) concentration as a diagnostic test for hyperthyroidism in cats, and to determine the influence of nonthyroidal disease on free T4 concentration in cats without hyperthyroidism. DESIGN: Prospective case series. ANIMALS: 917 cats with untreated hyperthyroidism, 221 cats with nonthyroidal disease, and 172 clinically normal cats. PROCEDURE: Serum free T4, total T4, and total triiodothyronine (T3) concentrations were measured in cats with untreated hyperthyroidism and cats with nonthyroidal disease. Serum total T4 and T3 concentrations were determined by use of radioimmunoassay, and free T4 concentration was measured by use of direct equilibrium dialysis. Reference ranges for hormone concentrations were established on the basis of results from the 172 clinically normal cats. RESULTS: Sensitivity of serum free T4 concentration as a diagnostic test for hyperthyroidism was significantly higher than the test sensitivity of either total T4 or T3 concentration. Of the 221 cats with nonthyroidal disease, 14 had a high free T4 concentration (ie, false-positive result). Therefore, calculated specificity of measuring serum free T4 concentration as a diagnostic test for hyperthyroidism was significantly lower than test specificity of measuring either the total T4 or T3 concentration. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that determination of free T4 concentration is useful in the diagnosis of hyperthyroidism, especially in cats in which hyperthyroidism is suspected but total T4 and T3 concentrations are within reference ranges. However, because some cats with nonthyroidal disease have high serum free T4 concentrations, hyperthyroidism should not be diagnosed solely on the finding of high free T4 concentration.

Neuropeptide- and tyrosine hydroxylase-immunoreactive nerve fibers in painful Morton's neuromas.

We examined the expression of three neuropeptides that have been implicated in nociceptive transmission, and the sympathetic nerve fiber marker tyrosine hydroxylase, in 11 painful human Morton's neuromas, using immunohistochemistry. Antibodies against the neural markers RT97 and PGP 9.5 were used to map the general nerve fiber organization of the neuromas. Four specimens of normal human peripheral nerves were used as controls. Substance P, calcitonin gene-related peptide, and neuropeptide Y immunoreactivities were more pronounced in neuroma tissue than in control nerves. Neuropeptide immunofluorescence was seen both in larger nerve fiber trunks and in masses of disorganized axon profiles dispersed in loose connective tissue. Tyrosine hydroxylase immunoreactivity was present at varying levels of expression in neuroma nerve fiber trunks, in connective tissue nerve fiber bundles, and around some blood vessels. Our findings suggest that neuropeptides are involved in the response to injury in Morton's neuromas and that they could play a role in initiation or modulation of pain. In addition, pain from Morton's neuromas could be influenced by sympathetic nerve fibers.

Serum total thyroxine, total triiodothyronine, free thyroxine, and thyrotropin concentrations in epileptic dogs treated with anticonvulsants.

OBJECTIVE: To determine whether administration of phenobarbital, potassium bromide, or both drugs concurrently was associated with abnormalities in baseline serum total thyroxine (T4), triiodothyronine (T3), free T4, or thyrotropin (thyroid-stimulating hormone; TSH) concentrations in epileptic dogs. DESIGN: Prospective case series. ANIMALS: 78 dogs with seizure disorders that did not have any evidence of a thyroid disorder (55 treated with phenobarbital alone, 15 treated with phenobarbital and bromide, and 8 treated with bromide alone) and 150 clinically normal dogs that were not receiving any medication. PROCEDURE: Serum total T4, total T3, free T4, and TSH concentrations, as well as serum concentrations of anticonvulsant drugs, were measured in the 78 dogs with seizure disorders. Reference ranges for hormone concentrations were established on the basis of results from the 150 clinically normal dogs. RESULTS: Total and free T4 concentrations were significantly lower in dogs receiving phenobarbital (alone or with bromide), compared with concentrations in clinically normal dogs. Administration of bromide alone was not associated with low total or free T4 concentration. Total T3 and TSH concentrations did not differ among groups of dogs. CLINICAL IMPLICATIONS: Results indicate that serum total and free T4 concentrations may be low (i.e., in the range typical for dogs with hypothyroidism) in dogs treated with phenobarbital. Serum total T3 and TSH concentrations were not changed significantly in association with phenobarbital administration. Bromide treatment was not associated with any significant change in these serum thyroid hormone concentrations.

Radiographic findings in dogs with naturally-occurring primary hypoadrenocorticism.

Survey radiographs often are obtained in dogs with primary hypoadrenocorticism in adrenal crisis as part of the routine evaluation of a critically ill dog. In this study, standardized methods of cardiac, pulmonary vasculature, and vena cava mensuration were used in 22 dogs with naturally-occurring primary hypoadrenocorticism, and the findings were compared with those in 22 breed-matched, clinically normal dogs. Most (81.8%) untreated dogs with primary hypoadrenocorticism had one or more radiographic abnormalities, including small size of the heart (45.5%), cranial lobar pulmonary artery (36.4%), caudal vena cava (54.5%), or liver (36.4%). Megaesophagus was not found in any of the dogs with hypoadrenocorticism, and therefore, compared to the other common radiographic findings, should be considered a rare finding.

Evaluation of a low-dose synthetic adrenocorticotropic hormone stimulation test in clinically normal dogs and dogs with naturally developing hyperadrenocorticism.

OBJECTIVE: To determine whether low doses of synthetic ACTH could induce a maximal cortisol response in clinically normal dogs and to compare a low-dose ACTH stimulation protocol to a standard high-dose ACTH stimulation protocol in dogs with hyperadrenocorticism. DESIGN: Cohort study. ANIMALS: 6 clinically normal dogs and 7 dogs with hyperadrenocorticism. PROCEDURE: Each clinically normal dog was given 1 of 3 doses of cosyntropin (1, 5, or 10 micrograms/kg [0.45, 2.3, or 4.5 micrograms/lb] of body weight, i.v.) in random order at 2-week intervals. Samples for determination of plasma cortisol and ACTH concentrations were obtained before and 30, 60, 90, and 120 minutes after ACTH administration. Each dog with hyperadrenocorticism was given 2 doses of cosyntropin (5 micrograms/kg or 250 micrograms/dog) in random order at 2-week intervals. In these dogs, samples for determination of plasma cortisol concentrations were obtained before and 60 minutes after ACTH administration. RESULTS: In the clinically normal dogs, peak cortisol concentration and area under the plasma cortisol response curve did not differ significantly among the 3 doses. However, mean plasma cortisol concentration in dogs given 1 microgram/kg peaked at 60 minutes, whereas dogs given doses of 5 or 10 micrograms/kg had peak cortisol values at 90 minutes. In dogs with hyperadrenocorticism, significant differences were not detected between cortisol concentrations after administration of the low or high dose of cosyntropin. CLINICAL IMPLICATIONS: Administration of cosyntropin at a rate of 5 micrograms/kg resulted in maximal stimulation of the adrenal cortex in clinically normal dogs and dogs with hyperadrenocorticism.

Measurement of serum total thyroxine, triiodothyronine, free thyroxine, and thyrotropin concentrations for diagnosis of hypothyroidism in dogs.

OBJECTIVE: To determine whether measurement of baseline serum concentrations of total thyroxine (T4), and triiodothyronine (T3), free T4, and thyrotropin (thyroid-stimulating hormone; TSH) would aid in the diagnosis of hypothyroidism in dogs. DESIGN: Prospective case series. ANIMALS: 54 dogs with hypothyroidism, 54 euthyroid dogs with nonthyroidal disease initially suspected to have hypothyroidism, and 150 clinically normal dogs. PROCEDURE: In the 54 dogs with hypothyroidism, diagnosis was established on the basis of clinical signs, results of routine laboratory and TSH stimulation tests, exclusion of concurrent nonthyroidal disease, and a good clinical response to treatment with L-thyroxine. Blood samples were collected from all dogs and were tested for thyroid hormone and TSH concentrations. Reference ranges for hormone concentrations were established on the basis of results for the 150 clinically normal dogs. RESULTS: Of the 54 hypothyroid dogs, 48 (89%) had low total T4 concentrations, 3 had low-normal concentrations, and 3 had high concentrations because of T4 autoantibodies. In contrast, only 10 (18%) euthyroid dogs had low total T4 concentrations. Only 3 of 31 (10%) hypothyroid dogs had low T3 concentrations; 23 had concentrations within the reference range, and 5 had high concentrations because of T3 autoantibodies. Only 3 of 38 euthyroid dogs had low T3 concentrations. Of the hypothyroid dogs, 53 (98%) had low free T4 concentrations and 1 had a low-normal concentration. Only 4 (7%) euthyroid dogs had low free T4 concentrations. Of the hypothyroid dogs, 41 (76%) had high TSH concentrations, and 13 had TSH concentrations within the reference range. Of the euthyroid dogs, only 4 (8%) had high TSH concentrations. Of all single hormone measurements evaluated, measurement of free T4 concentration had the highest sensitivity (0.98), specificity (0.93), and accuracy (0.95) as a test for hypothyroidism; measurement of total T4 concentration had a lower sensitivity (0.89), specificity (0.82), and accuracy (0.85). Compared with measurement of total or free T4 concentration, measurement of TSH concentration had a lower sensitivity (0.76) and accuracy (0.84) but specificity (0.93) equal to that for measurement of free T4 concentration. When T4 (total or free) and TSH concentrations were evaluated together, specificity was higher than when T4 or TSH concentration was evaluated alone. Only 1 euthyroid dog had low T4 (total and free) and high TSH concentrations. CLINICAL IMPLICATIONS: Results indicate that measurement of serum free T4 and TSH concentrations is useful for diagnosis of hypothyroidism in dogs. About a quarter of the dogs with confirmed hypothyroidism, however, will have serum TSH concentrations within reference limits.