RESUMEN
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.
Asunto(s)
Enfermedades de los Gatos/dietoterapia , Hipertiroidismo/veterinaria , Yodo/administración & dosificación , Alimentación Animal , Animales , Gatos , Dieta/veterinaria , Femenino , Hipertiroidismo/dietoterapia , Masculino , Estudios Retrospectivos , Tiroxina/sangre , Resultado del TratamientoRESUMEN
BACKGROUND: Because of the lack of a current validated assay for feline endogenous adrenocorticotropic hormone (ACTH) in response to administration of currently available ovine corticotropin-releasing hormone (oCRH) preparations, a complete evaluation of the hypothalamic-pituitary-adrenal axis in cats has not been possible. OBJECTIVE: This study was undertaken to (1) determine the pituitary (ACTH) and adrenal (cortisol) response to both IV and IM administration of a currently available oCRH product in healthy cats, and (2) validate an endogenous ACTH assay for use in cats. ANIMALS: Seventeen healthy cats receiving oCRH (n = 11) or placebo (n = 6). METHODS: Prospective, randomized, placebo-controlled study. oCRH at 1 µg/kg or placebo was given either IM or IV. Endogenous cortisol and ACTH concentrations were evaluated after the injection. A comparison of IM versus IV and placebo versus treatment was made. RESULTS: The DiaSorin immunoradiometric assay (IRMA) assay for ACTH performed well, showing both parallelism and acceptable intra- and interassay coefficients of variation. There was a significant difference between groups (P = .025) and a significant difference between times (P = .025) when endogenous ACTH concentrations were compared after oCRH IV or IM. No significant differences were observed in cortisol concentrations comparing IV to IM oCRH. CONCLUSIONS: IM administration of oCRH results in significantly greater ACTH concentrations but not cortisol concentrations when compared with IV administration. Samples should be drawn before and at 60 minutes after the injection. The Diasorin IRMA is valid for feline endogenous ACTH measurements.
Asunto(s)
Hormona Adrenocorticotrópica/sangre , Gatos/sangre , Hormona Liberadora de Corticotropina/administración & dosificación , Hidrocortisona/sangre , Ensayo Inmunorradiométrico/veterinaria , Hormona Adrenocorticotrópica/metabolismo , Animales , Gatos/metabolismo , Hidrocortisona/metabolismo , Ensayo Inmunorradiométrico/métodos , Inyecciones Intramusculares , Inyecciones Intravenosas , Reproducibilidad de los ResultadosRESUMEN
This article highlights the advances in feline endocrinology, excluding diabetes mellitus and hyperadrenocorticism, which have recently been reviewed elsewhere. The goal will be to provide clinically relevant information regarding pathogenesis, diagnosis, and treatment options for these feline endocrine disorders.
Asunto(s)
Enfermedades de los Gatos/diagnóstico , Enfermedades del Sistema Endocrino/veterinaria , Acromegalia/diagnóstico , Acromegalia/patología , Acromegalia/veterinaria , Insuficiencia Suprarrenal/diagnóstico , Insuficiencia Suprarrenal/veterinaria , Animales , Trastornos del Metabolismo del Calcio/diagnóstico , Trastornos del Metabolismo del Calcio/patología , Trastornos del Metabolismo del Calcio/veterinaria , Enfermedades de los Gatos/patología , Gatos , Diagnóstico Diferencial , Enfermedades del Sistema Endocrino/diagnóstico , Enfermedades del Sistema Endocrino/patología , Hiperaldosteronismo/diagnóstico , Hiperaldosteronismo/patología , Hiperaldosteronismo/veterinaria , Hipertiroidismo/diagnóstico , Hipertiroidismo/patología , Hipertiroidismo/veterinaria , Hipotiroidismo/diagnóstico , Hipotiroidismo/patología , Hipotiroidismo/veterinariaRESUMEN
OBJECTIVE: To evaluate thyroid function in healthy Greyhounds, compared with healthy non-Greyhound pet dogs, and to establish appropriate reference range values for Greyhounds. ANIMALS: 98 clinically normal Greyhounds and 19 clinically normal non-Greyhounds. PROCEDURES: Greyhounds were in 2 groups as follows: those receiving testosterone for estrus suppression (T-group Greyhounds) and those not receiving estrus suppressive medication (NT-group Greyhounds). Serum thyroxine (T4) and free thyroxine (fT4) concentrations were determined before and after administration of thyroid-stimulating hormone (TSH) and thyroid-releasing hormone (TRH). Basal serum canine thyroid stimulating hormone (cTSH) concentrations were determined on available stored sera. RESULTS: Basal serum T4 and fT4 concentrations were significantly lower in Greyhounds than in non-Greyhounds. Serum T4 concentrations after TSH and TRH administration were significantly lower in Greyhounds than in non-Greyhounds. Serum fT4 concentrations after TSH and TRH administration were significantly lower in NT-group than T-group Greyhounds and non-Greyhounds. Mean cTSH concentrations were not different between Greyhounds and non-Greyhounds. CONCLUSIONS AND CLINICAL RELEVANCE: Previously established canine reference range values for basal serum T4 and fT4 may not be appropriate for use in Greyhounds. Greyhound-specific reference range values for basal serum T4 and fT4 concentrations should be applied when evaluating thyroid function in Greyhounds. Basal cTSH concentrations in Greyhounds are similar to non-Greyhound pet dogs.
Asunto(s)
Perros/fisiología , Pruebas de Función de la Tiroides/veterinaria , Glándula Tiroides/fisiología , Animales , Perros/sangre , Femenino , Masculino , Valores de Referencia , Tirotropina/administración & dosificación , Tirotropina/fisiología , Hormona Liberadora de Tirotropina/administración & dosificación , Hormona Liberadora de Tirotropina/fisiología , Tiroxina/sangreRESUMEN
OBJECTIVE: To evaluate response rate and duration of malignant melanomas in dogs treated with carboplatin. DESIGN: Retrospective study. ANIMALS: 27 client-owned dogs with spontaneously occurring measurable malignant melanomas. PROCEDURE: Records of dogs with melanomas treated with carboplatin from October 1989 to June 2000 were reviewed. Carboplatin was administered IV at doses of 300 or 350 mg/m2 of body surface area. Response to treatment and evidence of drug toxicity were determined. RESULT: Response to treatment could be evaluated in 25 dogs. Of those, overall response rate was 28%. One dog had a complete response, 6 (24%) dogs had a partial response (> 50% reduction in tumor burden). Median duration of partial response was 165 days. Eighteen dogs had stable disease (n = 9; 36%) or progressive disease (9; 36%). Response to treatment was significantly associated with carboplatin dose on a milligram per kilogram basis (15.1 mg/kg 16.9 mg/lb] of body weight vs 12.6 mg/kg [5.7 mg/lb]). Evidence of gastrointestinal toxicosis could be assessed in 27 dogs. Mean body weight of 5 dogs that developed gastrointestinal toxicosis was significantly less than that of 22 dogs without gastrointestinal toxicosis (9.9 kg [21.8 lb] vs 19.3 kg [42.5 lb]). CONCLUSIONS AND CLINICAL RELEVANCE: Carboplatin had activity against macroscopic spontaneously occurring malignant melanomas in dogs and should be considered as an adjunctive treatment for microscopic local or metastatic tumors. Gastrointestinal toxicosis was associated with body weight. Because small dogs are more likely to have adverse gastrointestinal effects, gastrointestinal protectants should be considered for these patients.
Asunto(s)
Antineoplásicos/uso terapéutico , Carboplatino/uso terapéutico , Enfermedades de los Perros/tratamiento farmacológico , Melanoma/veterinaria , Neoplasias Cutáneas/veterinaria , Animales , Antineoplásicos/efectos adversos , Peso Corporal , Carboplatino/efectos adversos , Enfermedades de los Perros/patología , Perros , Relación Dosis-Respuesta a Droga , Femenino , Masculino , Melanoma/tratamiento farmacológico , Melanoma/secundario , Estudios Retrospectivos , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/patología , Resultado del TratamientoAsunto(s)
Envejecimiento/fisiología , Demencia/prevención & control , Inhibidores de la Monoaminooxidasa/uso terapéutico , Selegilina/uso terapéutico , Animales , Encéfalo/efectos de los fármacos , Encéfalo/crecimiento & desarrollo , Encéfalo/patología , Trastornos del Conocimiento/etiología , Trastornos del Conocimiento/prevención & control , Perros , Humanos , Modelos Biológicos , Monoaminooxidasa/metabolismoRESUMEN
Thrombocytopenia was documented in eight of 11 dogs with anticoagulant rodenticide-induced hemorrhage. Thrombocytopenia was transient and generally mild-to-moderate, but it became marked (i.e., less than 30,000 platelets/microl) in two cases. Petechial hemorrhages were not noted in any case. There was no relationship between hematocrit and platelet count. Platelet count changes in response to treatment with fresh-frozen plasma and isotonic electrolyte solutions were variable. Anticoagulant rodenticide toxicity should be included as a differential diagnosis for dogs with hemorrhage accompanied by mild-to-moderate thrombocytopenia.
Asunto(s)
Anticoagulantes/envenenamiento , Enfermedades de los Perros/etiología , Hemorragia/veterinaria , Rodenticidas/envenenamiento , Trombocitopenia/veterinaria , Animales , Proteínas Sanguíneas/uso terapéutico , Diagnóstico Diferencial , Enfermedades de los Perros/sangre , Enfermedades de los Perros/inducido químicamente , Perros , Hematócrito , Hemorragia/inducido químicamente , Hemorragia/complicaciones , Inmunoglobulina G/sangre , Soluciones Isotónicas/uso terapéutico , Recuento de Plaquetas , Intoxicación/complicaciones , Intoxicación/veterinaria , Trombocitopenia/diagnóstico , Trombocitopenia/etiologíaRESUMEN
In this chapter we have discussed the pathogenesis of canine PDH focusing on its relationship to aging, dopamine deficiency, and neurodegenerative disease. We have outlined the successful management of canine PDH patients with l-deprenyl, a selective MAO-B inhibitor. Treatment with l-deprenyl results in clinical and endocrinologic improvement (partial to complete) in approximately 83% of dogs, with improvement noted within the first 1 to 2 months of therapy. The safety profile of l-deprenyl is excellent, especially in light of the fact that the majority of patients are elderly. l-Deprenyl is a safe and effective first-line therapy for the medical management of uncomplicated cases of canine PDH.
Asunto(s)
Enfermedades de la Corteza Suprarrenal/veterinaria , Hiperfunción de las Glándulas Suprarrenales/veterinaria , Enfermedades de los Perros/tratamiento farmacológico , Inhibidores de la Monoaminooxidasa/uso terapéutico , Hipófisis/fisiopatología , Selegilina/uso terapéutico , Enfermedades de la Corteza Suprarrenal/tratamiento farmacológico , Enfermedades de la Corteza Suprarrenal/etiología , Hiperfunción de las Glándulas Suprarrenales/tratamiento farmacológico , Hiperfunción de las Glándulas Suprarrenales/etiología , Envejecimiento/fisiología , Animales , Enfermedades de los Perros/etiología , Enfermedades de los Perros/fisiopatología , Perros , Dopamina/fisiología , Relación Dosis-Respuesta a Droga , Inhibidores de la Monoaminooxidasa/efectos adversos , Selegilina/efectos adversosRESUMEN
Eighty two beagle dogs ranging in age from 2.8 to 16.4 years and in weight from 6.3 to 15.8 kg were allotted to 41 pairs and administered placebo or 1 mg/kg L-deprenyl orally once daily for 2 years and 10 weeks. When survivorship for all dogs in the study was analyzed there was no significant difference between the L-deprenyl and placebo treated groups, most likely due to the (expected) survival of virtually all young dogs in both groups for the duration of the study. To assess whether L-deprenyl treatment begun in later life might enhance canine longevity in a fashion similar to that documented in rodents we also examined survival in a subset of elderly dogs who were between the ages of 10 and 15 yrs at the start of tablet administration and who received tablets for at least 6 months. In this subset, dogs in the L-deprenyl group survived longer (p < 0.05) than dogs in the placebo group. Twelve of 15 (80%) dogs in the L-deprenyl group survived to the conclusion of the study, in contrast to only 7 of 18 (39%) of the dogs who received placebo (P=0.017). Furthermore, by the time the first L-deprenyl treated dog died on day 427, 5 placebo treated dogs had already succumbed, the first on day 295. Specifically with respect to dogs, the findings reported herein suggest daily oral administration of 1 mg/kg L-deprenyl prolongs life when begun in relatively healthy dogs 10-15 years of age and maintained for the duration of the individual's life, but in any event for no less than six months.
Asunto(s)
Longevidad/efectos de los fármacos , Selegilina/farmacología , Factores de Edad , Animales , Enfermedades de los Perros/prevención & control , Perros , Método Doble Ciego , Conducta Alimentaria/efectos de los fármacos , Femenino , Masculino , Neoplasias/veterinaria , Análisis de SupervivenciaRESUMEN
Intravenous immunoglobulin (IVGG) was administered to 13 of 37 dogs with immune-mediated hemolytic anemia. All dogs received concurrent prednisone therapy, 14 dogs also received cyclophosphamide; and a single dog each received cyclosporine, azathioprine, and danazol. Dogs that responded to prednisone therapy without IVGG generally did so within 7 days (mean +/- standard deviation = 5.6 +/- 2.9 days). Intravenous immunoglobulin was administered after 10.4 +/- 6.6 days of prednisone therapy as an intravenous infusion of 0.5 g/kg (range 0.25 to 0.73 g/kg). Eleven dogs received a single treatment, 2 dogs each received 2 treatments. No relevant adverse effects were noted. Eleven dogs had an increase in PCV of at least 4% 2.2 +/- 1.5 days after IVGG infusion. In 10 of these dogs, the PCV continued to increase until the time of hospital discharge. One responder died 1 hour after the increase in PCV, 1 dog was euthanized within 24 hours of IVGG administration, and 1 dog had no response over a period of 13 days. Results of this study suggest that IVGG therapy may be of value in dogs with immune-mediated hemolytic anemia that do not respond within 7 days of appropriate corticosteroid therapy.
Asunto(s)
Anemia Hemolítica/veterinaria , Enfermedades de los Perros , Inmunoglobulinas Intravenosas/uso terapéutico , Inmunosupresores/uso terapéutico , Anemia Hemolítica/inmunología , Anemia Hemolítica/terapia , Animales , Ciclofosfamida/uso terapéutico , Perros , Femenino , Hemólisis , Humanos , Masculino , Orquiectomía , Ovariectomía , Prednisona/uso terapéutico , Tasa de SupervivenciaRESUMEN
Diabetic ketoacidosis (DKA) is a complex and potentially fatal metabolic disorder in patients with diabetes mellitus. An understanding of the pathophysiology of DKA is essential in order to optimize patient management. A combination of insulin deficiency, increased stress hormone levels, and volume depletion account for the laboratory abnormalities and clinical signs observed in these patients. Successful therapy depends upon correction of hyperglycemia, dehydration, and electrolyte and blood gas abnormalities.
Asunto(s)
Cetoacidosis Diabética , Bicarbonatos/uso terapéutico , Cetoacidosis Diabética/etiología , Cetoacidosis Diabética/metabolismo , Cetoacidosis Diabética/fisiopatología , Cetoacidosis Diabética/terapia , Fluidoterapia , Humanos , Insulina/administración & dosificación , Insulina/deficienciaRESUMEN
This study was performed to determine the cardiovascular responses to isoflurane in euthyroid and hypothyroid dogs. Four healthy mixed-breed dogs were studied prior to thyroidectomy (PRE), 6 months after thyroidectomy (HYP), and after 2 months of oral supplementation with 1-thyroxine (SUP). Heart rate (HR), cardiac output (Q), stroke volume (SV), systolic, diastolic, mean arterial blood pressure (SAP, DAP, MAP), and total peripheral resistance (TPR) were determined in awake dogs and in the same dogs when end-tidal isoflurane concentration were 1.28%, 1.92%, and 2.56%. Ventilation was controlled in anesthetized dogs and PACO2 maintained between 38 to 42 mm Hg. Isoflurane caused significant (P < .05) dose-dependent reduction in Q, SV, SAP, DAP, and MAP in the PRE, HYP, and SUP dogs. Cardiac output was lower in the HYP dogs than in the PRE or SUP dogs during awake measurement. TPR was increased in the awake HYP dogs compared with the PRE or SUP dogs. During anesthesia, HYP dogs tended to have lower Q, SV, SAP, and MAP PRE or SUP groups, but the only significant reduction was SAP during 1.5 MAC. The cardiovascular responses to isoflurane in hypothyroid dogs are similar to euthyroid animals with a dose-dependent depression in Q, SV, and arterial pressure.
Asunto(s)
Anestésicos por Inhalación/farmacología , Enfermedades de los Perros/fisiopatología , Hemodinámica/efectos de los fármacos , Hipotiroidismo/veterinaria , Isoflurano/farmacología , Anestésicos por Inhalación/administración & dosificación , Animales , Enfermedades de los Perros/cirugía , Perros , Hipotiroidismo/fisiopatología , Hipotiroidismo/cirugía , Isoflurano/administración & dosificación , Tiroidectomía/veterinaria , Tiroxina/administración & dosificaciónAsunto(s)
Hiperfunción de las Glándulas Suprarrenales/tratamiento farmacológico , Degeneración Nerviosa/fisiología , Hipófisis/fisiopatología , Selegilina/uso terapéutico , Hiperfunción de las Glándulas Suprarrenales/fisiopatología , Animales , Modelos Animales de Enfermedad , Perros , Dopamina/metabolismoAsunto(s)
Enfermedad de Alzheimer/fisiopatología , Trastornos del Conocimiento/fisiopatología , Selegilina/uso terapéutico , Envejecimiento/fisiología , Enfermedad de Alzheimer/tratamiento farmacológico , Animales , Trastornos del Conocimiento/tratamiento farmacológico , Demencia/tratamiento farmacológico , Demencia/fisiopatología , Modelos Animales de Enfermedad , Perros , HumanosAsunto(s)
Alimentación Animal , Perros/sangre , Ácido Fólico/administración & dosificación , Vitamina B 12/administración & dosificación , Alimentación Animal/análisis , Animales , Bacterias/crecimiento & desarrollo , Cruzamiento , Recuento de Colonia Microbiana/veterinaria , Estudios Cruzados , Duodeno/microbiología , Femenino , Ácido Fólico/sangre , Masculino , Estudios Prospectivos , Vitamina B 12/sangreAsunto(s)
Enfermedades de los Gatos/diagnóstico , Síndrome de Cushing/veterinaria , Hormona Adrenocorticotrópica , Animales , Enfermedades de los Gatos/tratamiento farmacológico , Gatos , Síndrome de Cushing/diagnóstico , Síndrome de Cushing/tratamiento farmacológico , Dexametasona , Diagnóstico Diferencial , Perros , Humanos , Cetoconazol/uso terapéutico , Metirapona/uso terapéutico , Mitotano/efectos adversos , Mitotano/uso terapéutico , Tomografía Computarizada por Rayos X/veterinariaAsunto(s)
Enfermedad de Addison/veterinaria , Enfermedades de los Gatos/metabolismo , Enfermedad de Addison/diagnóstico , Enfermedad de Addison/tratamiento farmacológico , Enfermedad de Addison/metabolismo , Hormona Adrenocorticotrópica , Animales , Enfermedades de los Gatos/diagnóstico , Enfermedades de los Gatos/tratamiento farmacológico , Gatos , Dexametasona/uso terapéutico , Glucocorticoides/uso terapéutico , Mineralocorticoides/uso terapéuticoRESUMEN
Hypothyroidism is a possible predisposing factor in a number of disorders of companion psittacine birds. We developed and validated a thyroid-stimulating hormone (TSH) response testing protocol for cockatiels (Nymphicus hollandicus), using 0.1 IU of TSH/bird given IM, with blood sample collection at 0 and 6 hours after TSH, and a commercial radioimmunoassay for thyroxine (T4). This protocol was used to document a seasonal sex difference in stimulated T4 values--females responded with higher T4 values than those in males in summer--and a stress-induced depression of baseline T4 values was detected in a group of cockatiels with normal TSH response. An experimental model for mature-onset hypothyroidism in cockatiels was created by radiothyroidectomizing cockatiels with 3.7 MBq (100 microCi) of 131I/bird given IV. Induction of the hypothyroid state was confirmed by baseline T4 concentration, TSH response test results, thyroid pertechnetate scintigraphy, and gross and microscopic examinations. Classical signs of hypothyroidism (eg, hypercholesterolemia, obesity, poor feathering) were lacking or mild at 48 days after thyroid ablation.
Asunto(s)
Hipotiroidismo/fisiopatología , Tiroxina/sangre , Animales , Femenino , Hipotiroidismo/sangre , Hipotiroidismo/patología , Histerectomía , Radioisótopos de Yodo , Masculino , Loros , Proyectos Piloto , Estaciones del Año , Caracteres Sexuales , Glándula Tiroides/patología , Tiroidectomía , TirotropinaRESUMEN
Three dogs with gastrointestinal tract bleeding of sufficient severity to necessitate blood transfusion were determined to have hypoadrenocorticism on the basis of adrenocortical response to exogenous adrenocorticotropic hormone. All dogs survived the acute crisis and are being managed with fludrocortisone acetate. Hypoadrenocorticism should be considered in the differential diagnosis of acute severe gastrointestinal tract hemorrhage.