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Objective

To determine whether measuring change in serum thyroid-stimulating hormone (TSH) concentration in response to thyrotropin-releasing hormone (TRH) administration can be used as a test of thyroid function in dogs suspected of having hypothyroidism.

Design

Case-cohort study.

Animals

13 healthy dogs, 20 hypothyroid dogs, and 18 euthyroid dogs with concurrent diseases.

Procedure

Blood samples were collected before and 30 minutes after TRH administration, and serum TSH concentration was measured. The 13 healthy dogs were used to establish a reference range for change in TSH concentration after TRH administration. The remaining 38 dogs were categorized as hypothyroid or euthyroid on the basis of baseline total thyroxine (T4) and TSH concentrations, T4 concentration 4 hours after TRH administration, and clinical response to administration of sodium levothyroxine.

Results

Median baseline TSH concentration was 0.25 ng/ml (range, 0.03 to 0.44 ng/ml) in healthy dogs, 0.93 ng/ml (0.21 to 3.5 ng/ml) in hypothyroid dogs, and 0.21 ng/ml (0.03 to 0.63 ng/ml) in euthyroid dogs with concurrent diseases. Median percentage change in TSH concentration after TRH administration was 207% (range, 25 to 2,200%) in healthy dogs, 24% (-21 to 134%) in hypothyroid dogs, and 167% (69 to 1,800%) in euthyroid dogs with concurrent diseases. Overall accuracy of using the TRH-induced change in TSH concentration to identify hypothyroid dogs was 90%.

Clinical Implications

Although percentage change in TSH concentration in response to TRH administration can be used to differentiate euthyroid from hypothyroid dogs, the test has little advantage over measurement of baseline TSH and total or free T4concentration. (J Am Vet Med Assoc 1998;213:1435-1438)

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in Journal of the American Veterinary Medical Association

  • Heartworm disease in cats should be considered as a differential diagnosis for cats with sudden signs of respiratory distress caused by pneumothorax.

  • A diagnosis of heartworm disease is made on the basis of clinical signs, serologic test results for heartworm antigen and antibodies, and radiographic and ultrasonographic findings.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare dogs with glucocorticoid-deficient hypoadrenocorticism (GDH) with those with mineralocorticoid- and glucocorticoid-deficient hypoadrenocorticism (MGDH) and determine prevalence, historical and clinicopathologic markers, and outcome of dogs with GDH.

Design—Retrospective case series.

Animals—46 dogs with hypoadrenocorticism.

Procedures—Records in the veterinary medical database at Purdue University were searched for dogs in which hypoadrenocorticism had been diagnosed at the Veterinary Teaching Hospital from 1985 to 2005. Data pertaining to signalment, history, a minimum clinicopathologic database, treatment, and outcome were collected. Dogs with hypoadrenocorticism were classified as having MGDH if hyponatremia, hyperkalemia, or both were detected and as having GDH if hyponatremia and hyperkalemia were absent. Dogs were excluded if they had ever been treated with mitotane or had been treated with > 1 dose of corticosteroids within a month prior to the ACTH-stimulation test.

Results—35 dogs with MGDH and 11 dogs with GDH met the inclusion criteria. Dogs with GDH were older at the time of diagnosis and had a longer duration of clinical signs prior to diagnosis than those with MGDH. Dogs with GDH were more likely to be anemic, hypoalbuminemic, and hypocholesterolemic than dogs with MGDH.

Conclusions and Clinical Relevance—GDH was more common than reported in a referral hospital population of dogs with primary hypoadrenocorticism. Definitive diagnosis of GDH remains a clinical challenge. Absence of a stress leukogram in dogs with signs of illness (especially relating to the gastrointestinal tract) warrants further investigation. Most dogs with primary cortisol deficiency do not develop mineralocorticoid deficiency.

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in Journal of the American Veterinary Medical Association

Objective

To determine effect of time of sample collection on serum thyrotropin (canine thyroid-stimulating hormone [cTSH]) concentrations in euthyroid and hypothyroid dogs.

Design

Prospective study.

Animals

6 healthy adult euthyroid dogs, 6 adult Beagles with 131iodine-induced hypothyroidism before and during administration of levothyroxine sodium, and 6 adult dogs with naturally developing hypothyroidism.

Procedure

Healthy euthyroid dogs were identified. Hypothyroidism was induced by administration of 131sodium iodide and confirmed by thyroid-stimulating hormone testing. These dogs then received levothyroxine for 30 days. Naturally developing hypothyroidism was diagnosed on the basis of clinical signs, low serum thyroxine (T 4) concentrations, and high cTSH concentrations or abnormal results on a thyrotropin-releasing hormone response test. Samples for measurement of cTSH and T4 concentrations were obtained at 2-hour intervals from 8 AM to 8 pm.

Results

Mean (± SD) serum cTSH concentrations for healthy dogs, dogs with induced hypothyroidism before and during treatment, and dogs with naturally developing hypothyroidism were 0.11 ± 0.08, 3.31 ± 1.30, 0.08 ± 0.07, and 0.55 ± 0.27 ng/ml, respectively. Diurnal variation in cTSH concentrations was not detected. Clinically important random fluctuations in cTSH concentrations were detected for dogs with naturally developing hypothyroidism.

Clinical Implications

Sample collection time does not appear to predictably influence cTSH concentrations; however, dogs with naturally developing hypothyroidism may have random fluctuations in cTSH concentrations. (J Am Vet Med Assoc 1998; 212:1572–1575)

Free access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Objective—

To evaluate the efficacy and safety of intravenous administration of human immune globulin in the treatment of dogs with immune-mediated hemolytic anemia (IMHA).

Design—

Prospective clinical trial.

Animals—

10 dogs with confirmed primary IMHA that had failed to respond to conventional immunosuppressive treatment (administration of prednisone and cyclophosphamide or azathioprine).

Procedure—

Diagnosis of IMHA was confirmed by detecting spherocytosis or autoagglutination in blood smears and by excluding secondary causes of IMHA. Dogs were treated with human immune globulin (1 g/kg (0.45 glib] of body weight. IV) during a 6- to 12-hour period. Prednisone treatment was continued in all dogs, and cyclophosphamide treatment was continued in 4.

Results—

Median duration of prior immunosuppressive treatment was 12.5 days. Short-term response could not be evaluated in 2 dogs, because they were given blood transfusions within 7 days after immune globulin treatment. However, there was a significant increase in mean Hct and hemoglobin concentration in 8 other dogs from day 0 to 28 after treatment. Five dogs had clinically meaningful responses to treatment. Three dogs were alive 12 months after treatment. There were not any adverse effects that could be definitively attributed to immune globulin treatment; however, thrombocytopenia was observed in 6 dogs after treatment, and evidence of thromboembolism was detected at necropsy in 5 of the 7 dogs that died.

Clinical Implications—

Human immune globulin may be useful for Short-term stabilization of some dogs with IMHA; however, it did not appear to improve long-term survival. (J Am Vet Med Assoc 1997;210:1623–1627)

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in Journal of the American Veterinary Medical Association

Summary

A systemic necrotizing vasculitis of unknown etiopathogenesis may be termed juvenile polyarteritis syndrome (jps). The syndrome has been recognized primarily in young Beagles used for toxicologic studies. We studied 9 young Beagles with jps. Affected dogs had fever (40 to 41.5 C), anorexia, and signs of pain in the cervical area. They had a characteristic hunched stance, and were unwilling to move. Laboratory abnormalities in all dogs included nonregenerative anemia, hypoalbuminemia, and leukocytosis characterized by a mature neutrophilia. Analysis of csf revealed a moderate to severe neutrophilic pleocytosis and a mildly high protein concentration in most dogs. Signs of disease resolved rapidly with high doses (2.2 mg/kg of body weight, po) of prednisone. If untreated, clinical signs and laboratory abnormalities had a remitting and relapsing course in most dogs. Findings at necropsy included necrotizing arteritis with fibrinoid necrosis, periarteritis, thrombosis, and intimal proliferation that most frequently affected small- to medium-sized vessels in the cervical spinal cord, mediastinum, and heart. An immune-mediated pathogenesis for this disease is suspected.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the effect of vaccination on serum concentrations of total and antigen-specific IgE in dogs.

Animals—20 female Beagles.

Procedure—Groups of 5 dogs each were vaccinated repeatedly between 8 weeks and 4 years of age with a multivalent and rabies vaccine, a multivalent vaccine only, or a rabies vaccine only. A fourth group of 5 dogs served as unvaccinated controls. Serum concentrations of total immunoglobulins and antigen-specific IgE were determined following vaccination.

Results—The multivalent vaccine had little effect on serum total IgE concentrations. The concentration of IgE increased slightly following vaccination for rabies at 16 weeks and 1 year of age and increased greatly after vaccination at 2 and 3 years of age in most dogs, with a distinct variation between individual dogs. Vaccination had no effect on serum concentrations of IgA, IgG, and IgM as measured at 2 and 3 years of age. The rabies vaccine contained aluminum adjuvant in contrast to the multivalent vaccine. An increase of IgE that was reactive with vaccine antigens, including bovine serum albumin and bovine fibronectin, was detected in some of the dogs vaccinated for rabies. There was no significant correlation between serum concentrations of total IgE and antigen-specific IgE following vaccination. Serum total IgE concentration rapidly returned to preimmunization concentrations in most dogs, but high concentrations of antigenspecific IgE persisted.

Conclusions and Clinical Relevance—Vaccination of dogs for rabies increases serum concentrations of total IgE and induces IgE specific for vaccine antigens, including tissue culture residues. Vaccination history should be considered in the interpretation of serum total IgE concentrations. (Am J Vet Res 2002;63:611–616)

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate and compare characteristics of a commercially manufactured protamine zinc insulin (PZI) product and PZI products obtained from various compounding pharmacies.

Design—Evaluation study.

Sample—112 vials of PZI (16 vials of the commercially manufactured product and 8 vials from each of 12 compounding pharmacies) purchased over an 8-month period.

Procedures—Validated methods were used to analyze 2 vials of each product at 4 time points. Appearance, endotoxin concentration, crystal size, insulin concentration in the supernatant, pH, total insulin and zinc concentrations, and species of insulin origin were evaluated.

Results—All 16 vials of commercially manufactured PZI met United States Pharmacopeia (USP) specifications. Of 96 vials of compounded PZI, 1 (1 %) contained a concentration of endotoxin > 32 endotoxin U/mL, 23 (24%) had concentrations of insulin in the supernatant > 1.0 U/mL, and 45 (47%) had pH values < 7.1 or > 7.4; all of these values were outside of specifications. Several vials of compounded PZI (52/96 [54%]) did not meet specifications for zinc concentration (0.06 to 0.1 mg/mL for 40 U of insulin/mL, 0.075 to 0.12 mg/mL for 50 U of insulin/mL, and 0.15 to 0.25 mg/mL for 100 U of insulin/mL), and total insulin concentration in 36 [38%] vials was < 90% of the labeled concentration.

Conclusions and Clinical Relevance—Only 1 of 12 compounded PZI products met all USP specifications in all vials tested. Use of compounded PZI insulin products could potentially lead to serious problems with glycemic control in veterinary patients.

Full access
in Journal of the American Veterinary Medical Association