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Xifra P, Serrano SI, Peterson ME. Radioiodine treatment of hyperthyroidism in cats: results of 165 cats treated by an individualised dosing algorithm in Spain. J Feline Med Surg 2022; 24:e258-e268. [PMID: 35748791 PMCID: PMC10812264 DOI: 10.1177/1098612x221104743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES Although radioiodine (131I) is the treatment of choice for feline hyperthyroidism, 131I-dosing protocols commonly induce iatrogenic hypothyroidism and expose azotaemia. A recently reported patient-specific 131I dosing algorithm minimised the risk of 131I-induced hypothyroidism and azotaemia, while maintaining high cure rates. The aim of the study was to report results of 131I treatment in a European population of hyperthyroid cats using this patient-specific dosing algorithm. METHODS This prospective case series (before-and-after study) evaluated 165 hyperthyroid cats referred for 131I treatment. All cats had serum concentrations of thyroxine (T4), triiodothyronine (T3) and thyroid-stimulating hormone (TSH) measured (off methimazole ⩾1 week). Thyroid volume and percentage uptake of 99mTc-pertechnetate (TcTU) were determined using thyroid scintigraphy. An initial 131I dose was calculated by averaging dose scores for T4/T3 concentrations, thyroid volume and TcTU; 70% of that composite dose was then administered. Twenty-four hours later, percentage 131I uptake was measured, and additional 131I administered as needed to deliver an adequate radiation dose to the thyroid tumour(s). Serum concentrations of T4, TSH and creatinine were determined 6-12 months later. RESULTS Median calculated 131I dose was 2.15 mCi (range 1.2-7.5), with only 51 (30.9%) receiving ⩾2.5 mCi. Of 165 cats, 124 (75.2%) became euthyroid, seven (4.2%) became overtly hypothyroid, 27 (16.4%) became subclinically hypothyroid and seven (4.2%) remained hyperthyroid. A higher proportion of overtly (85.7%) and subclinically (26.9%) hypothyroid cats developed azotaemia than euthyroid cats (13.6%; P = 0.0002). Hypothyroid cats were older (P = 0.016) and more likely to have detectable TSH concentrations (P = 0.025) and symmetrical bilateral distribution of 99mTc-pertechnetate uptake (P = 0.0002), whereas persistently hyperthyroid cats had higher severity scores (P = 0.012). CONCLUSIONS AND RELEVANCE Our results confirm that 131I dosing with this new algorithm results in high cure rates, with a lowered prevalence of 131I-induced overt hypothyroidism and azotaemia. Age, serum TSH concentrations, bilateral, symmetrical uptake and severity score help predict outcome.
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Affiliation(s)
| | | | - Mark E Peterson
- Animal Endocrine Clinic, New York, NY, USA
- Cornell University, Ithaca, NY, USA
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Geddes R, Aguiar J. Feline Comorbidities: Balancing hyperthyroidism and concurrent chronic kidney disease. J Feline Med Surg 2022; 24:641-650. [PMID: 35481810 PMCID: PMC11107990 DOI: 10.1177/1098612x221090390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PRACTICAL RELEVANCE Both hyperthyroidism and chronic kidney disease (CKD) are common long-term conditions in older cats, which might be diagnosed concurrently or develop at different times. Hyperthyroidism may mask the presence of CKD, and vice versa, by various mechanisms that are described in this review. Hyperthyroidism treatment options should be carefully considered when CKD has also been diagnosed. CLINICAL CHALLENGES Although it can be difficult to diagnose hyperthyroidism and CKD simultaneously, given that one condition may mask the other, it is important to consider the presence of both diseases when examining an older cat presenting with vomiting, weight loss, polyuria/ polydipsia, anorexia or sarcopenia. The concurrent presence of hyperthyroidism and CKD requires careful monitoring of glomerular filtration rate biomarkers, and adequate and prompt support of kidney function when normal thyroid function is re-established. Iatrogenic hypothyroidism is a recognised complication of all of the treatment options for hyperthyroidism, and increases the risk of azotaemia. Therapy with levothyroxine is recommended for cats that are hypothyroid and azotaemic. EVIDENCE BASE The information in this review draws on current literature and guidelines related to the pathophysiology, diagnosis and treatment recommendations for feline hyperthyroidism and CKD.
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Affiliation(s)
- Rebecca Geddes
- Clinical Sciences and Services, Royal Veterinary College, University of London, London, UK
| | - Joana Aguiar
- Dick White Referrals, Station Farm, London Road, Six Mile Bottom, Cambridgeshire, UK
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3
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Peterson ME, Rishniw M. Predicting outcomes in hyperthyroid cats treated with radioiodine. J Vet Intern Med 2021; 36:49-58. [PMID: 34817910 PMCID: PMC8783366 DOI: 10.1111/jvim.16319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/05/2021] [Accepted: 11/15/2021] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Radioiodine (131 I) is the treatment of choice for cats with hyperthyroidism. After 131 I, however, euthyroidism is not always achieved, with 5% to 10% of cats remaining persistently hyperthyroid and 20% to 50% developing iatrogenic hypothyroidism. OBJECTIVES To identify pretreatment factors that may help predict persistent hyperthyroidism and iatrogenic hypothyroidism after treatment of cats using a novel 131 I dosing algorithm. ANIMALS One thousand and four hundred hyperthyroid cats treated with 131 I. METHODS Prospective, before-and-after study. Pretreatment predictors (clinical, laboratory, scintigraphic, 131 I dose, 131 I uptake measurements) of treatment failure or iatrogenic hypothyroidism were identified by multivariable logistic regression analysis. RESULTS Cats that developed iatrogenic hypothyroidism were more likely to be older (odds ratio [OR] = 1.10; 95% confidence interval [CI], 1.04-1.17; P = .001), female (OR = 2.04; 95% CI, 1.54-2.70; P < .001), have detectable serum thyroid-stimulating hormone (TSH) concentrations (OR = 4.19; 95% CI, 2.0-8.81; P < .001), have bilateral thyroid nodules (OR = 1.57; 95% CI, 1.19-2.08; P < .001), have homogeneous, bilateral distribution of 99m Tc-pertechnetate uptake (OR = 2.93; 95% CI, 2.05-4.19; P < .001), have milder severity score (OR = 0.62; 95% CI, 0.49-0.79; P < .001), and have higher 131 I uptake (OR = 2.40; 95% CI, 1.75-3.28; P < .001). In contrast, cats remaining persistently hyperthyroid were more likely to be younger (OR = 0.81; 95% CI, 0.72-0.92; P < .001), have higher severity score (OR = 1.87; 95% CI, 1.51-2.31; P < .001), and have lower 131 I uptake (OR = 3.50; 95% CI, 1.8-6.80; P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE Age, sex, serum TSH concentration, bilateral and homogeneous 99m Tc-pertechnetate uptake on scintigraphy, severity score, and percent 131 I uptake are all factors that might help predict outcome of 131 I treatment in hyperthyroid cats. Cats with persistent hyperthyroidism had many predictive factors that directly contrasted those of cats that developed 131 I-induced hypothyroidism.
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Affiliation(s)
- Mark E Peterson
- Animal Endocrine Clinic, New York, New York, USA.,College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Mark Rishniw
- College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.,Veterinary Information Network, Davis, California, USA
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Peterson ME, Rishniw M. A dosing algorithm for individualized radioiodine treatment of cats with hyperthyroidism. J Vet Intern Med 2021; 35:2140-2151. [PMID: 34351027 PMCID: PMC8478068 DOI: 10.1111/jvim.16228] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/02/2021] [Accepted: 07/13/2021] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Radioiodine (131 I) is the treatment of choice for hyperthyroidism in cats, but current 131 I-dosing protocols can induce iatrogenic hypothyroidism and expose azotemia. OBJECTIVES To develop a cat-specific algorithm to calculate the lowest 131 I dose to resolve hyperthyroidism, while minimizing risk of iatrogenic hypothyroidism and subsequent azotemia. ANIMALS One thousand and four hundred hyperthyroid cats treated with 131 I. METHODS Prospective case series (before-and-after study). All cats had serum concentrations of thyroxine (T4 ), triiodothyronine (T3 ), and thyroid-stimulating hormone (TSH) measured (off methimazole ≥1 week). Using thyroid scintigraphy, each cat's thyroid volume and percent uptake of 99m Tc-pertechnatate (TcTU) were determined. An initial 131 I dose was calculated by averaging dose scores for T4 /T3 concentrations, thyroid volume, and TcTU; 80% of that composite dose was administered. Twenty-four hours later, percent 131 I uptake was measured, and additional 131 I administered, as needed, to deliver an adequate radiation dose to the thyroid tumor(s). Serum concentrations of T4 , TSH, and creatinine were determined 6 to 12 months later. RESULTS The median calculated 131 I dose was 1.9 mCi (range, 1.0-10.6 mCi); 1380 cats required additional 131 I administration on day 2. Of the cats, 1047 (74.8%) became euthyroid, 57 (4.1%) became overtly hypothyroid, 240 (17.1%) became subclinically hypothyroid, and 56 (4%) remained hyperthyroid. More overtly (71.9%) and subclinically (39.6%) hypothyroid cats developed azotemia than euthyroid cats (14.2%; P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE Our algorithm for calculating individual 131 I doses resulted in cure rates similar to historical treatment rates, despite much lower 131 I doses. This algorithm appears to lower prevalence of both 131 I-induced overt hypothyroidism and azotemia.
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Affiliation(s)
- Mark E Peterson
- Animal Endocrine Clinic, New York, New York, USA.,College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Mark Rishniw
- College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.,Veterinary Information Network, Davis, California, USA
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Brame B, Cain C. Chronic Otitis in Cats: Clinical management of primary, predisposing and perpetuating factors. J Feline Med Surg 2021; 23:433-446. [PMID: 33896249 PMCID: PMC10741284 DOI: 10.1177/1098612x211007072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PRACTICAL RELEVANCE Chronic otitis can be one of the most frustrating diseases to manage for a small animal practitioner. While it occurs less commonly in the cat than the dog, it is no less challenging. The purpose of this review is to discuss the common and uncommon causes of chronic otitis in the cat within the clinical framework used for diagnosis and treatment. The focus is on diseases that affect the ear canal, rather than those restricted to the pinnae. CLINICAL CHALLENGES Otitis is multifactorial, which complicates management. A common clinical mistake is to focus solely on treating the infection present. Only by addressing all factors will a clinician successfully control chronic otitis. For the purposes of this review, the authors have adopted the established model of separating primary, predisposing and perpetuating causes of otitis. Primary factors are those that directly cause otitis (inflammation); predisposing factors are those that put the patient at risk for development of otitis; and perpetuating factors are those that result in ongoing clinical signs of otitis or that prevent clinical resolution. AUDIENCE This review is aimed at veterinarians who treat cats and particularly those with an interest in feline dermatology and otology. EQUIPMENT While many practitioners rely on a hand-held otoscope, a video-otoscope can be very helpful for the diagnosis and treatment of chronic otitis. EVIDENCE BASE This review presents up-to-date information regarding the diagnosis and treatment of chronic otitis in cats, with emphasis on the most recent peer-reviewed literature.
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Affiliation(s)
- Bailey Brame
- Department of Clinical Sciences and Advanced
Medicine, University of Pennsylvania, School of Veterinary Medicine, 3900 Spruce
Street, Philadelphia, PA 19104, USA
| | - Christine Cain
- Department of Clinical Sciences and Advanced
Medicine, University of Pennsylvania, School of Veterinary Medicine, 3900 Spruce
Street, Philadelphia, PA 19104, USA
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Yu L, Lacorcia L, Finch S, Johnstone T. Assessment of treatment outcomes in hyperthyroid cats treated with an orally administered fixed dose of radioiodine. J Feline Med Surg 2020; 22:744-752. [PMID: 31680613 PMCID: PMC10814508 DOI: 10.1177/1098612x19884155] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES The aims of this study were to describe the treatment outcomes following oral administration of a fixed dose (138 MBq; 3.7 mCi) of radioiodine in hyperthyroid cats and to examine the correlation between total thyroxine (TT4) concentrations before and after treatment. METHODS This was a retrospective cohort study that documented the TT4 concentration and clinicopathological parameters at the time of diagnosis and after treatment. Logistic regression was used to assess the relationship between TT4 concentrations before and after treatment. The difference in pre- and post-treatment variables between cats that had TT4 concentrations below or within the reference interval (RI) was compared by the Mann-Whitney U-test. RESULTS Of 161 cats, 133 (82.6%) cats had TT4 concentrations within the RI, four (2.5%) cats had TT4 concentrations above the RI and 24 (14.9%) cats had TT4 concentrations below the RI after treatment. The severity of hyperthyroidism at diagnosis, as measured by the percentage of TT4 elevation above the upper limit of the RI, had no impact on the odds of cats having low TT4 concentrations after treatment (odds ratio 1.00; 95% confidence interval 0.96-1.05; P = 0.828). CONCLUSIONS AND RELEVANCE When using an orally administered fixed dose of radioiodine for the treatment of feline hyperthyroidism, TT4 concentrations at diagnosis cannot be used to predict TT4 concentrations after treatment. The proportion of cats with TT4 concentrations below the lower limit of the RI after treatment was 14.9%. Further work is required to optimise oral radioiodine dosing to achieve maximal euthyroid outcomes.
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Affiliation(s)
- Lucia Yu
- Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC, Australia
| | - Lauren Lacorcia
- Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC, Australia
| | - Sue Finch
- Statistical Consulting Centre, The University of Melbourne, VIC, Australia
| | - Thurid Johnstone
- Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC, Australia
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7
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Yu L, Lacorcia L, Finch S, Johnstone T. Assessment of serum symmetric dimethylarginine and creatinine concentrations in hyperthyroid cats before and after a fixed dose of orally administered radioiodine. J Vet Intern Med 2020; 34:1423-1431. [PMID: 32506701 PMCID: PMC7379014 DOI: 10.1111/jvim.15831] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 12/11/2022] Open
Abstract
Background Serum symmetric dimethylarginine (SDMA) is a sensitive renal biomarker for detecting early chronic kidney disease (CKD) in nonhyperthyroid cats, but knowledge regarding its performance in hyperthyroid cats remains limited. Objectives To determine the relationship between serum SDMA, creatinine and total thyroxine (TT4) concentrations in hyperthyroid cats before (T0) and 3 months after (T1) receiving a PO fixed dose of radioiodine. Animals Eighty client‐owned hyperthyroid cats. Methods Prospective cohort study. Serum TT4, and SDMA, creatinine concentrations, and urine specific gravity were measured at T0 and T1. Nonparametric tests were used to determine the relationship among SDMA, and creatinine and TT4 concentrations. Agreement between SDMA and creatinine regarding CKD staging at both time points was assessed using Goodman and Kruskal's gamma statistic. Results Mean serum SDMA concentration increased after treatment of hyperthyroidism. However, 21 of 75 cats experienced a decrease in SDMA between T0 and T1, whereas creatinine decreased in only 2 cats. A moderate correlation between SDMA and creatinine was seen at T1 (r = 0.53; P < .001) but not at T0 (r = 0.13; P = .25). Where assessable at T1, poor agreement was observed between SDMA and creatinine and CKD stage (Goodman and Kruskal's gamma 0.20; P = .29). Conclusions and clinical importance Discordant outcomes between SDMA and creatinine after radioiodine treatment in cats with hyperthyroidism suggest extrarenal factors may interfere with the reliability of SDMA to adequately reflect renal function. As a result, SDMA should not be interpreted in isolation in hyperthyroid cats treated with radioiodine.
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Affiliation(s)
- Lucia Yu
- Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria, Australia
| | - Lauren Lacorcia
- Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria, Australia
| | - Sue Finch
- Statistical Consulting Centre and Melbourne Statistical Consulting Centre, The University of Melbourne, Victoria, Australia
| | - Thurid Johnstone
- Translational Research and Small Animal Clinical Trial Study Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria, Australia
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8
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Covey HL, Chang YM, Elliott J, Syme HM. Changes in thyroid and renal function after bilateral thyroidectomy in cats. J Vet Intern Med 2019; 33:508-515. [PMID: 30758070 PMCID: PMC6430951 DOI: 10.1111/jvim.15450] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 01/28/2019] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Iatrogenic hypothyroidism might worsen the prognosis of cats with azotemic CKD after thyroidectomy. Varying thyroxine concentrations influence utility of creatinine in assessing renal function. Symmetric dimethylarginine (SDMA) has limited studies in cats with changing thyroid status. OBJECTIVES Thyroid status is stable 6 months post-thyroidectomy. Symmetric dimethylarginine and creatinine are linearly associated without influence from total thyroxine concentration (tT4). ANIMALS Electronic records of 2 first opinion practices were searched using the term "thyroidectomy" to include 81 client-owned cats that had undergone bilateral thyroidectomy. METHODS Retrospective cross-sectional study assessing thyroid hormone concentrations of 68 cats within 6 months of surgery. A longitudinal study of thyroid status in 23 cats with >18 months follow-up post-thyroidectomy. A generalized estimating equation assessed the associations of bodyweight, tT4 and creatinine concentrations on SDMA concentration. RESULTS Sixty-eight cats had follow-up within 6 months. Fifteen cats (22%) had persistent, or recurrent, hyperthyroidism and 33 cats (49%) were hypothyroid. Twenty-three of the euthyroid/hypothyroid cats had long-term follow-up (595-1955 days); 4 cats (17%) remained hypothyroid, 19 cats (83%) were euthyroid (often transiently), and 9 of 23 cats (44%) developed recurrent hyperthyroidism. Symmetric dimethylarginine and creatinine were linearly associated, but hyperthyroid cats had higher SDMA concentrations, relative to creatinine (P = .003). CONCLUSIONS AND CLINICAL IMPORTANCE Cats have changes in thyroid function for years after bilateral thyroidectomy, with a high incidence of recurrent hyperthyroidism. Both SDMA and creatinine are affected by thyroxine concentrations, and the effect is greater in hyperthyroid cats.
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Affiliation(s)
- Heather L Covey
- Department of Clinical Science and Services, Small Animal Medicine and Surgery Group, The Royal Veterinary College, Hertfordshire, United Kingdom
| | - Yu-Mei Chang
- Research Support Office, The Royal Veterinary College, London, United Kingdom
| | - Jonathan Elliott
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
| | - Harriet M Syme
- Department of Clinical Science and Services, Small Animal Medicine and Surgery Group, The Royal Veterinary College, Hertfordshire, United Kingdom
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Buresova E, Stock E, Paepe D, Stammeleer L, Vandermeulen E, Smets P, Duchateau L, Lefebvre HP, Daminet S. Assessment of symmetric dimethylarginine as a biomarker of renal function in hyperthyroid cats treated with radioiodine. J Vet Intern Med 2019; 33:516-522. [PMID: 30632628 PMCID: PMC6430927 DOI: 10.1111/jvim.15407] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/29/2018] [Indexed: 12/27/2022] Open
Abstract
Background Measurement of serum creatinine (sCr) and urea nitrogen fail to detect decreased renal function in many hyperthyroid cats because of low muscle mass and glomerular hyperfiltration of affected cats. Serum symmetric dimethylarginine (sSDMA) is an earlier and more sensitive renal biomarker than sCr. Objective Evaluate sSDMA as a biomarker of renal function in hyperthyroid cats before (T0) and 1 month after (T1) radioiodine (131I) treatment. Animals Forty‐seven client‐owned hyperthyroid nonazotemic cats were evaluated at T0 and T1. Methods A prospective study in which sCr and sSDMA concentrations were determined in 47 hyperthyroid cats at T0 and at T1. Glomerular filtration rate (GFR) was estimated at T0 and T1 in 10 of these 47 cats using plasma exogenous creatinine clearance test. Results Serum SDMA was elevated (>14 μg/dL) in 6 of 47 cats at T0 and normalized after treatment in 4 of those cats. All cats remained nonazotemic after treatment. In 10 cats in which GFR was measured, correlation between GFR and sSDMA was low and not significant (τb = −0.35, P = .17 at T0 and τb = −.22, P = .41 at T1), whereas correlation between GFR and sCr was moderate and significant (τb = −0.52, P < .05 at T0 and τb = −.53, P = <.05 at T1). Conclusions and Clinical Importance Careful interpretation of mildly increased sSDMA with normal sCr in hyperthyroid cats is warranted as sSDMA values might normalize after resolution of hyperthyroidism in some cats. In this population of hyperthyroid cats, sSDMA was poorly correlated with GFR.
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Affiliation(s)
- Eva Buresova
- The Small Animal Department, Ghent University, Merelbeke, Belgium
| | - Emmelie Stock
- The Department of Medical Imaging of Domestic Animals, Ghent University, Merelbeke, Belgium
| | - Dominique Paepe
- The Small Animal Department, Ghent University, Merelbeke, Belgium
| | - Lisa Stammeleer
- The Small Animal Department, Ghent University, Merelbeke, Belgium
| | - Eva Vandermeulen
- The Department of Medical Imaging of Domestic Animals, Ghent University, Merelbeke, Belgium
| | - Pascale Smets
- The Small Animal Department, Ghent University, Merelbeke, Belgium
| | - Luc Duchateau
- The Biometrics Research Group, Ghent University, Merelbeke, Belgium
| | - Herve P Lefebvre
- The Department of Physiology, École Nationale Vétérinaire de Toulouse, Toulouse, France
| | - Sylvie Daminet
- The Small Animal Department, Ghent University, Merelbeke, Belgium
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Morré WA, Panciera DL, Daniel GB, Monroe WE, Werre S. Investigation of a novel variable dosing protocol for radioiodine treatment of feline hyperthyroidism. J Vet Intern Med 2018; 32:1856-1863. [PMID: 30328158 PMCID: PMC6271315 DOI: 10.1111/jvim.15296] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 05/21/2018] [Accepted: 07/17/2018] [Indexed: 12/03/2022] Open
Abstract
Background Radioiodine is the treatment of choice for hyperthyroidism in cats. The ideal method of dose determination of radioiodine remains controversial. Objective To compare a method of radioiodine dose determination that utilized thyroid scintigraphy with a standard fixed dose for treatment of hyperthyroidism. Animals Fifty‐seven and 23 client‐owned hyperthyroid cats in the variable and fixed dose groups, respectively. Methods Cats with a percent dose uptake using 99mTc‐pertechnetate uptake on thyroid scintigraphy <5%, 5%‐10%, and >10% were to receive 3, 3.5, or 4.5 millicuries (mCi) of radioiodine, respectively, administered SC. Radioiodine dose was adjusted according to thyroid gland size as determined by the thyroid:salivary size ratio and categorized as <5:1, 5‐10:1, and >10:1. If the thyroid size fell into a higher dosing category than the percent dose uptake, the dose was increased accordingly. Cats in the fixed dose group received 4.5 mCi. Six months after treatment, cats were determined to be euthyroid, hypothyroid, or hyperthyroid based on serum thyroxine and thyroid stimulating hormone concentrations. Results No difference in outcome was found between the variable and fixed dose treatment groups. Euthyroidism, hypothyroidism, and persistent hyperthyroidism developed in 61, 30, and 9% of cats in the fixed dose group compared to 58, 26, and 16%, respectively, in the variable dose group. Conclusions A variable dosing method of radioiodine based on percent dose uptake primarily and thyroid gland size secondarily did not improve outcome compared to a standard fixed dose method.
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Affiliation(s)
- Wendy A Morré
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia
| | - David L Panciera
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia
| | - Gregory B Daniel
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia
| | - William E Monroe
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia
| | - Stephen Werre
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia
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11
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Volckaert V, Vandermeulen E, Duchateau L, Daminet S, Saunders JH, Peremans K. Predictive value of scintigraphic (semi-)quantitative thyroid parameters on radioiodine therapy outcome in hyperthyroid cats. J Feline Med Surg 2018; 20:370-377. [PMID: 28689464 PMCID: PMC11129218 DOI: 10.1177/1098612x17713854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
Objectives The outcome of radioiodine therapy in hyperthyroid cats is suspected to be influenced by multiple factors. The degree of activity of the thyroid gland, represented by uptake of sodium pertechnetate or tracer activities of radioiodine by the thyroid gland on thyroid scintigraphy, has been suggested in the literature as one of those. Thyroid gland pertechnetate uptake can be represented by (semi-)quantitative factors such as the thyroid to salivary gland (T/S) ratio, the thyroid to background (T/B) ratio and the percentage technetium uptake by the thyroid glands (%TcU). The aim of this study was to investigate a possible relationship between these thyroid scan parameters and radioiodine therapy outcome. Methods Sodium pertechnetate thyroid scans of 75 hyperthyroid cats were retrospectively evaluated and statistical analysis was performed with and without correction for injected radioiodine activity. Three different background regions of interest (ROIs) were used to calculate the T/B ratio and %TcU: 'neck', 'circle' and 'copy ROI'. Results Higher T/S ratios were found to be significantly related to a persistent hyperthyroid outcome in both analyses. For the T/S ratio, a threshold value of 5.4 was determined, with a sensitivity of 73% and a specificity of 59%. An increased risk for persistent hyperthyroidism compared with a final euthyroid outcome with an increased T/Bcircle ratio was only found to be significant without correction for the activity of radioiodine administered. For the %TcU no statistical significance was reached. Regarding a low total thyroxine outcome, no significant relationships with any of the investigated parameters were found. Conclusions and relevance The findings of this study suggest that semi-quantification of thyroid gland uptake is best performed using the T/S ratio. A T/S ratio ⩾5.4 is a possible indicator for an increased risk of persistent hyperthyroidism.
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Affiliation(s)
- Veerle Volckaert
- Faculty of Veterinary Medicine, Department of Small Animal Medical Imaging and Orthopaedics, Ghent University, Merelbeke, Belgium
| | - Eva Vandermeulen
- Faculty of Veterinary Medicine, Department of Small Animal Medical Imaging and Orthopaedics, Ghent University, Merelbeke, Belgium
| | - Luc Duchateau
- Faculty of Veterinary Medicine, Department of Comparative Physiology and Biometrics, Ghent University, Merelbeke, Belgium
| | - Sylvie Daminet
- Faculty of Veterinary Medicine, Department of Medicine and Clinical Biology of Small Animals, Ghent University, Merelbeke, Belgium
| | - Jimmy H Saunders
- Faculty of Veterinary Medicine, Department of Small Animal Medical Imaging and Orthopaedics, Ghent University, Merelbeke, Belgium
| | - Kathelijne Peremans
- Faculty of Veterinary Medicine, Department of Small Animal Medical Imaging and Orthopaedics, Ghent University, Merelbeke, Belgium
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Peterson M, Varela F, Rishniw M, Polzin D. Evaluation of Serum Symmetric Dimethylarginine Concentration as a Marker for Masked Chronic Kidney Disease in Cats With Hyperthyroidism. J Vet Intern Med 2018; 32:295-304. [PMID: 29377360 PMCID: PMC5787157 DOI: 10.1111/jvim.15036] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 09/28/2017] [Accepted: 11/30/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Hyperthyroidism can complicate (mask) the diagnosis of chronic kidney disease (CKD) because it increases glomerular filtration rate and decreases body muscle mass, both of which can lower serum creatinine concentrations. Currently, there is no clinical test that can reliably predict which hyperthyroid cats have concurrent azotemic CKD that will become apparent after treatment of the hyperthyroidism. OBJECTIVES To investigate serum symmetric dimethylarginine (SDMA) concentration as a potential marker of masked azotemia in untreated hyperthyroid cats. ANIMALS Two hundred and sixty-two hyperthyroid cats and 206 aged-matched, clinically normal cats. METHODS Prospective study. We measured creatinine, urea nitrogen, SDMA, T4 , and TSH concentrations before and 1, 3, and 6 months after treatment with radioiodine (131 I) and classified 131 I-treated cats as azotemic or nonazotemic based on persistent, post-treatment creatinine concentrations >2.1 mg/dL. Groups were compared via nonparametric tests, and diagnostic accuracy was determined by receiver operating characteristic analysis and logistic regression. RESULTS No hyperthyroid cats were azotemic before treatment, but 42 (16%) became azotemic when rechecked at 4-8 months (median, 6 months) after 131 I treatment; of these, 14 had high SDMA concentrations before treatment. As a diagnostic test for pre-azotemic (masked) CKD in untreated hyperthyroid cats, SDMA showed a sensitivity of 33.3% and specificity of 97.7%. CONCLUSIONS AND CLINICAL IMPORTANCE Finding a high serum SDMA concentration in a hyperthyroid cat can help predict development of azotemia after treatment. The test has high diagnostic test specificity (few false-positive results) but relatively low sensitivity (fails to predict azotemia in most hyperthyroid cats).
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Affiliation(s)
- M.E. Peterson
- Animal Endocrine Clinic New YorkNY
- College of Veterinary Medicine Cornell UniversityIthacaNY
| | | | - M. Rishniw
- College of Veterinary Medicine Cornell UniversityIthacaNY
- Veterinary Information Network DavisCA
| | - D.J. Polzin
- University of Minnesota College of Veterinary Medicine St. PaulMN
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Peterson ME, Nichols R, Rishniw M. Serum thyroxine and thyroid-stimulating hormone concentration in hyperthyroid cats that develop azotaemia after radioiodine therapy. J Small Anim Pract 2017; 58:519-530. [DOI: 10.1111/jsap.12695] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 03/10/2017] [Accepted: 04/14/2017] [Indexed: 02/01/2023]
Affiliation(s)
- M. E. Peterson
- Animal Endocrine Clinic; New York NY 10025 USA
- Department of Clinical Sciences, College of Veterinary Medicine; Cornell University; Ithaca NY 14853 USA
| | - R. Nichols
- Animal Endocrine Clinic; New York NY 10025 USA
- Antech Diagnostics; Lake Success NY 11042 USA
| | - M. Rishniw
- Department of Clinical Sciences, College of Veterinary Medicine; Cornell University; Ithaca NY 14853 USA
- Veterinary Information Network; Davis CA 95615 USA
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Carney HC, Ward CR, Bailey SJ, Bruyette D, Dennis S, Ferguson D, Hinc A, Rucinsky AR. 2016 AAFP Guidelines for the Management of Feline Hyperthyroidism. J Feline Med Surg 2016; 18:400-16. [DOI: 10.1177/1098612x16643252] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Clinical context: Since 1979 and 1980 when the first reports of clinical feline hyperthyroidism (FHT) appeared in the literature, our understanding of the disease has evolved tremendously. Initially, FHT was a disease that only referral clinicians treated. Now it is a disease that primary clinicians routinely manage. Inclusion of the measurement of total thyroxine concentration in senior wellness panels, as well as in diagnostic work-ups for sick cats, now enables diagnosis of the condition long before the cat becomes the classic scrawny, unkempt, agitated patient with a bulge in its neck. However, earlier recognition of the problem has given rise to several related questions: how to recognize the health significance of the early presentations of the disease; how early to treat the disease; whether to treat FHT when comorbid conditions are present; and how to manage comorbid conditions such as chronic kidney disease and cardiac disease with treatment of FHT. The 2016 AAFP Guidelines for the Management of Feline Hyperthyroidism (hereafter referred to as the Guidelines) will shed light on these questions for the general practitioner and suggest when referral may benefit the cat. Scope: The Guidelines explain FHT as a primary disease process with compounding factors, and provide a concise explanation of what we know to be true about the etiology and pathogenesis of the disease. The Guidelines also: Distill the current research literature into simple recommendations for testing sequences that will avoid misdiagnosis and separate an FHT diagnosis into six clinical categories with associated management strategies. Emphasize the importance of treating all hyperthyroid cats, regardless of comorbidities, and outline the currently available treatments for the disease. Explain how to monitor the treated cat to help avoid exacerbating comorbid diseases. Dispel some of the myths surrounding certain aspects of FHT and replace them with an evidence-based narrative that veterinarians and their practice teams can apply to feline patients and communicate to their owners. Evidence base: To help ensure better case outcomes, the Guidelines reflect currently available, evidenced-based knowledge. If research is lacking, or if a consensus does not exist, the expert panel of authors has made recommendations based on their extensive, cumulative clinical experience.
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Affiliation(s)
- Hazel C Carney
- WestVet Emergency and Specialty Center, 5019 North Sawyer Avenue, Garden City, ID 83617, USA
| | - Cynthia R Ward
- University of Georgia, College of Veterinary Medicine, 2200 College Station Road, Athens, GA 30605,USA
| | - Steven J Bailey
- Exclusively Cats Veterinary Hospital, 6650 Highland Road, Ste 116, Waterford, MI 48327, USA
| | - David Bruyette
- VCA West Los Angeles Animal Hospital, 1900 South Sepulveda Blvd, Los Angeles, CA 90025, USA
| | - Sonnya Dennis
- Stratham-Newfields Veterinary Hospital, 8 Main Street, Newfields, NH 03856, USA
| | - Duncan Ferguson
- College of Veterinary Medicine – University of Illinois, Department of Comparative Biosciences, 3840 Veterinary Medicine Basic Sciences Bldg, 2001 South Lincoln Avenue, Urbana, IL 61802, USA
| | - Amy Hinc
- Cosmic Cat Veterinary Clinic, 220 East Main Street, Branford, CT 06405, USA
| | - A Renee Rucinsky
- Mid Atlantic Cat Hospital, 201 Grange Hall Road, Queenstown, MD 21658, USA
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Bettencourt A, Daniel GB, Panciera D, Larson M, Werre SR. EVALUATION OF THYROID TO BACKGROUND RATIOS AND COMPARISON OF VARIOUS SCINTIGRAPHIC MEASUREMENTS AND THEIR CORRELATION TO SERUM T4IN HYPERTHYROID CATS. Vet Radiol Ultrasound 2016; 57:290-8. [DOI: 10.1111/vru.12343] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/20/2015] [Accepted: 11/02/2015] [Indexed: 11/28/2022] Open
Affiliation(s)
- Ann Bettencourt
- Department of Small Animal Clinical Sciences; Virginia-Maryland College of Veterinary Medicine, Virginia Tech; Blacksburg VA 24061
| | - Gregory B. Daniel
- Department of Small Animal Clinical Sciences; Virginia-Maryland College of Veterinary Medicine, Virginia Tech; Blacksburg VA 24061
| | - David Panciera
- Department of Small Animal Clinical Sciences; Virginia-Maryland College of Veterinary Medicine, Virginia Tech; Blacksburg VA 24061
| | - Marti Larson
- Department of Small Animal Clinical Sciences; Virginia-Maryland College of Veterinary Medicine, Virginia Tech; Blacksburg VA 24061
| | - Stephen R. Werre
- Laboratory for Study Design and Statistical Analysis; Virginia-Maryland College of Veterinary Medicine, Virginia Tech; Blacksburg VA 24061
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16
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Volckaert V, Vandermeulen E, Dobbeleir A, Duchateau L, Saunders JH, Peremans K. Effect of thyroid volume on radioiodine therapy outcome in hyperthyroid cats. J Feline Med Surg 2015; 18:144-9. [PMID: 25769623 DOI: 10.1177/1098612x15576587] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Radioiodine therapy is commonly used in hyperthyroid cats and has a high success rate, ranging from 85-95%. As in humans, thyroid volume has been reported to influence radioiodine therapy outcome in hyperthyroid cats. The purpose of this study was to relate total thyroid volume, calculated by a newly constructed formula for feline patients (0.438 × length × width²), to the outcome of radioiodine therapy. To search for a correlation between total thyroid volume and therapy outcome, 167 hyperthyroid cats were included. Patients were categorised according to the administered radioiodine dose and therapy outcome. Our analysis did not show a significant relationship between an increasing total thyroid volume and the odds for a final low total thyroxine concentration (TT4; P = 0.3930) or a final hyperthyroid outcome (P = 0.0901). A significant relationship was found for an increase in the odds for a final low TT4 outcome with an increase in the number of foci detected on the pertechnetate thyroid scan (P = 0.0238). This was not true for a final hyperthyroid outcome (P = 0.7435). The number of detected foci was also significantly associated with the total thyroid volume (P = 0.0006). Findings indicated that the presence of multiple affected foci influences therapy outcome towards a low TT4 outcome. Bilateral hyperthyroidism and its potential effect on a final low TT4 outcome should therefore be addressed when informing owners of the possible outcomes of radioiodine therapy for their cat.
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Affiliation(s)
- Veerle Volckaert
- Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Eva Vandermeulen
- Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - André Dobbeleir
- Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium
| | - Luc Duchateau
- Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Jimmy H Saunders
- Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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17
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Prevalence and degree of thyroid pathology in hyperthyroid cats increases with disease duration: a cross-sectional analysis of 2096 cats referred for radioiodine therapy. J Feline Med Surg 2015; 18:92-103. [DOI: 10.1177/1098612x15572416] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Objectives Hyperthyroidism is common in cats, but there are no reports that evaluate its severity or underlying thyroid tumor disease based on disease duration (ie, time from original diagnosis). The objective of this study was to compare serum thyroxine (T4) concentrations and thyroid scintigraphic characteristics of cats referred for radioiodine treatment based on disease duration. Methods This was a cross-sectional study of 2096 cats with hyperthyroidism. Cats were divided into five groups based on time from diagnosis: ⩽1 year (n = 1773); >1–2 years (n = 169); >2–3 years (n = 88); >3–4 years (n = 35); and >4–6.1 years (n = 31). Methimazole, administered to 996 (47.5%) cats, was stopped at least 1 week prior to examination to allow for serum T4 testing. Each thyroid scintiscan was evaluated for pattern (unilateral, bilateral, multifocal), location (cervical, thoracic inlet, chest) and size (small, medium, large, huge) of the thyroid tumor, as well as features suggesting malignancy. Results Median serum T4 concentration increased with increasing disease duration from 100 nmol/l (⩽1 year) to 315 nmol/l (>4–6.1 years) ( P <0.001). Prevalence of unilateral thyroid disease decreased, whereas multifocal disease (three or more tumor nodules) increased ( P <0.001) with increasing disease duration. Median tumor volume in the five groups increased from 1.6 cm3 (⩽1 year) to 6.4 cm3 (>4–6.1 years). Prevalence of large (4–8 cm3) and huge (>8 cm3) thyroid tumors increased from 5.1% (⩽1 year) to 88.6% (>4–6.1 years), while the prevalence of intrathoracic tumor tissue increased from 3.4% (⩽1 year) to 32.3% (>4–6.1 years). Prevalence of suspected thyroid carcinoma (characterized by severe hyperthyroidism; huge, intrathoracic, multifocal tumors; refractory to methimazole treatment) increased with increasing disease duration from 0.4% (⩽1 year) to 19.3% (>4–6.1 years). Conclusions and relevance Our results indicate that the prevalence of severe hyperthyroidism, large thyroid tumors, multifocal disease, intrathoracic thyroid masses and suspected malignant disease all increase with disease duration in cats referred for radioiodine therapy.
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18
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Peterson ME, Broome MR. THYROID SCINTIGRAPHY FINDINGS IN 2096 CATS WITH HYPERTHYROIDISM. Vet Radiol Ultrasound 2014; 56:84-95. [DOI: 10.1111/vru.12165] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 03/06/2014] [Indexed: 11/28/2022] Open
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19
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Scrivani PV, Erb HN. Invited review: study design considerations for clinical research in veterinary radiology and radiation oncology. Vet Radiol Ultrasound 2013; 54:317-325. [PMID: 23578318 DOI: 10.1111/vru.12039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 02/23/2013] [Indexed: 12/01/2022] Open
Abstract
High quality clinical research is essential for advancing knowledge in the areas of veterinary radiology and radiation oncology. Types of clinical research studies may include experimental studies, method-comparison studies, and patient-based studies. Experimental studies explore issues relative to pathophysiology, patient safety, and treatment efficacy. Method-comparison studies evaluate agreement between techniques or between observers. Patient-based studies investigate naturally acquired disease and focus on questions asked in clinical practice that relate to individuals or populations (e.g., risk, accuracy, or prognosis). Careful preplanning and study design are essential in order to achieve valid results. A key point to planning studies is ensuring that the design is tailored to the study objectives. Good design includes a comprehensive literature review, asking suitable questions, selecting the proper sample population, collecting the appropriate data, performing the correct statistical analyses, and drawing conclusions supported by the available evidence. Most study designs are classified by whether they are experimental or observational, longitudinal or cross-sectional, and prospective or retrospective. Additional features (e.g., controlled, randomized, or blinded) may be described that address bias. Two related challenging aspects of study design are defining an important research question and selecting an appropriate sample population. The sample population should represent the target population as much as possible. Furthermore, when comparing groups, it is important that the groups are as alike to each other as possible except for the variables of interest. Medical images are well suited for clinical research because imaging signs are categorical or numerical variables that might be predictors or outcomes of diseases or treatments.
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Affiliation(s)
- Peter V Scrivani
- Departments of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853
| | - Hollis N Erb
- Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853
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20
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Campos M, van Hoek I, Peremans K, Daminet S. Recombinant human thyrotropin in veterinary medicine: current use and future perspectives. J Vet Intern Med 2012; 26:853-62. [PMID: 22676297 DOI: 10.1111/j.1939-1676.2012.00950.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Revised: 04/03/2012] [Accepted: 04/21/2012] [Indexed: 11/29/2022] Open
Abstract
Recombinant human thyrotropin (rhTSH) was developed after bovine thyrotropin (bTSH) was no longer commercially available. It was approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) as an aid to diagnostic follow-up of differentiated thyroid carcinoma in humans and for thyroid remnant ablation with radioiodine. In addition, rhTSH is used in human medicine to evaluate thyroid reserve capacity and to enhance radioiodine uptake in patients with metastatic thyroid cancer and multinodular goiter. Likewise, rhTSH has been used in veterinary medicine over the last decade. The most important veterinary use of rhTSH is thyroidal functional reserve testing for the diagnosis of canine hypothyroidism. Recent pilot studies performed at Ghent University in Belgium have investigated the use of rhTSH to optimize radioiodine treatment of canine thyroid carcinoma and feline hyperthyroidism. Radioiodine treatment optimization may allow a decreased therapeutic dosage of radioiodine and thus may improve radioprotection. This review outlines the current uses of rhTSH in human and veterinary medicine, emphasizing research performed in dogs and cats, as well as potential future applications.
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Affiliation(s)
- M Campos
- Department of Medicine and Clinical Biology of Small Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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21
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Blois SL, Abrams-Ogg ACG, Mitchell C, Yu A, Stoewen D, Lillie BN, Kiupel M. Use of thyroid scintigraphy and pituitary immunohistochemistry in the diagnosis of spontaneous hypothyroidism in a mature cat. J Feline Med Surg 2010; 12:156-60. [DOI: 10.1016/j.jfms.2009.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2009] [Indexed: 11/28/2022]
Abstract
A 12-year old, castrated male domestic shorthair cat presented with a 2-year history of poor hair coat, seborrhea, generalized pruritus and otitis externa. Low circulating concentrations of total serum thyroxine (TT4) and free thyroxine (fT4) and an elevated thyroid stimulating hormone concentration supported a diagnosis of primary hypothyroidism. Thyroid scintigraphy did not show uptake of radioactive technetium in the thyroid area. Treatment with levothyroxine resulted in clinical improvement. Recurrence of dermatitis 8 months after onset of treatment resulted in euthanasia of the cat. On post-mortem examination, thyroid tissue was not identified on gross or histological examination. Pituitary immunohistochemistry identified hyperplasia of chromophobe cells.
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Affiliation(s)
- Shauna L Blois
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Anthony CG Abrams-Ogg
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Colleen Mitchell
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Anthony Yu
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Debbie Stoewen
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Brandon N Lillie
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Matti Kiupel
- Department of Pathobiology and Diagnostic Investigations, Michigan State University, East Lansing, Michigan, USA
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22
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van Hoek IM, Vandermeulen E, Peremans K, Daminet S. Thyroid stimulation with recombinant human thyrotropin in healthy cats, cats with non-thyroidal illness and in cats with low serum thyroxin and azotaemia after treatment of hyperthyroidism. J Feline Med Surg 2009; 12:117-21. [PMID: 19783190 DOI: 10.1016/j.jfms.2009.08.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2009] [Indexed: 11/30/2022]
Abstract
This study investigated the recombinant human thyrotropin (rhTSH) stimulation test in healthy cats (group 1), cats with non-thyroidal illness (group 2) and cats with low serum total T(4) (TT(4)) and azotaemia after (131)I treatment (group 3). Serum TT(4) responses and thyroidal pertechnetate uptake after administration of 25 microg rhTSH IV were assessed. Baseline serum TT(4) was significantly lower in group 3 compared with group 1, but not between other group pairs. Serum TT(4) increased significantly in groups 1 and 2 but not in group 3 after rhTSH administration. Post-rhTSH serum TT(4) concentrations differed significantly between groups 1 and 3 and groups 2 and 3, but not between groups 1 and 2. Thyroid/salivary gland uptake ratio (T/S uptake ratio) differed only significantly between groups 1 and 3. Stimulation with rhTSH is valuable to differentiate euthyroidism from iatrogenic hypothyroidism in cats.
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Affiliation(s)
- Ingrid M van Hoek
- Department of Medicine and Clinical Biology of Small Animals, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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van Hoek I, Daminet S. Interactions between thyroid and kidney function in pathological conditions of these organ systems: a review. Gen Comp Endocrinol 2009; 160:205-15. [PMID: 19133263 DOI: 10.1016/j.ygcen.2008.12.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 12/02/2008] [Accepted: 12/03/2008] [Indexed: 11/25/2022]
Abstract
Thyroidal status affects kidney function already in the embryonic stage. Thyroid hormones influence general tissue growth as well as tubular functions, electrolyte handling and neural input. Hyper- and hypo-functioning of the thyroid influences mature kidney function indirectly by affecting the cardiovascular system and the renal blood flow, and directly by affecting glomerular filtration, electrolyte pumps, the secretory and absorptive capacity of the tubuli, and the structure of the kidney. Hyperthyroidism accelerates several physiologic processes, a fact which is reflected in the decreased systemic vascular resistance, increased cardiac output (CO), increased renal blood flow (RBF), hypertrophic and hyperplastic tubuli, and increased glomerular filtration rate (GFR). Renal failure can progress due to glomerulosclerosis, proteinuria and oxidative stress. Hypothyroidism has a more negative influence on kidney function. Peripheral vascular resistance is increased with intrarenal vasoconstriction, and CO is decreased, causing decreased RBF. The influence on the different tubular functions is modest, although the transport capacity is below normal. The GFR is decreased up to 40% in hypothyroid humans. Despite the negative influences on glomerular and tubular kidney function, a hypothyroid state has been described as beneficial in kidney disease. Kidney disease is associated with decreased thyroid hormone concentrations caused by central effects and by changes in peripheral hormone metabolism and thyroid hormone binding proteins. Geriatric cats form an animal model of disease because both hyperthyroidism and chronic kidney disease (CKD) have high prevalence among them, and the link between thyroid and kidney affects the evaluation of clinical wellbeing and the possible treatment options.
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Affiliation(s)
- Ingrid van Hoek
- Department of Medicine & Clinical Biology of Small Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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van Hoek I, Daminet S, Vandermeulen E, Dobbeleir A, Duchateau L, Peremans K. Recombinant Human Thyrotropin Administration Enhances Thyroid Uptake of Radioactive Iodine in Hyperthyroid Cats. J Vet Intern Med 2008; 22:1340-4. [DOI: 10.1111/j.1939-1676.2008.0191.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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25
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van Hoek IM, Peremans K, Vandermeulen E, Duchateau L, Gommeren K, Daminet S. Effect of recombinant human thyroid stimulating hormone on serum thyroxin and thyroid scintigraphy in euthyroid cats. J Feline Med Surg 2008; 11:309-14. [PMID: 18848482 DOI: 10.1016/j.jfms.2008.07.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2008] [Indexed: 11/18/2022]
Abstract
This study investigated the thyroidal response to administration of recombinant human thyroid stimulating hormone (rhTSH) by means of serum total thyroxine (TT(4)) concentration and pertechnetate uptake by the thyroid gland in six healthy euthyroid spayed female cats. A pertechnetate scan was performed on day 1 to calculate thyroid/salivary gland (T/S) uptake ratio. On day 3, 25 microg rhTSH was injected intravenously. Six hours later the thyroid scan was repeated as on day 1. Blood was drawn for serum TT(4) measurement prior to injection of rhTSH and performance of the pertechnetate scan. Statistically significant differences in mean serum TT(4) concentration, T/S uptake ratio before and 6h after rhTSH administration and T/S uptake ratio between left and right lobes were noted. We can conclude that 25 microg rhTSH increases pertechnetate uptake in the thyroid glands of cats, this should be taken into account when thyroid scintigraphy after rhTSH administration is interpreted.
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Affiliation(s)
- Ingrid M van Hoek
- Department of Medicine and Clinical Biology of Small Animals, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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Interference of iohexol with radioiodine thyroid uptake in the hyperthyroid cat. J Feline Med Surg 2008; 10:460-5. [DOI: 10.1016/j.jfms.2008.02.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2008] [Indexed: 11/19/2022]
Abstract
Absorbed thyroid dose and effective half-life were determined in 46 hyperthyroid cats after treatment with a low dose (mean 111 MBq) of radioiodine intravenously. Thirteen of these cats had received iohexol for glomerular filtration rate (GFR) measurement within 24 h before treatment with radioiodine in view of another ongoing study at our institution. Pre-therapy values were obtained for total thyroxine (TT4) and for the thyroid to salivary gland ratio with sodium pertechnetate γ-camera imaging. All cats underwent post-therapy scans at 24, 48 and 120 h for evaluation of radioactive iodine uptake (RAIU) and the effective half-life of radioiodine. The absorbed dose was calculated from the cumulative activity with Olinda software. Both groups were comparable in age, TT4 and the ratio of thyroid activity to salivary gland activity. Statistical analysis revealed a significant decreased absorbed dose in the thyroid in the iohexol group. This decreased uptake was not accompanied by an decreased effective half-life of the radioiodine. The variation of inter-individual RAIU decreased in this group and more homogenous absorbed doses were obtained. No significant difference in outcome could be demonstrated. However, a tendency towards a higher number of residual hyperthyroidism in the iohexol group was noted (15 versus 6% in control group). This study demonstrates that iohexol interferes with the uptake of radioiodine in the hyperthyroid cat but does not provoke increased turnover. In this study, albeit including a small number of cats, outcome did not seem to be significantly affected.
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27
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Feeney DA, Anderson KL. Nuclear Imaging and Radiation Therapy in Canine and Feline Thyroid Disease. Vet Clin North Am Small Anim Pract 2007; 37:799-821, viii. [PMID: 17619013 DOI: 10.1016/j.cvsm.2007.03.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The indications, techniques, and expectations for radionuclide diagnostic studies on canine and feline thyroid glands are presented. In addition, the considerations surrounding radioiodine or external beam radiotherapy for benign and malignant thyroid disease are reviewed. The intent of this article is to familiarize primary care veterinarians with the utility of and outcome of the ionizing radiation-based diagnostic and therapeutic techniques for assessing and treating canine and feline thyroid disease.
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Affiliation(s)
- Daniel A Feeney
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, 1352 Boyd Avenue, St. Paul, MN 55108, USA.
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