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Peterson ME, Rishniw M. Urine concentrating ability in cats with hyperthyroidism: Influence of radioiodine treatment, masked azotemia, and iatrogenic hypothyroidism. J Vet Intern Med 2023; 37:2039-2051. [PMID: 37668163 PMCID: PMC10658547 DOI: 10.1111/jvim.16849] [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] [Received: 01/10/2023] [Accepted: 08/23/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Hyperthyroid cats often have urine specific gravity (USG) values <1.035. It remains unclear how USG changes after treatment, if USG can be used to predict azotemia after treatment, or how iatrogenic hypothyroidism influences USG values. OBJECTIVES To determine the proportion of hyperthyroid cats with USG <1.035 vs ≥1.035; if USG changes after treatment; and whether USG <1.035 correlated with unmasking of azotemia or hypothyroidism. ANIMALS Six hundred fifty-five hyperthyroid cats treated with radioiodine; 190 clinically normal cats. METHODS Prospective, before-and-after study. Hyperthyroid cats had serum thyroxine, thyroid-stimulating hormone, and creatinine concentrations, and USG measured before and 6 months after successful treatment with radioiodine. RESULTS Of untreated hyperthyroid cats, USG was ≥1.035 in 346 (52.8%) and <1.035 in 309 (47.2%). After treatment, 279/346 (80.6%) maintained USG ≥1.035, whereas 67/346 (19.4%) became <1.035; 272/309 (88%) maintained USG <1.035, whereas 37/309 (12%) became ≥1.035. Only 22/346 (6.4%) with USG ≥1.035 developed azotemia after treatment, compared with 136/309 (44%) with <1.035 (P < .001). Of cats remaining nonazotemic, 38% had USG <1.035, compared with 20% of normal cats (P < .001). The 137 cats with iatrogenic hypothyroidism had lower USG after treatment than did 508 euthyroid cats (1.024 vs 1.035), but USGs did not change after levothyroxine supplementation. USG <1.035 had high sensitivity (86.1%) but moderate specificity (65.2%) in predicting azotemia after treatment. CONCLUSIONS AND CLINICAL IMPORTANCE Hyperthyroidism appears not to affect USG in cats. However, cats with evidence of sub-optimal concentrating ability before radioiodine treatment (USG < 1.035) are more likely to develop azotemia and unmask previously occult chronic kidney disease. Iatrogenic hypothyroidism itself did not appear to affect USG values.
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Affiliation(s)
- Mark E. Peterson
- Animal Endocrine Clinic, 21 West 100th StreetNew YorkNew YorkUSA
- College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
| | - Mark Rishniw
- College of Veterinary MedicineCornell UniversityIthacaNew YorkUSA
- Veterinary Information NetworkDavisCaliforniaUSA
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Williams JG, Hess RS. Concurrent disorders of cats with diabetes mellitus and arterial systolic hypertension. J Feline Med Surg 2023; 25:1098612X231187691. [PMID: 37470682 PMCID: PMC10812060 DOI: 10.1177/1098612x231187691] [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: 07/21/2023]
Abstract
OBJECTIVES The aim of the present study was to report the concurrent disorders and treatment success of cats with diabetes mellitus (DM) and arterial systolic hypertension (SH). METHODS A retrospective longitudinal study was conducted of 17 cats with DM and SH that were examined at a university teaching hospital between 1 January 2011 and 31 December 2021. The medical records of diabetic cats were searched for the keywords 'hypertension', 'blood pressure', 'amlodipine', 'benazepril' and 'telmisartan' to identify cats with SH, which was defined as systemic arterial blood pressure (SABP) ⩾160 mmHg, documented at least twice, over several days. Comorbidities, including chronic kidney disease and hyperthyroidism, were recorded. Medications used for the treatment of SH and the SABP response to treatment were also noted. RESULTS Most cats (13/17, 76%) with DM and SH had at least one other documented concurrent illness that could contribute to SH, including chronic kidney disease (12/17 cats, 71%), hyperthyroidism (4/17, 23%) and functional adrenocortical mass secreting either aldosterone alone (1/17, 6%) or glucocorticoids, and possibly also aldosterone (1/17, 6%). Out of 17 cats, 15 (88%) were treated with amlodipine, and none were treated with an angiotensin converting enzyme inhibitor or an angiotensin II receptor blocker. Mean SABP at the time of diagnosis of SH was 210 ± 23 mmHg and was significantly higher than the mean SABP at the first and second follow-up examinations after the introduction of amlodipine treatment (175 ± 33 mmHg, P = 0.008 and 172 ± 26 mmHg, P = 0.01, respectively). CONCLUSIONS AND RELEVANCE Cats with DM and SH should be evaluated for the presence of chronic kidney disease, hyperthyroidism and functional adrenal masses. Treatment with amlodipine appears to be effective in lowering SABP in cats with DM and SH.
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Affiliation(s)
- Jonathon G Williams
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rebecka S Hess
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Bugbee A, Rucinsky R, Cazabon S, Kvitko-White H, Lathan P, Nichelason A, Rudolph L. 2023 AAHA Selected Endocrinopathies of Dogs and Cats Guidelines. J Am Anim Hosp Assoc 2023; 59:113-135. [PMID: 37167252 DOI: 10.5326/jaaha-ms-7368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Canine and feline endocrinopathies reflect an endocrine gland disease or dysfunction with resulting hormonal abnormali ties that can variably affect the patient's wellbeing, quality of life, and life expectancy. These guidelines provide consensus recommendations for diagnosis and treatment of four canine and feline endocrinopathies commonly encountered in clini cal practice: canine hypothyroidism, canine hypercortisolism (Cushing's syndrome), canine hypoadrenocorticism (Addi son's disease), and feline hyperthyroidism. To aid the general practitioner in navigating these common diseases, a stepwise diagnosis and treatment algorithm and relevant background information is provided for managing each of these diseases. The guidelines also describe, in lesser detail, the diagnosis and treatment of three relatively less common endo crinopathies of cats: feline hyperaldosteronism, feline hypothyroidism, and feline hyperadrenocorticism. Additionally, the guidelines present tips on effective veterinary team utilization and client communication when discussing endocrine cases.
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Affiliation(s)
- Andrew Bugbee
- Department of Small Animal Medicine and Surgery, University of Georgia, Athens, Georgia (A.B.); Mid Atlantic Cat Hospital, Mid Atlantic Feline Thyroid Center, Queenstown, Maryland (R.R.); Boston Veterinary Clinic, Boston, Massachusetts (S.C.); KW Veterinary Consulting, LLC, Kansas City, Missouri (H.K.-W.); Mississippi State University, Mississippi State, Mississippi (P.L.); School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin (A.N.); Rowan College of South Jersey, Sewell, New Jersey (L.R.)
| | - Renee Rucinsky
- Department of Small Animal Medicine and Surgery, University of Georgia, Athens, Georgia (A.B.); Mid Atlantic Cat Hospital, Mid Atlantic Feline Thyroid Center, Queenstown, Maryland (R.R.); Boston Veterinary Clinic, Boston, Massachusetts (S.C.); KW Veterinary Consulting, LLC, Kansas City, Missouri (H.K.-W.); Mississippi State University, Mississippi State, Mississippi (P.L.); School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin (A.N.); Rowan College of South Jersey, Sewell, New Jersey (L.R.)
| | - Sarah Cazabon
- Department of Small Animal Medicine and Surgery, University of Georgia, Athens, Georgia (A.B.); Mid Atlantic Cat Hospital, Mid Atlantic Feline Thyroid Center, Queenstown, Maryland (R.R.); Boston Veterinary Clinic, Boston, Massachusetts (S.C.); KW Veterinary Consulting, LLC, Kansas City, Missouri (H.K.-W.); Mississippi State University, Mississippi State, Mississippi (P.L.); School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin (A.N.); Rowan College of South Jersey, Sewell, New Jersey (L.R.)
| | - Heather Kvitko-White
- Department of Small Animal Medicine and Surgery, University of Georgia, Athens, Georgia (A.B.); Mid Atlantic Cat Hospital, Mid Atlantic Feline Thyroid Center, Queenstown, Maryland (R.R.); Boston Veterinary Clinic, Boston, Massachusetts (S.C.); KW Veterinary Consulting, LLC, Kansas City, Missouri (H.K.-W.); Mississippi State University, Mississippi State, Mississippi (P.L.); School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin (A.N.); Rowan College of South Jersey, Sewell, New Jersey (L.R.)
| | - Patty Lathan
- Department of Small Animal Medicine and Surgery, University of Georgia, Athens, Georgia (A.B.); Mid Atlantic Cat Hospital, Mid Atlantic Feline Thyroid Center, Queenstown, Maryland (R.R.); Boston Veterinary Clinic, Boston, Massachusetts (S.C.); KW Veterinary Consulting, LLC, Kansas City, Missouri (H.K.-W.); Mississippi State University, Mississippi State, Mississippi (P.L.); School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin (A.N.); Rowan College of South Jersey, Sewell, New Jersey (L.R.)
| | - Amy Nichelason
- Department of Small Animal Medicine and Surgery, University of Georgia, Athens, Georgia (A.B.); Mid Atlantic Cat Hospital, Mid Atlantic Feline Thyroid Center, Queenstown, Maryland (R.R.); Boston Veterinary Clinic, Boston, Massachusetts (S.C.); KW Veterinary Consulting, LLC, Kansas City, Missouri (H.K.-W.); Mississippi State University, Mississippi State, Mississippi (P.L.); School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin (A.N.); Rowan College of South Jersey, Sewell, New Jersey (L.R.)
| | - Liza Rudolph
- Department of Small Animal Medicine and Surgery, University of Georgia, Athens, Georgia (A.B.); Mid Atlantic Cat Hospital, Mid Atlantic Feline Thyroid Center, Queenstown, Maryland (R.R.); Boston Veterinary Clinic, Boston, Massachusetts (S.C.); KW Veterinary Consulting, LLC, Kansas City, Missouri (H.K.-W.); Mississippi State University, Mississippi State, Mississippi (P.L.); School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin (A.N.); Rowan College of South Jersey, Sewell, New Jersey (L.R.)
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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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