Effect on Renal Function of Restoration of Euthyroidism in Hyperthyroid Cats with Iatrogenic Hypothyroidism

Williams, Tim; Elliott, Jonathan; Syme, H M

doi:10.1111/jvim.12359

Cited by 28 publications

(30 citation statements)

References 12 publications

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“…Correction of iatrogenic hypothyroidism resolved azotaemia in 50% of cats (Williams et al . ). However, given that, in our study, two of three hypothyroid cats with decreased GFR were non‐azotaemic, it is possible that many cats with resolved azotaemia may still have reduced renal function that is not detected by measuring serum creatinine concentration alone.…”

Section: Discussionmentioning

confidence: 97%

Thyroid and renal function in cats following low‐dose radioiodine (111Mbq) therapy

Finch

Stallwood

Tasker

et al. 2019

J of Small Animal Practice

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Objectives To describe the effect of low‐dose (111MBq) radioiodine therapy on thyroid and renal function in hyperthyroid cats over a 12‐month follow‐up period. Materials and Methods Client‐owned hyperthyroid cats underwent low‐dose radioiodine therapy and were followed‐up for 12 months. Immediately before radioiodine treatment, and at 1, 6 and 12 months afterwards, total thyroxine, thyroid stimulating hormone, serum creatinine and glomerular filtration rate were measured. Results Fifteen of the 24 (63%) cats achieved euthyroidism following low‐dose radioiodine treatment. The incidence of overt hypothyroidism was six of 24 (25%) cats. Of the six cats developing overt hypothyroidism, three had decreased renal function, with decreased glomerular filtration rate preceding azotaemia in two of these individuals. Transient overt or subclinical hypothyroidism before restoration of euthyroidism was not observed. Clinical Significance Low‐dose radioiodine is effective treatment for hyperthyroidism in most cats but overt hypothyroidism may develop in some. Concurrent early decline in renal function may only be detected by measuring glomerular filtration rate rather than serum creatinine in some cats. Monitoring following radioiodine treatment should include total thyroxine and thyroid stimulating hormone and measurement of glomerular filtration rate should be considered in non‐azotaemic cats.

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Section: Discussionmentioning

confidence: 97%

Thyroid and renal function in cats following low‐dose radioiodine (111Mbq) therapy

Finch

Stallwood

Tasker

et al. 2019

J of Small Animal Practice

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“…In one study of azotaemic cats that developed iatrogenic hypothyroidism following methimazole overdosage, lowering the daily dose to restore euthyroidism also led to a fall in creatinine concentrations, with azotaemia resolving in half of the cats (Williams et al . ). Similarly, levothyroxine replacement in our cats with iatrogenic hypothyroidism (both overt and subclinical) led to significant decreases in serum creatinine concentrations.…”

Section: Discussionmentioning

confidence: 97%

Serum thyroxine and thyroid‐stimulating hormone concentration in hyperthyroid cats that develop azotaemia after radioiodine therapy

Peterson

Nichols²,

Rishniw

2017

J of Small Animal Practice

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OBJECTIVES : The objectives of this study were to determine which serum thyroid hormone test best identifies iatrogenic hypothyroidism in cats that develop azotaemia after radioiodine treatment and to determine which thyroid test best differentiates these azotaemic, hypothyroid cats from azotaemic, radioiodine-treated euthyroid cats, as well as from azotaemic cats with chronic kidney disease and no history of thyroid disease. M ATERIALS AND M ETHODS : A total of 42 hyperthyroid cats that developed azotaemia (serum creatinine ê220 µmol/L) after radioiodine treatment had serum concentrations of thyroxine and free thyroxine by dialysis and thyroid -stimulating hormone measured at 3, 6 and 12 months. Iatrogenic hypothyroidism was confirmed (n=28) or excluded (n=14) on the basis of thyroid scintigraphy. A total of 14 cats with chronic kidney disease and 166 clinically normal cats underwent similar serum thyroid testing and scintigraphy.R ESULTS : Concentrations of thyroxine and free thyroxine were lower and thyroid-stimulating hormone higher in hypothyroid cats than in all three groups of euthyroid cats (P<0·0001). Of the hypothyroid cats, thyroxine and free thyroxine concentrations were low in 15 (53·6%) and seven (25%), respectively. Low serum thyroxine and free thyroxine concentrations were also detected in seven (50%) and two (14·3%) of the cats with chronic kidney disease. Thyroid-stimulating hormone concentrations were elevated in all hypothyroid cats but remained within the reference interval in all three groups of euthyroid cats.Serum thyroid -stimulating hormone had a higher test sensitivity and specificity than either thyroxine or free thyroxine concentration. C LINICAL SIGNIFICANCE : The finding of high serum thyroid-stimulating hormone concentrations best identifies feline iatrogenic hypothyroidism and differentiates it from non-thyroidal illness syndrome in cats that develop azotaemia after treatment. ttp://www.bsava.com/ M. E. Peterson et al.

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“…Supplementing cats with iatrogenic overt hypothyroidism with L‐T 4 to achieve a euthyroid state is expected to increase GFR and improve renal function 28, 30, 31. In this study, no improvement in serum creatinine was seen in 6 cats with either subclinical or overt hypothyroidism treated with L‐T 4 for 3 months.…”

Section: Discussionmentioning

confidence: 99%

Efficacy of Low‐dose (2 millicurie) versus Standard‐dose (4 millicurie) Radioiodine Treatment for Cats with Mild‐to‐Moderate Hyperthyroidism

Lucy

Peterson

Randolph

et al. 2017

Veterinary Internal Medicne

127

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BackgroundRadioiodine (131I) is effective treatment for hyperthyroidism in cats, but optimal dose to restore euthyroidism without inducing hypothyroidism is unclear. Treatment‐induced hypothyroidism can lead to azotemia and reduced duration of survival.ObjectiveTo compare efficacy and short‐term outcomes of low‐dose 131I versus higher, standard‐dose 131I as treatment for hyperthyroidism.AnimalsA total of 189 client‐owned cats undergoing 131I treatment for mild‐to‐moderate hyperthyroidism (serum T4 ≥ 4.0 μg/dL and <13.0 μg/dL).MethodsProspective, nonrandomized, cohort study comparing treatment with either low‐dose (2 mCi, n = 150) or standard‐dose (4 mCi, n = 39) 131I. Serum T4, thyroid‐stimulating hormone (TSH), and creatinine concentrations were measured after 1, 3, and 6 months to determine persistent hyperthyroidism, overt hypothyroidism (low T4, high TSH), subclinical hypothyroidism (normal T4, high TSH), and azotemia.ResultsThere was no significant difference in prevalence of cats with persistent hyperthyroidism between standard‐ and low‐dose treatment groups at 3 (0% versus 5.3%; P = .34) and 6 (0% versus 3.3%; P = .51) months. Overt (18% versus 1%; P = .0005) or subclinical (46% versus 21%; P = .004) hypothyroidism was more common in cats at 6 months after standard‐dose 131I. No difference in incidence of azotemia existed between groups, but cats treated with standard‐dose 131I had higher creatinine concentrations (P < .05) and higher percent rises in creatinine (P < .0001).Conclusions and Clinical ImportanceLow‐dose 131I is safe and effective for cats with mild‐to‐moderate hyperthyroidism, as evidenced by a cure rate of >95% with reduced frequency of iatrogenic hypothyroidism and azotemia.

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Effect on Renal Function of Restoration of Euthyroidism in Hyperthyroid Cats with Iatrogenic Hypothyroidism

Cited by 28 publications

References 12 publications

Thyroid and renal function in cats following low‐dose radioiodine (111Mbq) therapy

Thyroid and renal function in cats following low‐dose radioiodine (111Mbq) therapy

Serum thyroxine and thyroid‐stimulating hormone concentration in hyperthyroid cats that develop azotaemia after radioiodine therapy

Efficacy of Low‐dose (2 millicurie) versus Standard‐dose (4 millicurie) Radioiodine Treatment for Cats with Mild‐to‐Moderate Hyperthyroidism

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