Liver Function in Cats with Hyperthyroidism Before and After<sup>131</sup>I Therapy

Berent, Allyson; Drobatz, Kenneth J.; Ziemer, Lisa; Johnson, Victoria; Ward, Cynthia R.

doi:10.1111/j.1939-1676.2007.tb01941.x

Cited by 23 publications

(5 citation statements)

References 16 publications

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“…In total, 123/217 (56.7%) had an elevation in ALT, 53/215 (24.7%) had an elevation in ALP, and 29/186 (15.6%) had an elevation in AST. This finding is lower compared to 75.0–78.9% shown in previous reports with fewer hyperthyroid cats ( 9 , 15 ). Our study is the first to report the magnitude of ELEZ in a large cohort of cats presenting for I-131 treatment, with ~8% of cats having ALT >500 IU/L.…”

Section: Discussioncontrasting

confidence: 68%

“…A previous small prospective observational study showed that hyperthyroid cats can have normal liver function and no sonographic abnormalities within their livers despite ELEZ, and all the hyperthyroid cats in that study had NLEZ following I-131 therapy ( 15 ). In the present study with a larger cohort of cats, total thyroxine concentration had a positive correlation with liver enzyme activity elevations, and all cats with STFU or LTFU had NLEZ following euthyroidism after successful I-131 treatment.…”

Section: Discussionmentioning

confidence: 93%

“…A selection bias may have existed in the cats that were referred for I-131 therapy to our institution, as ill hyperthyroid cats with concurrent primary hepatobiliary disease may have not been considered for referral by the primary veterinarians. Our study did not include the measurement of plasma ammonia concentrations or paired fasted and post-prandial serum bile acid concentrations before and after I-131 treatment, and therefore, hepatic function cannot be assessed in our study; however, a previous study could not demonstrate hepatic dysfunction in hyperthyroid cats presenting for I-131 treatment ( 15 ).…”

Section: Discussionmentioning

confidence: 98%

“…In human thyrotoxicosis, ELEZ are common, with up to 76% of patients having at least one liver function test abnormality, and the ELEZ are often reversible once the patient achieves a euthyroid state, and there is also no correlation with histopathologic lesions and ELEZ ( 14 ). One study with 19 hyperthyroid cats treated with I-131 could not demonstrate an association with abnormalities in the sonographic appearance of the hepatic parenchyma or liver functional variables (serum bile acids, albumin, ammonia, cholesterol, and blood urea nitrogen) in hyperthyroid cats regardless of the degree of ELEZ (78.94% of the cats had ELEZ), and the liver enzymes (LEZ) in these cats after I-131 therapy had no significant difference with age-matched healthy control cats ( 15 ).…”

Section: Introductionmentioning

confidence: 89%

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The Prevalence, Magnitude, and Reversibility of Elevated Liver Enzyme Activities in Hyperthyroid Cats Presenting for Iodine-131 Treatment

Campbell¹,

Chapman²,

Klag³

2022

Front. Vet. Sci.

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ObjectivesThe primary objective of this study was to report the prevalence and magnitude of elevated liver enzyme activity in feline hyperthyroidism using a large cohort of cats presenting for iodine-131 treatment. The secondary objective was to determine if elevated liver enzyme activity was a reversible process following successful iodine-131 treatment.MethodsCases that presented for a single iodine-131 treatment were retrospectively reviewed. Short-term and long-term follow-up clinicopathologic data was then reviewed for the secondary objective.ResultsTwo hundred seventeen hyperthyroid cats met the inclusion criteria for the primary objective. In total, 123/217 (56.7%) of the cats had at least one liver enzyme elevation on their chemistry panel, with alanine transaminase activity being the most common. All cats who were successfully treated with iodine-131 had liver enzyme activity within the reference range at short-term follow-up and long-term follow-up points.Conclusion and RelevanceOur study demonstrates that elevated liver values are common in cats presenting for iodine-131 treatment. Additionally, our study demonstrates that even when liver values are markedly elevated prior to treatment, the liver enzyme activity will return to normal after successful resolution of hyperthyroidism using iodine-131 treatment. Investigation into hepatobiliary disease and liver function tests for cats with a diagnosis of hyperthyroidism may be unnecessary as the liver values will likely return to normal with successful iodine-131 treatment.

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Section: Discussioncontrasting

confidence: 68%

Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 89%

See 2 more Smart Citations

The Prevalence, Magnitude, and Reversibility of Elevated Liver Enzyme Activities in Hyperthyroid Cats Presenting for Iodine-131 Treatment

Campbell¹,

Chapman²,

Klag³

2022

Front. Vet. Sci.

View full text Add to dashboard Cite

show abstract

“… 25 – 27 Although previous recommendations included evaluating hyperthyroid cats with ALP or ALT activity >500 IU/L for concurrent disease, 2 , 14 , 15 further experience has revealed that the changes seen in the liver secondary to hyperthyroidism usually do not affect liver function testing, such as paired serum bile acids, so such testing may not be warranted. 28 In addition, histologic evaluation of the liver in cats with hyperthyroidism reveals nonspecific and mild changes, 4 and liver enzyme changes associated with hyperthyroidism usually return to within the reference interval with successful management of the disease. 29…”

Section: Clinical Presentationmentioning

confidence: 99%