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. 2022 Feb 16:9:830287.
doi: 10.3389/fvets.2022.830287. eCollection 2022.

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

Joseph Campbell  1 , Peter Chapman  1 , Alan Klag  1
Affiliations

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

Joseph Campbell et al. Front Vet Sci. .

Abstract

Objectives: The 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.

Methods: Cases 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.

Results: Two 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 relevance: Our 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.

Keywords: I-131 treatment; clinical pathology data; feline hyperthyroidism; liver enzyme elevations; thyroid nodular hyperplasia.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Relationship of ALT and thyroxine concentration in hyperthyroid cats presenting before I-131 treatment.
Figure 2
Figure 2
ELEZ T0, Subgroup of hyperthyroid cats presenting for I-131 treatment with elevated ALT activity outside of the reference range; ELEZ T1, Same group of cats with post-op ALT vales at STFU (2–8 weeks); ELEZ T2, Same group of cats with post-op ALT values at LTFU (9–12 weeks). Note: Outliers in the ELEZ T1 and ELEZ T2 data sets are cats that were not successfully treated with I-131 and had persistent elevated ALT activity. All hyperthyroid cats that were successfully treated had ALT activity within the reference range at STFU and LTFU.
See this image and copyright information in PMC

References

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