Serum Cobalamin and Methylmalonic Acid Concentrations in Hyperthyroid Cats Before and After Radioiodine Treatment.

Abstract

BACKGROUND:

Hyperthyroidism, the most common endocrine disorder in cats, has been associated with low serum cobalamin concentrations. Whether this is a functional cobalamin deficiency of clinical importance has not been assessed.

HYPOTHESIS/OBJECTIVES:

Cats with hyperthyroidism experience a functional cobalamin deficiency which correlates with their clinical catabolic state and is reversible with return of the euthyroid state.

ANIMALS:

Thirty-nine client-owned hyperthyroid cats.

METHODS:

Prospective observational study. Serum cobalamin, methylmalonic acid, and clinical scores were determined in each hyperthyroid cat at enrollment and when euthyroid (60 days after radioiodine treatment).

RESULTS:

Five of the 39 hyperthyroid cats (13%) had a low serum cobalamin concentration ranging from <150 to 290 ng/L. Serum cobalamin concentrations normalized to >350 ng/L in 2 of the hypocobalaminemic cats once euthyroid. None of the hyperthyroid/hypocobalaminemic cats had increased serum methylmalonic acid concentrations (175-601 nmol/L). In cats with clinical and biochemical hyperthyroidism, there was no correlation between serum cobalamin concentrations with total T4 concentration (P = .12) or clinical scores including body weight (P = .11) and BCS (P = .54).

CONCLUSIONS AND CLINICAL IMPORTANCE:

In this population of hyperthyroid cats, the prevalence of hypocobalaminemia was low. Specifically, hyperthyroid cats, in which concurrent gastrointestinal disease is unlikely. Hypocobalaminemia is not a functional deficiency requiring supplementation in hyperthyroid cats without gastrointestinal disease.

• Authors: B M Geesaman, W H Whitehouse, K R Viviano
• Journal: Journal of veterinary internal medicine (J Vet Intern Med) 2016 Mar-Apr Vol. 30 Issue 2 Pg. 560-5 ISSN: 1939-1676 [Electronic] United States
• PMID: 26934857 (Publication Type: Journal Article, Observational Study, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Chemical References

• Iodine Radioisotopes
• Methylmalonic Acid
• Vitamin B 12

Topics

• Animals
• Cat Diseases (blood, therapy)
• Cats
• Female
• Hyperthyroidism (therapy, veterinary)
• Iodine Radioisotopes (therapeutic use)
• Male
• Methylmalonic Acid (blood)
• Vitamin B 12 (blood)
• Vitamin B 12 Deficiency (blood, veterinary)