Sp. Dibartola et al., EFFECT OF TREATMENT OF HYPERTHYROIDISM ON RENAL-FUNCTION IN CATS, Journal of the American Veterinary Medical Association, 208(6), 1996, pp. 875
Objective-To determine whether increases in BUN and serum creatinine (
SCr) concentrations, which have been reported to develop after surgica
l bilateral thyroidectomy in hyperthyroid cats, also develop after tre
atment of hyperthyroidism with radioactive iodine and methimazole. Des
ign-Prospective, clinical trial. Animals-58 hyperthyroid cats. Procedu
re-Urine specific gravity, SCr, BUN, and serum thyroxine (T-4) concent
rations were determined before and 30 and 90 days after treatment of h
yperthyroidism with radioactive iodine, methimazole, or surgical bilat
eral thyroidectomy. Results-Mean SCr and BUN concentrations determined
30 and 90 days alter treatment were significantly higher than those m
easured before treatment. Mean SCr, BUN, and T-4 concentrations were n
ot different among groups before treatment or 30 and 90 days after tre
atment. Clinical Implications-Reduction of serum T-4 concentrations af
ter treatment of hyperthyroidism may result in azotemia in older cats
with chronic renal disease. Treating azotemic hyperthyroid cats with m
ethimazole until it can be determined whether correction of the hypert
hyroid state will exacerbate the azotemia may be prudent.