Effect of treatment of hyperthyroidism on renal function in cats.
OBJECTIVE
To determine whether increases in BUN and serum creatinine (SCr) concentrations, which have been reported to develop after surgical bilateral thyroidectomy in hyperthyroid cats, also develop after treatment of hyperthyroidism with radioactive iodine and methimazole.


METHODS
Prospective, clinical trial.


METHODS
58 hyperthyroid cats.


METHODS
Urine specific gravity, SCr, BUN, and serum thyroxine (T4) concentrations were determined before and 30 and 90 days after treatment of hyperthyroidism with radioactive iodine, methimazole, or surgical bilateral thyroidectomy.


RESULTS
Mean SCr and BUN concentrations determined 30 and 90 days after treatment were significantly higher than those measured before treatment. Mean SCr, BUN, and T4 concentrations were not different among groups before treatment or 30 and 90 days after treatment.


CONCLUSIONS
Reduction of serum T4 concentrations after treatment of hyperthyroidism may result in azotemia in older cats with chronic renal disease. Treating azotemic hyperthyroid cats with methimazole until it can be determined whether correction of the hyperthyroid state will exacerbate the azotemia may be prudent.
DiBartola
S P
SP
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, Columbus 43210, USA.
Broome
M R
MR
Stein
B S
BS
Nixon
M
M
D000818:Animals; D013956:Antithyroid Agents / Q000627:therapeutic use; D001806:Blood Urea Nitrogen; D002371:Cat Diseases / Q000503:physiopathology* / Q000628:therapy; D002415:Cats; D003404:Creatinine / Q000097:blood; D006980:Hyperthyroidism / Q000503:physiopathology / Q000628:therapy / Q000662:veterinary*; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D007668:Kidney / Q000503:physiopathology*; D008713:Methimazole / Q000627:therapeutic use; D011446:Prospective Studies; D013046:Specific Gravity; D013965:Thyroidectomy / Q000662:veterinary; D013974:Thyroxine / Q000097:blood; D014556:Urine / Q000737:chemistry
D013956:Antithyroid Agents; D007457:Iodine Radioisotopes; D008713:Methimazole; D003404:Creatinine; D013974:Thyroxine