· Species: Cat

· Age: approx. 12-13

· Sex/Neuter status: Female/Spayed

· Breed: DLH (Maine Coon mix)

· Body weight: approx. 10 lbs.

· History: Our cat was cared for by relatives for a few years while we lived abroad. About 9 months after returning to our care, we noticed she was losing some weight (previously a little over 11 lbs.) and was a bit cranky, but otherwise very healthy and energetic. We took her in for a regular checkup and bloodwork and on June 3 cat was diagnosed with hyperthyroidism, T4 levels were 9.4, also diagnosed with UTI. For thyroid: have been giving methimazole 0.5 ml twice daily for three weeks. For UTI: Orbax antibiotic 10 days. Bloodwork and urinalysis re-taken on June 20. New bloodwork shows thyroid levels back to normal range and no UTI. She also appears to have gained back some weight – spine feels less bony. Before proceeding with further thyroid treatment, we are trying to determine her kidney functioning; SMDA and Magnesium were the only biomarkers in high range. All other results from urinalysis and blood tests appeared to fall within normal range.

· We would like to treat the cat with radioactive iodine (I-131) for thyroid in three weeks, while we are scheduled to be out of town for a week, however vet’s office suggests continuing methimazole for 4 -6 weeks and then re-testing to determine any changes in kidney functioning before proceeding with I-131 treatment. So the question we have is, given what we know about her kidney functioning, is it necessary to do the additional testing, or if it would be safe to proceed with the I-131 at this point? We’d prefer to get it over with if we’re going to have to do it anyway, hopefully to reduce the trauma to our cat and our finances.

· Clinical signs: From bloodwork done on June 20:

SDMA level: 18 (Normal Range: 0-14 ug/dL)

Magnesium: 2.5 (Normal Range: 1.8-2.4 ug/dL)

Creatinine: 1.7 (Normal Range: 0.9-2.5)

BUN: 34 (Normal Range: 16-37 ug/dL)

T4: 1.3 (Normal Range: 0.8-4.7 mg/dL)

· Your general location: Memphis, TN, USA