24/08/2026
Meet Link, one of the most beautiful Ragdolls we’ve met (and he knows it!). Link’s hyperthyroidism was successfully treated with radioactive iodine, and his mum reports her gorgeous boy is doing well. Like many senior cats with hyperthyroidism, Link has concurrent chronic kidney disease (CKD). Despite this, optimal management of both hyperthyroidism and CKD is possible:
🔹 It is estimated that 20-50% of hyperthyroid cats have concurrent CKD.
🔹 CKD often masked by hyperthyroidism, which ‘artificially’ increases kidney blood flow as well as the glomerular filtration rate (GFR).
🔹 Successful treatment of hyperthyroidism decreases the GFR, which can result in an apparent worsening of kidney blood values. It is important to note that treatment of hyperthyroidism does not cause CKD; rather, it was just masked by the hyperthyroidism.
🔹 In cats with pre-exiting kidney disease prior to treatment of hyperthyroidism, we take the following precautions:
- 1. A treatment trial with an anti-thyroid medication is performed to ensure there is no deterioration in kidney function after normalising T4 levels. This is a reversible treatment that can be stopped if problems arise.
- 2. Furthermore, cats with IRIS stage 2 kidney disease (prior to treatment of hyperthyroidism) are discharged with levothyroxine supplementation following radioactive iodine treatment. This helps limit the progression of azotaemia by avoiding the transient period of hypothyroidism (underactive thyroid) that commonly develops after radioactive iodine treatment.
💙 So what about Link? He has since been successfully weaned off levothyroxine, and his kidney function remains stable. And he has been cured of hyperthyroidism 😍
