Radioiodine (I-131)Hill's Rx y/d Diet
(severely iodine deficient)
OUTCOMECures hyperthyroid stateHyperthyroidism is never curedHyperthyroidism is never cured
SIDE EFFECTSNoneUnknownCommon
COSTSOne timeOngoing for the life of the catOngoing for the life of the cat
CONCURRENT DISEASEDiet flexible to accommodate
other needs
Strict adherence to Y/D diet requiredDiet flexible to accommodate
other needs
TREATMENTSingle SQ injectionLife-long dietLife-long treatment
HYPOTHYROIDISMRare with customized I-131 dosingUnknownCommon
FOLLOW UP CARERoutineContinuousContinuous
No impactRequires independent
feeding of hyperthyroid patient
No impact
ADENOMADestroys adenomaAdenoma continues to grow
leading to possible loss of control
Adenoma continues to grow requiring regular dose adjustments
MALIGNANT TRANSFORMATIONPrevents malignant transformationMalignant transformation
not prevented
Malignant transformation
not prevented
CARCINOMAOnly effective treatment for cats with thyroid carcinomaAllows thyroid carcinoma
to progress
Allows thyroid carcinoma
to progress
HYPERTENSIONRenal hypertension and
proteinuria resolve
glomerular hypertension and proteinuria may persistRenal hypertension and proteinuria may persist
RENAL DISEASEStops progressionPoor control may allow progressionPoor control may allow progression
DIETVariable DietStrict diet adherence requiredVariable Diet
OBLIGATE CARNIVOREMeat based diets allowedHigh carbohydrate diet inappropriate for obligate
Meat based diets allowed
SURVIVALBest long term survivalSurvival unprovenShortest survival