Internal Medicine: Feline Hyperthyroid Treatment

Please note: Due to staffing limitations, we are currently not seeing any feline hyperthyroid patients for the I-131 therapy. We hope to resume in the fall of 2022.

Please contact your primary Veterinarian’s office for options regarding this diagnosis.

gray cat on lab tableHyperthyroidism is caused by a thyroid tumor (usually non-malignant) and is currently the most common endocrine disease in older cats. Clinical signs are progressive and can be severely debilitating and potentially fatal if the disease is left untreated. The Veterinary Hospital offers a dedicated hyperthyroid cat clinic at the NC State CVM in Raleigh, NC.

Overproduction of thyroid hormone causes an increase in a cat’s metabolic rate and can result in any of the following symptoms:

  • Significant weight loss in spite of constant or increased eating habits.
  • Vomiting and Diarrhea
  • Hypertension
  • Hyperactivity
  • Aggression
  • Unkempt appearance

Owners should consult their primary veterinarian for an initial assessment of their pet. A physical examination and diagnostic testing consisting of routine blood work, urinalysis and a thyroid level will be conducted to determine the overall health of the cat. Occasionally, further testing may be needed but the results of this initial assessment are often sufficient to diagnose hyperthyroidism and determine if the cat is a candidate for radioactive iodine treatment.

Treatment Overview 

Treatment: The current treatment of choice is destruction of the abnormal thyroid tissue with radioactive iodine (I131). A specific dose of radioactive iodine is administered by a single injection under the skin. (This is the same basic procedure as giving a vaccine.) The cat will then stay in the hospital for approximately 4 days so we can adequately monitor radiation levels. This single injection will cure 95% of cats with no need of further treatment for this disease. In addition to being safe and very effective, over time it is also likely to be the least costly and stressful way to treat hyperthyroidism.

 Hospitalization: Each cat will stay in our luxurious cat cottages with a faux sheepskin bed, cardboard scratching post and lots of toys. Our caring staff will make sure all of the cats receive lots of love and attention during their stay.

Post Treatment Care: Each cat will stay in the hospital for 4 days for monitoring of radiation levels, with a recheck at 30 days post discharge, 60 days post discharge and then annually thereafter. Certain precautions will need to be taken with litter disposal and contact for 14 days after bringing the cat home. We will go over these details and recommendations for follow up care at the time of discharge.