Hyperthyroidism in cats continued
Radiation therapy
Radioactive iodine (I-131) is considered the safest, simplest and most effective form of therapy. Cure is obtained in over 90% of cases with one treatment. There is no need for an anaesthetic, any ectopic gland tissue is treated and malignant tumours (carcinomas) can respond well. Hypothyroidism or recurrence of hyperthyroidism are rare, but may occur occasionally. The major disadvantages are the one-off cost of treatment and the need for hospitalisation in a radiation isolation ward for an average of seven days after treatment.
A consultation prior to therapy is necessary to fully assess suitability and to discuss treatment. Before treatment is performed tests to rule out the presence of concurrent disease are necessary. Your referring veterinarian will be able to perform some or all of these tests. These may include:
1. Haematology, serum biochemistry and urinalysis
2. Thyroid hormone level
3. Blood pressure measurement
4. Thoracic radiographs and/or echocardiography
The cost of radioactive iodine therapy, including the initial consultation, is approximately $1500. Any additional diagnostic testing that is considered necessary prior to treatment will incur additional fees and will be discussed during the initial consultation.
In summary, radioactive iodine therapy involves:
1. Administration of an oral dose of radioactive iodine, calculated for the individual patient.
2. Hospitalisation until the radioactivity emitted by the cat decreases to safe levels. The average length of stay in hospital is seven days.
3. Minimal side effects, although your cat may have a voice change for a short time.
4. Up to six months before the full effect of therapy is achieved
5. A second treatment may be needed in up to 4% of cats treated with radioactive iodine.
Radioactive iodine therapy is contraindicated when other serious diseases are present, particularly renal disease or congestive heart failure.
