Posted: August 24, 2011, 5 a.m. EDT
Guinea Pig Scribbles/Courtesy Lawrence LoVerme
Hyperthyroidism in guinea pigs is somewhat common, and treatment options are still being explored.
At the beginning of August I was able to attend the yearly conference of the Association of Exotic Mammal Veterinarians (AEMV) up in Seattle. The weather was absolutely amazing. The high temperature for most of the days was only in the low 70s. For the veterinarians from Texas and Oklahoma, this was a much-needed escape from this summer’s extreme heat wave. Of course the continuing education was great, too.
Topics for this year’s AEMV conference covered ferrets, rabbits, guinea pigs, chinchillas, gerbils, hamsters, mice and rats. In addition, an avian veterinary conference and a reptile veterinary conference occurred during the same week.
Two of the presentations at the AEMV conference were on hyperthyroidism in guinea pigs. Hyperthyroidism is a common problem in older cats, and it appears to be somewhat common in guinea pigs over the age of 3. The typical signs of hyperthyroidism in guinea pigs include hyperactivity, increased appetite with a loss of body weight, increased water consumption and increased urine production. These signs are similar to the signs cats have with hyperthyroidism.
Treatment of hyperthyroidism in guinea pigs is also similar to the treatment of it in cats. The thyroid gland can be surgically removed, but this is a difficult surgery to do. Vital nerves and blood vessels are close to the thyroid glands. Plus, the parathyroid glands may be removed with the thyroid glands, which would make calcium supplementation necessary after the surgery.
Medical treatment is a safer option for guinea pigs with hyperthyroidism. Radioactive iodine therapy is commonly used in cats, but it is an expensive option. In a few guinea pig cases that have used radioactive iodine, it appears that it works well in guinea pigs, too. The final option is to use a daily medication called methimazole (Tapazole). Guinea pigs require a higher dose of methimazole than cats. In the few guinea pig cases where methimazole was tried, it seemed to work well to control the thyroid hormone levels.
Unfortunately, guinea pigs seem to have a higher risk for having a thyroid tumor than cats do. Some of the tumors are mixed thyroid tumors, which contain bone and can be malignant. We have a lot to learn about guinea pig thyroid problems and how best to treat them.
See all of Dr. Murray's columns>>