Patient: An eleven year old neutered male Domestic Short-hair
cat named Willie.
Problem: Willie has been eating well, but losing weight.
History: Willie’s owner felt that he seemed thin and made
an appointment with his veterinarian. During the examination
the veterinarian found that Willie had lost two pounds since
his last visit (which was six months prior). Willie now weighed
eight pounds, having lost 20 percent of his body weight. His
heart rate was faster than usual; his hair appeared dull and
he looked unthrifty. Willie’s veterinarian ran tests to evaluate his condition. Blood tests
included complete blood cell count, electrolytes, blood chemistry screen and thyroid
levels. Tests showed his thyroid level to be very high.
Diagnosis: Willie was diagnosed with hyperthyroidism, a common condition in older
cats. About 98 percent of feline hyperthyroid cases are due to a benign enlargement and
over-activity of the thyroid gland. This increases the body’s metabolism and leads to
weight loss despite a big appetite. The heart rate can also increase dangerously.
Other possible signs of hyperthyroidism include increased thirst and urination, diarrhea
or increased fecal volume, panting, poor hair coat, appetite or activity level changes.
Any change in your cat’s behavior, eating or bathroom habits should be noted and a trip
to the veterinarian should be scheduled promptly.
Treatment: There are three main options for treating hyperthyroidism in cats.
1. Medical treatment consists of an antithyroid drug given orally. This medicine must be
given daily. It prevents the formation of the active thyroid hormone in the gland. Periodic
blood tests are needed to judge the medication’s effectiveness. Some side effects
include intestinal, liver or blood problems. Many cats do well with with antithyroid drugs,
but some develop stomach upset or other problems and do not tolerate it.
2. Surgery is also available to remove the thyroid glands. This is curative, but there is a
risk of serious complications in the immediate post-operative period. Your veterinarian
can go into the pros and cons of surgical removal of the thyroid glands.
3. Radioiodine therapy is a one-time injection given at a special hospital facility that
causes the thyroid gland to shrink without any harm to the cat. No anesthesia is needed.
Availability of this treatment has increased dramatically in recent years. The major factor
to consider with radioiodine therapy is cost. However, long term medical treatment with
daily medication or surgery may result in similar costs.
Willie’s owner opted to take him for radioiodine therapy. The cost was about $1,200.
Willie was admitted to a special hospital for his injection. He also had a cardiologist
check his heart using ultrasound.
It was determined that his increased heart rate was secondary to his thyroid condition
and that no cardiac medication was required at this time. He would need a follow up
cardiac ultrasound in six months. Willie had to stay at the hospital for three days after his
injection for monitoring.
Outcome: Within two months Willie had gained one pound and his thyroid level had
returned to normal.
All geriatric cats should have periodic blood screening to detect medical problems early,
before they start to lose weight and look sickly. Depending on an adult cat’s medical
history and age, he or she may need tests such as blood screening, x-rays, blood
pressure and EKG every three months or annually.
Ask the Vet is not intended to be a substitute for the regular veterinary care a licensed veterinarian
provides through routine physical exams, and should only be used for personal, educational and
informational purposes only. Responses do not establish a veterinarian-client-patient relationship,
and are not intended as veterinary medical advice.
| Case Study - MY OLDER CAT IS LOSING WEIGHT |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| Dr. Karen Zelinski works at Animal General Veterinary Hospital at 725 River Road, Edgewater, N.J. She graduated from Cornell College of Veterinary Medicine in 1993; she has two Dalmatians and three cats. |