Hypothyroidism is a disease caused by insufficient thyroid hormone production.  The thyroid gland is located in the neck, on either side of the trachea.  It produces two hormones: thyroxine (T4) and triiodothyronine (T3).  Thyroid hormones affect the rate of metabolism in most of the tissues in the body.  Thyroid hormone deficiency leads to illness.

Clinical Signs

• Weight gain
• Skin infections
• Ear infections
• Lethargy
• Dull, brittle hair coat
• Cold intolerance
• Reproductive problems
• Neurologic problems

Any breed may be affected, although Golden Retrievers and Doberman Pinschers are at increased risk.

Hypothyroidism usually affects dogs over three years old.

Diagnosis is made by blood tests, often of a Total T4 along with blood chemistry tests and a complete blood count to rule out other illnesses.  Sometimes a Free T4 test may be added.

Treatment is by supplementation with synthetic thyroid hormone.  Levothyroxine (L-thyroxine), also known by the brand names Soloxine and Synthroid, is effective, safe, and readily available.  Improvement is usually seen within 1-2 weeks, though it can take up to 8 weeks for dermatological problems to improve.

Often the dose needs to be adjusted after the first month or two, and it is important to follow up with rechecks.  After that most dogs do well with yearly rechecks.

Greyhounds are a breed known to have low physiologic Total T4 levels.  The significance of this is unclear, and most do not need to be treated.

Evesham Veterinary Clinic

Marlton, NJ 08053

(856) 983-9440

The post Hypothyroidism in Dogs appeared first on Evesham Veterinary Clinic.

Hyperthyroidism

The thyroid is a two-lobed gland located in the lower part of the neck.  It produces a substance called thyroid hormone, which is transported via the blood to the cells in the body.  Thyroid hormone regulates how fast cells function.  Too much thyroid hormone speeds up the metabolism and causes illness.  No matter how much the cat eats, they burn calories faster than they can replace them.  Hyperthyroidism is the most common endocrine disease in cats.  It usually occurs in cats eight years of age or older.

Symptoms:

• Weight loss
• Increased appetite (polyphagia) or decreased appetite
• Increased water intake and urine output
• Hyperactivity
• Dysphonia (change in meow)
• Change in coat
• Vomiting

It is unknown why cats develop hyperthyroidism.  15% of cats have a solitary thyroid tumor and 80% have excess activity on both sides of the thyroid.

Diagnosis is made by a blood test.  In most cases a Total T4 is run along with chemistry tests to rule out other diseases and to assess the liver and kidneys, and a CBC is done to look at cell counts.  In some cases a Free T4 may be added.

Treatment is by one of four methods:

1) Methimazole – reliable, generic, inexpensive drug that has been used successfully for decades.  It works by suppressing the thyroid gland.  It requires periodic rechecks for dose adjustments and to assess liver and kidney function.  It is the generic form of Tapazole.

2) Hills y/d Feline Thyroid Health Adult Cat Food – a new treatment that uses a food very low in iodine, the building block of thyroid hormone.  It works well when fed exclusively.

3) Radioactive iodine injection (I131) – permanent cure.  Must be done with care because it is irreversible and temporarily makes the cat radioactive.  Done by specialists, it costs more than other treatments in the short term.

4) Surgery – rarely done anymore due to risk and availability of better alternatives.

Cats living with hyperthyroidism must be monitored for weight changes and also for high blood pressure, which may need additional treatment with a drug called amlodipine.  The disease is very rewarding to treat, with many cats regaining weight and living for years after diagnosis.

For more information or if you believe your cat might have hyperthyroidism, please call us.

Evesham Veterinary Clinic

Marlton, NJ 08053

(856) 983-9440

The post Hyperthyroidism in Cats appeared first on Evesham Veterinary Clinic.