What Are the Treatments for Feline Hyperthyroidism and Kidney Disease?

Annual exams ensure your cat is not "hiding" kidney disease or hyperthyroidism.

Hyperthyroidism occurs when a feline's thyroid gland is enlarged and produces too much T3 and T4 thyroid hormones. Feline kidney disease is the result of the nephrons (the small microscopic units that comprise the kidneys) slowly dying off because of kidney damage or age. In some cases, hyperthyroidism is curable; kidney disease is not. Both illnesses have a variety of treatments that, if successful, can restore a relative healthy (albeit temporary in some cases) balance to the feline's life.

Diet

Dry food is not recommended for cats with kidney disease.

Proper diet is critical in treating kidney disease and special diets are often prescribed to reduce the workload on the kidneys. Kidney diet food is specifically formulated to be low in phosphorus, sodium and protein to minimize the amount of minerals that the kidneys must filter out of the bloodstream. Certain formulations of these diets also include omega-3 fatty acids and vitamins B and C, which are believed to aid in kidney health.

Medication

Methimazole reduces a feline's thyroid hormone production and is used in some cases as an effective lifelong treatment of hyperthyroidism. Methimazole does not cure hyperthyroidism, but it will regulate the production of T3 and T4 hormones if a dosage balance is achieved. Side effects of methimazole can be severe, however, and include "vomiting, anorexia, fever, anemia and lethargy," according to Cornell University.

Medications for kidney disease are as varied as the problems the condition causes. Erythropoietin is prescribed for kidney disease-causing anemia. Calcium imbalances are rectified with Calcitriol. Aluminum hydroxide prevents excess phosphorus from entering the bloodstream--critical in the care of kidney function. Appetite stimulants and acid controllers are used to control the disease-related digestive issues. Calcium channel blockers are required if the kidney disease is causing high blood pressure. (Refs. 3 and 4)

Radioactive Iodine Therapy

Radioactive iodine therapy requires special facilities and hospitalization.

This treatment is exclusive to hyperthyroidism and, while 95 percent successful in curing hyperthyroidism, may not be very appealing to the cat or its owner. Radioactive iodine is injected into the cat's bloodstream, where it travels to and is absorbed by the thyroid gland. The radiation kills off abnormal thyroid tissue and normal hormone function usually resumes in one to two weeks.

Because the cat becomes radioactive, however, this treatment is only authorized in facilities that are properly licensed to perform the procedure. Additionally, the feline will not be permitted home for at least two weeks after the treatment to allow the radiation levels inside the animal to minimize to a safe level. In most cases, Cornell University states visitation of the hospitalized cat is not permitted.

Surgery

Cornell University reports that a thyroidectomy is generally a successful cure of hyperthyroidism in most cats. The surgery does come with some risks, however, as the surgeon may cause damage to the parathyroid glands while removing the thyroid gland. The parathyroid glands are critical in stabilizing blood-calcium levels, and damaging them can be extremely detrimental to the cat.

Surgery is also an option in severe cases of kidney disease, according to Pet Education.com. There are a number of veterinarians in the United States that perform kidney replacement surgery for dogs and cats. However, many cat owners opt for the less invasive treatment of intravenous fluid therapy, an in-home kidney dialysis of sorts. With IV therapy, the cat is administered fluids on a regular basis to aid in cleansing the blood and keeping the cat adequately hydrated. Dialysis can also be performed at some veterinary clinics, if necessary.

References

• Cornell University College of Veterinary Medicine: Hyperthyroidism in Cats
• Washington State University: Chronic Kidney Disease and Failure (CKD, CRF, CRD)
• Doctors Foster and Smith Pharmacy: Patient Information Sheet: Methimazole
• Feline CRF Information Center: Medications
• Doctors Foster and Smith Pet Education.com: Kidney Disease: Causes, Signs, Diagnosis and Treatment

Resources

• Feline CRF Information Center