Dogs and cats commonly develop thyroid disease, but they experience different disorder types. Middle-aged and older cats most often develop an overactive thyroid (i.e., hyperthyroidism), while middle-aged dogs develop an underactive thyroid (i.e., hypothyroidism). The thyroid gland secretes hormones that control your pet’s metabolism, so imbalances have far-reaching effects that can change your pet’s weight, appetite, kidney function, heart function, blood pressure, and body temperature regulation. The Columbia Pike Animal Hospital team can manage chronic thyroid disease in dogs and cats, but they need your help as a pet owner to recognize subtle changes at home. Here are the top 10 thyroid disease signs to look for as your pet gets older.

#1: Pet weight changes

Hypothyroid dogs often gain weight despite eating the same amount of food, or they may have difficulty losing weight. Many untreated hypothyroid dogs struggle with obesity and related diseases, but obesity is so prevalent in pets that most veterinarians don’t suspect thyroid disease right away. Hyperthyroid cats lose weight and muscle as their metabolism goes into overdrive.

#2: Pet appetite changes

Hyperthyroidism causes pets to feel hungry all the time because they’re burning calories and losing nutrients more quickly than they can replenish them. Hypothyroid pets may have a normal appetite, although many have less interest in food. 

#3: Pet thirst and urination changes

Many hormonal diseases can cause increased thirst or urination in pets, including hyperthyroidism. Kidney disease is another common cause, and many older cats develop both conditions at the same time. Sometimes, pets are treated for high thyroid levels, and this unmasks kidney changes that were not previously apparent.

#4: Pet vomiting, diarrhea, or constipation

Thyroid changes can alter your pet’s ability to absorb nutrients properly, and can speed up or slow down digestion. Hyperthyroid cats may develop chronic diarrhea or increased vomiting, while hypothyroid dogs may experience constipation.

#5: Pet hair loss or skin infections

Thyroid disease can alter or arrest hair growth cycles, so hypothyroid dogs can lose excessive hair or fail to regrow hair after shaving or a heavy shedding cycle. Sometimes hair becomes thinner, finer, or coarser. These pets are also prone to chronic skin infections because the thyroid disease affects their immune function and bacterial balance. 

#6: Pet activity level changes

Energy level changes are one of the subtleties in thyroid disease that—when pet owners notice them—can help result in an earlier diagnosis. Hyperthyroid cats may suddenly develop increased energy, making them seem young and vital, but this positive change usually gives way to more detrimental signs. Hypothyroid dogs seem to slow down, sleep more, and have less interest in play, which pet owners may consider normal for an aging pet. Pet owners should be aware that sudden activity changes are abnormal, no matter their pet’s age.

#7: Pets seeking heat sources

Hypothyroid dogs—and people—feel cold and have trouble maintaining their own body heat. They may have chronic, low-level hypothermia, causing them to seek heat wherever they can find it. This may mean cozying up to other pets or people, burrowing under blankets, or sitting near heat sources in your home. 

#8: Fast or slow pet heartbeat

An excess of thyroid hormone can cause your pet’s heart rate and blood pressure to increase, sometimes making them feel anxious, too. Pets with low thyroid levels may have an unusually slow heart rate, but some athletic dogs have a slow heart rate normally.

#9: Pet vision or eye changes

Hyperthyroidism in cats often results in extremely high blood pressure, which can happen quickly and damage their retinas. This damage usually leads to permanent blindness, which may be the first noticeable sign of high thyroid levels. Regular wellness blood pressure screenings in older cats can help to catch rising numbers earlier.

#10: Trouble breathing

If thyroid hormones are high for a long time, the stress placed on the heart to work harder and faster can lead to congestive heart failure, causing fluid buildup in the lungs. Pets with heart failure have a faster breathing rate, and also may cough. 

Thyroid disease diagnosis and treatment

Pets who show signs of thyroid disease can be diagnosed with a simple blood test to check their thyroid levels. Thyroid hormone production is closely related to dietary iodine, so high levels in cats can be suppressed using a special iodine-deficient diet, or by using radioactive iodine that selectively kills overactive thyroid cells. Other options for cats include daily medication or surgical removal of the thyroid gland. Dogs with a low thyroid level need a daily synthetic hormone pill to replace what they’re missing. 

Rarely, dogs may develop a high thyroid level, or cats may develop a low level. These uncommon changes may be the result of a tumor, which needs oncological treatment and care after the gland is removed entirely. 

Thyroid disease is generally worse for cats than dogs, but early detection can improve treatment outcomes. Call us to schedule an appointment, and ask our Columbia Pike Animal Hospital team about early disease screening tests, including blood work and blood pressure measurement.