Veterinary Detective

History:

Walter, a neutered eight-year-old male Golden Retriever, had been slowing down. His family had noticed he seemed a bit low in energy and had gained some weight, but they attributed this to Walter “getting older.” Walter also had some hair loss on his sides which didn’t improve even after they bathed him, tried a flea preventative, and changed his food. His family had resigned themselves to the new Walter until they took him for his senior wellness vet check-up…

Walter’s Check Up:

At the time of Walter’s check-up, the clinic scale confirmed what his family had suspected. Walter had gained seven pounds (three kilograms) in the last six months. His veterinarian noticed his hair loss but told the family it did not appear to be due to parasites or bacterial infection. Walter’s mobility and joint range of motion seemed unchanged from previous visits, so osteoarthritis was not at the top of the list for reasons he might be slowing down. The vet recommended senior-dog lab work consisting of blood and urine samples. This lab work also allowed for a general health screen, including Walter’s kidney and liver values, blood sugar, red and white blood cells, platelets, and blood proteins. Suspecting Walter might have a thyroid issue, the vet asked the lab to add on two extra thyroid parameters. When the results came back, the lab work along with the reported clinical signs confirmed Walter was indeed hypothyroid. 

Breeds Most Commonly Affected:

Hypothyroidism is a fairly common condition in dogs, and is generally straight forward to treat. Breeds such as Golden Retrievers, Doberman Pinschers, Labrador Retrievers, and Boxers are predisposed, but this condition can occur in any breed. The average age at diagnosis is seven years, but this can vary. As in Walter’s case, common clinical signs are weight gain, lethargy, exercise intolerance, and changes to the fur and skin. These dogs commonly display hair loss, which is usually either symmetrical on either side of the thorax and abdomen, or on the tail. They are also predisposed to bacterial skin infections called pyoderma, and might experience slow growth after their fur has been trimmed. The fur may also appear duller, missing its previous shine. Less commonly, dogs can experience neurological signs or changes to the eyes. 

The thyroid gland is located within the neck and is responsible for many different functions within the body. This is why so many different clinical signs can occur from a decrease in thyroid hormone production. Thyroid hormones exist in different forms within the body, which is why your veterinarian may recommend adding an additional thyroid test to the more common blood panels to assess thyroid function more thoroughly. The most common reason that the thyroid stops producing the normal amount of thyroid hormones is because the dog’s own immune system destroys the thyroid gland. This is usually for unknown reasons, which is referred to as being ‘idiopathic,’ but could also be linked to low iodine in the diet or a problem that the dog is born with. 

Walter’s Update:

Walter was started on a medication called levothyroxine sodium, which is a tablet he will now take twice a day for the rest of his life. Within the first couple of weeks, his family noticed that his energy seemed to perk up and he was more excited to go for walks. By the end of the first month, when Walter went in for his follow up lab work, he had lost two pounds (one kilogram). Walter’s lab work showed that the medication was working and his thyroid values were now within normal range. By the third month, Walter’s coat had grown in, and everyone noticed he was looking shinier than he had in a while. Walter’s family is looking forward to many more years with him.