Thyrotoxicosis

Causes and risk factors

The most common cause of thyrotoxicosis in dogs is the administration of too much thyroid hormone as medication. This can happen if your dog has an underactive thyroid gland (hypothyroidism) and is receiving hormone replacement therapy. If the dose is too high or not adjusted properly, this can lead to hyperthyroidism.

Another possible cause of thyrotoxicosis in dogs is a thyroid tumor that autonomously produces hormones. However, this is very rare and usually affects older dogs.

Some factors can increase the risk of thyrotoxicosis in dogs, such as

• A genetic predisposition
• A diet with too much iodine
• A concurrent disease that affects the metabolism
• An interaction with other medications

Symptoms and consequences

The symptoms of thyrotoxicosis in dogs can vary depending on the severity and individual reaction. The most common signs include

• Weight loss despite increased appetite
• Restlessness, nervousness and hyperactivity
• Increased heart rate and blood pressure
• Panting, trembling and sweating
• Diarrhea, vomiting and increased thirst
• Hair loss, skin changes and infections
• Muscle weakness and atrophy
• Behavioral changes such as aggressiveness or anxiety

Untreated thyrotoxicosis can lead to serious consequences for your dog, such as

• Heart failure
• liver damage
• kidney failure
• Eye problems such as glaucoma or retinal detachment
• Bone fractures due to osteoporosis

Diagnosis and treatment

If you suspect that your dog is suffering from thyrotoxicosis, you should take him to the vet as soon as possible. The vet will perform a thorough physical examination and order blood tests to measure hormone levels. They may also perform an ultrasound scan or scintigraphy of the thyroid gland to determine the cause of the hyperthyroidism.

The treatment of thyrotoxicosis in dogs depends on the underlying cause. If the condition is caused by an overdose of thyroid hormones, the dose will need to be reduced or discontinued. The vet will monitor your dog regularly to find the right dose.

If the condition is caused by a thyroid tumor, surgery or radioiodine therapy may be necessary. These treatments aim to remove or destroy the tumor. In some cases, your dog may need lifelong hormone replacement therapy after treatment.

In addition to treating the cause, your dog will also need symptomatic treatment. This means that he may be given medication to improve his heart function, lower his blood pressure or relieve his gastrointestinal symptoms. You should also make sure that your dog receives a balanced diet that meets his energy needs but does not contain too much iodine.

Prevention and prognosis

The best way to prevent thyrotoxicosis in dogs is to check their thyroid function regularly, especially if your dog is on hormone replacement therapy or is in a high-risk group. You should take your dog to the vet at least once a year to check his blood levels and adjust his dose.

The prognosis for a dog with thyrotoxicosis depends on the severity of the condition, the cause and the treatment. In most cases, thyrotoxicosis in dogs can be well controlled if detected and treated early. However, your dog may require lifelong monitoring and medication to regulate their thyroid function.