Parathyroidectomy in Dogs

The parathyroid glands are four hormone-secreting glands located in the neck. They are small in size and flat in shape. The job of the parathyroid is to regulate the level of calcium in the blood by triggering the body's organs to collect more. When a tumor develops on a parathyroid gland, the gland will begin to secrete too much of the parathyroid hormone (PTH), leading to hypercalcemia. If left untreated, this can have a toxic effect on the organs and become life-threatening.

Parathyroid tumors are not common in dogs, but they do occur. The general protocol to treat a parathyroid that has developed a tumor is to remove the entire gland in a surgical process known as a parathyroidectomy. This procedure should only be performed by an ACVS board-certified veterinary surgeon. Dogs who have parathyroid tumors generally have calcium stone formations and often experience constipation, frequent urination, and vomiting. The condition can be confirmed by a simple blood test.

To determine if the surgery can be performed, the dog will need to have pre-anesthetic blood work run. This can identify any potential health risks in the animal. An ultrasound will be used to locate and assess the tumor present. Most parathyroid masses simply look like an enlarged parathyroid gland. If the dog is deemed fit for surgery, a date will be booked for the operation.

Before the procedure can begin, the neck of the dog will need to be shaved and cleaned. An incision is then made down the middle of the neck, below the throat. The layers of skin will need to be held out of the way using gelpi retractors. The surgeon will examine all of the glands to ensure no other growths exist. Then, with great care, the tumor will be excised using bipolar cautery. In many cases, the entire affected gland will also be removed, to ensure no remaining parts of the growth are left in the dog. The incision is then closed with sutures or staples.

If the dog recovers from surgery, an excision of the damaged gland is often all that is needed to cure the condition. The main factor that can change this prognosis is if any of the tumor is left in the animal, or if other tumors exist. If the gland is savable, another procedure may be performed. An ultrasound-guided ethanol ablation is a non-invasive option to treat parathyroid tumors. A long needle is inserted into the tumor and ethanol is injected into it, destroying the growth. This may not be an alternative in severe instances. 

The dog will need to be monitored closely as it awakens to ensure that the body is resuming proper function. Immediate measures may be needed to keep the dog from a hypocalcemic state. This can be done by supplementing the dog with both vitamin D and oral calcium. In dogs who are high risk, supplementation may even begin before the procedure is started. It is of the utmost importance to prevent hypocalcemia as it can cause severe seizures and even death in some cases. It can take a whole week after surgery for the remaining parathyroid glands to begin to monitor calcium in the body properly.

Pain medication is often needed during the few days after the procedure. An Elizabethan collar may be needed to prevent the dog from scratching at its incision site. A follow-up appointment will be required two weeks after the surgery has been performed to assess healing. If cancer has been diagnosed, a treatment plan can be started at this time. 

The cost of a parathyroidectomy is generally quite high, ranging anywhere from $3,000 all the way up to over $10,000. The average cost for this procedure is about $8,000. A parathyroid tumor can not be left in a dog, as the dog will eventually die from hypercalcemia. Euthanasia may be chosen over this, as hypercalcemia will slowly kill the organs, causing the dog pain. An alternative procedure which can be used in some cases is an ultrasound-guided ethanol abolition, but this is often not much more cost effective, as general anesthesia and ultrasound equipment are still needed to complete the treatment.

As with all surgeries, complications may arise from the use of anesthesia. These issues can be exacerbated in dogs with heightened calcium levels, leading to cardiac problems. Approximately 10% of dogs who undergo a parathyroidectomy will go on to develop hypocalcemia, which can be life-threatening. This condition can be treated if monitored appropriately. The tumor and/or parathyroid gland must be removed for long-term survival of the dog to be possible.

Like many tumors, there are no known causes of parathyroid growths in dogs. Some studies have suggested that this problem could be a genetic trait. It is seen more often in the Keeshond breed of dog than any other. There have been no links made suggesting that age or sex have any bearing on tumor development. 

It is always wise to enquire about the parents’ health before acquiring a new dog. If you have a more susceptible breed or a dog who is high risk, getting regular blood work as a part of an annual check-up up may be advised to catch growths early.