Anna, a 10-year-old chestnut colored boxer with dark brown ears and a white patch on her chest, had always been a healthy and active dog. But in the spring of 2014, her owner, Sundays Hunt of Salt Lake City, Utah, noticed Anna grew lethargic and was less interested in playing with the other two dogs. She was also eating all the time. “I couldn’t feed her enough,” says Hunt. “It was never enough.”
In less than three months, Anna gained nearly 30 pounds and had a pronounced potbelly. She could barely muster the energy to get up and go outside. The skin on her back was covered with scaly patches; some were as big as Hunt’s hand. “In a short period of time everything changed so fast,” says Hunt. She took Anna to her local veterinarian for a wellness check. A blood test confirmed Anna had Cushing’s disease.
Each year in the United States, roughly 100,000 dogs are diagnosed with Cushing’s. Roughly 85 percent of dogs with Cushing’s have pituitary dependent hypercortisolism, or PDH, caused by a pituitary tumor that triggers excessive levels of the stress hormone cortisol. When functioning normally, the pituitary, a pea-sized gland at the base of the brain, produces adrenocorticotropic hormone, ACTH, which stimulates the adrenal glands near the kidneys to produce cortisol. Like Anna, dogs with the disease may be ravenous, have skin lesions, or both. They may also drink excessive amounts of water, urinate more frequently, or experience muscle weakness or hair loss. Left untreated, a pituitary tumor could grow large enough to press on the brain, causing neurological symptoms such as difficulty walking or seeing, or other conditions including diabetes or seizures, and eventually death.
Hunt’s local veterinarian put Anna on medication to reduce the production of cortisol and control the symptoms. But after a month, Anna seemed to be feeling worse, not better. “I was at a loss and had no answers,” says Hunt. “It was challenging to see her so sick and not know why.” Average life expectancy for boxers is 9 to 13 years, and Hunt knew Anna had lived a good life. But she hoped more could be done. So Hunt took Anna to see Dr. Melissa Tucker, an internal medicine specialist in Salt Lake City. After reviewing Anna’s medical records, Tucker determined Anna likely had a pituitary tumor, which she confirmed using MRI. She first called WSU veterinary oncologist Janean Fidel to discuss using radiation as an option to reduce the size of the tumor. For smaller tumors, radiation can work well, and in about 25 percent of cases radiation can shrink a tumor by about half. But it does not control the hormonal effects of the tumor well, says Dr. Tina Owen, a WSU veterinary surgeon who specializes in pituitary surgery. Because of Anna’s neurological symptoms and because she was weakened from the disease, surgically removing the tumor was the best option. Tucker, who had also been a veterinary resident at WSU, referred Anna to Owen. WSU is currently the only veterinary hospital in the country to offer this type of surgery for animal patients.
“Surgery is the first line of treatment in humans with Cushing’s,” says Owen. It is also the first line of treatment for dogs in the Netherlands where the surgery is done routinely. But in the United States, it has been more common to treat dogs with medication or radiation, which only manages the symptoms, says Owen. “Pituitary surgery has the potential for curing,” she says. According to Owen, roughly 85 to 95 percent of dogs who have the tumor removed have hormonal remission, meaning it cures the hormonal imbalance and the symptoms. “With a successful surgery a dog can live a normal life for many years,” she says.
Called transsphenoidal surgery, Owen uses an exoscope, a long tube with magnification and a light at the end, to reach the pituitary at the base of the skull by entering through the soft palate in the mouth. Popularized in veterinary medicine by Dr. Bjorn Meij at Utrecht in the Netherlands, Owen and her colleagues improved the surgical technique for dogs by adding a high definition video telescope to the procedure. Compared to cranial surgery where part of the skull is removed, transsphenoidal surgery is less invasive to the patient. Like with any surgery in the brain, however, there are a number of potential risks.
With a successful surgery a dog can live a normal life for many years.
Hunt didn’t think Anna was strong enough to fly to Pullman for the surgery, so they drove 12 hours from Salt Lake City. The next day, on November 12, 2014, they met the WSU pituitary team. WSU veterinary neurologist Dr. Annie Chen-Allen performed the neurological testing on Anna. “It was incredible,” says Hunt. “Everybody from the start of the process was on the ball.”
The delicate surgery, performed by Owen, took six hours. After the surgery, Dr. Linda Martin, a WSU veterinary critical care specialist, monitored Anna’s recovery in the intensive care unit. A CT scan of her brain showed the tumor had been successfully removed. The team approach at WSU “leads to better care and long term outcomes,” says Martin.
“It was so touching to me that the staff was so attentive, sensitive, and caring,” says Hunt.
Immediately after surgery, Anna was not walking well and developed aspiration pneumonia. Hunt began to wonder if she had done too much, if Anna was ever going to be able to have a normal dog’s life again. But within just a few days the pituitary team began to see Anna’s symptoms improve. Six weeks after the surgery, Hunt says Anna was behaving like her old self.
Hunt and Anna traveled to the California coast three times over the past year so Anna could walk along the beach and run in the water. “It was such a treat to make these memories with her,” says Hunt. “It was truly a miracle that we experienced a one-year anniversary.”
When Anna returned for her six-month checkup with Dr. Tucker, an MRI test showed Anna was tumor free and she had no signs of Cushing’s. But by January 2016, Anna’s health started to decline unexpectedly. Anna no longer wanted to eat or ride in the car, one of her favorite things to do. During the last few weeks of Anna’s life, Hunt says her dog “Sophie,” who is also Anna’s daughter, wouldn’t leave Anna’s side. Anna died of unknown causes on January 30, 2016, more than 14 months after her pituitary surgery.
“Anna really enjoyed life to the very end,” says Hunt. “I have so much peace that we made so much out of every day.”
Cats are Not Small Dogs
Unlike dogs, cats with pituitary tumors typically show an excess amount of growth hormone. They become diabetic and insulin resistant. Their jaw bones and feet look large and their hearts can enlarge. There is no good drug treatment for cats with pituitary tumors, so radiation and surgery are the best options. In 70 to 80 percent of the cats who get the surgery, their symptoms improve or disappear, says Dr. Tina Owen, a WSU veterinary surgeon who specializes in pituitary surgery.