This image from Makana’s CT scan shows how close her tumor was to vital structures.
“Case of the Month” – August 2017
Makana, a 7-year-old female yellow Labrador retriever, was diagnosed with bilateral adrenal tumors so her owners brought her to the UC Davis veterinary hospital. Working together with the Internal Medicine Service, who were managing Makana’s case, surgeons with the Soft Tissue Surgery Service developed a plan to address her complicated condition. Surgeons at UC Davis are pioneering laparoscopic procedures for small animals, and have extensive experience in dealing with adrenal tumors.
To get a better understanding of the size and positioning of the tumors—as well as develop a potential surgical plan—surgeons collaborated with specialists in the Diagnostic Imaging Service to perform a CT scan on Makana. The scan revealed large adrenal tumors present on both sides without significant evidence of invasion into the vasculature or surrounding structures. A surgical excision of both adrenals was recommended.
An adrenal tumor removal is traditionally one of the most challenging procedures in small animal surgery, as the adrenal gland is located in a difficult position next the vena cava (the largest vein in the abdomen) as well as the renal arteries and veins (to the kidneys), the aorta, and other vital structures. Additionally, many adrenal tumors will release excessive amounts of hormones that can cause clinical problems in dogs. When tumors occur in the gland, they can invade surrounding structures including these blood vessels, making them challenging to resect.
UC Davis soft tissue surgeons Drs. Philip Mayhew, Michele Steffey, Bill Culp, Michelle Giuffrida and Ingrid Balsa are making advancements in laparoscopic approaches to these surgeries. A laparoscopic adrenalectomy is a keyhole alternative to traditional open surgery and allows a minimally invasive approach that is less painful for the patient. It also may reduce post-operative complications. Bilateral tumors are rare in dogs, and bilateral laparoscopic adrenalectomy is very rarely performed. UC Davis has performed more laparoscopic adrenalectomies than any veterinary hospital in the world.
The Anesthesia/Critical Patient Care Service prepared Makana for surgery and monitored her vitals throughout the procedure. Dr. Mayhew, along with surgery resident Dr. Jeremy Fleming, utilized four keyhole ports in the left side of her abdomen and three in her right side to successfully remove both adrenal glands. Makana was stable under anesthesia throughout her surgical procedure and recovered without complication.
Now that Makana has had both adrenals removed, she will no longer be able to produce certain hormones that are essential for day-to-day life, and is now regarded as a dog with Addison’s disease. She can no longer produce corticosteroids, which are essential for numerous bodily functions including gut health, or mineralocorticoids, which are essential for maintaining the body’s electrolyte and water balances.
When adrenal glands no longer produce these hormones, dogs may show signs of lethargy, excess urination and thirst, loss of appetite, vomiting/diarrhea, low blood pressure, dehydration, and muscle weakness. The most dangerous effects are low sodium and increased potassium levels. If potassium levels get too high, life-threatening heart issues can arise. Because of this, Makana will need to be supplemented with both hormones for the rest of her life. This will include taking daily pills and receiving monthly injections.
Makana—which means “gift” in Hawaiian—was hospitalized for three days before she recovered adequately to be discharged. She was welcomed home by her fellow pets: a Chiweenie named Sammy and three cats – Dixon, Winston and Quincy.
She was bright, alert, and responsive at her 2- and 4-week recheck examinations, and is recovering well from surgery.
Dogs with Addison’s disease commonly live a long normal life as long as they receive their medications and are monitored carefully.
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