My pal Buster is a pound dog, so his actual birthday is unknown. I do, however, know that he was between nine and 11 months of age when I first met him. Using that information, I can calculate his age today. He’s 10.
Buster is not a purebred Labrador Retriever, but he looks and acts exactly like one. That means that my dog, for all intents and purposes, is an old Lab.
For that reason, I regularly take him to work so that I can examine him with an ultrasound device. Specifically, I look at his spleen. Older Labs are, in my experience, are predisposed to life-threatening spleen crises. Labs are not alone — all elderly dogs, especially large ones who weigh more than 40 pounds, are prone to crises involving the spleen.
The spleen is located in the abdomen near the stomach. It is a blood-filtering and storage organ. Lots of blood flows through it, and it has lots of blood vessels. And in older Labs, it is a common site of cancer.
Cancer of the spleen usually takes the form of a scary-sounding and scary-in-real-life tumor called hemangiosarcoma. Hemangiosarcoma is a cancer that arises from blood vessel cells.
Hemangiosarcomas of the spleen develop gradually and asymptomatically. The tumor can grow for months, and there will be no way to know that it is present (unless one regularly performs ultrasound exams of the spleen, which is half of the reason why Buster gets the probe so regularly). The dog will not feel sick in any way until the day a crisis occurs.
Hemangiosarcomas of the spleen arise from blood vessels, and lots of blood flows through them. And here’s the problem: They are fragile. At some point, most hemangiosarcomas will break open. When that happens, affected dogs may go straight from feeling fine to being on the verge of death.
Ruptured hemangiosarcomas have the potential to lead to severe internal bleeding. That, in turn, leads to poor blood pressure and anemia. The condition has a name: hemoabdomen, which is medical jargon for an abdomen that fills with blood.
The bleeding of hemoabdomen occurs around but not into the vital organs and intestines. Vomiting blood and bloody diarrhea generally are not symptoms of hemoabdomen.
Instead, dogs show symptoms compatible with low blood pressure, shock, and anemia. Dogs with hemoabdomen often exhibit profound lethargy and weakness to the point of being unable to stand. They may breathe heavily. Their gums will be pale. In later stages of the syndrome, the abdomen may become visibly distended with blood.
Hemoabdomen is a medical crisis that, in most instances, requires an immediate life or death decision on the part of the owner. Rarely, ruptured spleen tumors will clot, which leads to a spontaneous recovery. Such recoveries invariably are temporary. Dogs with hemoabdomen caused by spleen tumors eventually will bleed to death if they do not undergo surgery.
Surgery for hemoabdomen requires removal of the entire spleen. Generally the dog is stabilized, and shock is treated with intravenous fluids before surgery is begun. Preoperative blood transfusions are necessary in some cases. Screening diagnostics, including chest X-rays and, when available, ultrasound of the abdomen, generally are performed to assess for obvious spread of the cancer to other tissues (so-called macroscopic metastasis). If obvious spread is seen, the owner may elect against surgery because the dog will have a very poor prognosis — in some instances dogs with macroscopic metastasis may die of complications from the spread of the cancer before they heal from the surgery to remove the spleen.
Although I have focused on cancerous hemangiosarcomas so far, it should be pointed out that there are other, non-cancerous splenic masses that can cause hemoabdomen. They are equally deadly in the short term, but if a dog affected by a benign mass of the spleen survives the crisis, surgery, and postoperative period, he will be expected to make a complete recovery. The only way to determine whether a dog has hemangiosarcoma or a benign mass is to remove the spleen and submit it to a laboratory.
Unfortunately, a large majority of dogs with hemoabdomen will not have benign masses. Most cases of hemoabdomen, by a significant amount, are caused by hemangiosarcomas.
Hemangiosarcoma is an aggressive cancer, and it spreads early. A huge majority of dogs who develop hemoabdomen as a consequence of hemangiosarcoma will already have significant spread of the disease that cannot be detected with X-rays or ultrasound. These so-called microscopic metastases will continue to grow and eventually will lead to fatal complications. (Note that dogs with hemangiosarcoma that is detected and removed before hemoabdomen occurs have better prognoses — which is the other half of the reason that I perform ultrasounds on my pal Buster so often.)
Therefore, when I discuss surgery with owners of dogs with hemoabdomen, I tell them that they should view the surgery as a temporary measure. Without surgery, their dog would be likely to die within days or even hours. With surgery, they likely will get to enjoy his company for longer.
But the big question has always been, “How much longer?” In my experience, it can vary wildly. I have known dogs who made it only a few weeks, and I have known others who lasted more than six months. What I didn’t have, however, was a modern, large study to help answer the question.
Enter Dr. Kristin Wendelburg et al., who recently published such a study in the Journal of the American Veterinary Medical Association. The study evaluated a number of different scenarios, including dogs treated only with surgery as well as dogs treated with surgery and chemotherapy. The results of chemotherapy treatment were complex and beyond the scope of this post (although they should by all means be discussed with a veterinary oncologist if your dog ever suffers hemoabdomen).
There was, however, one piece of data that stood out to me. The authors calculated a median survival time for dogs with hemoabdomen. Half of dogs will die before the interval is up, and half will die after (in some cases, long after).
The calculated time was 1.6 months. It’s not a number I like, but at least now I can offer a number to owners who are struggling with the decision whether to put their dog through surgery.
The number is much lower than I would prefer. For now, however, at least I can take some comfort from the fact that Buster’s last ultrasound was clean.
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