Benign hematoma or deadly cancer, what most commonly leads to death around the time of the operation in the 8 percent of dogs who die in the hospital is either bleeding in overdrive or clotting in overdrive. If theres bleeding in overdrive, its not just in the spleen but also all over the body. The bleeding at the site of the spleen consumes the dogs clotting factors in an all-out effort to staunch the flow of blood, so the dog now becomes prone to bleeding in other areas of the body. Its called coagulopathy.
Clotting in overdrive – thrombosis – occurs in some dogs because the presence of the mass in the spleen compresses large blood vessels elsewhere in the abdomen. That causes poor blood flow through those vessels, and the sluggishly moving blood becomes more likely to form clots. Those little clots can then travel to other places, such as the major veins of the liver or lungs. Death ensues.
Some dogs with bleeding splenic masses also suffer from shock, which is essentially very, very low blood pressure. But veterinarians are good at recognizing shock, and very good at treating it, says Dr. Berg, so dogs tend not to die from that complication. We are less good at recognizing and treating coagulopathies and thrombosis, he says. Thats a major area for improvement.