Hi janice118 -
Can you tell me what your dog's total protein (also called total solids) was when the hematocrit was 16%? These two tests are usually run together.
The answer to your question is yes, a tumor can indirectly cause bleeding. Cancer can be an underlying cause for a condition called immune mediated thrombocytopenia, (IMT) which is a condition in which the body destroys its own platelets. Normal platelet count is usually around 200,000 to 500,000. When they drop below 50,000 you can get bleeding. At the current level of 6000, certainly that could be one explanation for the bleeding that poor Jake is experiencing. Unfortunately, replacing these platelets is not as simple as doing a blood transfusion, as they stick to the blood containers, and thus even a blood transfusion does not do a good job at replacing them. We do have medications that we can use to treat this condition though. Hopefully the blood transfusion will help buy him some time to sort all this out as you suggested.
Having said that, though, low platelet count is more likely to cause bruising in the skin, bleeding from gums or nose, blood in urine or stool, bleeding from blood draws or surgical sites rather free blood into a body cavity such as it sounds like you may be describing, so there may be something else going on here as well if there is a fair amount of free blood present within the abdominal cavity. It would be a good idea for them to run a coagulation panel which may give a better idea about what part of the clotting process is being affected here. This is a group of tests that checks various aspects of the clotting mechanism, and can help determine if it is just the platelets causing the problem, or if there are also clotting protein issues.
Other causes of low platelet counts that your vet may need to check out would be the tick borne diseases (Lyme, Anaplasma, Ehrlichia, Rocky Mountain Spotted Fever), blood parasites (Babesia), reactions to certain drugs, systemic lupus (rare) Other causes of bleeding (related to inadequate clotting proteins rather than low platelets) would include certain types of mouse or rat poison, and severe liver disease.
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Veterinarian
I have over 20 years experience in small animal and emergency veterinary medicine