Woody was an 11-year-old male golden retriever who was brought to the ER for a sudden onset of coughing that ended with him bringing up a small amount of blood.

Bleeding from anywhere is worrisome, even if only a small amount, so needless to say his parents were worried and had rushed him in early in the morning.

Fortunately by the time he arrived there was no further coughing or blood. The attending doctor took X-rays that revealed changes consistent with aspiration pneumonia. Since he was stable, the ER veterinarian decided to hold off on any further testing and let me figure things out when I (Perry Jameson) arrived the next morning.

So why would a healthy-appearing dog suddenly start bleeding, and from all places, his lungs? To figure this out, I first thought of what prevents bleeding in the first place: blood vessel walls, platelets and clotting factors.

  • The blood vessel wall has to be intact. The walls are what hold blood in place. If they rupture, you bleed. Ruptured vessels can result from multiple causes. The most common is from any type of accident. Cancer also may damage vessels as it grows, resulting in bleeding. The platelets are small fragments of cells that form the initial plug when a vessel is damaged. If the hole is small and the platelets work, you never even notice. The platelets cannot do this if there are not enough or the ones present do not clump together.
  • Decreased platelets result from conditions where the bone marrow does make enough or when they are being used or destroyed faster than the bone marrow can produce them. Decreased platelet clumping can be the result of medications such as aspirin.
  • The clotting factors are proteins made by the liver that help to shore up that initial plug made by the platelets. If they are not present, then the platelet plug will not hold and bleeding will resume.

There are congenital diseases such as hemophilia where a dog or cat is lacking a factor from birth and will bleed. Most of these pets are identified early in life as they bleed heavily during their spay or neuter.

The most common cause for an acquired clotting factor problem is rat bait ingestion. Many rat baits work by inhibiting one of the clotting factors, therefore causing the rat to bleed to death. Unfortunately, it will do the same thing to your dog or cat if they eat the bait or a rat that died from eating the bait. Fortunately, the antidote to this poison is vitamin K.

Another cause for clotting factor issues and low platelets is severe infections or certain cancers.

Chest X-rays of Woody revealed a focal area in his lungs that had the appearance of aspiration pneumonia. His blood count test revealed his platelets were decreased but not low enough to result in bleeding. I suspected they were being used to stop the bleeding and were not the actual cause.

His clotting study came back with the same pattern we see with dogs and cats with hemophilia, not ones who have consumed rat poison. How could a dog with this condition be neutered and have lived this long without major bleeding? This made me worry there was something using up his clotting factors.

An ultrasound was performed to look for infections or tumors that could be the cause. Unfortunately for Woody, he had tumors in his liver and spleen, and the area in his lung was a mass, not pneumonia. I suspect the lung mass ruptured a vessel, resulting in the coughing of blood.

Given the extent of his cancer, I was not able to help Woody. Bleeding, however, has many causes, some of which we can treat and reverse.

Dr. Henri Bianucci and Dr. Perry Jameson are with Veterinary Specialty Care LLC. Send questions to petdocs@postandcourier.com.


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