Canine AutoImmune Thrombocytopenia

Shirley writes: Our dog died two days ago and the symptoms were those associated with ingesting rat poison. But we don’t have any poison in our house or in our yard. We don’t have rats. We adopted our dog four weeks ago (three years old about 55 pounds). We were with him when he was anywhere out of our house or yard. Could the poison have been in his food? Is it possible he ingested the poison before he came to live with us (four weeks prior to his death)? He was at a city shelter for several months, so it is unlikely he would have been around poison. I know I can’t change the outcome, we are very sad, he was so good for us, but I feel so awful and would like to know how long the poison can stay in a dog before he dies. He went for a long walk in the morning and a shorter one in the afternoon. He was fine. We went out to dinner, got home to find him limp. The ER doctor could not save him.

Shirley, please accept our condolences on the loss of your beloved pet. We understand how hard it is to lose a pet, especially when the circumstances come so suddenly.While your pet has symptoms similar to anticoagulant rodenticide poisoning,

Professional pest control operators place rodenticides in childproof and petproof bait stations.

it is more likely that he suffered from a problem that kept him from clotting his blood as he should, most likely autoimmune thrombocytopenia or AITP, also known as Immune-Mediated Thrombocytopenia or IMTP.

AITP is an attack on the platelets of the body. Platelets are fragments of cells called thrombocytes and are very important in the clotting of blood. If platelet production is too low, or platelet destruction or usage is too high, normal clotting fails and bleeding ensues. In the case of autoimmune thrombocytopenia, platelets are diminished because of an attack by the immune system. For whatever reason, the immune system begins to think the thrombocytes and/or platelets are foreign objects in the body and need to be removed.

The trigger for this condition is almost never identified.

Autoimmune thrombocytopenia usually has a very rapid course. Onset is usually “sudden.” I put sudden in quotation marks because we rarely know when the actual beginning of an episode is, we only know it’s going on when we see evidence of bleeding.

Treatment usually begins with a transfusion of platelets. Platelets are rarely available anywhere but an emergency or referral center, so your pet’s doctor usually doesn’t have them sitting on his shelves. Whole blood transfusion doesn’t include enough platelets to suffice, although it is better than doing nothing and the loss of red blood cells and volume still needs to be accounted for.

Many of these patients die because the process has gone too far by the time treatment has begun, because of lack of platelet availability, or because the immune system’s attack cannot be stopped.

For completeness’ sake I will address your other questions.

While you don’t have rats, plural, it takes only one. Dogs eating a mouse or rat with active rodenticide in its gastrointestinal (GI) tract can easily become poisoned. A thorough necropsy of the entire GI tract might locate such an animal or its parts. Modern rat poisons are very effective in very small amounts, so the quantity a mouse might eat could easily poison a 55-pound dog.

Poison he might have been exposed to weeks ago would not take this long to cause problems. If rodenticide was his problem, he ate it very recently.  The likelihood of rat poison being in his food from the manufacturer is close to zero.

All of our readers share in your sense of loss.

See you tomorrow, Dr. Randolph.


  1. Our dog Ele, snoodle, poodle and schnauzer mix. She is 13 and has a extrenely low red cell count. Her stomach is extended. She has cried out in pain but now on pain oil treatment plus steroids. She was given weeks to live, however she has a good appitite and does go outside to walk around. She had collapsed twice before steroids. Were praying for more time. Seeing vet tomorrow for second opinion.drinks a lot of water. What should we expect?

    • “What should we expect?” Before anyone can answer that question, Ele needs a diagnosis. While she might have an autoimmune condition, she might also have a mass in her spleen, liver or both that is bleeding. Or, a dozen other possibilities. In general, prognosis depends on an accurate diagnosis, however, the combination of clinical signs that Ele is exhibiting is not consistent with a good outcome in many cases. Please follow up and let us know what her doctor says about her. Meanwhile, I’m praying with you and for you. Thanks for reading, Dr. Randolph.

  2. Hi Dr. Randolph,
    I wanted to share my experience. My 2 year old potcake (mutt from the bahamas) has immune mediated thrombocytopenia. She did have a tick bite prior to her initial symptoms, and they included swelling, fever, vomiting, petechia, and bleeding from her orifices. She did pull through due to doxycycline and prednisone. Whether or not her first bout was due to a tick disease, we will never know because her blood was not tested for the appropriate bacterial agents. Either way, she know has this chronic condition, and we have mixed feelings. We are very happy that she survived (because she was so sick), but this chronic condition feels like a heavy weight. Thank you for giving me the opportunity to read comments from others who have been through this…

  3. hello i just lost my dog bella an beautiful long haired jack russel to a desease i never hear of thrombocytopenia!! she seemed happy an healthy just a week ago i dont get it!!! she started bleeding from a small cut on her face that she got sticking her noise thru the fence !! suddenly stopped eating we took her to the vets they started treating her for the desease n she suddenly went down hill an was gone in 24 hours!!! i dont get this any advice you guys can offer would be appreciated because i want learn all i can about this terrible desease thank you ed

    • “We” don’t have any advice for you, Edward. We do have prayers for you, because your dog got a bad, bad disease, neither you nor we will ever know what triggered this condition, and treatment is sketchy even for patients diagnosed early, when the condition is relatively mild. A large percentage of these patients go on to die later, even under treatment. Bella had a bad, bad disease, and all we can say is we join you in grieving for Bella, and we are so sorry that you lost her. Click here for an article on grieving.

  4. This story and others sound very similar to what we just experienced with our dog. Day 1 our Australian shepards face suddenly swelled it looked as if he had two balls one in each check. We live on a greenbelt so I instantly was worried he was bitten by a rattlesnake and rushed him to the vet where we were unable to find any bite marks only a slight bruise on his gums. The vet administered cortisone or benadryl shot and said they would think if it was a rattlesnake bite it would have been more swollen and he would have distinct fang marks. In 24 hours after the shot the swelling disappeared completely so I was not concerned about it. Then on day 5 after the swelling I noticed a little blood coming from his gums. I checked him and nothing was alarming and the bleeding appeared to have stopped. He chews on random sticks in our backyard so I figured a stick caused it. Then about 6 hours later I noticed one of his eyes the pupil was red and reflected red back at me when I shined a light into it showing signs of hemorrhage. We rushed him to the vet and by then his second eye began to turn red. The vet confirmed he was bleeding from every orifice and he had 0 platlets. She gave us the rat poisoning theory and agreed the facial swelling was odd and too much time has lapsed from the swelling to bleeding symptoms and thought he was bit by something or had and allergic reaction and now the bleeding isn’t connected. We do not own or buy rat poison and in fact we use Organic Pest Control because we are so careful about the use of toxic chemicals since we also have a 2 year old. She also called and talked to a specialist that theorized that a coral snake bite could have triggered the bleeding or triggered an auto immune disease response. She tested his blood cells for autoimmune and the blood cell didn’t react the way it would if it was autoimmune and strongly thinks every symptom lines up with rat poisoning. End of the story he died a little over 48 hours vomiting blood then progressed to his lungs filling up with blood. He had great energy and appeared strong until his lungs filled up with blood on the last day and he passed. He was treated with the vitamin K to try and get his blood to clot again. Any insight would be greatly appreciated since we are struggling to believe he died from rat poison. Our 3 closest neighbors don’t use rat poison either and he doesn’t eat dead animals. We’ve caught him catching rabbits and playing with them but never eating them. We also searched our whole yard for dead animals found none but his feces did have some dead dung beetles around them. Not sure if that’s another sign of rat poisoning too. Thank you very much!

  5. My Boxer/Lab mix developed bruising and would be extremely slow to heal little nicks and scratches. His platelets were at a 6, and supposed to be 200 I believe. He survived with the help of a experienced specialist, whose dog had passed of the same condition. Whether my dog was poisoned or not was never confirmed, but it was that or Comfortis flea medication, which showed no record of causing the issue in their reports. Pet insurance covered about half of the cost ( $2000 reimbursed), and Banfield adult care plan was a great cost saver, they recognized the issue very quickly, and referred it to more appropriate hands. In Austin, TX, they care about dogs immensely, so I believe their caring effort made a lot of the difference regardless of the overall quality of Banfield around the country.

    • My 3 year old Coton de Tulear was recently diagnosed with very low platelets (16) and an autoimmune disorder. He is on a lot of medication and seems to be doing OK. He has been on Comfortis flea medication for about 2 years and I really wonder if it had anything to do with the problem. My vet told me in all her years she has never had a case of bleeding and low platelet count and in the last 3 or 4 months she has had 4 including a cat. I am in Long Beach

    • We have been dealing with the same autoimmune problem with our silky. He became very weak and tired. He wasn’t able to go on his walk without us picking him up and carrying him after a short distance. This happened two days in a row and we took him to our vet who thought it was rat poison and bless his heart used his dog as a blood donor as vets cannot keep blood on hand . This improved his condition with lots of drugs. He told us he may need another transfusion that he would order that was more specific to his needs. The first blood transfusion was losing its effectiveness quicker than he could make new blood so the blood was ordered and the transfusion was done several weeks later. Rascal was on Comfortis as well. We never bought the rat poison theory as Rascal is never allowed out even in our fenced yard without us right by him or on a leash. His food is very tightly controlled as well. Rascals vet has worked very diligently to save Rascal. We go in this AM to get his blood checked again. We have had it checked weekly for two months and I believe he has turned the corner and will recover from this. But he almost died. Its been very expensive but we still have our little guy thanks to a fantastic vet

  6. My husband and I have also just lost our wonderful Boxer (Sammy) to this elusive condition. It is soul-destroying not being able to figure out why or how this happened. Sammy, aged 8, also did not have access to any type of rat poison and has never eaten anything other than dried dog food and the odd dental stick from time to time!

    • Donna, we are so sorry for the untimely loss of your Sammy. When patients with this condition respond to treatment we are thankful, while knowing that any minute that good response could turn bad. I’m so sorry you had to experience this. I lost a patient last week to IMHA that had been well-controlled. As it, too, is an immune system malfunction, we are on the edge of our seats from the time the diagnosis is made. May the Lord comfort you.

  7. Hello, our dog has been on Vitamin K1 for almost 6 weeks. We were afraid she may have eaten a mouse poison pellet so we took her to her veterinarian for treatment. She will be at end of k1 treatment cycle in few days. When k1 treatment is complete, how many days do we wait to take her for her blood clotting test and what is the test called? Thank You for your help. You helped us very much through this scary time with our dog.

    • CB, the most commonly-used test is PTT, Prothrombin Time. Every case is different, and you should be guided by your veterinarian as to when he would prefer to perform the test. We are happy we could help and all of our readers whose pets have suffered similar fates breathe a sigh of relief with you.

  8. My 10 year old poodle was just diagnosed with autoimmune thrombocytopenia. She has been in the hospital for 2 days. She was improving, then started bleeding into the abdomen. Her doctor gave her a blood transfusion. Bleeding has stopped. She is stable, but critical. Blood count is 4. What are her chances of survival? If you could please advise me. Thank you.

    • Jay, if, by “blood count” you mean red blood cell count, “4” is just under the minimum of normal for our lab, which is 4.8. Of course, many of those RBCs came from the transfusion, and it may take more transfusions before the platelet-destruction process is stopped. Some patients respond to corticosteriod-only treatment, while others require more advanced (and more expensive) therapies. I cannot accurately prognose your girl based on RBC count alone, but her primary veterinarian should be able to give you information. Sadly, in some patients, AITP cannot be stopped, and those pets succumb. I’m sorry you are having to face this. Please keep us posted on her progress, Dr. Randolph.

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