Dear Dr. Robin: I have raised Shih Tzus for years and have read about pets having bad reactions to vaccinations. My dogs have received their vaccinations 1½ to 2 years apart. In May of this year, I was going on vacation and my dogs went in to receive their vaccinations since I would be stopping at rest areas.
One week later, I woke up and my little male was nearly dead. He showed very little life and had white gums. I rushed him to the emergency room and they said he had immune mediated destruction of his red blood cells.
They said it was triggered by his vaccination. He was on prednisone for 2½ months, and he seems fine now, but I was told he should never have another vaccination because it could trigger it all over again.
Now I am afraid to have any of my dogs vaccinated. I felt that I was helping him, and now I feel guilty that because of me, he almost died. How common is this?
– D.L., Denver
A: Immune-mediated hemolytic anemia (IMHA) is a process of premature destruction of red blood cells due to a “short circuit” of the immune system during which the body recognizes its own cells as foreign.
The liver or spleen may filter the red blood cells out of the circulation, or the red cells may simply be destroyed within the blood vessels.
Isolated families of dogs have been documented to be affected, but no genetic basis for IMHA has been established.
The mean age at diagnosis is 5 to 6 years, and more females than males are affected. IMHA has many diverse causes, yet in many cases, the exact trigger is never uncovered.
Some triggers include infectious diseases, canine heartworm disease, certain medications, and cancer.
At this point, a connection between vaccination and IMHA is difficult to prove. It is true, though, that once a dog has a diagnosis of IMHA, we do our best to prevent them from being exposed to any potential trigger – including certain medications and vaccinations.
The fact is that vaccinations save lives. And it is impossible to predict if a dog will have an adverse reaction to a vaccination.
That said, there are strategies for prolonging the interval between vaccines, though we do not have a fool-proof method for knowing precisely how long we can wait before re-vaccinating.
A blood test can measure antibodies against several of the diseases against which we vaccinate.
Talk to your veterinarian about the pros and cons of these tests and how to interpret the results.
Dr. Robin Downing will respond to your questions in her column, but cannot answer individually. Send questions to: Robin Downing, DVM, P.O. Box 460, Windsor, CO 80550 or drrobin@windsorvet.com.
