I had known Wolfy most of his life. He was a feisty old Pomeranian mix, and when his family said he wasn’t acting like himself, I wasn’t too worried. At least not at first. There are many easily treatable things that can make a senior dog feel a bit off.
On initial exam, his temperature was elevated, but otherwise, there were no obvious abnormalities except an unusually subdued demeanor. ”What exactly are you noticing at home?” I asked.
Wolfy had barely eaten for two days. Little dogs are notoriously picky, but this was more than that. He had been coughing, but he had a history of coughing in the past. He might have eaten a few M&Ms several days ago, and his legs were shaking sometimes, but any effects of eating chocolate would have passed by now, and “shaking legs” is a very nonspecific sign. With nothing much to go on, we needed to run tests.
We started with a blood chemistry panel, assessing parameters like liver and kidney function, blood sugar, and electrolytes. Normal. A 4DX test ruled out heartworm infection and several tick-borne diseases, including Lyme. Next, radiographs looking for tumors, foreign bodies, heart or lung disease — anything to explain Wolfy’s malaise. It’s not unusual to pick up a number of “incidental findings” when working up a case, especially with an older animal. Wolfy’s x-rays showed mild heart enlargement, but since he did not have a murmur and his lungs were clear, this didn’t suggest serious cardiac disease. He had mineralization of part of one kidney, but all his kidney function tests were normal, so no serious renal disease. Then I saw his CBC.
A complete blood count (CBC) examines the cellular components of the blood: the number and size of the red blood cells (RBC) that transport oxygen throughout the body; the percentage of RBCs to serum (the fluid part of the blood); the amount of hemoglobin inside the RBCs. The CBC also quantifies white blood cells (WBC) by type and number. WBCs fight infection. The distribution of the different types can point us toward whether we are dealing with something viral, bacterial, allergic, or parasitic. Finally, the CBC quantifies thrombocytes, also called platelets, cells essential for normal clotting.
Wolfy’s complete blood count was abnormal. He was extremely anemic, with a very low red blood cell count and percentage. Now, when lay people hear “anemia,” they often think things like, “He must need more iron,” or, “He should eat more meat.” Nope.
Anemia caused by inadequate iron in the diet is very uncommon in adults. I had to consider three major reasons we see anemia in dogs: blood loss, decreased RBC production, or increased RBC destruction.
First, blood loss. Trauma, surgery, bleeding tumors, bleeding ulcers, anticoagulant rodent poison, inherited hemophilia-like diseases, even blood-sucking intestinal parasites such as severe flea or tick infestations can all cause excessive blood loss, leading to anemia. In the old days, before we had so many good flea-control products, it wasn’t uncommon to see kittens with life-threatening anemia from heavy flea infestations. I transfused more than one little kitty in my day who was literally being killed by fleas. But Wolfy did not have fleas, or any of these other conditions.
Second, decreased production. Technically referred to as “nonregenerative anemia,” in these cases the animal’s bone marrow, where red blood cells normally get made, stops generating new RBCs. Why? Lots of reasons. Chronic infection, kidney disease, viruses like feline leukemia and parvo, certain drugs that can cause bone marrow suppression, certain cancers. All these things can cause decreased RBC production. But Wolfy had “regenerative” anemia. His bone marrow was making new red blood cells. It just couldn’t keep up with whatever was taking them away. Which brings us to the third and final cause.
Third, increased destruction. Immune-mediated hemolytic anemia (IMHA) is a condition in which an animal’s immune system is destroying and removing red blood cells at an abnormal rate. “Hemo” means blood. “Lytic” means decomposition. So literally, RBCs are being decomposed. IMHA can be primary, also known as idiopathic. This means we don’t know why it happens. It just does. Or IMHA can be secondary, when we identify an initiating cause that sets off this autoimmune reaction. This can be certain toxins such as zinc overdose or mothball ingestion, parasites that infect RBCs, like babesia, even an aberrant immune response to vaccination.
Did Wolfy have IMHA? It occurs most often in young to middle-age dogs, but Wolfy was older. Breeds that are predisposed include cocker spaniels, miniature schnauzers, collies, Dobermans, Old English sheepdogs, bichon frisés, and Maltese, to name a few. Wolfy was a Pomeranian cross. Signs can include weakness, loss of appetite, lethargy, vomiting, diarrhea, nosebleeds, bruises, blood in the stool or urine, fever, trouble breathing, and jaundice. Wolfy had several of these signs, but not all. However, when we centrifuged his blood sample, we could see that the serum was abnormally yellow. Jaundice: a pretty good indicator of RBC destruction, once liver disease has been ruled out.
There was a quick test I could do to confirm my suspicions. Mixing a drop of Wolfy’s blood with a drop of saline on a slide, I rolled it back and forth. In just a minute, the RBCs clumped together giving a granular appearance.This is called autoagglutination, and supports a diagnosis of IMHA.
The prognosis for IMHA varies. Although some dogs respond well to treatment, fewer than half survive a year, and many die or are euthanized within two weeks of diagnosis. We started Wolfy immediately on corticosteroids and anticlotting medication (since IMHA dogs are prone to blood clots). This is one reason why your veterinarian often suggests a full array of tests in cases where the diagnosis is not easily determined just by physical exam.
His owners had sensed correctly that something was seriously wrong, even though his initial symptoms had been vague. Sadly, Wolfy’s condition worsened rapidly. We had to say goodbye to him soon after. He will be deeply missed.
