Anemia in the Cat

When dealing with any case where we find the animal to be anemic (defined as a low red blood cell count), we tend to think of it as happening in 3 main ways:


1. loss of red blood cells - a common example would be animal hit by a car with internal bleeding


2. decreased production of red blood cells - this is generally a problem with the bone marrow not regenerating red blood cells like it's supposed to


3. increased destruction of red blood cells - can happen for a variety of reasons

This is how we can start to find the cause and then, hopefully, successfully treat our patient and bring them back to full health.  We also look at whether or not the animal is making more RBC's in response to this anemia or not - so is the anemia regenerative or not? Again, this can help narrow down causes. 


Obviously with trauma, it's fairly straightforward. It's 2 and 3 that can cause some trouble - especially with cats. Now, there are some common, easily tested for things we can find in cats that can cause anemias: infections with agents like - feline leukemia virus, feline immunodeficiency virus and hemobartonellosis (now renamed to feline hemotropic mycoplasma) - a disease transmitted via flea bites (YET another reason for monthly topical products like Revolution!). 
If the cat is in kidney failure (simple blood work will tell us this), we will also see anemia due to reduced production of a hormone that stimulates RBC formation. 


Some of these cases we can manage with medications.


However, there are a group of cats whose cause of anemia is often nebulous - especially in middle aged-older cats. I always assume cancer somewhere (even in the bone marrow) until proven otherwise. It usually requires more than just blood work to get to the bottom of it - xrays, ultrasounds, bone marrow aspirates, etc. I've had several cases where we just couldn't find the cause. This was either because  the tests were normal/negative (some of us medical professionals KNOW that doesn't mean that NOTHING is wrong) or the owners didn't wish to pursue further testing. These cats were treated symptomatically - with steroids and supplements and sometimes antibiotics (to hit possible things like hemobart). 


I had one case, though, where a very wonderful and attentive cat owner did pursue her cat's anemia. This cat was only 1 1/2 or so when this problem started. She ended up having several blood transfusions and being on various medications. Initially she was treated for IMHA (like our dogs as discussed yesterday). However, the cat kept relapsing and she ended up going to a genetic specialist at the Univ of Penn Vet School. The cat was diagnosed with osmotic fragility - basically something caused this cat's RBC's to be fragile and break down very easily.  


For more info on all these causes and more, this is a paper by the veterinarian at UPenn:  Causes of Feline Anemias