The Oncologist’s Perspective on Chemotherapy and Low White Blood Cell Counts: Part 3

Finally, part 3 of my posts on chemotherapy and low white blood cells counts. (You can read Part 1 and Part 2 to catch up.) Today I will talk about severely low white blood cell counts and sepsis. Happily, this is NOT common in dogs getting chemotherapy. However, you should know about it if you are thinking about chemotherapy for your dog.

Sepsis in Dogs

Rarely, a dog’s white blood cell count plunges so low that it leads to sepsis, a systemic infection. In short, that means that they have an infection in lots of tissues. This is really serious, as you can imagine.

Typically, dogs have a fever and are very sick. Common symptoms include depression, lethargy, vomiting, diarrhea, and poor appetite.

This is an emergency and demands immediate hospitalization for IV fluids, broad-spectrum antibiotics, and supportive care.  Sepsis rarely leads to death, but even so, if your pet is not feeling well after chemotherapy treatments, you really should seek medical attention immediately.

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What Causes Sepsis After Chemotherapy

Some guardians think that chemotherapy itself causes sepsis, but that’s not actually what happens. Instead, chemo can lower the number of white blood cells called neutrophils, which are the cells that fight infection. Lower neutrophil numbers means less protection if an infection occurs. And if an infection happens, that can lead to sepsis.

Interestingly, the bacteria involved in these infections are usually already on and in your dog. Just like us, dogs have normal populations of bacteria in the body that don’t cause problems when the immune system is healthy.

But when the white blood cell count is lowered, the bugs on their skin and in the GI tract can get out of control. They can even get into circulation, in the blood and lymph. When that happens, infection can happen anywhere.

For example, when a dog is septic, I often check for pneumonia and a urinary tract infection.

How to Treat Sepsis

Typically the white blood cells will rebound in a day or two, and those new cells will start to fight the infection.

Until those fresh troops arrive, however, it is vital to use supportive care to prevent further deterioration and get that infection under control. IV fluids and antibiotics are amazing, and no matter how dumpy your dog looks when she is admitted, it’s worth it to give them for a day or two until her white blood cells have a chance to regenerate.

From my heart to yours, I beg you not to give up and euthanize your pet if he gets really sick after chemo. Give supportive care and re-evaluate in a day or two. Often, that’s all it takes.

After sepsis, we always re-evaluate our next steps in future chemotherapy treatments. We either skip that agent or way reduce doses to make sure this never happens again!

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For more helpful information on Chemotherapy, treatment options and dog cancer, get a copy of the Dog Cancer Survival Kit

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Neupogen

If the white blood cells are not rebounding within a day or two, a human medication called Neupogen may be recommended. Neupogen stimulates the bone marrow to make white blood cells.  Like all medications, Neupogen has its pros and cons to be considered before recommending it. In my opinion, is rarely needed.

Silver Lining for Dogs Who Experience Low White Blood Cell Counts!

In a recent study of dogs with lymphoma, those who had moderate to severe low white blood cell counts during chemotherapy actually experienced longer first remissions. This is despite dosage reductions and treatment delays due to the low counts.

We often are concerned that lowering the dose of chemo and delaying treatment hurts remission. But in this study, dosage reductions (to avoid repeat low WBC) and treatment delays (to give the WBC time to rebound) did not shorten how long the first remission lasted. That’s good news of your dog does get a low WBC.

On the flip side, lymphoma dogs in this study that did NOT develop low white blood counts had shorter first remissions. So … maybe these dogs would have done better with increased dosages.

In other words, it looks like pushing the immune system hard may have resulted in longer remissions. This is a future area to be worked out.

Chemo Can and Should Be Customized to Your Dog

As I have said many times, no one, especially me, wants your dog to get sick from chemotherapy.

Like most oncologists, I customize each dog’s protocol for the individual cancer, your dog’s own reactions to the treatment, and for concurrent medical conditions.

My goal is that my patients have fewer complications and lead relatively normal happy lives. I want your pet to not just live as long as possible but to live well.

There is more information about chemotherapy and its side effects in the Dog Cancer Survival Guide.

All my best,

Dr. Sue Cancer Vet

Also, See:

The Oncologist’s Perspective on Chemotherapy and Low White Blood Cell Counts: Part 1

The Oncologist’s Perspective on Chemotherapy and Low White Blood Cell Counts: Part 2

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