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, but you should know about it anyway if you are thinking about chemotherapy for your dog.
Rarely a dog may get a low white blood cell count that leads to sepsis, which is a systemic infection. Typically, these dogs have a fever and are sick (depressed, lethargic, vomiting, diarrhea, poor appetite). This is an emergency and best treated with immediate hospitalization for IV fluids, broad-spectrum antibiotics, and supportive care. While sepsis causing death is rare, if your pet is not feeling well after treatment, seek medical attention immediately.
Interestingly, the bacteria that causes these infections are usually already on and in your dog. Dogs have normal populations of bacteria in the body that don’t cause routine problems when the immune system is normal. But when the white blood cell count is lowered, dogs are at risk of infections from the bugs that reside on their skin and in the GI tract. These can get into circulation. When a dog is septic, I will often check for pneumonia or a urinary tract infection.
Typically the WBC will rebound on its own in a day or two, while supportive care prevents further deterioration and gets the infection under control. So don’t be discouraged if your pet looks really dumpy when she gets admitted. You will be amazed what some IV fluids and antibiotics will do. I beg you not to give up and euthanize your pet if he gets so sick. Give her supportive care and re-evaluate in a day or two.
If the WBC is not rebounding within a day or 2, a human medication called Neupogen may be recommended to stimulate the bone marrow to make WBC. Like all medications, Neupogen has its pros and cons to be considered before recommending it to a patient, and, in my opinion, is rarely needed.
There is actually a silver lining of a low white blood cell count. In a recent study, dogs with moderate to severe low white blood cell counts during chemotherapy for lymphoma actually experienced longer 1st remissions. While we often get concerned that lowering the dose of chemo and delaying treatment may hurt remissions, 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 WBC had shorter first remissions, so maybe these dogs will do better with increased dosages. This is a future area to be worked out. We will talk about dose intensity and chemotherapy in the future.
As I said in the beginning of my post on GI side effects, no one, including me, wants your dog to get sick from chemotherapy. I customize each dog’s protocol for the individual cancer, reactions to treatment, and for potential 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 E.
