The privilege of being a pediatrician, especially a pediatric oncologist, is that while fighting alongside parents for their child’s well-being, we can almost palpate that love between parents and child. Often when I discuss with parents about protecting their child from infection during chemotherapy, their first instinct is to put their child in a “bubble”. Since I trained at the hospital where the “boy in the bubble” was treated, this seems like an apt analogy. Certainly I want them to protect their child from infection, but it must be a balance because complete social isolation would not be healthy psychologically and is often not required to make their child safe.
Recap from last post: Why we are at increased risk of infection during cancer therapy?
Low white blood cell (WBC) count.
Chemotherapy lowers our WBC count. Acute leukemia can also lower this count. These WBCs include neutrophils that fight bacterial infections and lymphocytes that fight viral infections. During bone marrow transplant, both types of cells are affected, but during regular chemotherapy lower neutrophils is the major problem. Unfortunately, unlike platelets and red blood cells, these cannot easily be replaced through transfusions. (In rare cases of severe infection they can be transfused, but because of the side effects this approach is used judiciously.) Our doctor will keep us informed of our absolute neutrophil count (ANC). It is critical to let our doctor know right away if we experience fever. Typically an immediate evaluation in the emergency room is needed. Depending on the specifics of our case, our doctor may define a fever as 100.4 F (38 C) or 101 F (38.4 C). If our white count is low and we have fever, we will be treated with antibiotics. An ANC under 500 is very low, and it is during this time that we are at the greatest risk of infection. Doctors take many different variables into consideration to determine if antibiotics are to be given as an outpatient or inpatient. The greatest impact on our WBC is quantitative (decreased numbers), but some cancers (especially leukemia) and some therapies (such as steroids) can also disturb the quality of the WBC response, making the WBC present less functional.
Disruptions in our first line of defense against infection: skin and mucus membranes.
Our skin and the mucous lining of our mouth and gut are barriers and our first line of defense against infection. Our skin and mucus membranes are also sites where bacteria live. Therefore many of the bacterial infections that occur during cancer therapy are not acquired from the community but from ourselves. During cancer therapy these barriers are disrupted in multiple ways. Catheters, which are needed to deliver chemotherapy into large vessels and to reduce the need for frequent blood draws, are often placed through the skin and stay in for several months, providing a porthole for infection. Additionally, surgeries and tumors can also either cut into or cause impingement on these barriers and may increase the risk of infection. Furthermore, as discussed in my last post, chemotherapy irritates our mucus membranes and causes breakages such as sores that can be another source of bacterial entry. This is why oncologists are insistent about things such as mouth care and line care, because they help prevent some infections. Besides these physical breakdowns of barriers, chemotherapy can also cause temporary loss of some of the specialized antibacterial cells that exist in our mouth and gut.
Disruption in our normal gut bacteria
In the 1970’s studies first established the importance of antibiotic therapy during chemotherapy, and their routine use since has significantly improved outcomes during cancer therapy and reduced mortality from serious bacterial infections. So overall antibiotics are beneficial and an important part of cancer therapy. But there are some downsides to such frequent antibiotic usage, which include decreasing the numbers of our normal resident bacteria. These bacteria have multiple roles, and typically have a low risk of causing infection (low virulence). However, exposure to frequent antibiotic courses can cause what is called a shift in virulence, meaning that these normal bacteria can be replaced by bacteria more capable of causing infection.
Protection against infection
Most people will get a fever at least once during chemotherapy. I did. I have some patients that see this as some type of personal failure but it is not. It is just something that can happen. Fevers can be caused by viruses such as the common cold or flu acquired from the community. But unlike others in the community, when we cancer patients get a fever, because we may lack adequate immune function to fight a serious viral or bacterial infection and because we are at higher risk of such infections, we must seek medical attention rapidly. These infections may come from ourselves as a result of the therapy or may be a community-acquired bacterial infection such as pneumonia. Luckily today we know that giving routine antibiotics when we have fever and neutropenia (ANC less then 500) can significantly improve the outcomes during therapy. There are certain clinical situations such as bone marrow transplants when ability to fight viral infections is also altered, so we should clarify our risk with our doctor. Furthermore, patients are susceptible to certain medications used during routine chemotherapy such as steroids that can affect our ability to respond to viruses, such as shingles.
We want to protect ourselves from serious infections, not only because infection during cancer therapy can cause us to become gravely ill, but also because it means another ER visit. We already spend enough time in doctors’ offices and hospitals. Infections are clearly something to avoid, but since some of the most serious ones come from ourselves, even complete social isolation would not thwart all infections. What I typically tell my patients is that there is a balance. We want to decrease their risk of infection, but at the same time interacting with loved ones is important psychologically. Certainly we should practice common sense. This means avoiding contact with anyone who may have an acute infectious illness. It means practicing good hygiene such as hand washing. As we go through therapy we become aware of when our ANC is going down. At its lowest, our risk of infection is at its highest. Mostly it is about making good choices. As much as possible, we should avoid places where lots of people are together in a confined space. Instead of attending a movie on a Friday evening, we can easily choose an alternate low traffic time such as a weekday matinee. Being able to visit with friends and family is important, but we can remind them not to visit us when they are ill. Tell your friends to come after they drop off their toddler at day care, instead of bringing with them the toddler who has been exposed to day care. If there is a toddler at home with you, do not schedule play dates with friends who are sick but wait until they’re better. Home schooling during the months when children are getting intense chemotherapy is typically arranged through the school and a clinic social worker. We can still attend important large family events, but it is best to plan ahead and discuss with our oncologist in order to schedule this during the time when the ANC is expected to be above 500 and rising. When unclear about attendance at an event or how to approach certain visitors, it is best to get guidance from your doctor and/or nurse. There are additional special recommendations for bone marrow transplant patients and other patients who have decreased lymphocyte function and therefore cannot properly defend themselves from community-acquired viral infections. Those patients should make sure that they clarify with their doctors and nurses how to handle visitations. As the case for all my posts, I can not make specific recommendations for each reader. Only your doctor is familiar with your case, so always make sure you follow his recommendations.
A few final points
Sometimes we can have infections during chemotherapy without having fever. Sometimes our fever response may be muted, especially in specific clinical situations, as with children under one year of age or with certain medications such as steroids. So if you suspect that you or your child who is getting chemotherapy is acting acutely ill but does not have a fever, discuss the symptoms immediately with your doctor.
Since acute illness can occur during traveling, it is a good idea to discuss this with one’s doctor ahead of time. Our doctors can recommend certain hospitals that have the most experience with cancer patients, although typically when you are being evaluated for infection often the nearest hospital is the best choice. Our doctors can also provide a summary of our case and recommendations to carry with us. This is often the quickest way to communicate our needs to doctors who are not familiar with our situation. How infections are treated varies and is not only based upon symptoms and WBC count but also on such variables as the specific cancer diagnosis, treatment protocol, history of prior infections (what bacteria caused the infection and the antibiotic susceptibility profile).
Sending you love and strength,