Infections are now the leading cause of death in people with multiple myeloma. Advances in treatment have extended survival; however, certain myeloma therapies weaken patients' immune systems. For these reasons, the spectrum of infections appearing in people with multiple myeloma has changed.
High Risk for Infection
People with multiple myeloma have higher risk for infection due to their suppressed immune system. The cancer cells destroy normal antibodies and produce white blood cells that don't work. Immunodeficiency related to complications of the disease and the type of medication used also raises the risk for repeated infections, including pneumonia, sinusitis, bladder and kidney infections, skin infections and shingles, reports the Mayo Clinic.
People with multiple myeloma get bacterial, fungal and viral infections, according to expert hematologists. The most common pathogen is gram-negative bacteria, which causes kidney infection. Pneumonia caused by various pneumoniae pathogens frequently occurs. Recently, a sharp increase in invasive fungal infections caused by molds has occurred in patients with multiple myeloma, reports Seminars in Hematology.
Certain medications increase the risk for infection in people with multiple myeloma. Therapy with bortezomib, a new class of medication that causes cancer cells to die by blocking proteasomes, reactivates the herpes simplex and herpes zoster viruses, according to Clinics for Infectious Disease. The novel immunomodulating drugs thalidomide and lenalidomide are often used in combination with chemotherapy, which by itself kills healthy white blood cells. These high-powered combinations cumulatively suppress the immune system, increasing susceptibility to many types of infections, such as oral candidiasis, sepsis, febrile neutropenia, herpes and other viruses. Respiratory and urinary tract infections can occur as well. According to a study reported by the American Society of Hematology, about 18 percent of patients on thalidomide experience severe infection, most commonly pneumonia (60 percent) and unidentifiable fever (23 percent). Another severe infection is bacteria in the blood (15 percent), which can lead to death.
Infections Related to Stem Cell Transplantation
Stem cell transplants prolong life; however, patients must stay in the hospital for weeks until their transplanted stem cells begin to produce enough white blood cells. The spectrum of infections following transplant includes unusual pathogens such as Clostridium difficile, cytomegalovirus and opportunistic molds, according to Clinics for Infectious Disease.