Multiple myeloma is a blood cancer originating in the bone marrow. Patients often face infections, particularly pneumonia. Their compromised immune system, combined with cancer treatments, makes them vulnerable to various pathogens. Understanding the link between multiple myeloma and pneumonia is important for improving patient care and outcomes.
Understanding Multiple Myeloma
Multiple myeloma is a cancer that develops from plasma cells, a type of white blood cell found primarily in the bone marrow. Healthy plasma cells produce antibodies that fight infections, but in multiple myeloma, these cells become cancerous and multiply uncontrollably. These abnormal plasma cells, known as myeloma cells, can crowd out healthy blood-forming cells in the bone marrow, leading to a range of complications.
The disease directly impacts the immune system by interfering with normal antibody production. Cancerous plasma cells produce dysfunctional M proteins, which do not fight infections, leaving patients vulnerable. These malignant cells also reduce the number and function of other immune cells, like T cells, further compromising defenses.
Patients with multiple myeloma often experience symptoms such as bone pain, especially in the spine, ribs, or hips, due to myeloma cells damaging bone tissue. Other common symptoms include fatigue, tiredness, and frequent infections, which stem from the weakened immune system. Kidney problems, nausea, constipation, and weight loss can also occur due to abnormal protein buildup or high calcium levels in the blood.
Pneumonia and Myeloma: A Dangerous Combination
Multiple myeloma patients are susceptible to pneumonia. Myeloma’s immune dysfunction, including reduced healthy antibody production and impaired T-cell function, increases infection risk. This suppression makes patients vulnerable to pathogens that healthy individuals typically resist.
Multiple myeloma treatments, including chemotherapy, corticosteroids, and novel agents, further suppress the immune system. These therapies can cause low white blood cell counts, especially neutrophils, which fight bacterial infections. High-dose chemotherapy followed by stem cell transplantation also profoundly impacts immune function, leading to prolonged infection susceptibility.
Pneumonia in multiple myeloma patients can progress rapidly and often presents with atypical symptoms, making early diagnosis challenging. These infections can quickly become severe, leading to serious complications. Patients face a higher risk of bacterial infections (approximately seven times the general population) and viral infections (up to 18 times higher in the first year after diagnosis).
Common pathogens causing pneumonia in this patient group include bacteria like Streptococcus pneumoniae, Haemophilus influenzae, and various Gram-negative bacteria. Viral infections, such as influenza, respiratory syncytial virus (RSV), and herpes viruses (e.g., herpes zoster, herpes simplex), are also prevalent. Fungal infections and Pneumocystis jirovecii pneumonia (PJP), an opportunistic infection, are additional concerns, especially with certain immunosuppressive therapies.
Factors Influencing Outcomes
Several factors influence pneumonia severity and mortality in multiple myeloma patients. Older individuals face a higher risk of severe infections and poorer outcomes. Coexisting health conditions, such as heart disease, kidney impairment, and diabetes, also increase infection risk and mortality. Renal impairment, for example, is a known risk factor for pneumonia in early multiple myeloma.
The stage of multiple myeloma at diagnosis influences infection risk, with advanced stages often leading to more infections. Specific treatments also impact pneumonia susceptibility. Some therapies cause prolonged low white blood cell counts or other immune deficiencies, increasing vulnerability.
The type of pathogen causing pneumonia is another factor; certain bacteria, viruses, or fungi can lead to more aggressive infections in immunocompromised individuals. Streptococcus pneumoniae, for instance, commonly causes pneumonia in these patients. Timely diagnosis and prompt treatment initiation are crucial, as delays can lead to rapid deterioration and worse outcomes. Infections, including pneumonia, account for approximately 45% of early deaths in multiple myeloma patients.
Prevention and Management
Preventing pneumonia in multiple myeloma patients involves proactive strategies. Vaccinations are a primary prevention method, including annual influenza and pneumococcal vaccines (e.g., PCV20 or PCV15 followed by PPSV23). These vaccines stimulate antibody production, though their effectiveness can vary. Post-vaccination antibody titers may be measured to assess immune response, and revaccination might be necessary.
Good hygiene, such as frequent handwashing, is important for reducing pathogen exposure. Prophylactic medications, including antiviral agents (e.g., acyclovir for herpes simplex and varicella zoster) and antibacterial agents (e.g., trimethoprim-sulfamethoxazole or dapsone for Pneumocystis jirovecii pneumonia), may be considered during heightened infection risk. Some patients with frequent bacterial infections may also benefit from regular antibiotic use or intravenous immunoglobulin infusions.
Early recognition of pneumonia symptoms, such as fever, cough, and shortness of breath, is important for prompt intervention. Treatment for pneumonia in immunocompromised multiple myeloma patients typically involves broad-spectrum antimicrobial therapy, often initiated quickly while awaiting specific pathogen identification. Consultation with an infectious disease specialist is recommended to guide treatment choices, which may include targeted antibiotic, antiviral, or antifungal therapies based on the identified pathogen and the patient’s immune status.