Leukemia is a type of cancer that originates in the blood-forming cells of the bone marrow. It leads to the production of an excessive number of abnormal blood cells, often white blood cells, called blasts or leukemia cells. These abnormal cells do not mature properly and can interfere with the bone marrow’s ability to produce healthy blood components like red blood cells and platelets. The progression of leukemia can be rapid, as seen in acute forms, or slower, as in chronic types. While the direct impact of leukemia on various body systems is complex, its relationship with hearing health is a significant concern for many individuals.
How Leukemia Itself Affects Hearing
Leukemia can directly influence hearing through several biological mechanisms, though this is less common than treatment-related hearing loss. One way is through leukemic infiltration, where cancer cells invade inner ear structures like the cochlea or auditory nerve. This can disrupt normal function, leading to hearing loss or other auditory symptoms.
Another mechanism is hyperviscosity syndrome, occurring when a high number of leukemic cells, particularly in types like chronic myeloid leukemia (CML), thicken the blood. This impairs blood flow to small vessels, including those supplying the inner ear. Reduced blood flow can deprive the inner ear of oxygen and nutrients, potentially causing hearing loss or tinnitus, a ringing in the ears. This syndrome can sometimes be an initial symptom leading to a leukemia diagnosis.
Complications like severe anemia or thrombocytopenia can also indirectly affect hearing. Anemia, a low red blood cell count, reduces oxygen delivery to the inner ear. Thrombocytopenia, low platelet counts, increases bleeding risk. Hemorrhage into the inner ear, though uncommon, can damage auditory structures, leading to sudden hearing loss.
Hearing Loss from Leukemia Treatments
Leukemia treatments are a more frequent cause of hearing loss than the disease itself. Chemotherapy drugs, particularly platinum-based agents like cisplatin and carboplatin, are known for their ototoxic effects, meaning they can damage the inner ear. Cisplatin, used in various cancers including some leukemias, can cause permanent hearing loss in a significant percentage of patients, affecting up to 40-80% of adults and at least 50% of children. These drugs primarily damage cochlear hair cells, specialized sensory cells essential for converting sound vibrations into electrical signals.
Cisplatin accumulates in the cochlea, leading to mitochondrial dysfunction and cell death in outer hair cells. Other chemotherapy agents, such as vincristine, cyclophosphamide, and doxorubicin, also have ototoxic potential. Vincristine’s ototoxicity is often associated with higher doses, and some studies suggest an increased risk of hearing loss in children treated with it.
Radiation therapy, especially to the head and neck, can also contribute to hearing loss by damaging inner ear structures or the auditory nerve. The risk and severity depend on the radiation dose to the cochlea. This damage can be permanent and progressive, sometimes appearing months or years after treatment.
High-dose chemotherapy and radiation used in stem cell transplantation (SCT) can amplify hearing loss risk. Certain antibiotics, like aminoglycosides, given to leukemia patients for infections, are also ototoxic. The overall risk and severity of hearing loss from these treatments are influenced by factors like specific drugs, dosage, treatment duration, and individual patient characteristics, including age and genetics.
Identifying Hearing Changes and Next Steps
Recognizing early hearing changes is important for individuals undergoing leukemia treatment. Common signs include difficulty understanding speech, especially in noisy environments, needing to increase device volume, and experiencing tinnitus, a ringing or buzzing in the ears. Some might also notice trouble hearing high-pitched sounds or distinguishing certain sounds.
Patients and caregivers should promptly report any new or worsening hearing symptoms to their oncology team. This ensures concerns are addressed and integrated into the treatment plan. Healthcare providers can then assess potential causes and determine appropriate next steps.
The diagnostic process for hearing loss typically involves a comprehensive evaluation by an audiologist. This includes tests like pure-tone audiometry, which measures the softest sounds a person can hear across different frequencies. This test helps identify the type and degree of hearing loss, often revealing sensorineural hearing loss, which is damage to the inner ear or auditory nerve. Baseline hearing tests before starting ototoxic treatments are often recommended to monitor for changes.
Managing hearing loss in leukemia patients involves various approaches aimed at improving communication and quality of life. Hearing aids are a common solution for many with moderate to severe hearing loss, amplifying sounds to make them more accessible. Assistive listening devices and communication strategies, such as lip-reading or reducing background noise, can further aid comprehension. For severe cases, cochlear implants, which directly stimulate the auditory nerve, may be an option. Early detection and intervention are important for minimizing the impact of hearing loss on daily life and overall well-being.