Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation primarily targeting the joints. While its effects on the hands, wrists, and knees are well-known, RA is a multisystem disorder that can manifest outside of the skeletal system, affecting organs like the heart, lungs, and eyes. This broader inflammatory scope means the inner workings of the body, including the delicate sensory organs, are also susceptible to damage. Research confirms that the chronic inflammatory processes associated with RA can extend to the auditory system.
The Clinical Link Between Rheumatoid Arthritis and Hearing Loss
Patients diagnosed with rheumatoid arthritis have a significantly increased likelihood of developing hearing impairment compared to the general population. The most prevalent form of co-occurring auditory dysfunction is sensorineural hearing loss (SNHL), which results from damage to the inner ear, specifically the cochlea or the auditory nerve. Studies indicate that the prevalence of SNHL in RA patients ranges widely, from approximately 25% to over 70%.
The hearing loss often presents as a bilateral impairment, typically affecting the higher frequencies first. This can make understanding speech in noisy environments particularly challenging. While less common, conductive hearing loss (CHL) can also be observed in RA patients. This type occurs when sound transmission is blocked in the outer or middle ear before reaching the inner ear structures. A mixed hearing loss, encompassing both sensorineural and conductive elements, is also possible in this patient population.
Pathological Mechanisms of Auditory Damage
The systemic nature of rheumatoid arthritis provides several biological pathways through which hearing damage can occur. Chronic, uncontrolled inflammation is a primary driver, as the inflammatory mediators that attack joint tissue can also reach the highly sensitive structures of the inner ear. This ongoing inflammatory assault can directly damage the hair cells within the cochlea, which are responsible for converting sound vibrations into electrical signals for the brain.
Another mechanism involves vasculitis, which is the inflammation of blood vessel walls. The inner ear relies on a precise and robust blood supply, and vasculitis affecting the small arteries in this region can lead to ischemia, or a lack of oxygen and nutrients. This reduced blood flow can cause permanent damage to the cochlear structures and the auditory nerve, resulting in SNHL.
For the conductive component of hearing loss, the disease can directly affect the small synovial joints found in the middle ear. These tiny joints connect the three ossicles (malleus, incus, and stapes) that transmit sound mechanically. Inflammation and subsequent erosion of these joints can cause them to stiffen or fuse, impairing the efficient movement of sound waves across the middle ear.
Distinguishing Treatment-Related Ototoxicity
It is important to differentiate between hearing loss caused by the rheumatoid arthritis disease process and hearing loss arising as a side effect of necessary treatments, known as ototoxicity. Several medication classes routinely used to manage RA have the potential to cause auditory damage. Nonsteroidal anti-inflammatory drugs (NSAIDs), for example, are a common treatment that, when used frequently or at high doses, have been associated with an increased risk of hearing loss.
Another class of drugs with known ototoxicity includes the antimalarials, such as hydroxychloroquine (HCQ). Cases of sensorineural hearing loss have been reported with HCQ use, sometimes requiring the discontinuation of the medication. Certain disease-modifying antirheumatic drugs (DMARDs), including methotrexate, have also been documented to have ototoxic effects.
Determining the exact cause of hearing loss is crucial because the management strategy changes significantly depending on whether the disease or the drug is the culprit. If a medication is identified as the source, reducing the dosage or switching to a different treatment may reverse the damage or prevent further progression. If the disease activity is the cause, more aggressive management of the underlying RA is required to protect the auditory system.
Screening and Management Strategies
Given the established link, a proactive approach to monitoring auditory health is necessary for individuals with rheumatoid arthritis. Audiological screening should be considered at the time of an RA diagnosis and continued on a regular basis thereafter, even in the absence of noticeable symptoms. Standard pure-tone audiometry is the usual starting point, but specialized tests like extended high-frequency audiometry can detect subtle damage earlier than traditional hearing tests.
The management of RA-related hearing loss requires collaboration between the rheumatologist, who manages the systemic disease, and an audiologist or otolaryngologist. The most fundamental management strategy involves achieving tight control over the underlying rheumatoid arthritis. Reducing systemic inflammation helps protect the inner ear from further inflammatory damage, which may involve adjusting DMARDs or starting a biologic therapy.
For the hearing loss itself, treatment options depend on the type and severity of the impairment. Sensorineural hearing loss often benefits from hearing aids to amplify sound and improve communication. In cases of rapid onset or worsening SNHL, a short course of corticosteroids may be initiated to reduce acute inflammation in the inner ear. Conductive hearing loss, particularly if related to ossicular joint issues, may sometimes be addressed surgically.