From the Guidelines
Non-mechanical causes of sudden hearing loss include viral infections, vascular events, autoimmune disorders, and ototoxic medications, as well as metabolic and neurological conditions. The most recent and highest quality study, 1, highlights that sudden sensorineural hearing loss (SSNHL) can be caused by various non-mechanical factors, including infections such as Lyme, syphilis, and human immunodeficiency virus, as well as autoimmune inner ear disease. Other studies, such as 1 and 1, also support the idea that non-mechanical causes of sudden hearing loss can include:
- Viral infections (particularly herpes viruses, influenza, and cytomegalovirus)
- Vascular events (such as strokes or microvascular occlusions)
- Autoimmune disorders (like Cogan's syndrome or systemic lupus erythematosus)
- Ototoxic medications, such as certain antibiotics (aminoglycosides like gentamicin), chemotherapy drugs (cisplatin), high-dose salicylates (aspirin), loop diuretics (furosemide), and some antimalarials
- Metabolic conditions, such as diabetes and thyroid disorders, which can affect blood supply or nerve function in the inner ear
- Neurological disorders, like multiple sclerosis or acoustic neuromas, which may cause sudden hearing loss as well. Treatment depends on the underlying cause, but often includes corticosteroids as first-line therapy, with prompt medical attention being crucial for the best chance of hearing recovery, as noted in 1.
From the Research
Non-Mechanical Causes of Sudden Hearing Loss
- Autoimmune inner ear disease (AIED) is a condition where the immune system mistakenly attacks the inner ear, leading to sensorineural hearing loss 2, 3, 4, 5.
- Viral infections are also a proposed cause of sudden sensorineural hearing loss 6.
- Vascular insufficiency is another potential cause of sudden hearing loss 6.
- Autoimmune disorders, such as those that cause AIED, can also lead to sudden hearing loss 2, 6, 5.
- Stress theory is also a proposed cause of sudden sensorineural hearing loss, although the exact mechanism is not well understood 6.
Characteristics of Autoimmune Inner Ear Disease
- AIED typically presents with asymmetric bilateral sensorineural hearing loss 2, 5.
- The hearing loss is often fluctuant, but can progress rapidly without early medical intervention 5.
- Word recognition is usually disproportionately poor in patients with AIED 5.
- AIED can also be associated with vestibular disorders, such as vertigo and tinnitus 2, 3.
Diagnosis and Treatment of AIED
- The diagnosis of AIED is often based on exclusion, as there are no standardized diagnostic criteria or reliable diagnostic tests 2.
- Systemic corticosteroids are the first line treatment for AIED, although alternative treatment modalities such as intratympanic steroid injections and biologic agents may also be effective 3, 4.
- Early identification and treatment of AIED are critical to achieving acceptable hearing outcomes 2, 5.