Challenges in Diagnosing Sudden Sensorineural Hearing Loss : The Hearing Journal – LWW Journals
Idiopathic sudden sensorineural hearing loss (ISSNHL) is a medical emergency that hearing care professionals frequently encounter. Despite being identified over a century ago, ISSNHL remains a clinical enigma, in terms of both diagnosis and management. Unlike the majority of disorders causing hearing loss in adults, which progress slowly and quietly, ISSNHL is a frightening and mysterious event due to its sudden, often unannounced appearance. ISSNHL is defined as a unilateral acu…….
Idiopathic sudden sensorineural hearing loss (ISSNHL) is a medical emergency that hearing care professionals frequently encounter. Despite being identified over a century ago, ISSNHL remains a clinical enigma, in terms of both diagnosis and management. Unlike the majority of disorders causing hearing loss in adults, which progress slowly and quietly, ISSNHL is a frightening and mysterious event due to its sudden, often unannounced appearance. ISSNHL is defined as a unilateral acute sensorineural hearing loss of 30 decibels or more over at least three contiguous frequencies, occurring within 72 hours. It has an estimated annual incidence of 5 to 27 per 100,000 persons,1 which is likely an underestimate because spontaneous hearing recovery may discourage some patients from seeking medical attention. The incidence may vary from country to country possibly due to the different health care systems across the globe.
Proposed ways of managing ISSNHL. Abbreviations: AC, Air Conduction; BC, Bone Conduction; ISSNHL, Idiopathic Sudden Sensorineural Hearing Loss.
Hearing loss in ISSNHL has been linked to damage to the cochlea or auditory nerve, which, if not treated promptly, can leave patients with permanent hearing deficits. It can happen to anyone at any time, regardless of age or previous hearing problems. Although ISSNHL can be caused by a multitude of factors, around 90% of the cases are idiopathic, where no definitive underlying cause can be determined at the time of presentation, and treatment decisions are made even before the cause is determined.2 It is regarded as a medical emergency because the hearing can be recovered, often completely, if prompt action is taken. Therefore, the evaluation of the patient should be done as soon as possible since the prognosis is directly proportional to the time taken between onset of symptoms and initiation of treatment.
RECOGNIZING AND DIAGNOSING ISSNHL
Clinical features of ISSNHL include unilateral rapid onset of hearing loss, with or without associated symptoms such as tinnitus, vertigo, and stuffy ear. Evaluation of the patient includes taking a comprehensive history of onset, duration and laterality of hearing loss along with associated symptoms like headache, tinnitus, dizziness, focal neurological deficits, and predisposing factors like infection, trauma, or excessive alcohol consumption. This may help narrow down the differential diagnosis and determine the urgency for a referral as required. The sensation of a stuffy or full ear should not deter the examining physician from suspecting ISSNHL as the underlying condition.
Aural fullness, tinnitus, and muffled hearing are the most common symptoms, which are typically non-specific. As a result, the first step in diagnosis is to determine the type of asymmetrical hearing loss, whether conductive hearing loss (CHL) or sensorineural …….
