What to look for
Evaluation of tinnitus begins with a thorough history and physical exam (FIGURE 1).2,6,7,9 Key components of the exam include inspecting the ears, nose, and throat and evaluating cranial nerve function. Weber and Rinne tuning fork testing can help to confirm a conductive hearing loss. When evaluating a patient who reports pulsatile tinnitus, perform auscultation over vascular structures in the neck, temple, and around the ear.
Obtain targeted laboratory studies if there is a suggested metabolic etiology for tinnitus (TABLE 1).2,6,7 Handheld tympanometry that is flatlined or fluctuates with breathing can help support the diagnosis of a subtle middle ear effusion or patulous eustachian tube, respectively.
It is important to quantify how tinnitus affects a patient’s mood, including irritability and concentration. Tinnitus can be measured on several scales, including the Tinnitus Functional Index (TFI),10 which is easily completed in the office. It has been validated to quantify the severity of symptoms and can be used to monitor a patient’s progress. A copy of the TFI and its scoring instructions are available at http://www.ohsu.edu/xd/health/services/ent/services/tinnitus-clinic/tinnitus-functional-index.cfm.
Refer most patients to audiology. Patient’s symptoms often correlate poorly with acoustic functioning.6 Unless you find simple, reversible causes of tinnitus on history and physical, a comprehensive audiologic evaluation is essential. Components of these evaluations include pure-tone thresholds, tympanometry, speech thresholds, and speech discrimination testing.7
Image when necessary. If audiometric testing indicates cochlear damage, imaging generally is unnecessary because SNHL has been confirmed.7 However, if a retrocochlear hearing deficit is detected, auditory brainstem response testing is useful to help locate the lesion. Gadolinium-enhanced magnetic resonance imaging of the internal auditory canals also can be performed to evaluate for central nervous system lesions.2,7 This will detect vestibular schwannoma, which is the most frequent cause of tinnitus apparent on imaging.11
Pulsatility is the one true red flag feature of tinnitus and regardless of audiometry, patients with pulsatile tinnitus require imaging to rule out vascular lesions. The petrous carotid system is a common culprit; therefore, contrast-enhanced high-resolution computed tomography (CT) of the temporal bone is a reasonable initial study since it also will detect osseous abnormalities of the inner ear. However, angiography often is eventually necessary (conventional, magnetic resonance, or CT) to exclude a dural arteriovenous fistula or malformation-the most common cause of objective, pulsatile tinnitus.11 When tinnitus is pulsatile, unilateral, atypical in nature, or associated with deafness, imaging plus referral to a neurologist or otolaryngologist is advisable.6
Medications, and other factors to consider
Many different types of medications and substances can have ototoxic effects, mainly on the cochlear hair cells (TABLE 2).12 The damage may be reversible or irreversible. When doing so would be clinically prudent, consider tapering a patient off a drug that may be causing tinnitus.7
Other causes to consider. Pain in the jaw or neck may be due to a temporomandibular joint disorder or a cervical spine problem like whiplash; these conditions are associated with tinnitus and vertigo.7,13 The combination of low-pitched tinnitus, vertigo, aural fullness, and hearing loss often signifies Meniere’s disease—especially if symptoms are episodic.
Address mood disorders. Although insomnia, anxiety, depression, and posttraumatic stress disorder generally are not considered causes, these conditions are associated with tinnitus and can exacerbate the condition. Tinnitus can trigger depression, and vice versa. Optimizing treatment for these common problems can significantly reduce suffering.6,7
For most patients, you'll focus on prevention, rather than Tx
Treatment for tinnitus (which we’ll describe in a bit) is necessary only for patients for whom the condition has substantially affected the quality of their life.2 Greater emphasis should be placed on prevention.
Most tinnitus originates from the auditory system and is considered irreversible, but up to 25% of patients with chronic tinnitus report an increase in severity over time.14 Therefore, prevention can be beneficial not only for patients at risk of developing tinnitus, but also for those already affected by it. Prevention efforts should focus on protecting hearing by reducing noise levels and exposure time to certain noise thresholds.
The decibel (dB) scale is logarithmic; perception of sound loudness doubles every 10 dB. The sound of a vacuum cleaner is approximately 70 dB; the average human pain threshold is roughly 110 dB, which is the loudness of live rock music. Eardrum rupture occurs at approximately 150 dB—the equivalent of hearing a jet take off at 25 meters.