ear, nose, and throat disorders
Tinnitus
Evaluation of Tinnitus
History of present illnessshould note duration of tinnitus, whether it is in one or both ears, and whether it is a constant tone or intermittent. If intermittent, the clinician should determine whether it is regular and whether it is about the rate of the pulse or sporadic. Any exacerbating or relieving factors (eg, swallowing, head position) should be noted. Important associated symptoms include hearing loss, vertigo, ear pain, and ear discharge. Review of systemsshould seek symptoms of possible causes, including diplopia and difficulty swallowing or speaking (lesions of the brain stem) and focal weakness and sensory changes (peripheral nerve disorders, including dysfunction of the 8th cranial nerve). The impact of the tinnitus on the patient also should be assessed. Whether the tinnitus is sufficiently distressing to cause significant anxiety, depression, or sleeplessness should be noted. Past medical historyshould ask about risk factors for tinnitus, including exposure to loud noise, sudden pressure change (from diving or air travel), history of ear or central nervous system infections or trauma, radiation therapy to the head, and recent major weight loss (risk of eustachian dysfunction). Drug use should be ascertained, particularly any salicylates, aminoglycosides, or loop diuretics. Physical examination focuses on the ear and the nervous system. The ear canal should be inspected for discharge, foreign body, and cerumen. The tympanic membrane should be inspected for signs of acute infection (eg, redness, bulging), chronic infection (eg, perforation, cholesteatoma), and tumor (red or bluish mass). A Physical examination should be done, including Cranial nerves, particularly vestibular function (see Dizziness and Vertigo ), are tested along with peripheral strength, sensation, and reflexes. A stethoscope is used to listen for vascular noise over the course of the carotid arteries and jugular veins and over and adjacent to the ear. The following findings are of particular concern: Bruit, particularly over the ear or skull Accompanying neurologic symptoms or signs (other than hearing loss) Unilateral tinnitus In some cases, tinnitus may indicate retrocochlear pathology, such as an Vestibular Schwannoma (benign but invasive tumor originating from the vestibular portion of the 8th cranial nerve in the internal auditory canal). It is important to note whether the tinnitus is unilateral because vestibular schwannomas may manifest only with unilateral tinnitus. This diagnosis is more likely if there is also unilateral sensorineural hearing loss or asymmetric hearing loss with worse hearing in the ear with tinnitus. It also is important to distinguish the uncommon cases of objective tinnitus from the more common cases of subjective tinnitus. Tinnitus that is pulsatile or intermittent is almost always objective (although not always detectable by the examiner), as is that associated with a bruit. Pulsatile tinnitus is nearly always benign. Continuous tinnitus is usually subjective (except perhaps for that caused by a venous hum, which may be identified by presence of a bruit and often by a change in tinnitus with head rotation or jugular vein compression). Specific causes can often be suspected by findings on examination (see table). In particular, exposure to loud noise, barotrauma, or certain drugs before onset suggests those factors as the cause. All patients with tinnitus should be referred for comprehensive audiologic evaluation to determine the presence, degree, and type of Hearing Loss . In patients with unilateral tinnitus and hearing loss, vestibular schwannoma should be ruled out by gadolinium-enhanced MRI. In patients with unilateral tinnitus and normal hearing and physical examination, MRI is not necessary unless tinnitus persists>6 months. Other testing depends on patient presentation (see table). Patients with visible evidence of a vascular tumor in the middle ear require CT, gadolinium-enhanced MRI, and referral to a subspecialist if the diagnosis is confirmed. Patients with pulsatile, objective tinnitus and no ear abnormalities on examination or audiology require further investigation of the vascular system (carotid, vertebral, and intracranial vessels). The usual test sequence is to begin with CT angiography (CTA). However, because CTA is not very sensitive for dural AVMs, many clinicians then consider doing an MR angiogram or conventional arteriogram. Because dural AVMs are rare, the significant risks of arteriography must be weighed against the potential benefit of diagnosis and treatment (with embolization) of this vascular anomaly. Patients who report hearing clicking sounds in one or both ears should be evaluated for the presence of objective tinnitus. This evaluation may be done by auscultation using a stethoscope or with tympanometry to identify clonus of the tensor tympani, stapedius, and/or palatal muscles. Palatal myoclonus should be visible on physical exam of the oral cavity. 