Objective

Vascular abnormalities: Arteriovenous malformation, glomus tumors, stenotic carotid artery, vascular loops, persistent stapedial artery, dehiscent jugular bulb, hypertension

Tympanic muscle disorders: Palatomyoclonus, idiopathic stapedial muscle spasm

Patulous eustachian tube

Central nervous system anomalies: Congenital stenosis of the sylvian aqueduct, type 1 Arnold-Chiari malformation

From Lucente FE, Har-El G: Essentials of Otolaryngology. Philadelphia, LippincottWilliams & Wilkins, 1999, p 110.

heard by the patient and the examiner. In most cases, tinnitus is secondary to bilateral sensorineural hearing loss and requires no further evaluation. In rare cases, tinnitus can be a symptom of a vascular abnormality (aneurysm or arteriovenous malformation), hypermetabolic state, or intracranial mass that, if not evaluated, could result in delayed treatment. Middle ear and rarely external ear pathology can also cause tinnitus, as can numerous medications (Box 19-2). The patient's medications should be reviewed.

Evaluation of tinnitus begins with a complete medical history, including duration of symptoms, possible inciting event (e.g., acoustic trauma), and accompanying symptoms (e.g., vertigo, hearing loss, headache, vision changes). Specific questions regarding the tinnitus are critical: Is it unilateral or bilateral? What is the quality of the tinnitus (pitch, volume)? Does it sound like a heartbeat or rushing blood? Does it change? A complete ENT evaluation should be performed, and audiometry is mandatory.

In general, if the tinnitus is bilateral, not particularly intrusive, not pulsatile, and associated with symmetric hearing loss, it is likely secondary to the hearing loss itself. The hearing loss requires further evaluation with magnetic resonance imaging (MRI) with contrast if it is asymmetric.

In cases of pulsatile tinnitus with normal otoscopy, magnetic resonance angiography (MRA) is performed to evaluate for vascular abnormalities. If otoscopy identifies a retrotym-panic mass, a temporal bone CT is obtained to evaluate for a vascular mass or abnormality. Blood tests can be performed to rule out anemia or hyperthyroidism, which can result in a hypermetabolic state and cause tinnitus secondary to increased blood flow near the cochlea. Auscultation of the neck, periauricular area, and chest may identify a bruit or murmur, indicating a need for a carotid duplex ultrasound study or echocardiogram, respectively. Most cases of arterial pulsatile tinnitus are secondary to atherosclerotic carotid artery disease. Venous pulsatile tinnitus often improves with digital pressure over the internal jugular vein. Etiologies include idiopathic venous hum, a high-riding jugular bulb, or benign intracranial hypertension.

Effective treatment of tinnitus is difficult and usually requires various approaches. Finding and eliminating potential causes (especially pharmaceutical) is imperative. Patients should be counseled to avoid caffeine and nicotine. No single medicine has been proved effective in treating tinnitus. Antidepressants have shown promise, especially if depression coexists. Intravenous lidocaine eliminates tinnitus in some patients but is not practical and has obvious potential side effects. Various homeopathic treatments and nutritional supplements are effective in some cases, but most have not been evaluated in controlled studies. Hearing aids are beneficial in masking the tinnitus if hearing loss exists. Tinnitus maskers can be purchased that essentially drown out the tinnitus with various distracting noises. Biofeedback and a technique called tinnitus retraining therapy are helpful for some patients. These techniques can be learned through various publications or at a tinnitus treatment center. All patients with obtrusive tinnitus are encouraged to join the American Tinnitus Association, the largest tinnitus support group and an excellent source of reliable information.

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