Tinnitus

( from the Latin word tinnītus meaning "ringing") is the perception of sound within the ear in the absence of corresponding external sound. http://en.wikipedia.org/wiki/Tinnitus

Clinical explanation: Tinnitus is not a disease, but a symptom that can result from a wide range of underlying causes.The exact physiological cause or causes of tinnitus are not known. There are, however, several likely sources, all of which are known to trigger or worsen tinnitus.

Noise exposure - Exposure to loud noises can damage and even destroy hair cells, called cilia, in the inner ear. Once damaged, these hair cells cannot be renewed or replaced.
Head and neck trauma - Physical trauma to the head and neck can induce tinnitus. Other symptoms include headaches, vertigo, and memory loss.
Certain disorders, such as hypo- or hyperthyroidism, Lyme disease, fibromyalgia, and thoracic outlet syndrome, can have tinnitus as a symptom. When tinnitus is a symptom of another disorder, treating the disorder can help alleviate the tinnitus.
Certain types of tumors
Wax build-up
Jaw misalignment
Cardiovascular disease
Ototoxicity - Some medications are ototoxic, that is, the medications are toxic to the ear. Other medications will produce tinnitus as a side effect without damaging the inner ear. Effects, which can depend on the dosage of the medication, can be temporary or permanent. Before taking any medication, make sure that your prescribing physician is aware of your tinnitus, and discuss alternative medications that may be available. There are some websites that provide information on drug interactions. Two popular resources for this are Drugwatch.com and the Physicians Desktop Reference websites.
Pulsatile tinnitus - Rare type of tinnitus that sounds like a rhythmic pulsing in the ear, typically in time with one's heartbeat.

This kind of tinnitus can be caused by abnormal blood flow in arteries or veins close to the inner ear, brain tumors or irregularities in brain structure. Abnormally loud sounds in the ear canal for even the briefest period (but usually with some duration) , ear infections, foreign objects in the ear including, nasal allergies that prevent (or induce) fluid drain, or wax build-up. Withdrawal from a benzodiazepine addiction may cause tinnitus as well. In-ear headphones, whose sound enters directly into the ear canal without any opportunity to be deflected or absorbed elsewhere, is a common cause of tinnitus when volume is set beyond moderate levels. Tinnitus can also be caused by natural hearing impairment (as is often seen in aging), as a side effect of some medications, and as a side effect of genetic (congenital) hearing loss. However, the most common cause is noise-induced hearing loss. http://en.wikipedia.org/wiki/Tinnitus

Please visit the American Tinnitus Association's web page for more detailed information and patient tips