II./2.: Diseases of the tympanic membrane
How do tympanic membrane injuries originate?
Isolated diseases of the tympanic membrane are rare, their alterations are usually connected to the middle ear pathology, they will be discussed in the referring chapter. The examination of the tympanic membrane can be done with otoscopy but microscopic and endoscopic visualisations are also recommended.
Picture 1.: Intact Tympanic Membrane.
Injuries
Connection to the hearing diagnostics chapter
Most frequently, foreign body getting into the ear canal (e.g. cotton bud), or a hit on the ear (slap) can cause the rupture of the tympanic membrane. Pain, hearing loss, and tinnitus appear. A laurel or triangular shaped tear is visible on the tympanic membrane, which is usually accompanied by bleeding. In its examination audiological measurements are prior to differentiate conductive or neural origin of hearing loss. Mild conductive hearing loss is caused by isolated tympanic membrane injury, higher degree of conductive loss draws the attention to the rupture of the ossicular chain, while the perceptional hearing loss refers to the damage of the inner ear. Plain x-ray is recommended, e.g. Schüller.
Connection to the hearing rehabilitation chapter
Corrosive material e.g. acid, which gets into the ear canal, can reach the tympanic membrane. The tympanic membrane can be damaged during a skull-base fracture. In this case CT is necessary.
The perforation should be closed by a sterile cellophane sheet. To avoid infection per os antibiotics can be considered. Under the sheet the injury of the tympanic membrane heals from the edges. If the perforation is not closed or the ossicular chain is ruptured surgery (tympanoplasty) is necessary. The patient is not allowed to blow their nose (healing is slowed down by the air that is pressed to the tympanic cavity through the Eustachian tube), furthermore, water must not penetrate into the ear canal.
Isolated inflammation of the tympanic membrane (myringitis) In case of myringitis granulosa the skin of the tympanic membrane damages due to inflammation, then granulation tissue forming begins from this surface inducing excretion. Its treatment is silver nitrate on the granulation tissue, and use of antibiotics and local steroids.
Haemorrhagic bullous myringitis: it is a bleeding bulla triggered by viral infection (flu virus) on the upper dorsal part of the tympanic membrane. Its symptoms are severe ear pain, and the general symptoms of flu. The flu infection involves the middle ear mucosa, too. Bigger bullas can be opened sterile, antibiotics and pain killers are
also recommended.
Miliary tuberculosis: Nowadays it is a rarely seen TB manifestation, which leads to multiple tympanic membrane perforation.
