Otology is the study of diseases of the ear. This includes hearing, balance, the temporal bone and related structures.
The ear consists of an outer ear, middle ear and inner ear.
The outer ear consists of the auricle (or pinna) and the external ear canal. It collects sound energy and concentrates it on the ear drum.
The middle ear lies between the ear drum and inner ear. It is filled with air and is ventilated by the Eustachian tube. It has three bones or ossicles (the malleus, incus and stapes) that transmit the sound energy from the ear drum to the cochlea.
The inner ear (labyrinth) consists of the cochlea (hearing part) in front and the vestibule with semicircular canals (balance part) at the back.
The two main types of hearing loss are 1. Conductive hearing loss and 2. Sensorineural hearing loss. Conductive hearing loss occurs due to interference of sound energy transmission from the outer ear, ear drum through the ossicles up to the cochlea. Otosclerosis is a condition where the stapes gets fixed in its bony window on the cochlea.
Sensorineural hearing loss is caused by damage to the cochlea and/or nerve to the brain. It might be due to ageing or noise exposure or more serious diseases.
Vertigo is a sensation of spinning dizziness. It is often associated with nausea, vomiting and sweating. Vertigo is a symptom of a range of conditions. It can happen when there is a problem with the inner ear, brain or sensory nerve pathways.
The three most common inner ear causes are
1. Ménière’s disease, 2. Benign paroxysmal positional vertigo (BPPV) and 3. Vestibular neuritis.
Ménière’s disease is a buildup of fluid in the inner ear, which leads to episodes of hearing loss, vertigo and tinnitus. It usually lasts days to weeks.
Benign paroxysmal positional vertigo is where calcium carbonate crystals become dislodged from the otolith organs and fall into the semicircular canals. This causes vertigo during certain head movements. The vertigo is only for a few seconds, until the crystals settle down.
Vestibular neuritis is a viral inflammation of the balance nerve. This causes vertigo without any hearing symptoms. Symptoms usually last for weeks.
Infections can occur in the outer, middle or inner ear.
Outer ear infections, like Swimmers ear, often occur after swimming or fiddling with ear buds in ears. A blocked ear, pain and a discharge are the most common symptoms.
Middle ear infections or otitis media is frequent in children. A buildup of pus/ fluid behind the ear causes extreme pain and fever. When the eardrum ruptures a bloody or pus like discharge appear, with improvement in pain and fever. Eardrum perforation with longstanding infection is often a complication of acute otitis media. Skin from the outer ear canal can sometimes grow into the middle ear cavity, causing a condition known as cholesteatoma. This is a slow progressive disease with bone destruction and infection. This is one of the ear conditions that need to be managed surgically.
Inner ear infections or labyrinthitis cause hearing and balance symptoms. Infections are usually viral but may be secondary to bacterial middle ear infections.
Tinnitus is a noise (ringing, buzzing or pulsation) in one or both ears. It may be constant or intermittent. It affects 15-20% of people. It is usually a symptom of an underlying condition, like sensorineural hearing loss. Although troublesome it is usually (not always) not due to something serious. It needs to be accessed by an Otologist or Ear, nose and throat specialist.
Several tumors can develop in the external ear, middle ear or even in the inner ear and nerves. Since the ear is part of the skull base, skull base tumors like Glomus tumors affect the ear. Acoustic neuromas (vestibular Schwannomas) are noncancerous (benign) tumors that grow in the balance (vestibular) nerve. Symptoms of ear tumors might be hearing loss, vertigo, pain, bleeding from the ear or tinnitus (pulsating in glomus).