Balance or the ability of humans to remain upright is dependent on three sensory systems providing input to the brain. The principal source of this sensory input is vision, but also position sense organs within the limbs and joints and information from the inner ear. “Dizziness” or vertigo is defined as the illusion of movement. The person feels that they are moving or the environment is moving when no such movement is in fact taking place. There are many different causes for dizziness and a number of these do not include problems with the balance organs. Problems with blood pressure or the heart, fainting attacks and conditions affecting the brain can give rise to feelings of light-headiness. Classically, dizziness originating from the inner ear is rotational in nature although not always.
The balance organ is made up of three semi-circular canals and the vestibule, all of which are filled with liquid. The semi-circular canals sense rotation whereas the vestibule senses acceleration, deceleration and position. Many different factors can affect the inner ear and cause dizziness. If vertigo persists more than a few days, then review by an Ear, Nose and Throat (ENT) specialist may be considered. The ENT specialist will perform tests within the clinic and also organise investigations to determine the cause of the vertigo. The majority of patients who experiences episodes of vertigo will recover without any long-term ill effects, usually within a few weeks or months from the onset of the symptoms. The treatment can be medical, but may also include vestibular rehabilitation exercises, repositioning manoeuvres and, only very rarely, surgical intervention.
The ear is divided into three parts. The outer ear includes the structure we see on the side of the head with the ear canal down to the eardrum. The middle ear is behind the eardrum and includes the three little bones (malleus, incus and stapes) and connects to the mastoid cavity within the skull and anteriorly ventilates through the Eustachian tube, which opens to the back of the nose. The inner ear is embedded within the temporal bone of the skull and includes the cochlear responsible for hearing and the semi-circular canals and the vestibule responsible for balance.
Outer ear infections (otitis externa) are infections of the skin of the ear canal and are relatively common. The ear canal can become swollen and blocked with secretions, such that the hearing is reduced and there can be considerable pain. These sorts of infection are most commonly due to bacteria, but sometimes can be due to moulds. Treatment is usually in the form of antibiotic eardrops applied to the ear canal, but sometimes if the infection has spread more widely, antibiotics may also be given by mouth. If there is debris within the ear canal, this needs to be cleaned under the microscope as it would interfere with the application of eardrops. Very occasionally, the ENT specialist may place a little wick in the ear to allow eardrops to enter the deeper part of the ear canal.
Middle ear infections (acute otitis media) occur most commonly in children. They are characterised by severe earache, high temperature and association with hearing loss. Quite often, the eardrum will burst to release pus and the child receives relief, from pain, following this. Sometimes, the infection can spread backwards into the mastoid cavity and cause an infection of the bone, termed mastoiditis. Very rarely, these infections can spread upwards towards the brain. Most of these infections are treated with antibiotics. However, if they occur frequently then your ENT specialist may recommend that grommets be inserted into the eardrum (tiny ventilation tubes) until such time as the child grows out of the problem.
Inner ear infections are very rare, but can lead to dizziness (vertigo) usually with hearing loss. Anyone who develops a sudden hearing loss should seek the advice of their general practitioner and, in most cases, these patients should be referred promptly to an Ear, Nose and Throat specialist.
Glue ear is defined as non-infective fluid in the middle ear that persists for more than three months. This is a relatively common finding in children under the age of two years. Most of the time, this fluid causes no problems whatsoever, but in some patients can lead to hearing loss, repeated infections, balance problems or earache. It is common for most people to have fluid in the middle ear, following “colds” and “flus”, but if this fluid persists and causes some of the symptoms described above, then further investigation and management may be necessary. In most cases, this may simply mean a period of observation, sometimes medical treatment and occasionally, insertion of a grommet into the eardrum. Grommets are tiny little tubes that are placed in the eardrum usually under a general anaesthetic and allow the fluid in the middle ear to drain away. This usually restores hearing and can also reduce potential complications from recurrent infections in the middle ear.
In adult patients who have persistent fluid behind one eardrum, the postnasal space must be examined to rule out any obstructive masses impacting on drainage of the middle ear (i.e. adenoids) through the Eustachian tube. Persistent fluid in one middle ear in an adult can on rare occasions be due to tumours in the back of the nose.
Tinnitus is defined as a condition where a person perceives noises in the ear that do not have an external source. The nature of this sound can be a high pitched whistling, ringing or a white noise effect. Most people will experience tinnitus from time to time, but this is usually transient or evident only in a very quiet environment.
Tinnitus is often linked with a hearing loss which is associated with loss of hair cells in the inner ear (sensorineural hearing loss). Certain drugs can precipitate tinnitus and tinnitus is also associated with medical problems such as Meniere’s disease. In most cases, tinnitus is benign and does not represent an underlying disease process. Tinnitus affecting one ear (unilateral tinnitus) does however require further investigations and patients are usually referred to an ENT specialist. Once tinnitus has been diagnosed as benign, it is most commonly managed by tinnitus counselling, where patients are taught to understand and control this symptom in their daily life. Other measures include the use of mechanical devices, such as hearing aids or white noise generators to mask the noise in the inner ear.
Hearing loss can affect any age group. In children it is most commonly due to fluid behind the eardrum (glue ear) or is a congenital problem. Hearing loss is also common in the older age group and this group is a part of the normal aging process. Occasionally, hearing loss can be due to viral illnesses or vascular diseases involving the inner ears.
ENT specialists divide hearing loss into two broad types:
Conductive hearing loss occurs when there is failure of the transmission of sound on its path down the ear canal, through the eardrum, vibrating the middle ear bones and then transmitting the sound to the fluid in the cochlear (inner ear). Anything that impedes the passage of this sound energy may cause a conductive hearing loss. It can be due to wax in the ear canal, damaged eardrum, fluid in the middle ear or scarring or fixation of the bones in the middle ear.
The other sort of hearing loss is referred to as sensorineural hearing loss and this relates to problems in the inner ear or the nerve that carries a signal from the inner ear to the hearing centres in the brainstem. Again, there are many causes. In the older population, this tends to be related to the normal degeneration of the hair cells in the cochlear, called presbycusis. This age related hearing loss affects principally the higher frequencies and can be associated with noises in the ear that do not have an external source (tinnitus). The inner ear can also be damaged by infections, excessive noise exposure or trauma to the ear drum, such as explosions or other loud noises. Certain drugs can also irreversibly damage the inner ear. Sometimes, patients can develop sensorineural hearing loss at a younger age and there is usually a family history of early hearing loss. Very rarely is hearing loss due to tumours in the inner ear or the brain.
Any patient with a sudden hearing loss should urgently see their General Practitioner (GP), even if it is only affecting one ear. After confirming the diagnosis the GP will usually refer the patient on to an ENT specialist. In such circumstances, if the hearing is to be saved then treatment should be commenced within the first day or two of onset of this hearing loss. Often a scan of the ear and adjacent brain is indicated.
The eardrum or tympanic membrane is a thin sheet of tissue that lies at the bottom of the ear canal and separates the outer ear from the middle ear. A perforation in the eardrum can result from trauma or as a part of an infection or disease process in the middle ear. In most cases, traumatic perforations will heal spontaneously, providing there was no infection and the ear is kept dry. An operation designed to repair a perforated eardrum is called a myringoplasty. Often, the reason for performing this operation is to prevent water entering the middle ear and causing repeated ear infections. This particular surgery is not necessarily designed to restore the hearing, but will allow an assessment to be made of the bones in the middle ear and, if indicated, an additional procedure may be performed to assist with the hearing loss. Myringoplasties are usually performed under general anaesthesia and a cut is made either at the top of the ear canal or behind the ear. The eardrum is elevated and a ‘patch’ of tissue is placed under the perforation, the eardrum is replaced and a dressing is then placed in the ear canal. The ‘patch’ of tissue is usually obtained from tissue found within the incision behind the ear.
The ear canal and the outside of the eardrum are lined with skin. There is no skin in the middle ear cavity. Sometimes, a longstanding retraction of the eardrum will allow skin and debris to accumulate within it. This accumulated skin can then grow backwards into the middle ear. This slow growing ‘sack’ of skin is called a cholesteatoma, and it can lead to infections and an offensive discharge from the ear. If a cholesteatoma is left untreated, it can destroy the hearing, it sometimes affects the balance, but may also damage the nerve that moves the side of the face (the facial nerve). Surgery to remove cholesteatoma is usually approached through an incision behind the ear and drilling of the mastoid, which is the sponge-like bone behind the ear canal into which the cholesteatoma often grows. After the cholesteatoma is removed, the surgeon may need to graft the eardrum to repair the hole that is usually present and place some temporary dressings in the ear canal at the end of the surgery. There are many variations of the mastoid operation, which your surgeon will discuss with you, and he or she will also discuss any potential risks of the surgery.
