Ear infections – better health channel feeling of fluid in ear

The ear is made up of three parts. The outer ear includes the part you can see and the canal that leads to the eardrum. The middle ear is separated from the outer ear by the eardrum and contains tiny bones that amplify sound. The inner ear is where sounds are translated to electrical impulses and sent to the brain.

Any of these three parts can become infected by bacteria, fungi or viruses. Children are particularly prone to middle ear infections (otitis media). It is estimated that around four out of five children will experience a middle ear infection at least once.

The ear is connected to the back of the nose via the Eustachian tube. This tube equalises air pressure inside the ear, and funnels secretions from the middle ear into the throat. The walls of the Eustachian tube lie flat against each other to prevent the migration of bacteria or other germs into the ear from the nose and throat.

Whenever we swallow, a small muscle flexes and opens the tube, allowing air pressure equalisation and the drainage of secretions. If the Eustachian tube is blocked, secretions and associated bacteria build up inside the middle ear. This can cause ear infections, mild deafness and an increased likelihood of a ruptured eardrum.

Otitis externa is an infection or inflammation of the ear canal between the eardrum and the outer ear. It can be triggered by exposure to dirty water or by mechanical damage due to overzealous cleaning. The infectious agent can be either fungal or bacterial.

Otitis media is an infection of the middle ear, which can be either acute or chronic. Children are most commonly affected by acute otitis media because it is caused by colds and blocked Eustachian tubes – both typical ailments of childhood. The infectious agent can be either viral or bacterial, with research suggesting that viruses are responsible for most cases.

Serous otitis media is known as glue ear. Children aged between six months and two years of age are most vulnerable to this type of ear infection. Glue ear commonly develops after a middle ear infection, and is characterised by the build-up of fluid and pus within the middle ear. Treatment options include antibiotics.

Infectious myringitis is inflammation of the eardrum, caused by infection from either viruses or bacteria. The eardrum responds to the inflammation by forming small blisters. This can be quite painful. If fever is present, the infectious agent is almost certainly bacterial.

The bone that can be felt immediately behind the ear is called the mastoid. Acute mastoiditis is infection of this bone, caused by prior acute otitis media. The symptoms include reddened and swollen skin over the mastoid, fever, discharge from the ear and intense pain.

The inner ear contains the organs of balance – the vestibular system. It includes three fluid-filled loops (semi-circular canals) which respond to the rotation of the head. Near the semicircular canals are the utricle and saccule, which detect gravity and back-and-forth motion. When the head is moved, signals from these organs are sent via the vestibular nerve to the brain where it is processed

Vestibular neuronitis is inflammation of the vestibular nerve, probably caused by a viral infection. The main symptom is sudden and dramatic vertigo, which may be accompanied by nausea and vomiting. The eyes may also involuntarily flutter towards the affected side of the head.

Sound is sent as electrical impulses to the brain via the cochlear nerve. Herpes zoster of the ear is an infection of this auditory nerve by the herpes zoster virus. Symptoms include ear pain, vertigo, and small blisters on the outer ear and ear canal and perhaps on the face and neck.