Infectious processes may involve the outer ear, middle ear (behind the ear drum), or the inner ear. These processes may present with pain, drainage, a plugged ear sensation, decreased hearing or dizziness. In each case, accurate diagnosis is based first on history and physical exam. Where children are concerned, a physical exam is taken on with care to decrease the stress or discomfort that it may elicit. Other means of diagnosis include an examination of the microscope and imaging studies such as CT scan.
External ear infections are often managed with medication and surgery is rarely required. Other conditions, such as diabetes, may complicate ear canal infections and are considered seriously in the management of these infections.
Middle ear infections involve the cavity behind the eardrum. They may result from dysfunction of the Eustachian Tube. This is the passage that connects the ear to the nose, the tube that one insufflates when blowing against a closed nose and closed mouth on an airplane. Through the opening of the Eustachian tube during swallowing, air escapes from the nose into the ear and air pressure is equalized. Because the eustachian tube is short and relatively horizontal in young children, ear infections and fluid retention in the middle ear is most common in this age group. As we age, the eustachian tube grows longer and becomes more vertically oriented, making these problems less likely. Middle ear infections and fluid may also occur in association with upper respiratory infections because the opening of the Eustachian tube into the back of the nose becomes swollen. For similar reasons, the doctor must also consider management of allergy and the adenoids, which sit in the back of the nose adjacent to the Eustachian tube opening.
With repeated infections, especially in children, one must consider placement of tubes in the eardrums and perhaps the removal of the adenoids. Eardrum tubes essentially perform the same function as the Eustachian tube in allowing air pressure to equalize between the outside world and the middle ear. They also allow drainage of fluid from the middle ear.
Sometimes non-infected fluid or mucus may persist behind the eardrum in the middle ear for long after the infection has been cleared. This fluid dampens the transmission of sound from the outside world into the inner ear, resulting in muffled hearing. In children, this hearing loss may contribute to speech delays and difficulty in progressing in school. In these cases, attempts are made optimise Eustachian tube function such that the fluid may clear. If this fails, eardrum tubes may be necessary.
In cases of long-standing inflammation and infection of the middle ear, the eardrum may become pulled into the middle ear - a “retraction pocket” of the eardrum forms. A collection of dead skin within this retraction pocket may form an enlarging mass called a cholesteatoma; this can enlarge over time and destroy middle structures. This requires intensive management.
Inner ear infections are thankfully rare. However, they may result in severe dizziness and loss of hearing. These are often emergent issues that may require involving colleagues who specialize in the management of the inner ear.