Acute Otitis Media
Acute otitis media, acute inflammation of the middle-ear cavity, is a common condition and is frequently bilateral. It occurs most commonly in children and it is important that it is managed with care to prevent subsequent complications.
It most commonly follows an acute upper respiratory tract infection and may be viral or bacterial. Unless the ear discharges pus from which an organism is cultured it is impossible to decide one way or the other.
Acute otitis media is an infection of the mucous membrane of the whole of the middle-ear cleft—Eustachian tube, tympanic cavity, attic, aditus, mastoid antrum and air cells. The bacteria responsible for acute otitis media are: Streptococcus pneumoniae 35%, Haemophilus influenzae 25%, Moraxella catarrhalis 15%. Group A streptococci and Staphylococcus aureus may also be responsible.
The sequence of events in acute otitis media is as follows:
- organisms invade the mucous membrane causing inflammation, oedema, exudate and later, pus;
- oedema closes the Eustachian tube, preventing aeration and drainage;
- pressure from the pus rises, causing the drum to bulge;
- necrosis of the tympanic membrane results in perforation;
- the ear continues to drain until the infection resolves.
Causes of Acute Otitis Media are,
- Common cold
- Acute tonsillitis
- Coryza of measles, scarlet fever
- whooping cough
- Trauma to the tympanic membrane
- Barotrauma (air flight)
- Temporal bone fracture
Earache may be slight in a mild case, but more usually it is throbbing and severe. The child may cry and scream inconsolably until the ear perforates, the pain is relieved and peace is restored.
Deafness is always present in acute otitis media. It is conductive in nature and may be accompanied by tinnitus. In an adult, the deafness or tinnitus may be the first complaint.
The child is flushed and ill. The temperature may be as high as 40°C.
There is usually some tenderness to pressure on the mastoid antrum.
Changes in tympanic membrane
The tympanic membrane varies in appearancenaccording to the stage of the infection.
- Loss of lustre and break-up of the light reflex.
- Injection of the small vessels around the periphery and along the handle of the malleus.
- Redness and fullness of the drum; the malleus handle becomes more vertical.
- Bulging, with loss of landmarks. Purple colour. Outer layer may desquamate, causing blood-stained serous discharge. Early necrosis may be recognized, heralding imminent perforation.
- Perforation with otorrhoea, which will often be blood-stained. Profuse and mucoid at first, later becoming thick and yellow.
Mucoid discharge from an ear must mean that there is a perforation of the tympanic membrane. There are no mucous glands in the external canal.
The treatment depends on the stage reached by the infection.The following stages may be considered: early, bulging and discharging.
Penicillin remains the drug of choice in most cases, and ideally should be given initially by injection followed by oral medication. In children under 5 years, when Haemophilus influenzae is likely to be present, amoxycillin will be more effective, and should always be considered if there is not a rapid response to penicillin. Co-amoxiclav is useful in Moraxella infections. Be guided by sensitivity reports from the laboratory.
Simple analgesics, such as aspirin or paracetamol, should suffice. Avoid the use of aspirin in children because of the risk of Reye’s syndrome.
- Nasal vasoconstrictors
The role of 0.5% ephedrine nasal drops is traditional but its value is uncertain in the presence of acute inflammation of the middle ear.
- Ear drops
Ear drops are of no value in acute otitis media with an intact drum. Especially illogical is the use of drops containing local anaesthetics, which can have no effect on the middle-ear mucosa yet may cause a sensitivity reaction in the meatal skin.
Myringotomy is necessary when bulging of the tympanic membrane persists, despite adequate antibiotic therapy. It should be carried out under general anaesthesia in theatre and a large incision in the membrane should be made to allow the ear to drain. Pus should be sent for bacteriological assessment.
Following myringotomy, the ear will discharge and the outer meatus
should be dry-mopped regularly.
If the ear is already discharging when the patient is first seen, a swab should be sent for culture of the organism. Antibiotic therapy should be started but modified if necessary when the result