The inner ear is responsible for transforming these mechanical vibrations into electrical signals. These signals are then sent to the auditory nerve, which connects directly to the brain. When these nerve impulses reach the brain, they are interpreted as sound.

The Eustachian Tube

• For the middle ear to function optimally, the pressure within it needs to be the same as the air pressure in the external environment. This pressure regulation is the role of the Eustachian tube, a small passage connecting the middle ear to the nasopharynx, the upper part of the throat behind the nose.
• By allowing air to enter the middle ear, the Eustachian tube ensures that the air pressure inside matches the air pressure outside. You might experience this equalization as a “popping” sensation in your ears when you yawn or swallow; this indicates that the Eustachian tubes are actively adjusting the air pressure in your middle ears. The Eustachian tube also serves as a drainage pathway, allowing mucus and other debris to move from the middle ear into the throat.
• Sometimes, the Eustachian tube can become blocked or fail to work properly. This can happen during a cold or an allergy, where inflammation and swelling can thicken the lining of the Eustachian tube or lead to a buildup of mucus within it. This blockage traps fluid within the normally air-filled middle ear.
• Otitis media often develops as a consequence of Eustachian tube dysfunction.
• The Eustachian tube, connecting the middle ear to the nasopharynx, is typically closed, narrow, and angled downwards. This configuration usually prevents microorganisms from the pharyngeal cavity from entering the middle ear space.
• It opens intermittently to allow for the drainage of normal secretions produced by the middle ear lining and to equalize the air pressure between the middle ear and the external environment.
• When drainage is impaired due to a blocked Eustachian tube, a pathological condition arises because secretions become trapped within the middle ear.

Diagnosis/Investigations

• History taking: Gathering information about the patient’s symptoms and medical history.

• Pus swab for microscopy, culture and sensitivity: If there is ear discharge, a sample can be taken to identify the specific bacteria causing the infection and determine the most effective antibiotics.

• Physical examination of the ear using Otoscope: A visual inspection of the ear canal and eardrum is crucial for diagnosis.

To perform the ear examination, an otoscope is utilized. This handheld device, similar in appearance to a small flashlight, is equipped with a magnifying lens and a light source at its tip. It allows healthcare professionals to visualize the internal structures of the ear.

Other tests or investigations that may be performed include:

1. Tympanometry: This test assesses the movement and flexibility of the eardrum in response to changes in air pressure within the ear canal. A healthy eardrum should move freely when the air pressure changes. During the test, a probe is gently inserted into the ear canal, and it changes the air pressure at regular intervals while also emitting a sound into the ear. The probe measures how much sound is reflected back from the eardrum and how changes in air pressure affect these sound reflections. If less sound is reflected back when the air pressure is high, it often suggests the presence of fluid or infection in the middle ear.

2. A computer tomography (CT) scan: This imaging technique might be employed if there’s a concern that the infection has spread beyond the middle ear. A CT scan utilizes X-rays taken from multiple angles and a computer to create detailed cross-sectional images of the skull.

3. Tympanocentesis: This procedure involves using a small needle to withdraw fluid from the middle ear. The collected fluid can then be sent to a laboratory to identify the specific bacteria or viruses responsible for the infection.

Management

1. Amoxicillin is typically the first-line antibiotic prescribed for otitis media.

2. For patients with a confirmed penicillin allergy, trimethoprim-sulfamethoxazole is often used as an alternative.

3. Second-line antibiotics that may be considered if the initial treatment is ineffective or if there are specific circumstances include:

   • Amoxicillin/clavulanate

   • Ampicillin/sulbactam

   • A cephalosporin antibiotic

4. Children under the age of 2 years are considered to be at a higher risk for experiencing repeated episodes of otitis media, developing chronic otitis media, and having serious complications from the infection.

5. Antibiotics may be prescribed as follows: For adults, capsules of Amoxicillin 500mg four times a day (QID) for 5 days. For children, the dosage is typically 15mg per kilogram of body weight.

6. Erythromycin tablets 500mg four times a day (QID) for 5 days can be used in adults who have an allergy to penicillin antibiotics.

7. Analgesics (pain relievers) are often recommended to manage pain associated with otitis media. Examples include: Paracetamol 1 gram three times a day (tds) for 3 days, OR Ibuprofen tablets 400mg three times a day (tds) for 3 days.

8. Topical antibiotic ear drops, such as Gentamicin, can be applied directly into the ear canal. The usual application is 2 drops three times a day (tds) for 5 days, typically after gently cleaning any discharge from the ear (ear wicking).

9. A follow-up review is usually scheduled after 5 days of treatment. If the eardrum is still inflamed (red), the treatment regimen may be repeated.

Surgical Management

1. Grommets: For children who experience frequent and severe middle ear infections, small tubes, known as grommets or tympanostomy tubes, can be surgically inserted into the eardrum. These tubes help to drain fluid from the middle ear and ventilate the space.

2. Myringotomy: This is a surgical procedure where the surgeon makes a tiny incision in the eardrum. This can help to relieve pressure within the middle ear and allows for the drainage of excess fluid. In some instances, a myringotomy is followed by the insertion of a grommet.

3. Tympanotomy: This surgical procedure involves creating a surgical opening in the eardrum, also known as the tympanic membrane. The purpose is to facilitate the drainage of infected fluid from the middle ear. Surgical tubes may be implanted into the eardrum to provide ongoing drainage. This procedure might be considered when there is scarring or minimal damage to the eardrum, or in cases of deafness or hearing impairment.

4. Myringoplasty: This surgical procedure aims to repair a hole or perforation in the eardrum. The repair is achieved by placing a graft over the perforation. The graft material can be a small piece of tissue taken from another part of the patient’s body or a specially designed gel-like material.

5. Tympanoplasty: This more extensive surgical procedure involves the repair of damaged ossicles, the tiny bones in the middle ear. This may involve replacing the damaged ossicles with a small piece of bone or a prosthetic device.