Mastoiditis describes inflammation of the mastoid, the triangular protrusion of the base of the temporal bone, located behind the ear. Mastoiditis usually occurs when an ear infection is not or poorly treated: the infection then spreads from the middle ear to the mastoid. It is one of the most common complications of acute otitis media in children under two years of age. Left untreated, it can have serious consequences such as deafness or sepsis.

Definition of mastoiditis

Mastoiditis describes inflammation of the mastoid. The mastoid is the triangular protruding part of the base of the temporal bone, located behind the ear. It acts as a resonator thanks to its cavities, or cells, filled with air.

Mastoiditis usually occurs when an ear infection is not or poorly treated: the infection then spreads from the middle ear to the mastoid. Before the advent of antibiotics, mastoiditis was one of the leading causes of death in children.

Types of mastoiditis

Two forms of mastoiditis can be distinguished:

• Chronic mastoiditis;
• Acute mastoiditis: masked mastoiditis, or decapitated mastoiditis, and externalized mastoiditis.

Causes of mastoiditis

Chronic mastoiditis is caused by chronic otitis, which lasts over time.

Most acute mastoiditis is caused by pneumococcal bacteria. But other germs can be involved: the pyocyanic bacillus (Pseudomonas aeruginosa), Haemophilus influenzae, Proteus mirabilis and other anaerobic germs.

Externalized mastoiditis is a complication of acute otitis media.

Masked mastoiditis develops during otitis for which the antibiotic treatment is poorly adapted. Rare, it is sometimes difficult to diagnose because the eardrum remains normal.

Diagnosis of mastoiditis

The patient’s symptoms are the first diagnosis of mastoiditis by the attending physician.

A bacteriological sample associated with an antibiogram then makes it possible to identify the bacteria causing the infection and to determine the appropriate antibiotic.

Other examinations can be performed to complete the diagnosis:

• A CT scan of the lateral part of the skull just at the level of the ear;
• An otoscopy (visualization of the eardrum and the external auditory canal) to look for the causal otitis.

People affected by mastoiditis

With approximately one case in 25, mastoiditis is one of the most common complications of acute otitis media in children under two years of age.

Factors favoring mastoiditis

The main factor favoring mastoiditis is the late management of acute otitis media.

Otalgie

Symptoms of a mastoid appear a few days to a few weeks after acute otitis media. The spread of infection to the mastoid destroys its internal part and can cause persistent, shooting pain (earache) in and around the ear.

Otorrhée

With mastoiditis, a lump of pus can form in the bone, causing a large, thick discharge from the external ear canal (otorrhea).

Swelling behind the ear

When inflamed, the skin covering the mastoid may turn red, swell, and become painful. The outer ear is pushed down laterally.

Hearing loss

Mastoiditis causes hearing loss that can progressively worsen until hearing loss.

Other symptoms

• High fever;
• Chills;
• Headache;
• Postauricular redness, subcutaneous abscess;
• Facial paralysis;
• Detachment of the pinna from the ear;
• Neurological signs;
• Sepsis;
• Meningitis;
• Brain abscess;
• Dead.

When caught early enough, mastoiditis can be treated with oral or intravenous antibiotics.

The bacteriological sample associated with an antibiogram then makes it possible to orient the rest of the treatment:

• Continuation of antibiotics for at least two weeks;
• Hospitalization for a few days for follow-up.

If an abscess forms in the bone, surgery, performed under general anesthesia, may be necessary:

• Paracentesis or puncture of secretions accumulated in the middle ear;
• Installation of a transtympanic aerator to facilitate the evacuation of secretions;
• Mastoidectomy (removal of part of the mastoid) and surgical drainage.

The best ways to prevent mastoiditis are to:

• Provide early treatment and close follow-up for acute otitis media;
• Vaccinate against pneumococcus.