Suppurative otitis media (SOM) is an infection of the air-filled space behind the eardrum, known as the middle ear cavity. The term “suppurative” refers to the presence of pus, which is a collection of dead white blood cells, bacteria, and tissue debris. This condition represents a progression from simple middle ear fluid buildup to an active bacterial infection.
The Mechanism: Causes and Pathogenesis
The development of SOM typically begins with dysfunction of the Eustachian tube, the canal connecting the middle ear to the back of the nose and throat. This tube equalizes pressure and drains secretions from the middle ear space. When an upper respiratory infection, often viral, causes swelling, the Eustachian tube becomes blocked, trapping fluid within the middle ear.
This trapped fluid, known as an effusion, allows bacteria to multiply, leading to the formation of pus (suppuration). Bacteria commonly migrate from the nasopharynx through the compromised Eustachian tube. In acute cases, the primary culprits are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.
Bacterial colonization leads to a rapid inflammatory response, increasing fluid volume and pressure behind the eardrum. If the infection becomes chronic, lasting more than six weeks, the microbial profile often shifts to include organisms such as Pseudomonas aeruginosa and Staphylococcus aureus.
Recognizing the Signs and Symptoms
The onset of SOM is marked by intense ear pain (otalgia), caused by substantial pressure from pus accumulation against the eardrum (tympanic membrane). Patients often experience fever, and children may show irritability, difficulty sleeping, or loss of balance.
A conductive hearing loss is common, resulting from the fluid-filled middle ear hindering the vibration of the tiny bones that transmit sound. The most distinct sign of a suppurative infection is otorrhea—the discharge of purulent fluid from the ear canal. This discharge occurs when extreme pressure causes the eardrum to spontaneously tear or perforate.
In acute SOM, pain is severe until the eardrum perforates and relieves the pressure, after which the pain subsides. Chronic SOM often presents with persistent, long-term otorrhea through a non-healing perforation, and pain may be minimal or absent. Infants may only show non-specific signs like tugging at the ear or unusual fussiness.
Medical Management and Treatment Pathways
Diagnosis begins with a clinical examination using an otoscope to inspect the eardrum. Providers look for signs of inflammation, such as redness, bulging, and limited mobility, indicating fluid buildup. Tympanometry, which measures eardrum movement in response to air pressure, can also confirm the presence of middle ear effusion.
The standard treatment for confirmed bacterial SOM is antibiotic therapy. Amoxicillin is commonly prescribed as a first-line treatment, but high-dose amoxicillin-clavulanate may be used for resistant infections. For cases involving a perforated or draining ear, topical antibiotic drops, such as fluoroquinolones, are preferred to deliver medication directly to the infection site.
Pain management is an integral part of the initial treatment, utilizing analgesics like acetaminophen or ibuprofen to alleviate earache and reduce fever.
If the infection is recurrent or fails to clear after multiple antibiotic courses, a surgical procedure called a myringotomy may be necessary. This involves a small incision in the eardrum to drain pus and relieve pressure.
Tympanostomy Tubes
Sometimes, a tiny tube is placed through the incision to ventilate the middle ear space for a prolonged period. These tympanostomy tubes allow air to enter, preventing future fluid accumulation and reducing recurring infections. Follow-up appointments monitor the infection’s resolution and check the eardrum and hearing function. Ongoing observation is important in children to ensure temporary hearing loss does not interfere with speech and language development.
Addressing Potential Long-Term Complications
If SOM is severe, recurrent, or left untreated, it can lead to several adverse outcomes. Conductive hearing loss is the most frequent complication. This loss can be temporary due to fluid or permanent if the infection damages the eardrum or the delicate bones of hearing (ossicles). Persistent drainage lasting over six weeks, often through a permanent eardrum perforation, defines chronic suppurative otitis media.
Infection can spread beyond the middle ear cavity to surrounding structures. Mastoiditis occurs when the infection moves into the mastoid bone behind the ear, causing inflammation and destruction of the air cells.
The most serious, though rare, complications involve the spread of bacteria into the inner ear or the brain. This can lead to conditions such as:
- Labyrinthitis
- Facial nerve palsy
- Meningitis
- Brain abscess
A non-healing perforation can also lead to the formation of a cholesteatoma, an abnormal skin growth in the middle ear. This growth erodes bone and soft tissue and acts as a reservoir for persistent infection. Prompt medical attention and adherence to the prescribed treatment plan minimize the risk of these long-term sequelae.