Serous otitis media (SOM) is characterized by the presence of non-purulent fluid in the middle ear, with the tympanic membrane remaining intact. This fluid may have a mucous, serous, or mixed appearance and can vary in composition as the condition progresses. SOM is very common in children, although it can also occur in adults. The most frequent symptoms include hearing loss and a feeling of ear fullness, but it typically does not cause ear pain or fever. In children, the hearing loss is often mild and may only be detected through audiometric testing.
Pathophysiology of Serous Otitis Media:
SOM often occurs after the resolution of inflammation in acute otitis media (AOM). Regardless of the cause of AOM, Eustachian tube dysfunction is a near-universal finding in SOM. Once the acute inflammation and bacterial infection resolve, failure in the clearance mechanism allows fluid to remain in the middle ear. Many factors contribute to this clearance failure, including ciliary dysfunction, mucosal edema, fluid hyperviscosity, and possibly an unfavorable pressure gradient.
Etiology and Predisposing Factors:
- Environmental factors: Bottle-fed infants, babies fed while lying completely flat (which may promote reflux into the Eustachian tube during swallowing), having siblings with AOM, attending daycare, allergic sensitivity to common allergens, passive smoking, and parents with a history of SOM.
- Age: Young children are more prone to SOM due to anatomical features of their Eustachian tubes (shorter, more horizontal).
- Eustachian tube dysfunction: As noted, any disruption in normal tube function predisposes to SOM. This is more common in children with cleft palate, Down syndrome, or other palatal conditions.
Symptoms:
In children, the most common reason for consulting a doctor is parental concern about hearing loss. Parents may report that their child turns up the TV volume excessively, sits very close to the screen, fails to respond when spoken to, or frequently asks “What?”
In adults, symptoms include ear fullness and pressure, hearing loss, and often a recent history of upper respiratory infection, scuba diving, air travel, or respiratory allergies.
Diagnosis:
At our ENT clinic in Madrid, physical examination is often sufficient for diagnosis, but we also use additional valuable tools such as tympanometry and audiometry.
Findings on Otoscopy
Otoscopic Findings:
On otoscopy, SOM may reveal air-fluid levels in the tympanic cavity. In adults with unilateral SOM, especially if recurrent, it’s important to evaluate the nasopharynx to rule out neoplasms. This is done using nasopharyngoscopy. In children, this is also used to detect adenoid hypertrophy, a frequent contributing factor.
Treatment of Serous Otitis Media:
- Pharmacological: Various treatments have been described, such as corticosteroids, antihistamines, and mucolytics, but their effectiveness remains controversial.
- Surgical: When indicated, a myringotomy may be performed, with or without placement of tympanostomy tubes. In some cases, adenoidectomy is also recommended, especially in children with chronic nasal obstruction or adenoiditis.
- Other methods: Techniques such as autoinflation have shown some benefit in managing this condition.
Prognosis:
Generally, the prognosis is good, with most episodes resolving without treatment. About 5% of children who do not undergo surgical treatment will still have SOM after one year. Surgery significantly improves middle ear clearance, although its benefits for language development and quality of life remain under debate.
After tympanostomy tubes are extruded, 20–50% of patients experience recurrence of SOM, possibly requiring new tube placement and, depending on the case, an adenoidectomy.
It is essential to educate parents and teachers to watch for any speech or language delays in affected children. Early detection allows for timely intervention.
Prevention of Serous Otitis Media:
These recommendations may help reduce SOM episodes:
- Avoid smoking around children.
- Breastfeed whenever possible.
- Do not feed babies while they are lying completely flat.
- Minimize crowding with other children.
- Avoid exposing at-risk children (e.g., those with cleft palate) to additional risk factors.