ear, nose, and throat disorders
Otitis Media (Serous)
Introduction
Serous otitis media is an effusion in the middle ear resulting from incomplete resolution of acute otitis media or obstruction of the eustachian tube without infection. Symptoms include hearing loss and a sense of fullness or pressure in the ear. Diagnosis is based on appearance of the tympanic membrane and sometimes on tympanometry. Most cases resolve in 2 to 3 weeks. If there is no improvement in 1 to 3 months, some form of myringotomy is indicated, usually with insertion of a tympanostomy tube. Antibiotics and decongestants are not effective. Normally, the middle ear is ventilated 3 to 4 times a minute as the eustachian tube opens during swallowing, and oxygen is absorbed by blood in the vessels of the middle ear mucous membrane. If patency of the eustachian tube is impaired, a relative negative pressure develops within the middle ear, sometimes leading to fluid accumulation. This fluid may cause hearing loss. Serous otitis media is a common sequela to Otitis Media (Acute) or upper respiratory infection in children (often identified during a routine ear recheck) and may persist for weeks to months. Eustachian tube obstruction may also be secondary to the following: Inflammatory processes in the nasopharynx Allergies Hypertrophic adenoids Other obstructive lymphoid aggregations on the torus of the eustachian tube and in the Rosenmüller fossa Benign or malignant tumors The effusion may be sterile or (more commonly) contain pathogenic bacteria sometimes as a biofilm, although inflammation is not observed. Rarely, a spontaneous cerebrospinal fluid (CSF) leak due to erosion through the lateral skull base may manifest as otitis media with effusion. 