Aetiology

The aetiology of secretory otitis media is not fully understood.

The following factors have been implicated which is thought to increase the risk of developing OME:

• age - 6 years or younger
• household smoking
• attending a day care centre
• large number of siblings
• low socioeconomic group
• recurrent upper respiratory tract infections
• bottle feeding (1).

The importance of Eustachian tube dysfunction is, however, widely accepted. One possible mechanism is that negative pressure develops within the middle ear cavity as a result of Eustachian tube dysfunction and the continual absorption of oxygen by respiratory epithelium. This negative pressure then encourages the formation of a mucosal transudate. Some common causes of tubal dysfunction are

• functional problems and its intrinsic system of opening and closing
• immunological and genetic disorders
• gastroesophageal reflux
• rhinosinusitis
• enlarged adenoid (2)

Thus, secretory otitis media may be caused by:

• nasopharyngeal obstruction:
  • large adenoids
  • nasopharyngeal tumours in adults
• otic barotrauma
• sinusitis
• there is an increased incidence in
  • cleft palate - due to impaired function of the Eustachian tube associated with palatal anomaly (2)
  • Down's syndrome - caused by impaired immune system and mucosal abnormality which results in an increased susceptibility to ear infection (2)
• allergic rhinitis may also predispose to secretory otitis media by affecting Eustachian tube function.
• passive smoking may be a factor

However, many cases of secretory otitis media have no apparent cause.

Reference:

• (1) Williamson I. Otitis media with effusion. Clinical Evidence 2006
• (2) Di Francesco R et al. Craniofacial morphology and otitis media with effusion in children. Int J Pediatr Otorhinolaryngol. 2008;72(8):1151-8
• (3) National Institute for Health and Clinical Excellence (NICE) 2008.Surgical management of otitis media with effusion in children