Chronic suppurative otitis media (CSOM) is a chronic inflammation of the middle ear and mastoid cavity. Clinical features are recurrent otorrhoea through a tympanic perforation, with conductive hearing loss of varying severity. Experts dispute the duration of otorrhoea required to determine it as a chronic infection - the World Health Organization's definitions suggest more than two weeks; others contend longer (e.g. up to six weeks).¹

Epidemiology

• In Britain, 0.9% of children and 0.5% of adults have CSOM, with no difference between the sexes.²
• Worldwide, there are between 65-330 million sufferers, of whom 60% receive significant hearing loss. This burden falls disproportionately on children in developing countries.³

Risk factors²

• Multiple episodes of acute otitis media (AOM).
• Living in crowded conditions.
• Being a member of a large family.
• Attending daycare.
• Studies of parental education, passive smoking, breast-feeding, socioeconomic status, and the annual number of upper respiratory infections (URTIs) show inconclusive associations only.
• Craniofacial anomalies increase risk: cleft lip or palate, Down's syndrome, cri du chat syndrome, choanal atresia, and microcephaly all increase the risk of CSOM.

Presentation

Symptoms

• CSOM presents with a chronically draining ear (>2 weeks), with a possible history of recurrent AOM, traumatic perforation, or insertion of grommets.
• The otorrhea should occur without otalgia or fever.
• Fever, vertigo and otalgia should prompt urgent referral to exclude intratemporal or intracranial complications.
• Hearing loss is common in the affected ear. Ask about the impact of this on speech development, school or work. Mixed hearing loss (conductive and sensorineural) suggests extensive disease.

Signs

• The external auditory canal may possibly be oedematous but is not usually tender.
• The discharge varies from fetid, purulent and cheese-like to clear and serous.
• Granulation tissue is often seen in the medial canal or middle ear space.
• The middle ear mucosa seen through the perforation may be oedematous or even polypoid, pale, or erythematous.

Differential diagnosis¹

• Otitis externa (inflamed, eczematous canal without a perforation)
• Foreign body
• Impacted ear wax
• Cholesteatoma
• Wegener's granulomatosis
• Neoplasm

Investigations

• Do not swab the ear in primary care as the clinical utility of this is uncertain.¹
• An audiogram will normally show conductive hearing loss.⁴ Mixed hearing loss may suggest more extensive disease and possible complications.

Imaging studies may be useful:

• CT scanning for failed treatment may show occult cholesteatoma, foreign body or malignancy.
• A fine-cut CT scan can reveal bone erosion from cholesteatoma, ossicular erosion, involvement of petrous apex and subperiosteal abscess.
• MRI is better if intratemporal or intracranial complications are suspected. It shows soft tissues better and can reveal dural inflammation, sigmoid sinus thrombosis, labyrinthitis, and extradural and intracranial abscesses.

Management

Primary care

• If there is postauricular swelling or tenderness (suggesting mastoiditis), facial paralysis, vertigo or evidence of intracranial infection, arrange urgent assessment or admission with an ENT team.
• Refer cases of CSOM without these features for routine ENT assessment. Current Clinical Knowledge Summaries' guidance suggests that GPs should not initiate treatment - this is because few non-specialists have the equipment or training to carry out aural cleaning; additionally, the topical antibiotics used by specialists are either used off licence (quinolones) or are not recommended in the presence of a tympanic perforation (aminoglycosides).¹
• Patients should be advised to keep the affected ear dry.
  

  Swimming advice: Patients with CSOM are usually advised to avoid swimming but, if they swim, they should dry their ears afterwards. Evidence is limited.5 One paper from Canada6 reports that surface swimming in fresh or ocean water is not contra-indicated in children with otitis media or in children with tympanostomy tubes. Diving should be prohibited in children with acute or chronic otitis media or in children with tympanostomy tubes. Hot tub water, bath water, chlorinated water, or water from stagnant ponds may pose a risk for either otitis media or otitis externa.

• Hearing tests are usual.

Secondary care

Conservative treatment of CSOM consists of 3 components:

• An appropriate antibiotic, usually given topically
• Regular intensive aural toilet to remove debris
• Control of granulation tissue

Drugs

• Aural toilet and topical antibiotics appear effective at resolving otorrhoea.⁷ Long-term outcomes (e.g. healing of tympanic perforation, recurrence prevention and hearing improvement) need further study.
• Topical treatment is more effective at clearing aural discharge than systemic therapy,⁸ probably due to the higher local concentrations of antibiotic achieved.
• Antibiotics should have activity against Gram-negative organisms, especially pseudomonas, and Gram-positive organisms, especially Staphylococcus aureus.
  • Aminoglycosides and the fluoroquinolones both meet these criteria but there remain safety concerns with both. The Committee on Safety of Medicines has advised that topical aminoglycosides should not be used with tympanic perforation due to their ototoxicity.⁹ However, many specialists continue to use them carefully, considering that undertreated otitis media carries a higher risk of hearing impairment and complications.
  • Topical quinolones are effective compared to no drug treatment or topical antiseptics only; however, evidence for their superiority over other topical antibiotics is only indirect.¹⁰ In the UK, ciprofloxacin or ofloxacin ear (and eye) drops are unlicensed but widely used by ENT specialists to treat CSOM as a safer alternative to topical aminoglycosides.¹¹ There are specific concerns about the use of fluoroquinolones in children because of juvenile animal studies indicating a risk of joint injury in the young. However this has not been found clinically among children with cystic fibrosis who have been treated with high doses of fluoroquinolones for prolonged periods.^12,13
  • Antibiotic failure is usually due to failure to penetrate the debris rather than bacterial resistance.
• Topical steroids are used to reduce granuloma formation and it is conventional to use combined antibiotic/steroid preparations.
• Systemic therapy is reserved for failure to respond to topical therapy. If a focus of infection in the mastoid cannot be reached by topical drops, then systemically administered antibiotics (usually IV) can penetrate in sufficient concentrations to control or eliminate infection. Topical therapy is continued simultaneously. This is usually done in hospital with an accompanying regime of intensive aural toilet.
• Treatment should continue for three to four weeks after the end of otorrhoea.

Surgical

• In safe inactive CSOM, once infection has been controlled, a tympanoplasty is usual to prevent recurrent infection.
• If otoscopy reveals granulation tissue of the unsafe variety, aural polyps or infection persists despite appropriate medical treatment, cholesteatoma should be sought. The goal of ensuing treatment is to create a safe ear, though the appropriate surgical procedure is often controversial
• Surgery is required in unsafe CSOM, as cholesteatoma can cause serious and possibly fatal complications. Classical radical mastoidectomy, modified radical mastoidectomy or the 'combined approach tympanoplasty' may be used depending on the extent of cholesteatoma and, more importantly, the experience of the surgeon. Whatever the procedure chosen, the aim of surgery is to remove all disease and to give the patient a dry and functioning ear.
• Facial paralysis can occur with or without cholesteatoma. Surgical exploration with mastoidectomy should be undertaken promptly.
• Labyrinthitis occurs when infection has spread to the inner ear. Early surgical exploration to remove the infection reduces damage to the labyrinth. Aggressive surgical debridement of the disease (including labyrinthectomy) is undertaken to prevent possibly fatal meningitis or encephalitis.
• Where conductive hearing loss has resulted from CSOM (due to perforation of the tympanic membrane and/or disruption in the ossicular chain), surgical removal of the infection and cholesteatoma, followed by ossicular chain reconstruction, will reduce hearing loss.
• Cochlear implants have been used in CSOM but it is essential to eradicate all disease first.^14,15

Complications

Complications of CSOM are rare but potentially life-threatening.
Intratemporal complications include:

• Petrositis
• Facial paralysis
• Labyrinthitis

Intracranial complications include:

• Lateral sinus thrombophlebitis
• Meningitis
• Intracranial abscess

Sequelae include:

• Hearing loss
• Tympanosclerosis

Prognosis

• There is a good chance of control of infection.
• The recovery of hearing loss varies, depending on the cause. Conductive hearing loss often can be partially corrected with surgery.

Document references

1. Otitis media - chronic suppurative, Clinical Knowledge Summaries (October 2008)
2. Parry D, Middle ear chronic suppurative otitis, medical treatment, eMedicine July 2009.
3. Woodfield G, Dugdale A; Evidence behind the WHO guidelines: hospital care for children: what is the most effective antibiotic regime for chronic suppurative otitis media in children? J Trop Pediatr. 2008 Jun;54(3):151-6.
4. Kaplan DM, Fliss DM, Kraus M, et al; Audiometric findings in children with chronic suppurative otitis media without cholesteatoma. Int J Pediatr Otorhinolaryngol. 1996 Apr;35(2):89-96. [abstract]
5. Basu S, Georgalas C, Sen P, et al; Water precautions and ear surgery: evidence and practice in the UK. J Laryngol Otol. 2007 Jan;121(1):9-14. Epub 2006 Nov 14. [abstract]
6. Robson WL, Leung AK; Swimming and ear infection. J R Soc Health. 1990 Dec;110(6):199-200. [abstract]
7. Acuin J, Smith A, Mackenzie I; Interventions for chronic suppurative otitis media. Cochrane Database Syst Rev. 2000;(2):CD000473. [abstract]
8. Macfadyen CA, Acuin JM, Gamble C; Systemic antibiotics versus topical treatments for chronically discharging ears with underlying eardrum perforations. Cochrane Database Syst Rev. 2006 Jan 25;(1):CD005608. [abstract]
9. CSM Current Problems in Pharmacovigilance, December 1997.
10. Macfadyen CA, Acuin JM, Gamble C; Topical antibiotics without steroids for chronically discharging ears with underlying eardrum perforations. Cochrane Database Syst Rev. 2005 Oct 19;(4):CD004618. [abstract]
11. Pappas S, Nikolopoulos TP, Korres S, et al; Topical antibiotic ear drops: are they safe? Int J Clin Pract. 2006 Sep;60(9):1115-9. [abstract]
12. Hampel B, Hullmann R, Schmidt H; Ciprofloxacin in pediatrics: worldwide clinical experience based on compassionate use--safety report. Pediatr Infect Dis J. 1997 Jan;16(1):127-9; discussion 160-2. [abstract]
13. Grady R; Safety profile of quinolone antibiotics in the pediatric population. Pediatr Infect Dis J. 2003 Dec;22(12):1128-32. [abstract]
14. Donnelly MJ, Pyman BC, Clark GM; Chronic middle ear disease and cochlear implantation. Ann Otol Rhinol Laryngol Suppl. 1995 Sep;166:406-8. [abstract]
15. Basavaraj S, Shanks M, Sivaji N, et al; Cochlear implantation and management of chronic suppurative otitis media: single stage procedure? Eur Arch Otorhinolaryngol. 2005 Oct;262(10):852-5. Epub 2005 Mar 9. [abstract]

Internet and further reading

• Weisskopf PA; Middle Ear, Chronic Suppurative Otitis, Surgical Treatment. eMedicine June 2006.
• WHO Chronic suppurative otitis media - burden of illness and management options, 2004.
• The National Deaf Children's Society.

Acknowledgements