Chronic Suppurative Otitis Media (CSOM)

Chronic suppurative otitis media is the commonest form of chronic otitis media. Clinical features are otorrhoea and conduction hearing loss of variable severity. The eardrum is perforated and it has to persist for at least 6 to 12 months to be called chronic. It is classified into tubotympanic that is usually "safe" and atticoantral that is often "unsafe". Safe or unsafe depends on the presence of cholesteatoma.

Acute infection of the middle ear causes irritation and inflammation of the mucosa of the middle ear with oedema. Inflammation produces mucosal ulceration and breakdown of the epithelial lining. Granuloma formation can develop into polyps in the middle ear. The cycle of inflammation, ulceration, infection, and granulation tissue formation may continue, destroying surrounding structures and leading to the various complications of chronic suppurative otitis media.

In Britain 0.9% of children and 0.5% of adults have chronic suppurative otitis media with no difference between the sexes.¹

Risk Factors

• Multiple episodes of acute otitis media
• Living in crowded conditions
• Being a member of a large family
• Studies of parental education, passive smoking, breastfeeding, socioeconomic status, and the annual number of upper respiratory infections are inconclusive.
• 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, presumably from altered eustachian tube anatomy and function.

Symptoms

• CSOM presents with a chronically draining ear and history of recurrent acute otitis media, traumatic perforation, or insertion of grommets.
• They usually have pain or discomfort.
• A common presentation is hearing loss in the affected ear.

Signs

• The external auditory canal may possibly be oedematous and usually is not 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 erythaematous.

• Foreign body
• Cholesteatoma
• Wegener Granulomatosis

Chronic serous otitis media is not the same as chronic suppurative otitis media. The former may be defined as a middle ear effusion, without perforation, persisting for more than 1 to 3 months, depending on the author.

• Obtain fluid for culture and sensitivity
• An audiogram will normally show conductive hearing loss.² 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 depends upon classification:

• In safe inactive CSOM, infection must be controlled but then a tympanoplasty should be performed to prevent recurrent infection.
• If otoscopy reveals granulation tissue in the unsafe variety, aural polyps or middle ear infection that is resistant to conservative treatment, cholesteatoma should be sought. With modern endoscopic equipment and CT, assessment of the middle ear has become much more accurate. The goal of treatment is to produce a safe ear.

Treatment consists of 3 components:

• An appropriate antibiotic preparation
• Regular intensive aural toilet as topical preparations cannot penetrate affected tissues until the debris is removed.
• Control of granulation tissue.

Drugs

• Topical treatment is better than systemic therapy.³ This is probably because a higher local concentration of antibiotic is achieved.
• The antibiotic should have activity against gram-negative organisms, especially pseudomonas, and gram-positive organisms, especially Staphylococcus aureus. The aminoglycosides and the fluoroquinolones both meet these criteria but the former may be ototoxic.⁴ Failures of the antibiotic are usually due to failure to penetrate the debris rather than bacterial resistance. Topical steroids are used to reduce granuloma formation.
• 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, although concentrations are lower. Topical therapy is continued simultaneously. This is usually done in hospital and the more intensive aural toilet in hospital is probably as important if not more so.
• Treatment should continue for 3 to 4 weeks after the end of otorrhoea.
• Fluoroquinolones are not approved for use in children because of joint injury in young experimental animals but many children with cystic fibrosis have been treated with high doses of fluoroquinolones for prolonged periods and the risk is not real.⁵ No case of permanent joint injury has been reported.
• Aminoglycosides are contraindicated because there is evidence that they may cause hearing loss. The therapy should be adjusted to the needs of the individual.⁶ The aural toilet is very important.

Surgical

• Surgery should be considered for failure to respond to a combination of topical and systemic therapy. A tympanomastoidectomy can eliminate infection and stop otorrhoea in 80% of patients.
• Tympanoplasty can seal a perforation and prevents transfer of bacteria from the external ear canal into the middle ear.
• Surgery is required in unsafe CSOM as cholesteatoma can cause serious and possibly fatal complications. The surgical procedure employed is controversial. 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.
• Cochlear implants have been used in CSOM but it is essential to eradicate all disease first.^{7 8}

There have been a number of Cochrane reviews of management of CSOM.

• One from 2000 concluded that⁹ "Treatment of CSOM with aural toilet and topical antibiotics, particularly quinolones, is effective in resolving otorrhoea and eradicating bacteria from the middle ear. Long-term outcomes such as preventing recurrences, closure of tympanic perforation and hearing improvement need to be further evaluated."
• Another from 2006 examined the use of topical antibiotics without steroids.¹⁰ It concluded that topical quinolones can clear aural discharge better than no drug treatment or topical antiseptics. Benefits of other antibiotics are less clear. Further trials should clarify outcomes for resolution, healing, hearing, or complications and if quinolones may result in fewer adverse events than other topical treatments.
• A further review, also from 2006, examined systemic versus topical antibiotics.³ It concluded that topical quinolone antibiotics can clear aural discharge better than systemic antibiotics. Evidence regarding safety was weak.

• Intratemporal complications include petrositis, facial paralysis, and labyrinthitis. Intracranial complications include lateral sinus thrombophlebitis, meningitis, and intracranial abscess. Sequelae include hearing loss, cholesteatoma and tympanosclerosis.
• Facial paralysis can occur with or without cholesteatoma. Surgical exploration with mastoidectomy, should be undertaken promptly.
• Labyrinthitis occurs when the infection spreads to the inner ear. Symptoms are acute onset of vertigo and hearing loss. Early surgical exploration to remove the infection reduces damage to the labyrinth. Patients present with profound hearing loss, tinnitus, and vertigo with nausea and vomiting. There is nystagmus with the rapid component directed toward the affected ear. They later develop nystagmus after destruction of the membranous labyrinth, away from the affected ear. Treatment includes aggressive surgical debridement of the disease (including labyrinthectomy) to prevent the possibly fatal meningitis or encephalitis.
• Chronic labyrinthitis produces gradual onset of vertigo, tinnitus, and hearing loss. Treatment involves mastoidectomy, culture, and appropriate medical therapy.
• Lateral sinus thrombophlebitis occurs when infection extends through the mastoid bone into the sigmoid or lateral sinus. The infected thrombus may release septic embolic causing distal infarcts.
• Rarely, patients with chronic suppurative otitis media develop intracranial abscesses.
• Conductive hearing loss from CSOM may result from the perforated tympanic membrane, a disruption in the ossicular chain, or both. Surgical removal of the infection and cholesteatoma with ossicular chain reconstruction reduces hearing loss.
• Patients with CSOM are usually advised to avoid swimming but if they swim they should dry their ears after. Evidence about the risk of swimming in patients with CSOM is limited. Once typanoplasty has been performed there seems little reason to object but a paper from Canada¹¹ reports that surface swimming in fresh or ocean water is not contraindicated 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.

• 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.