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as prednisolone). Oclacitinib and lokivetmab are not effective. Ciclosporin has also been shown to be effective in some cases but is only useful for chronic otitis.
3. Remove debris and discharge
Ear flushing is imperative to remove discharge from the external ear canal and/or the middle ear. Removal of debris and purulent material greatly improves
the efficacy of topical antimicrobials, especially aminoglycosides and polymixin B.
Excess hair should be clipped from the medial aspect of the pinna and excess exudate removed from the pinna and around the entrance to the external ear canal. One method of ear flushing is performed with a three-way tap or stopcock connected to a 10ml syringe, warmed saline in a fluid bag and a 5-French feeding tube or 8-French polypropylene urinary catheter. It is often better to insert the feeding tube or catheter to
a deeper part of the canal and backflush the material.
A pulsing action can assist with dislodging trapped exudate. The external ear canal is alternately flushed and aspirated, removing the remaining exudate and debris allowing visualization of the tympanic membrane with
an otoscope or video otoscope. For suppurative otitis externa, 2% acetic acid or 2% acetic acid and 2% malic acid can be used for flushing ears instead of saline for infections with Pseudomonas otitis. Two and five minutes contact with 2% acetic acid is lethal to Pseudomonas and Staphylococcus respectively. Acidic cleaners may inactive some antimicrobials (especially aminoglycosides and fluoroquinolones), although ear canals have good buffering capacity and the pH rapidly returns to normal.
Biofilms
Biofilms can be physically broken up and removed by thorough flushing and aspiration. Topical trizEDTA and 2% n-acetylcysteine can disrupt biofilms, facilitating their removal and enhancing penetration of antimicrobials. Systemic administration of n-acetylcysteine is well tolerated and can help dissolve biofilms in the middle ear and other mucous surfaces.
4. Treat otitis media
Inflammation in the ear canal will also affect the tympanic
membrane, which may become oedematous, thickened or dilated. Rupture of the tympanum is common. Infection within the tympanic bulla leads to inflammation of the delicate mucoperiosteum lining of the bulla and the production of mucus, which traps infection within the bulla cavity, making it inaccessible to topical drugs. Biofilms are common within the middle ear of children.
Appropriate measures to resolve infection in the middle ear include: flushing of the bulla and the instillation
of appropriate drugs into the site, which may include biofilm busting agents, anti-inflammatory drugs and antimicrobials. Where disease within the bulla is not managed, granulation tissue and bony change lead
to irreversible damage that may only be successfully resolved by surgical intervention.
If the tympanic membrane is ruptured, repeated flushing of the middle ear should be performed. The tip of
the feeding tube is placed adjacent to the tympanic membrane or, if the tympanic membrane is ruptured, into the middle ear under visualization through an operating otoscope. It is important to angle the tip ventrally to avoid the sensitive structures in the dorsal part of the middle ear cavity. The ear canals and middle ear are alternately flushed and aspirated until completely clean. Retrograde flushing using this technique is very effective at removing deep material and is the only effective way to clean the middle ear.
Opinion is divided on the systemic treatment of otitis media; some referral clinicians always use systemic treatment, others instil antimicrobials directly into
the middle ear every three to 10 days (enrofloxacin, marbofloxacin, gentamicin appear to be safe used in this way), some use topical therapy and some a combination of approaches. It is likely that antimicrobials persist for several days following direct application into the middle ear, because this is effectively a blind-ending sac with limited drainage into the pharynx.
If the tympanic membrane is intact but appears abnormal and otitis media is suspected a myringotomy (the deliberate rupture of the tympanic membrane) should
be performed to obtain samples for cytology, culture
and sensitivity and to flush the middle ear cavity. An open-ended 3.5-French tomcat catheter is used to make the incision. Experimentally ruptured normal tympanic membranes heal in three to five weeks. If the ear is kept free from infection following myringotomy the tympanic membrane should heal.
5. Topical and systemic antimicrobial therapy
Topical therapy should be used. This results in high concentrations in the ear canals. Systemic treatment is very useful in suppurative otitis externa and/or otitis media where there is an active inflammatory discharge with concurrent infection in the deep ear canal tissues and middle ear. Pseudomonas are
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