Audit: Investigation & management of otitis externa Zhaobo Liu (Paul) Mohd Afiq Mohd Slim Catherine Scally

Introduction Otitis externa is a common condition Managed in the outpatient settings Fast turn over of junior doctors Lack of experience and knowledge Non-standardised management Otitis externa is a common condition affecting more than 1% of the UK population each year. It is managed in the outpatient settings, such as the ENT treatment room of Antrim Area Hospital These patients are often seen by junior grade doctors and there is concern of non-standardised management due to a lack of experience and knowledge

Aim To assess the current management of otitis externa in the ENT treatment room of Antrim Area Hospital The aim of this audit is to…

Current recommendations: NICE Clinical Guideline Ear Swabs Treatment

Current recommendations: NICE Clinical Guideline Ear Swabs Treatment Performed only in cases of failed treatment Sensitivities are determined for systemic not topical abx Difficult to distinguish contaminant from disease causing organisms (https://cks.nice.org.uk/otitis-externa#!scenario) When to investigate When should I investigate someone with acute diffuse otitis externa? Investigations are rarely useful. However, if treatment fails or otitis externa recurs frequently, consider sending an ear swab for bacterial and fungal microscopy and culture. A swab is best taken from the medial aspect of the ear canal under visualization to reduce contamination. Identifying the organism, and especially distinguishing a fungal infection from a bacterial infection, can be of therapeutic significance. However, interpretation of culture results is difficult: Reported bacterial susceptibility may not correlate with clinical outcomes because sensitivities are determined for systemic (not topical) administration. Much higher concentrations of antibiotic can be achieved with topical application. It is not possible to tell from the culture results whether the isolated organisms are causing the disease or are merely contaminants. In particular, there is likely to be a fungal overgrowth after using antibacterial drops as these will have suppressed the normal bacterial flora.

Current recommendations: NICE Clinical Guideline Ear Swabs Treatment Performed only in cases of failed treatment Sensitivities are determined for systemic not topical abx Difficult to distinguish contaminant from disease causing organisms No single eardrop is recommended for topical application Depends on: bacteria or fungal infection presence of systemic signs tympanic membrane integrity (https://cks.nice.org.uk/otitis-externa#!scenario) When to investigate When should I investigate someone with acute diffuse otitis externa? Investigations are rarely useful. However, if treatment fails or otitis externa recurs frequently, consider sending an ear swab for bacterial and fungal microscopy and culture. A swab is best taken from the medial aspect of the ear canal under visualization to reduce contamination. Identifying the organism, and especially distinguishing a fungal infection from a bacterial infection, can be of therapeutic significance. However, interpretation of culture results is difficult: Reported bacterial susceptibility may not correlate with clinical outcomes because sensitivities are determined for systemic (not topical) administration. Much higher concentrations of antibiotic can be achieved with topical application. It is not possible to tell from the culture results whether the isolated organisms are causing the disease or are merely contaminants. In particular, there is likely to be a fungal overgrowth after using antibacterial drops as these will have suppressed the normal bacterial flora.

There is a huge variety of eardrops available, which one to pick?

Methods Case notes of 19 first attenders to ENT treatment room from July to October 2016 were reviewed Data extracted Type of topical antibiotic Investigation performed (microbiology only) Culture grown A retrospective audit of clinical practice took place, we reviewed case notes of 19 patients seen over a period of 4 months from July to October 2016

Results

Ear swabs taken Out of 19 patients, 14 had swabs taken and 5 did not.

Ear swab results The most commonly cultured organisms were pseudomona aeruginosa and staphylococcus aureus, which is consistent with previously published literature

Choice of eardrops The most commonly prescribed eardrops were Sofradex, followed by Gentasone and Betnesol-N

Sensitivity Profile Pseudomonas Staph Aureus Strep Group A Aspergillus fumigatus Sofradex susceptible resistant Gentasone Betnesol-N Otomize Chloramphenicol Locorten-Vioform (Clioquinol) Canesten Here is a table summarising the sensitivity profile of the commonly used antimicrobial eardrops (left) and the commonly cultured organisms in otitis externa (top) As you can see, the top 3 most common prescribed ear drops cover the 3 most commonly cultured organisms (pseudomonas, staph aureus and group A strep) Clioquinol and Canesten have antifungal properties, in particular, clioquinol has antiprotozoal property. Clioquinol is antibacterial and antifungal and has lower risks of skin reactions and ototoxicity than aminoglycosides. Therefore, on theoretical grounds, the combination flumetasone–clioquinol (Locorten–Vioform®) ear drops might be slightly preferred over preparations containing aminoglycosides — CKS found no direct evidence from comparative trials to support this. https://www.researchgate.net/publication/16980755_Efficacy_of_clioquinol-_and_tribromophenoLwismut_zinc_oxide_preparations_in_antimicrobial_topical_treatment (Clioquinol is ineffective against pseudomonas)

Non-combined Preparation Costs Non-combined Preparation Combined Preparation All prices taken from the latest version of BNF Combined preparations of steroid and antibiotic drops are known to be superior to topical steroids alone for acute otitis externa And in the combined preparation group, Betnesol-N is the cheapest option. Abelardo E, Pope L, Rajkumar K, Greenwood R, Nunez DA (2009) A double-blind randomised control trial of the treatment of otitis externa using topical steroid alone versus topical steroid-antibiotic therapy. Eur Arch Otorhinolaryngol 266(1):41–45 (Epub 2008 Jun 17) ****careful with Locorten as there was a supply issue last year when I was there and in royal so we end up using canesten, best double check with the pharmacy 1st***

Non-combined Preparation Costs Non-combined Preparation Combined Preparation Corticosteroid Predsol = £2.00 Betnesol = £2.32 Antibiotic Gentamicin 0.3% = £2.55  Chloramphenicol 5% = £57.90 Antifungal Clotrimazole 1% = £1.15 Combined corticosteroid & antibiotic Betnesol-N (neomycin) = £2.39 Gentisone (gentamicin) = £4.76 Otomize (neomycin) = £6.54 Sofradex (framycetin) = £7.50 Combined corticosteroid & antiprotozoa/antifungal Locorten-Vioform = £2.35 All prices taken from the latest version of BNF Combined preparations of steroid and antibiotic drops are known to be superior to topical steroids alone for acute otitis externa And in the combined preparation group, Betnesol-N is the cheapest option. Abelardo E, Pope L, Rajkumar K, Greenwood R, Nunez DA (2009) A double-blind randomised control trial of the treatment of otitis externa using topical steroid alone versus topical steroid-antibiotic therapy. Eur Arch Otorhinolaryngol 266(1):41–45 (Epub 2008 Jun 17) ****careful with Locorten as there was a supply issue last year when I was there and in royal so we end up using canesten, best double check with the pharmacy 1st***

Conclusions Commonly used antimicrobial eardrops cover the most frequently grown organisms in otitis externa Betnesol-N is cheaper compared to other antibiotic eardrops while maintaining its antimicrobial effectiveness

Recommendations Ear swabs should only be reserved for refractory or recurrent cases of otitis externa Rx: 1st line: Betnesol-N Aural toileting ± Otowick If not resolving Ear swabs  consider anti-fungal Re-evaluate diagnosis Ear swabs should only be reserved for refractory or recurrent cases of otitis externa We recommend Betnesol-N together with aural toilet or otowick to get rid of debris and provide sustained antibiotic delivery Re-evaluate diagnosis: dermatitis or malignancy (BCC)

Estimated cost savings Cost of ear swab: £15 Price difference of Sofradex and Betnesol-N: £5.11 Estimated cost savings in 1 year (approx. 57 cases): £814 Each ear swab costs £15 in Northern Trust Price difference of Sofradex, the commonly prescribed eardrop, and the cheapest alternative is £5.11 To extrapolate from this audit, we an estimated 57 cases of otitis externa per year (19 in 4months), and estimated cost saving can be as high as £921 per year (15x14)+(12x5.11)=813.96

Moving forward New guideline to be disseminated Department meetings Email reminders to junior grade doctors Reminder poster to be displayed in the ENT treatment room Re-audit in 4 month’s time

Any Questions? Rx of otitis externa in primary care A survey of GPs in 2011 showed that 42% of patients received no treatment by their GPs prior to referral and a further proportion of patients were not treated with antibiotic ear drops. http://link.springer.com.ezproxy.is.ed.ac.uk/article/10.1007/s00405-011-1687-7 This could be due to the fact that the most commonly available ear drops are aminoglycosides which are ototoxic.