Pseudomonas otitis media - the medical approach. Peri Lau-Gillard DrVetMed CertVD DipECVD MRCVS Vale Referrals Stinchcombe, Gloucestershire

Transcription

1 Pseudomonas otitis media - the medical approach Peri Lau-Gillard DrVetMed CertVD DipECVD MRCVS Vale Referrals Stinchcombe, Gloucestershire

2 Why does otitis externa occur?

3 1. Alteration of physical and micro-biological state leading to inflammation Increased volume of ear secretion

4 2. Inflammation followed by stenosis causing v v v v Lack of air circulation Development of moist environment Reduced exit of secretions and inflammatory debris Decreased ability of topical TX to enter the ear canal

5 3. Ear canal becomes overgrown or colonized by microorganisms Inflammation Increased production of cerumen Pinnae Nutrition for the normal ear flora Tympanic membrane Middle ear

6 Why can otitis externa transform to otitis media?

7 Dendritic cell Neutrophil Macrophage Bacterial proteases Collagenases and elastases Pinnae Lysosymes Inflammation Enzymatic destruction Epithelial necrosis Collagen breakdown Middle ear Tympanic membrane

8 What happens after the tympanic membrane has ruptured? numbers of secretory cells and glands in bulla Quantity of exudate increases mucus membrane Chronic inflammation leads then to Mucosal oedema Thickening of epithelial lining Breakdown of the epithelial lining Granulation tissue formation With chronicity Connective tissue Scar tissue Bony changes Pinnae

9 Diagnosis of Pseudomonas aeruginosa otitis media

10 Obtaining clues from the patient`s history

11 Obtaining clues from your physical examination

12 Obtaining clues from your otoscopic examination Obvious cases of OM: No TM present. v OM without suppuration will look like a deep dark hole. v Intact TM does not rule out OM. v Mucus-filled canal is suspicious for OM v If fluid behind TM, TM may bulge into the external ear canal. v Purulent material in middle ear may be seen as yellow fluid behind TM. v

13 Myringotomy Pars flaccida Manubrium of malleus Pars tensa Pars tensa Myringotomy site Courtesy Pascal Prélaud Courtesy Pascal Prélaud

14 Importance of ear cytology v Perform cytology in all cases. v Take samples from the external canal and the middle ear cavity if possible as the results can differ! v Perform cytology also at each subsequent visit to monitor response to therapy and to determine when infection has resolved.

15 Cocci on cytology Cocci seen on cytology

16 Cocci on cytology Cocci seen on cytology

17 Malassezia on cytology

18 Mixed infection on cytology

19 Mixed infection on cytology When rods seen on cytology

20 Corynebacterium Although gram positive, appears on cytology as pleomorphic, club shaped rods

21 When to culture?

22 Usefulness of culture results Different opinions! Useful for determining antimicrobial susceptibility Others think it is of little value as based upon attainable BLOOD levels of antibiotics. The conc. attained in the external canal with topical antibiotic drops is much higher (up to 1000-fold higher than serum levels) effective even when C & S indicates resistance

23 Usefulness of culture results The presence of exudate in the infected ear canal may result in antimicrobial dilution. Cerumen and pus may affect the in vivo antimicrobial efficacy by interfering with antimicrobial activity Cerumen and pus providing physical protection to the target pathogen

24 Diagnostic imaging: Useful tool or not? Presence of fluid/masses in middle ear/ear canal. v Presence of osteomyelitis of the bulla. v Degree of narrowing and/or calcification of the canals. v

25 Treatment of Pseudomonas otitis media Stepwise protocol for maximal effect

26 Treat stenotic ear canals first

27 Systemic glucocorticoids 1-1.5mg/kg/day for 4 days then tapered to EOD 0.5-2mg/kg/ day for 7-10 days then tapered to EOD

28 Cyclosporin? Hall, J.A., Waisglass, S.E., Mathews, K.A., Tait, J.L. (2003): Oral cyclosporin in the treatment of end-stage ear disease: a pilot study. Veterinary Dermatology 2003; 14: 212 Five dogs with end-stage proliferative otitis externa were included in this study (one Golden Retriever, four Cocker Spaniels) which were referred for total ear canal ablation. They were treated with Cyclosporin A (5 mg/kg BID) for at least 12 weeks. All dogs showed significant clinical improvement with a much better life quality and an increasing diameter of the stenotic ear channel. None of the dogs had to go to surgery.

29 Topical glucocorticoids

30 Flush ear canal and bulla

31 Suitable flushing solutions TrisEDTA 15% chlorhexidine gluconate TrisEDTA Boric acid Acetic acid Sterile saline Water

32 Propylene glycol is ototoxic Propylene glycol Propylene glycol Propylene Propylene TrisEDTA glycol glycol PCMX TrisEDTA Salicylic acid Chlorhexidine Docusate sodium Xylene Polyethylen glycol Glycerine Menthol Propylene glycol Salicylic acid Polyethylen glycol Glycerine

33 Ear flushing with handheld otoscope

34 Ear flushing using video-otoscope

35 View with video-otoscope before flushing

36 View with videootoscope during flushing

37 Infuse topical medication into bulla

38 Reduce inflammation with the use of topical corticosteroids

39 Use of systemic and topical antimicrobials

40 Treatment of Pseudomonas otitis media Tim Nuttall and Lynette K. Cole: Evidence-based veterinary dermatology: a systematic review of interventions for treatment of Pseudomonas otitis in dogs. Vet Derm 2007; 18: There is insufficient evidence for or against recommending the use of any of these treatments for Pseudomonas otitis in dogs Future studies need to be prospective, randomized, blinded and controlled

41 Licensed products useful? Orbifloxacin Mometasone furoate Posaconazole Marbofloxacin Dexamethason Clotrimazole Gentamicin sulfate Hydrocortisone aceponate Miconazole Gentamicin sulfate Betamethasone valerate Clotrimazole Polymyxin B sulfate Prednisolone acetate Miconazole nitrate

42 Benefit of using TrisEDTA Increases the permeability of bacterial cell membranes by binding Ca and Mg ions. Sparing effect on the MIC of enrofloxacin against ciprofloxacin resistant Pseudomonas as well as resolving clinical cases resistant to cephalosporin or enrofloxacin It was also shown effective in vivo in a small number of cases when combined with a low level (0.15%) of chlorhexidine digluconate

43 Off-labelled topical preparations Inactive in pus % diluted in saline diluted 1:4 in saline SID or BID Undiluted ml/ear Sid or BID 5ml marbofloxacin diluted with 1ml inject. dexa-methasone ml/ear diluted 1:4 in saline SID or BID Undiluted ml/ear Sid or BID 4ml enrofloxacin 2.5% with 4ml inject. Dexa-methasone (4mg/ml) and 8ml saline Ciprofloxacin 0.2% soln ml/ ear SID or BID

44 What about tobramycin or ticarcillin and other more unusual drugs? Some clinicians recommend also Imipenim, cilastin, piperacillin or tazobactam diluted and used as ear drops This practice should be seriously questioned as these are rescue drugs for serious human infections Indiscriminate use in the veterinary field could jeopardize their value.

45 Systemic treatment for Pseudomonas otitis media

46 15-20 mg/kg SID 3-5 mg/kg SID 3 mg/kg SID pradofloxacin

47 Regular rechecks with repeated in-house cytology

48 Regular use of an ear cleaner long term

49 S. I. Steen, S. Paterson: The susceptibility of Pseudomonas spp. Isolated from dogs with otitis to topical ear cleaners. JSAP 2012; Volume 53, Issue 10, p Lactic acid: reduce the ph of the product & effective in disrupting the outer cell membrane of gram- bacteria Isopropyl alcohol, PCMX, monosaccharides, salicylic acid and EDTA, had inconsistent activity against Pseudomonas Cleaners containing acetic acid, lactic acid and chlorhexidine at 0.15%, in combination with TrisEDTA showed excellent activity against Pseudomonas.

50 So which cleaner to use once TM is intact?

51 Last but not least: Identify and control the underlying aetiologies The PSPP system

52 Predisposing factors Squamous cell tumour

53 Primary factors

54 Primary factors Allergies

55 Courtesy J Rybnicek Primary factors

56 Secondary factors

57 Perpetuating factors

58 Perpetuating factors

59 Conclusion vearly intervention. videntifying organism involved (external ear canal and middle ear if possible). vtreat stenotic ear canals first. vuse of combined topical and systemic TX and flushing of ear canal and bulla. vregular ear cytology and RX for monitoring. vlong term treatment with ear cleaner. vit is CRUCIAL to identifying underlying causes

60 Any questions?