Bacterial corneal ulcer (2).pptx CORNEA

Corneal ulcer

1. Bacterial corneal ulcer Dr.Mamata Subhakar.R Assistant Professor. A.C.S .Medical college &Hospital

2. Bacterial Ulcer Bacterial keratitis implies any form of corneal inflammation either superficial, interstitial or deep caused by bacteriae When this inflammation is accompanied by a loss of epithelium, it is termed a Corneal Ulcer.

3. Eitiology Gram positive bacteriae : Staphylococcus aureus, epidermidis and other  Streptococcus pneumoniae . Viridans , pyogenes  Corynebacterium  Enterococcus  Bacillus species  Propionibacterium acnes  Micrococcus spp , Peptostreptococci , Clostridium perfringens

4. Gram Negetive Bacteria  Pseudomonas aeruginosa Neisseria species Haemophilus specie Moraxella species Serratia marcescens Proteus sp., Acinetobacter sp., Enterobacter sp, E. coli, Klebsiella sp., Eikenella sp. Pasteurella multocida , Xanthomonas sp.,

5. Other Organisms  Aerobic, nonfermenting gram negative rods Achromobacter xylosoxidans and Stenotrophomonas maltophilia are important causes for contact lens induced keratitis. These are resistant to fluoroquinolones and aminoglycosides Actinomycetes including Nocardia are common in developing countries With orthokeratology lenses Pseudomonas, S.aureus , Acanthamoeba and Stenotrophomonas are found

6. Bacteria that can penetrate the normal epithelium Normally the epithelium protects the cornea from getting infected. But these bacteriae can penetrate the epithelium Neisseria gonorrhoeae , Neisseria meningitidis Corynebacterium diphtheriae  Haemophilus aegypticus Listeria species

7. Predisposing factors Ulcers can occur as secondary infection from the conjunctival commensals , from the lids or from the sac when it is inflamed. This will happen when there is an abrasion. This is the reason why when there is a chronic dacryocystitis it must be immediately dealt with Diabetes and immuno suppressives will also predispose the person to infection Contact lens wear

8. Trichiasis – a predisposing factor

9. Signs and symptoms Watering, pain and redness usually following injury. Defective vision. More if the ulcer is in the center Lid edema, muco purulent discharge  Circum corneal congestion, sometimes conjunctival congestion also. Chemosis if there is severe inflammation Opacity in the cornea which will take up fluorescein stain as the epithelium will be abraded.

10. Signs Pupil will be constricted and sluggishly reactive due to irritation to the iris. This toxic reaction can produce hypopyon which will be sterile in bacterial ulcer. In fungal ulcer fungal hyphae may be present. Injury with vegetative matter should make one suspect fungal etiology If chronic dacryocystitis is present Pneumococcal infection must be thought of

11. stages  Stage of progressive infiltration  Stage of active ulceration  Stage of regression  Stage of cicatrization

12.  STAGE OF PROGRESSIVE INFILTRATION Entry and adherance of organism to breached epithelium enters into stroma . PMNs and lymphocytes infiltrate into stroma and epithelium. Infective organism multiplies release toxins and enzymes.

13. STAGE OF ACTIVE ULCERATION  Necrosis occurs due to toxins and enzymes released by infective organism. Sloughing of epithelium and stroma ulcer. Ulcer Borders thickening due to infiltrates and edema. It is associated with iritis due to diffusion of toxins of infecting bacteria into AC.

14. Sometimes iridocyclitis is so severe that it is accompanied by outpouring of leucocytes from uveal blood vessels and these cells gravitate to bottom of the AC to form hypopyon (sterile).

15. STAGE OF REGRESSION Natural host defense & antimicrobial treatment Line of demarcation forms around ulcer which contains leucocytes which phagocytose the organism & necrotic debris Necrotic material fall off- ulcer becomes larger -> infiltration and swelling reduce and disappears -> margin & floor becomes smooth. Vascularization develops from limbus to corneal ulcer to restore lost tissue and to supply antibodies.

16. STAGE OF HEALING Vascularization is followed by cicatrization due to regeneration of collagen and formation of fibrous tissue Newly formed fibers are laid down irregularly, not conforming to normal pattern of stromal fibers. Therefore this fibrous tissue refracts light irregularly and forms opacity.

17. Staphylococcus aureus  Characteristics Suppuration is the hallmark Yellow – white, oval, densely opaque ulcer with relatively clear surrounding cornea with or without hypopyon Two types of stromal infiltration: small, discrete, peripheral anterior stromal infiltrates (free of replicating bacteria large, severe, central stromal infiltrates (replicating bacteria present) Tissue damage irreversible and leads to permanent scarring

18. Staphylococcal ulcer

19. Pneumococcal Ulcer Often seen when chronic dacryocystitis is present Suppuration and cicatrization are seen together. Ulcer progresses on one side when the other side is healing Hypopyon will be present as this causes severe iridocyclitis See the sutures made for sac excision

20. Pseudomonas ulcer Irregular ulcer with thick greenish mucopurulent exudate and ground glass appearance of surrounding cornea (mushy/soupy stroma ) Presence of hypopyon Rapid course – liquefactive necrosis, Descemetocoele and perforation in 1 or 2 days Most common pathogen in bacterial keratitis associated with contact lens wear

21. Staphylococcal epidermidis  This is a commensal organism present on the skin and conjunctiva Opportunistic infection Usually causes secondary infection on HSV keratitis, or on bullous keratopathy Here the ulcer is on a leucoma

22. Moraxella  Usually uniocular , mild, paracentral or perilimbal Central grey infiltrate – ulcer with grey membranous base Second area of infiltration around it in the deep layers of stroma with clear area in between Infiltrated margin lacking and remaining cornea relatively clear

23. Moraxella ulcer

24. Crystalline Keratopathy  Commonest cause is Streptococcus viridans  Other etiologic agents: like Staph. epidermidis , Pseudomonas, Mycobacteria , Enterococci , Strep. pneumoniae , Peptostreptococcus and Haemophilus also can rarely cause crystalline keratopathy Serratia marcescens also will give raise to satellite lesions

25. Other Organisms Corynebacterium also can cause ulcer in preexisting corneal lesions Bacillus species will cause a rapidly progressing ulcer. There will be a ring infiltrate remote from the site of injury Enterobacteriaceae will give raise to a shallow ulcer with grayish white pleomorphic suppuration opaque stroma and ring infiltrates -> ->

26. Investigations When you see an ulcer the following tests must done to find the causative organism Smear KOH suspension Culture Detection of antigens, antibodies and endotoxins Immunoglobulins PCR Confocal microscopy – not possible to see bacteriae as they are only 0.5 microns in size

27. Collecting and processing the Samples Apply topical anesthetic and wait for 3 – 5 mins for the anesthetic to drain off Remove the purulent material with a cotton swab and discord Use a Kimura’s spatula or a surgical blade to take the sample. This is preferably done under a slit lamp. The spatula can be sterilized with flame or 70% alcohol. Contamination by eye lashes is avoided by using a speculum Immediate transfer needed due to small sample

28. Stains used Gram stain: for bacteria, yeasts, cysts of Acanthamoeba . Can detect 60 – 70% of bacteriae . Fungal hyphae are Gram negative or faintly stained walls with unstained protoplasm Giemsa: viral and Chlamydia inclusion bodies, polymorphs and mononuclear cells besides the above microbes Ziehl -Neilson: Mycobacteria and Nocardia Acridine orange: bacteria, fungi and Acanthamoeba cysts

29. Culture   Blood agar: for aerobic bacteriae and fungi esp. Fusarium Chocolate agar: Haemophilus , Neissaria and Moraxella Sabouraud’s dextrose agar: fungus Thioglycollate broth: both aerobic and anaerobic Non nutrient agar with E. coli – Acanthamoeba  Thayer Martin agar: to isolate Neisseri Brain heart infusion: filamentous fungi and Yeast Lowenstein Jenson for Mycobacteria

30. Smear and Culture Not satisfactory because of Small sample Prior antibiotic use Many organisms are difficult to grow – Streptococci and Propionibacterium Polymicrobial keratitis can occur. It is difficult to differentiate this from contamination So while specificity is satisfactory sensitivity is poor

31. Investigations Elisa for detecting different antigens Serological tests for IgG and IgM to detect viruses and Microsporidia Limuluslysate test: to detect endotoxins Eubacterial PCR is done for all bacteriae

32. Next generation Sequencing A DNA sequence determination is coupled with bioinformatic analysis to detect matches between the sample and a data base of reference genome sequence. Rapid and highly accurate identification is possible

33. Treatment  Aim of the treatment To reduce the number of organisms as much and as quickly as possible To reduce the detrimental changes to the cornea caused by the inflammation

34. Treatment Atropine eye drops are given to cause dilatation and cycloplegia . This will reduce pain as ciliary spasm which is the cause for the pain is relieved Dilatation will break any synechiae and also prevent further synechiae from forming Atropine reduces the tear secretion and there by increases the lysozomal content of the tears It also separates the corneal lamellae and helps in penetration of the drops applied

35. Pupil dialated with Atropine

36. Treatment If chronic dacryocystitis is present sac excision has to be done As diabetes may predispose to infection and delay healing, this must be checked for History must be taken regarding use of immunodepressants and immunosuppression

37. Treatment of Bacterial ulcer Broad spectrum fortified antibiotic drops like Gentamycin and Tobramycin for gram negative organisms Cefuroxime 500 mg in 2 ml if mixed with 8 ml of tear substitute will give a fortified i.e. 50 mg in one ml solution Loading dose for the first half an hour or so and then every hour initially Once healing starts it can be tapered a little but not like steroids as tapering might cause resistance

38. Advantages of Flouroquinolones Has a broad spectrum – even against penicillin and methicillin resistant bacteriae  Acts against anaerobes and atypical mycobacteriae Has a higher solubility than the earlier antibiotics Minimum concentration needed is low  It is bactericidal Toxicity and allergenicity are low

39. Flouroquinolones Moxifloxacin is less active against Pseudomonas but more active against Mycoplasma than Gatifloxacin . It is less likely to give raise to resistance as two mutations are needed. Moxifloxacin is self preserved and hence preservatives are not needed Since it reaches a higher concentration in the anterior chamber development of mutation are prevented Gatifloxacin acts against even Chlamydia and Mycoplasma

40. Topical Antibiotic Therapy based on Gram stain findings Recommended drugs Alternative drugs No organism Cefuroxime + Tobramycin or Ciprofloxacin Bacitracin Gentamicin Ofloxacin Gram positive cocci Cefuroxime Bacitracin Vancomycin + Tobramycin Gram negative cocci Cefuroxime Ciprofloxacin Fortified Ceftriaxone Gram negative bacilli Tobramycin or Ciprofloxacin Gentamicin Ofloxacin Gram negative diplobacilli Moraxella sp Cefuroxime or Ciprofloxacin Fortified Ceftriaxone Ofloxacin

41. . HYPOPYON CORNEAL ULCER IT IS ALSO CALLED ULCUS SERPENS COMMONLY CAUSED BY PNEUMOCOCCUS SOURCE OF INFECTION:CHRONIC DACRYOCYSTITIS ( Lacrimal sac infection due to naso lacrimal duct obstruction It may also caused by other organisms like staphylo,strepto,gonococci

42. FACTORS RESPONSIBLE VIRULENCE OF BACTERIA RESISTANCE OF TISSUES MOST COMMONLY SEEN IN DEBILITATED,ALCOHOLIC

43. MECHANISAM OF HYPOPYON CORNEAL ULCER+IRITIS(DUE TO BACTERIAL TOXINS) SEVERE IRITIS CAUSES OUTPORING OF LEUKOCYTES CELLS DEPOSIT TO BOTTOM OF AC TO FORM HYPOPYON

44. IS IT STERILE? YES, THE LEUCOCYTES CAME OUT DUE TO TOXINS SO NO BACTERIA INVOLVED SO IT WILL BE RESOLVED WHEN ULCER IS TREATED

45. CLINICAL FEATURES • YELLOISH DISC SHAPED ULCER • SERPINGINOUS ULCER PATERN • VIOLENT IRIDOCYCLITIS • SECONDARY GLAUCOMA • EARLY PERFORATION

46.  MANAGEMENT TOPICAL ANTIBIOTICS • CEFAZOLINE FORTIFIED • TOBRAMYCIN • CYCLOPLEGIC DRUGS(FOR REDUCE PAIN,AND BLOOD SUPPLY) • TIMOLOL MALEATE(SEC.GLAUCOMA) • DACRYOCYSTECTOMY(IF IT IS DUE TO DACRYOCYSTITIS)

47. Complication of corneal ulcer Complications of corneal ulcer can be described under two headings : 1.Before perforation 2.After perforation

48.  Before perforation :  • Anterior uveitis • Hypopyon • Secondary glaucoma • Descemetocele • Corneal scarring - Nebula - Macula - Leucoma

49. After perforation : Anterior synaechiae Iris prolapse Adherent leucoma Complicated cataract Sublaxation of the lens Anterior staphyloma Endophthalmitis Phthisis bulbi