infectious bacterial keratitis (corneal ulcer) Flashcards
infectious bacterial keratitis (corneal ulcer)
assess low, borderline, high risk of vision loss
chlorofluoroquinolone (Besivance) / 4th generation fluoroquinolones off-label older fluoroquinolones on-label
cycloplegia for secondary uveitis, no steroids
using steroids to speed healing / timing and cautions
tapering medications / signs of improvement
outpatient care / hospital inpatient care Tx decisions and issues
culture and sensitivity, repeat if needed
fortified antibiotic drops (need compounding pharmacy)
symptoms
R S Sensitive to light with Red eye (intensely) V Vision change (reduced, disrupted) and P Pain (acute unilateral, can include profuse tearing)
signs
focal stromal infiltration surrounding excavation (ulcer) AC cells and flare (hypopyon?) conjunctival injection (even deeper to episcleral?) purulent discharge? mucoid plugs? eyelid edema? folds in Descemet’s membrane?
pathophysiology
• once corneal defenses are breached – direct corneal trauma, chronic eyelid disease, tear film abnormalities affecting the ocular surface, hypoxic trauma from contact lens wear, etc. – the cornea is prone to infection
• pathogenic bacteria colonize the corneal stroma and immediately become antigenic by releasing enzymes and toxins
→ antigen-antibody immune reaction
→ inflammatory reaction
• the body releases PMNs (PolyMorphoNuclear leukocytes) which
aggregate at the area of infection, creating an infiltrate
• the PMNs phagocytize and digest the bacteria
• the collagen stroma is poorly tolerant of the combined bacterial and
leukocytic enzymes and undergoes degradation, necrosis, and thinning → scarring of cornea
→ cornea may perforate
→ possibility for endophthalmitis
• the most common infective organism in bacterial keratitis is
Staphylococcus aureus; in cases involving contact lens wear and cosmetics, the most common infective organism can be Pseudomonas aeruginosa
mild diameter and stromal depth
< 1-2 mm and < 20%
mild setting and course
outpatient, 5-10 days
moderate diameter and stromal depth
2-4 mm and 20-50%
moderate setting and course
outpatient, 10-20 days
severe diameter and stromal depth
> 4 mm and > 50%
severe setting and course
hospital and 3 weeks
Low AC reaction
none to minimal
Low RSVP
c/w signs
Low discharge
none to minimal
borderline AC reaction
mild
borderline RSVP
c/w signs
borderline discharge
moderate
high AC reaction
moderate
high RSVP
quick onset
high discharge
mucopurulent
How do you treat low risk infectious bacterial keratitis?
4th and 3rd generation fluoroquinolones off/on-label
4th generation fluoroquinolones off-label
o moxifloxacin (Vigamox) o gatifloxacin (Zymar)
• chlorofluoroquinolone off-label
o besifloxacin (Besivance) with DuraSite vehicle
What does DuraSite do?
increases ocular surface residence time for lids, conj, and cornea
What do we use for patients 12 years and older for treating corneal ulcers?
Ciloxan (ciprofloxacin)
What do we use for treatment of bacterial corneal uclers in patients 1 and older?
Oculflox (ofloxacin)
1-2gtt q30min while awake and
awaken 4-6h after retiring to instill 1-2gtt X 2 days
then 1-2gtt QID X 5-7 days
How do we treat secondary iritis?
cycloplegia
o cyclopentolate,homatropine,or atropine according to size/location
odose frequency often higher than with abrasions, other less serious corneal conditions
When can we consider steroids?
after ulcer is sterile and before cornea reepithelializes
When NOT to use steroids alone?!
- Epithelial (non-stromal) Herpes Simplex Keratitis – NO EXCEPTIONS!
- Active Bacterial or Fungal Infection
- Large Corneal Epithelial Defects
- Unsure of Diagnosis
Exceptions to Steroids (Antibiotic + Steroid)
- Epithelial (non-stromal) Herpes Simplex Keratitis - NO EXCEPTIONS!
- Bacterial Infections IF clinically significant concurrent secondary inflammation present
