Case Study with one of the differential diagnosis is bacterial keratitis

1. Bacterial keratitis
By:
Chong Chen Yee
Noor Munirah binti Awang Abu Bakar
-Optometrist-

2. Case:
• 23 years old lady, presented with 4 days history of redness of
the LE associated with pain. The RE BCVA is 6/6, LE BCVA 6/24.
• 23 years old, young
• Lady
• 4 days
• Unilateral reduced vision LE
• With complaints of redness and pain

3. Differential Diagnosis

4. Corneal disease- Cause
Bacterial infection causes
acute ocular pain, redness &
reduced vision

5. Bacterial keratitis
• What is bacterial keratitis?
• An infection of the cornea due to bacteria
• Causes pain, redness, reduced vision, light sensitivity, corneal
infiltrates, ulcerations, anterior chamber inflammation and
tearing or discharge from eye.
• A sight-threatening process
• Usually develops very quickly, and if left untreated, can cause
blindness.
• The bacteria usually responsible:
• Staphylococcus Aureus (Infection)
• Pseudomonas Aeruginosa(CL wearer)

6. Bacterial keratitis
• Superficial keratitis:
• Affects uppermost layers of the cornea.
• Once healed, there is usually no scar on the cornea.
• Deep keratitis:
• Affects deeper corneal layers.
• Once healed, can be a scar left after healing which may or may
not affect vision, depending on where the scar is located.

7. Etiologies

8. Symptoms:
Patients with bacterial keratitis usually complain of rapid onset (acute) of :

9. Signs: (Chronological order)
(Kanski, 2003)

10. Other Signs:
• Folds in the Descemet membrane
• Upper eyelid edema
• Posterior synechiae
• Conjunctival hyperemia
• Adherent mucopurulent exudate
• Endothelial inflammatory plaque

11. Pathogenesis (Endothelium)
Within hours to 48 hours

12. Pathogenesis (Endothelium-stroma)

13. Pathogenesis

14. Investigation 1
• History taking
Important step in management of corneal infection.
Corneal ulcer and Corneal abrasion (what, when, where, how?)

15. • Clinical Signs (must document them carefully which helpful
in management)
Eyelid abnormalities (trichiasis, lagophthalmos)
Corneal sensation
Corneal epithelial defects (fluorescein staining, size and shape)
Corneal inflammatory infiltrate (size and shape)
Thinning or perforation of the cornea (complications)
Hypopyon
Investigation 2

16. • Role of laboratory culture
Investigation 3

17. Culture Media for Bacteria
Keratitis
Standard Media Common Isolates
Blood agar Anaerobic bacteria
(P. aeruginosa, S.
aureus, S. epidermidis,
S. pneumoniae)
Chocolate agar Anaerobic bacteria
(H. influenzae, N.
gonorrhoeae,
Bartonella species)
Thioglycollate
broth
Anaerobic bacteria
• Topical anesthetics
(minimal inhibitory effects
on organism recovery)
• Multiple samples from the
advancing borders of
representative area of the
ulcer are often required to
achieve maximal yield of
organisms.

18. Gram stain
To confirm the presence of microorganism with sensitivity 55-79%.
To distinguish bacteria from fungi
Gram-positive retain the gentian violet-iodine complex and appear
bluish-purple.
Gram-negative lose the gentian violet-iodine complex by
decolorization with acid alcohol and appear pink when counterstained
with safranin.

19. Management
Central or severe keratitis
Loading dose of fluoroquinolone eye drops every 5 to 15 mins for 1st
hour,
hourly day and night (48 hours)
hourly day and 2H night (3rd
day)
2H day and 4H night (4th
& 5th
day)
4H day and night (6th
& 7th
day)
After 7th
day, tapered to 6H and stopped when appropriate.
Cycloplegic agents use to decrease shynechia formation and decrease pain and
ciliary spasm.
Use of topical corticosteroids with topical antibiotics. The corticosteroids used
to achieve control of inflammation.

20. Management

21. Management

22. Conclusion
• In this case, this young lady presented with 4 days painful
unilateral reduced vision LE associated with redness.
• The differential diagnosis for this case can uveitis, scleritis,
corneal infection and trauma.
• For corneal infection, among all the possible
microorganisms (Bacteria, virus, fungi, acanthamoeba etc),
only bacterial infection can cause acute ocular pain,
redness and reduced vision.
• The laboratory culture must be made in order to confirm the
diagnosis.
• For other possible diagnosis, special investigations must be
conducted.

23. References:
• Bartolomei, A. 2014. Bacterial Keratitis.American Academy of
Ophthalmology. From
http://eyewiki.aao.org/Bacterial_Keratitis
• Murillo-Lopez, F.H. 2014. Bacterial Keratitis. Medscape. From
http://emedicine.medscape.com/article/1194028
• Kanski, J,J. 2003. Clinical Ophthalmology: A Systematic
Approach. Butterworth-Heinemann.
• Jay H. Krachmer, MD, Mark J. Mannis MD, and Edward J.
Holland. Cornea (Fundamentals, diagnosis and management).
3rd
edition. 2011. Elsevier.

24. Thank You