BACTERIAL CORNEAL ULCER
| A | Neisseria meningitidis |
|
| B | Pseudomonas pyocyanea | |
| C |
Pneumococcus |
|
| D |
Streptococcus haemolyticus |
The organism which can invade the intact corneal epithelium and produce purulent corneal ulcer is:
| A |
Neisseria meningitidis |
|
| B | Pseudomonas pyocyanea | |
| C |
Pneumococcus |
|
| D |
Streptococcus haemolyticus |
Ans. Neisseria meningitidis
Commonest causative organism of corneal ulcer is:
| A |
Pneumococci |
|
| B |
Streptococci |
|
| C |
Staphylococci |
|
| D |
Fungal |
Ans. Staphylococci
Earliest symptom in corneal ulcer is:
| A |
Loss of sensation |
|
| B |
Diminished vision |
|
| C |
Photophobia |
|
| D |
Pain |
Ans. Pain
Perforated corneal ulcer gives rise to:
September 2012
| A |
Anterior capsular cataract |
|
| B |
Posterior subcapsular cataract |
|
| C |
Vossius ring |
|
| D |
Rosette shaped cataract |
Ans. A i.e. Anterior capsular cataract
Which organismal infection is highly virulent and may cause corneal ulcer perforation within 48 hours?
| A |
Herpes simplex |
|
| B |
Pseudomonas |
|
| C |
Staphylococci |
|
| D |
Aspergillus |
Ans. b. Pseudomonas
Pseudomonas Keratitis
- Pseudomonas aeruginosa is the MC gram-negative organism isolated from corneal ulcers and is a frequent cause of contact lens-associated keratitis.
Source of Infection:
- These aerobic bacilli are found in moist environments.
- Frequently contaminate inadequately chlorinated swimming pools and hot tubs, ventilators, nebulizer and vaporizer solutions, and ophthalmic solution bottles.
Pathophysiology:
- The organism readily adheres to the damaged epithelium, and stromal invasion is rapid.
- Pseudomonas keratitis tends to progress rapidly if inadequately treated.
- Most commonly, the organism produces destructive enzymes such as protease, lipase, elastase, and exotoxin, which results in necrotic, lipase, elastase, and exotoxin, which results in necrotic, soupy ulceration.
- The ulcer often extends peripherally and deeply within hours and can rapidly involve the entire cornea.
- Ring ulcers can develop, and the corneal epithelium peripheral to the primary ulcer typically develops a diffuse grey, ground-glass appearance.
- The corneal stroma appears to dissolve into a greenish-yellow mucous discharge that fluoresces under ultraviolet (but not under cobalt blue) light.
- The suppurative ulcer frequently thins to a descemetocele that perforates.
- The ulcer is often associated with a marked anterior chamber reaction and hypopyon formation.
- Extensive keratitis can extend to the limbus and produce an infectious scleritis.
