Microbiology

Question 1

Treatment of bacterial conjunctivitis

Answer 1

Chloramphenicol
Fusidic acid (Staph)
Gentamicin (Pseudomonas)

Question 2

How is bottle contamination stopped?

Answer 2

Preservative - keeps for 4 weeks

Question 3

Common contaminant

Answer 3

Pseudomonas

Question 4

Causes of contact lens conjunctivitis/keratitis

Answer 4

Acanthamoeba

Pseudomonas

Question 5

Causes of viral conjunctivitis

Answer 5

Adenovirus
Herpes simplex (white vesicles)
Herpes zoster (Hutchison Robinson sign)

Question 6

Chlamydial conjunctivitis symptoms/signs

Answer 6

Young, bilateral
Follicles
Subtarsal scarring
Urethritis, vaginitis

Question 7

Hypopyon

Answer 7

Level of WBCs/inflammatory cells in anterior chamber

Question 8

Bacterial keratitis cause

Answer 8

Usually in association with other corneal pathology, e.g. abrasion/dry/contacts

Question 9

Treatment of bacterial keratitis

Answer 9

Admit for hourly drops 1st 48 hours - Ofloxacin, Gentamicin

Corneal scrape

Question 10

Adenoviral keratitis features

Answer 10

Follows URTI
Bilateral, contagious, may affect vision
Subepithelial infiltrates

Question 11

Treatment of adenoviral keratitis

Answer 11

Chloramphenicol to prevent secondary infectoin

Steroid (if you know its not herpetic)

Question 12

Herpetic keratitis features

Answer 12

Very painful
Branching ulcers
Reduced corneal sensation

Question 13

Treatment of herpetic keratitis

Answer 13

NOT STEROIDS = corneal melt

Acyclovir

Question 14

Fungal keratitis features

Answer 14

More indolent, slower
History of trauma from vegetation (farmers)
Takes long time to heal

Question 15

Features of orbital cellulitis

Answer 15

Young kids
Very painful (especially on eye movements)
Proptosis, pyrexia, sight threatening
Often due to paranasal sinusitis/chalazion

Question 16

Investigation for orbital cellulitis

Answer 16

CT to identify orbital abscess

Question 17

Treatment for orbital cellulitis

Answer 17

Antibiotics, scan, drain

Question 18

Causes of orbital cellulitis

Answer 18

Staph, Strep, Coliforms, Haemi influenzae, Anaerobes

Question 19

Endopthalmitis

Answer 19

Infection of whole eye, sight threatening

Extremely painful, red, decreasing vision, systemically unwell

Question 20

Casuses of endophthalmitis

Answer 20

Commensals

Staph epidermidis

Question 21

Treatment of endophthalmitis

Answer 21

Intravitreal antibiotics

Question 22

Causes of chorioretinitis

Answer 22

CMV (in AIDS)
Toxoplasma gondii
Toxocara canis (worm)

Question 23

CMV chorioretinitis

Answer 23

Fast onset blindness

Treat with intravitreal injections

Question 24

Toxoplasma gondii chorioretinitis

Answer 24

Protozoan infection (tick bites)
Flu-like
Can reactivate
Systemic treatment if sight threatening

Question 25

Toxocara canis chorioretinitis

Answer 25

``` Parasitic nematode (roundworm) Often self limiting (cannot replicate in human) Seed in eye, form granulomas = irreversible vision loss ```

Question 26

Diagnosis of eye infections

Answer 26

Swab for culture (chlamydial needs patient permission) Corneal scrape (bacterial keratitis) Microscopy/culture (acanthamoeba) Serology (toxoplasma/toxicara)

Question 27

Antibiotic that inhibits bacterial protein synthesis

Answer 27

Chloramphenicol- inhibits peptidyl transferase

Question 28

Is chloramphenicol bactericidal or bacteriostatic?

Answer 28

Bactericidal for Strep and Haemophilus | Bacteriostatic for Staph

Question 29

Side effects of chloramphenicol

Answer 29

Aplastic anaemia | Grey baby syndrome

Question 30

Antibiotics that inhibit cell wall synthesis

Answer 30

Penicillins and Cephalosporins (B lactam ring = inhibits enzyme) Flucloxacillin and Fluoroquinolone for bacterial cellulitis

Question 31

Antibiotics that inhibit nucleic acid synthesis

Answer 31

Quinolones, e.g. ofloxacin (inhibits gyase = no supercoils)

Question 32

Treatment of chlamydial conjunctivitis

Answer 32

Oxytetracycline Azithromycin for genital infection Contact tracing

Question 33

Dacrocystitis

Answer 33

Infection of lacrimal sac