Microbiology

Question 1

What are the causal organisms in bacterial conjunctivitis in neonates?

Answer 1

Staph aureus, neisseria gonorrhoeae, chlamydia trachomatis-refer all to ophthalmology

Question 2

What are the causal organisms in bacterial conjunctivitis in adults and children?

Answer 2

S. aureus, strep pneumonia, haemophilus influenzae (esp. children)

Question 3

What is the treatment of bacterial conjuctivitis?

Answer 3

Swab
Topical antibiotic-usually chloramphenical qds
Drops vs ointment

Question 4

When should you avoid chloramphenicol in bacterial conjuctivitis?

Answer 4

If pt has histry of aplastic anaemia or allergy

Question 5

What are the pathogens that can cause viral conjuctivitis?

Answer 5

Adenovirus, herpes simplex, herpes zoster

Question 6

How will herpes simplex conjunctivitis present?

Answer 6

Grouped painful vesicles below eye. Redness, pain around eye

Question 7

What is herpes zoster ophthalmicus?

Answer 7

Subtype of shingles associated with CNV1

Question 8

What is the history of a patient with chlamydial conjunctivitis?

Answer 8

Often chronic history, Unresponsive to treatments. Suspect in bilateral conjunctivitis in young adults. May/may not have symptoms of urethritis/vaginitis.

Question 9

What does a case of chlamydial conjunctivitis require?

Answer 9

Contact tracing

Question 10

What is the appearance of chlamydial conjunctivitis?

Answer 10

Usually unilateral red eye with purulent discharge, predominant follicular conjunctivitis

Question 11

What type of pathogens can cause microbial keratitis?

Answer 11

Bacterial, viral, fungi

Question 12

What will bacterial keratitis present with?

Answer 12

Hypopyon

Question 13

Do bacterial keratitis pts require admission?

Answer 13

Yes-hourly drops and daily review

Question 14

What is usually associated with bacterial keratitis?

Answer 14

Other corneal pathology or contact lens wear

Question 15

What will herpetic keratitis present with?

Answer 15

Dendritic ulcer

Question 16

What do recurrences of herpetic keratitis result in?

Answer 16

Reduced corneal sensation

Question 17

What can happen if herpetic keratitis is treated with steroids?

Answer 17

Cause a corneal melt and perforation of the cornea

Question 18

What will adenoviral keratitis present with?

Answer 18

Subepithelial infiltrates

Question 19

What are the clinical features of adenoviral keratitis?

Answer 19

Bilateral, usually follows URTI. Contagious, may affect vision

Question 20

What is the treatment of adenoviral keratitis?

Answer 20

Topical AB to prevent secondary infection. Can require steroids to speed up recovery if becomes chronic

Question 21

What organisms can cause keratitis due to contact lenses?

Answer 21

Acanthamoeba, pseudomonas aeruginosa

Question 22

What will fungal keratitis present with?

Answer 22

Hypopyon

Question 23

What kind of history will a fungal keratitis have?

Answer 23

More indolent than microbial keratitis. Usually history of trauma from vegetation

Question 24

How will orbital cellulitis present with?

Answer 24

Painful-especially on eye movement. Proptosis, often associated paransal sinusitis, pyrexial

Question 25

Can orbital cellulitis affect sight?

Answer 25

Yes-sight threatening

Question 26

How are orbital abscesses identified in orbital cellulitis?

Answer 26

CT

Question 27

Where can an orbital cellulitis have spread from?

Answer 27

Direct extension from sinus, extension from focal orbital infection (infected chalazion, dacryocystiitis)

Question 28

What must be differentiated between in orbital cellulitis?

Answer 28

Preseptal and orbital

Question 29

What organisms can cause orbital cellulitis?

Answer 29

Staph, strep, coliforms, haemophilus influenzae, anaerobes

Question 30

When should a scan always happen in orbital cellulitis?

Answer 30

If any suggestion of restriction of muscles or optic nerve dysfunction

Question 31

What is the treatment for orbital cellulitis?

Answer 31

Broad spectrum AB, sometimes abscess drainage

Question 32

What is endophthalmitis?

Answer 32

Infection inside of the eye-post surgical or endogenous

Question 33

How will endophthalmitis present?

Answer 33

Very painful, with decreasing vision. Very red eye, threat to sight

Question 34

What organisms cause endophthalmitis?

Answer 34

Often conjunctival commensals-most common staph epidermidis

Question 35

What is the treatment for endophthalmitis?

Answer 35

Intravitreal amikacin and vancomycin and topical antibiotics

Question 36

What can cause chorioretinitis?

Answer 36

CMV in AIDS, toxoplasma gondii, toxocara canis (worm)

Question 37

How will toxoplasmosis present?

Answer 37

Mild flu like illness, rarely causes further problems. In immunocompromised patients it enters latent phase with cysts forming

Question 38

Can toxoplasmosis reactivate?

Answer 38

Yes

Question 39

What treatment is required in sight threatening toxoplasmosis?

Answer 39

Systemic treatment

Question 40

What is toxocara caused by?

Answer 40

Toxocara canis-parasitic nemotode (roundworm)

Question 41

What can toxocara form?

Answer 41

Granulomas which can cause irreversible visual loss

Question 42

What is the difference between toxocara in cats/dogs and humans?

Answer 42

Affects cats/dogs, unable to replicate in humans-remains in immature form of worm

Question 43

Rather than swabs what is used in bacterial keratitis diagnosed?

Answer 43

Corneal scrapes

Question 44

What should be used in diagnosis of endophthalmitis?

Answer 44

Aqueous/vitreous culture

Question 45

How does chloramphenicol act?

Answer 45

Inhibits peptidyl transferase enzyme (therefore stops bacterial protein synthesis)

Question 46

What is the effect of chloramphenicol on strep, haemophilus and staph?

Answer 46

Bacterocidal for strep and haemophilus, bacterostatic for staph

Question 47

What are the side effects of chloramphenicol?

Answer 47

Allergy, irreversible aplastic anaemia, grey baby syndrome

Question 48

What is dacrocystitis?

Answer 48

An infection of the lacrimal sac, secondary to obstruction of the nasolacrimal duct at the junction of lacrimal sac.

Question 49

What is a common contaminant of bottles?

Answer 49

Pseudomonas

Question 50

What are antivirals used for?

Answer 50

Dendritic ulcers of the cornea-do not use steroid drops

Question 51

What can chloramphenicol be used for?

Answer 51

Most bacteria in conjuctivitis except Pseudomonas aeruginosa

Question 52

What bacterial conjunctivitis is fusidic acid used to treat?

Answer 52

S. aureus

Question 53

What bacterial conjunctivis can gentamicin be used for?

Answer 53

Most Gram -ve bacteria including coliforms, Pseudomonas aeruginosa

Question 54

What is used to treat chlamydial conjunctivitis?

Answer 54

Topical oxytetracycline (adults may also need oral azithromycin for genital infection)

Question 55

What bacterial keratitis is A 4-quinolone (Ofloxacin) used to treat?

Answer 55

Most Gram -ve bacteria including coliforms, Pseudomonas aeruginosa, Haemophilus influenza.

Question 56

What bacterial keratitis can gentamicin and cefuroxime be used to ttreat?

Answer 56

Combination will treat most Gram +ve and Gram -ve organisms

Question 57

How will a patient with adenoviral conjunctivitis present?

Answer 57

Redeye, itchy eyes. May give history of recent exposure to an individual with red eye, or history of recent symptoms of URTI. The eye infection may be unilateral or bilateral.

Question 58

What should be used in diagnosis for acanthamoeba?

Answer 58

Microscopy/culture

Question 59

What should be used in diagnosis for toxoplasma and toxocara?

Answer 59

Serology