Microbiology

Question 1

conjunctivitis

Answer 1

conjunctiva is red and inflamed

acuity, pupillary responses and corneal lustre are unaffected

eyes itch, burn and lacrimate

there may be photophobia

often bilateral with lids sticking together

Question 2

papillae conjunctivitis

Answer 2

red dots of varying size

allergic and bacterial

Question 3

follicular conjunctivitis

Answer 3

Question 4

course of conjunctivitis

Answer 4

usually self-limiting

Question 5

what should you consider in prolonged conjunctivitis - especially in YP or those with sexual disease

Answer 5

chlamydial conjunctivitis

Question 6

common organisms of bacterial conjunctivitis in neonates

Answer 6

• Staph. aureus*
• Neisseria gonorrhoea*
• Chlamydia trachomatis*

Question 7

common organisms for bacterial conjunctivitis in all other ages

Answer 7

• Staph. aureus*
• Strep, pneumoniae*
• H. influenzae* (especially in children)

Question 8

what can allergic conjunctivitis be treated with

Answer 8

anti histamine drops

Question 9

how does the discharge of bacterial conjunctivitis differ from viral etc

Answer 9

more purulent and eye more red

Question 10

what is the first line treatment for bacterial conjunctivitis

Answer 10

swab of eye and treat with topical ABx, usualyl chloramphenicol

Question 11

2nd and 3rd line treatment for bacterial conjunctivitis

Answer 11

2 - fusidic acid (S. Aureus)

3 - gentamicin (Gram-negatives, severe but good)

Question 12

what organism does chloramphenicol not treat

Answer 12

Pseudomonas aeruginosa

Question 13

when should chloramphenicol be avoided

Answer 13

anaplastic anaemia (possible association) or allergy

Question 14

describe the defining features of viral conjunctivitis

Answer 14

more pink than bacterial

there is no green/yellow pus, more of a thick watery secretion

there is often a history of URTI, and pre-oricular and submandibular lymph nodes often are enlarged

very contagious

red velvety appearance of conjunctiva and raised follicles

Question 15

what is the most common cause of viral conjunctivitis

Answer 15

Adenovirus

Question 16

adenovirus conjunctivitis

Answer 16

often follows URTI

small lymphoid aggregates appears as follicles on conjunctiva

Question 17

HSV conjunctivitis

Answer 17

usually a manifestation of primary infection

treated with acyclovir (analogue of guanosine)

Question 18

ophthalmic shingles

Answer 18

can present with purulent conjunctivitis etc

pain and neuralgia in the distribution of CNV1 dermatome precedes blistering rash

Hutchison’s sign may be present - tip of nose from nasociliary branch

Question 19

chlamydial conjunctivitis history

Answer 19

unresponsive to treatments

chronic and may last for months

Question 20

who usually gets chalmydial conjunctivitis

Answer 20

more common in newborns

also young adults

Question 21

symptoms of chlamydial conjunctivitis

Answer 21

unilateral conjunctivitis (less commonly bilateral)

chronic history

there may be symptoms of urethritis and vaginitis

Question 22

describe the eye in chlamydial conjunctivitis

Answer 22

it is a chronic follicular conjunctivitis

the follicles are described as being like rice grains, can lead to subtarsal scarring

Question 23

treatment of chlamydial conjunctivitis

Answer 23

topical oxytetracycline

oral azithromycin may also be needed for genital chlamydial infection

Question 24

keratitis

Answer 24

Corneal inflammation, identified by a white area on the cornea indicating a collection of white cells.

Question 25

hypopyon

Answer 25

a collection of inflammatory cells seen in the anterior chamber, also called sterile pus

Question 26

treatment of bacterial keratitis

Answer 26

hourly drops of a 4-quinolone eg **ofloxacin** (doesnt treat *S. Pneumoniae)* also gentamicin and cefuroxim

Question 27

HSV keratitis

Answer 27

classical **dendritic ulcer** as this is where the infection is very painful and may be recurrent DO NOT treat with steroids - **acyclovir**

Question 28

adenovirus keratitis

Answer 28

bilateral and usually follows UTI contagious may affect vision small white flecks are seen - subepithelial infiltrates

Question 29

fungal keratitis

Answer 29

usually seen in contact lense wearers common organisms are: acanthamoeba and pseudomonas aeruginosa there is typically more of a chronic indolent history, often with note of trauma from vegetation less of a red eye is seen

Question 30

orbital cellulitis

Answer 30

inflammation of the eye tissues behind the orbital septum, sight threatening it is important to distinguish from pre-septal cellulitis as this is not that severe

Question 31

typical patient with orbital cellulitis

Answer 31

Typically children with lid swelling, fever, orbital inflammation, and decreased eye mobility

Question 32

what other clinical features are often present in orbital cellulitis

Answer 32

infection is often spread from paranasal sinus infection - there will be mucous coming out the nose check the ears and pupils in children

Question 33

organisms commonly causing orbital cellulitis

Answer 33

* Staphylococci * Streptococci * Coliforms * H. influenzae * Anaerobes

Question 34

investigation and treatment of orbital cellulitis

Answer 34

CT scan to identify orbital abscesses broad spectrum ABx and monitor closely abscess may require drainage

Question 35

what is the most common organism causing endophthalmitis

Answer 35

Staph epidermidis

Question 36

endophthalmitis

Answer 36

devastating infection of entire globe of eye very painful and associated with decreased vision, can be sight threatening