Ocular Infections

Question 1

what are the causes of bacterial conjunctivitis?

Answer 1

Adults – Staph Aureus, Strep Pneumoniae, Haemophilus influenzae
Neonates – staph aureus, Neisseria gonorrhoea, chlamydia trachomatitis

Question 2

what are the causes of viral conjunctitis?

Answer 2

Adenovirus
Herpes Simplex
Herpes Zoster

Question 3

what is the cause of chlamydia conjunctivits?

Answer 3

chlamydia (coming out of womb)

Question 4

what are the clinical features of bacterial conjunctivitis?

Answer 4

Mucopurulent discharge
Sticky eyelashes/eyelids matted
Gritty 
NOT periauricular enlargement
Eyelid oedema
Conjunctival redness
One eye then next
Skin around eye affected

Question 5

what are the clinical features of viral conjunctivitis?

Answer 5

Watery discharge 
Often bilateral 
Enlarged follicular bumps
Some papillary conjunctival reaction
Gritty/burning
Enlarged periauricular
Fine diffuse pinkness
Adenovirus – follows cold
Herpes – vesicles
Blood vessels arise near base of elevated vessels

Question 6

what are the clinical features of chlamydia conjunctivitis?

Answer 6

Often chronic history
Unresponsive
Suspect in bilateral young adults
\+/- urethritis vaginitis
Contact tracing 
Subtarsal scarring

Question 7

how is vision affected in conjunctivitis?

Answer 7

normal or very mildly reduced – acuity will always improve with pinhole

Question 8

how is conjunctivitis diagnosed?

Answer 8

swab

Question 9

how is bacterial conjunctivitis managed?

Answer 9

Topical antibiotics
Chloramphenicol (treats most)
Fusidic Acid (staph aureus)
Gentamicin

Question 10

how is viral conjunctivitis managed?

Answer 10

Supportive – cool compress and lubricants

Question 11

how is chlamydia conjunctivitis managed?

Answer 11

Oxytetracycline

Question 12

how is chloramphenicol?

Answer 12

antibiotic eye ointment

Question 13

what is the action of chloramphenicol?

Answer 13

o Inhibits peptidyl transferase – inhibit protein synthase

Question 14

what are the side effects of chloramphenicol?

Answer 14

allergy, anaemia, grey baby syndrome

Question 15

what is the management of seasonal allergy conjunctivitis?

Answer 15

antazoline (anti histamine)

Question 16

what is the physiology of seasonal allergy conjunctivitis?

Answer 16

acute IgE-mediated reaction to airborne allergens which interact with IgE primed conjunctival mast cells. Leads to mast cell degranulation with the release of preformed histamine, responsible for the acute phase response.

Question 17

what is keratoconjunctivitis sicca?

Answer 17

tear film abnormalities and/or ocular surface inflammation

Question 18

what is the management of keratoconjunctivitis sicca?

Answer 18

topical lubricants

Question 19

what are the causes of bacterial keratitis?

Answer 19

Streptococcus
Pseudomonas
Enterobacteriaceae
Staphylococcus
Risks: contact lenses, trauma, steroids

Question 20

what are the causes of herpetic keratitis?

Answer 20

Herpes Simplex Type 1

Question 21

what are the causes of adenovirus keratitis?

Answer 21

Usually follows URTI

Most commonly adenovirus serotype 8, 19, 37

Question 22

what are the causes of fungal keratitis?

Answer 22

Aspergillus falvus
Aspergillus fumigates
Fusarium
Candida

Question 23

what is the pathophysiology of bacterial keratitis?

Answer 23

Corneal inflammation
Diffusion of inflame cells into AC settles as Hypopyon
Bacterial toxins and enzyme destroy cornea = CORNEAL ULCER

Question 24

what is the pathophysiology of herpetic keratitis?

Answer 24

After initial infection virus spreads from epithelial cells to sensory nerve endings to cell body of CNV
ganglion
Formation of DENDRITIC ulcer

Question 25

what is the pathophysiology of adenovirus keratitis?

Answer 25

Highly contagious – eye secretions, air droplets

Question 26

what is the pathophysiology of fungal keratitis?

Answer 26

Trauma with vege/organic matter | Grows slowly then proliferates and breaks into anterior chamber

Question 27

what are the clinical features of bacterial keratitis?

Answer 27

``` Anterior chamber reaction +/- hypopyon Painful red eye Visual loss Corneal inflam Ciliary injection Eyelid oedema Ulcer = opacity ```

Question 28

what are the clinical features of herpetic keratitis?

Answer 28

``` Pain Photophobia Blurred vision Tearing Redness Recurrent Dendritic ulcer -branches/tree Vesicular lid lesions Follicular conjunctivitis, preauricular nodes ```

Question 29

what are the clinical features of adenovirus keratitis?

Answer 29

Bilateral Blurring/photophobia Subepithelial infiltrates – central ulceration with irregular border + grey dots Redness of bulbar and palpebral conjunctiva Preauricular lymphadenopathy Conjunctivitis if severe

Question 30

what are the clinical features of fungal keratitis?

Answer 30

``` Conjunctival injection Epithelial defect Suppuration Stromal infiltrate Redness Hypopyon Gray/brown pigmentation ```

Question 31

what is the management of bacterial keratitis?

Answer 31

Eye threatening Hourly drops of topical steroids Abx e.g luxacin

Question 32

what is the management of herpetic keratitis?

Answer 32

AVOID steroids | Gangcyclovir for ulcer

Question 33

what is the management of adenovirus keratitis?

Answer 33

Give topical AB to prevent secondary | Steroids to speed recovery if chronic

Question 34

what are the causes of orbital cellulitis?

Answer 34

* Staphylococci * Streptococci * Coliforms * Haemophilus Influenzae * Anaerobic

Question 35

what is the route of infection in orbital cellulitis?

Answer 35

o Direct extension from sinus o Extension from focal orbital infection o Post-operative

Question 36

what is orbital cellulitis?

Answer 36

Infection of the soft tissues of the orbit posterior to the orbital septum

Question 37

what is preorbital cellulitis?

Answer 37

Infection of soft tissue of the eyelids + periocular region anterior to the orbital septum

Question 38

what are the clinical features of orbital cellulitis?

Answer 38

* Painful – especially on eye movements – kids will move their heads * Proptosis – bulging of the eye * Dark red discolouration of the orbit, chemosis, hyperaemia of the conjunctiva * Resistance to opening * Often associated with paranasal sinus * Sight threatening * Pyrexial

Question 39

what is the management of orbital cellultitis?

Answer 39

* Need to differentiate between pre-septal and orbital * If any suggestions restriction of muscle or optic nerve dysfunction then scan * Broad spectrum AB and monitor * Sometimes abscess will require drainage * CT scan

Question 40

what is endophtalmitis?

Answer 40

Extreme form of posterior uveitis

Question 41

what is the cause of endophtalmitis?

Answer 41

* Often conjunctival “commensal” | * Most common staph epidermis – post surgery or penetrating injury

Question 42

what are the clinical features of Endophthalmitis?

Answer 42

* Very red eye * Eyelid swelling * Vitreous is opacified – infiltration by (PMNs) * Injected conjunctiva and sclera * Hypopyon, white lesions, cotton wool spots * Cells + flare on silt lamp examination * Uveitis

Question 43

how is endophthalmitis diagnosed?

Answer 43

aqueous/vitreous for culture

Question 44

what is the management of endophthalmitis?

Answer 44

* Intravitreal amikacin/ceftazidime/vancomycin * Topical antibiotics * EVS

Question 45

what is the pathophysiology of endophthalmitis?

Answer 45

* Blood borne organisms permeate the blood ocular barrier either by direct invasion or by changes in vascular endothelium by substrates released during infection * Destruction of intraocular tissues may be due to direct invasion or from inflammatory mediators

Question 46

what is pan ophthalmitis?

Answer 46

inflammation of all coats of eye

Question 47

what is the chorioretinitis?

Answer 47

inflammation of the choroid

Question 48

what are the causes of chorioretinitis?

Answer 48

* CMV in AIDs * Toxoplasma gondii – protoxin infection – cats + raw meat * Toxocara canis – parasitic nematode

Question 49

what are the clinical features of toxoplasmosis chorioretinitis?

Answer 49

``` Mild flu like illness Enters latent phase with cysts forming Scarring of sclera White fluffy thig Can reactivate ```

Question 50

what are the clinical features of Toxocara chorioretinitis?

Answer 50

Worm cannot replicate – self limiting | Form granulomas

Question 51

what are the general clinical features of Chorioretinitis?

Answer 51

``` Floating black spots Blurred vision Redness Excessive tearing Sensitivity to light ```

Question 52

how is Chorioretinitis diagnosed?

Answer 52

serology

Question 53

how is Chorioretinitis managed?

Answer 53

combo of steroids + antibiotics