Ocular Infections Flashcards
what are the causes of bacterial conjunctivitis?
Adults – Staph Aureus, Strep Pneumoniae, Haemophilus influenzae
Neonates – staph aureus, Neisseria gonorrhoea, chlamydia trachomatitis
what are the causes of viral conjunctitis?
Adenovirus
Herpes Simplex
Herpes Zoster
what is the cause of chlamydia conjunctivits?
chlamydia (coming out of womb)
what are the clinical features of bacterial conjunctivitis?
Mucopurulent discharge Sticky eyelashes/eyelids matted Gritty NOT periauricular enlargement Eyelid oedema Conjunctival redness One eye then next Skin around eye affected
what are the clinical features of viral conjunctivitis?
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
what are the clinical features of chlamydia conjunctivitis?
Often chronic history Unresponsive Suspect in bilateral young adults \+/- urethritis vaginitis Contact tracing Subtarsal scarring
how is vision affected in conjunctivitis?
normal or very mildly reduced – acuity will always improve with pinhole
how is conjunctivitis diagnosed?
swab
how is bacterial conjunctivitis managed?
Topical antibiotics
Chloramphenicol (treats most)
Fusidic Acid (staph aureus)
Gentamicin
how is viral conjunctivitis managed?
Supportive – cool compress and lubricants
how is chlamydia conjunctivitis managed?
Oxytetracycline
how is chloramphenicol?
antibiotic eye ointment
what is the action of chloramphenicol?
o Inhibits peptidyl transferase – inhibit protein synthase
what are the side effects of chloramphenicol?
allergy, anaemia, grey baby syndrome
what is the management of seasonal allergy conjunctivitis?
antazoline (anti histamine)
what is the physiology of seasonal allergy conjunctivitis?
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.
what is keratoconjunctivitis sicca?
tear film abnormalities and/or ocular surface inflammation
what is the management of keratoconjunctivitis sicca?
topical lubricants
what are the causes of bacterial keratitis?
Streptococcus Pseudomonas Enterobacteriaceae Staphylococcus Risks: contact lenses, trauma, steroids
what are the causes of herpetic keratitis?
Herpes Simplex Type 1
what are the causes of adenovirus keratitis?
Usually follows URTI
Most commonly adenovirus serotype 8, 19, 37
what are the causes of fungal keratitis?
Aspergillus falvus
Aspergillus fumigates
Fusarium
Candida
what is the pathophysiology of bacterial keratitis?
Corneal inflammation
Diffusion of inflame cells into AC settles as Hypopyon
Bacterial toxins and enzyme destroy cornea = CORNEAL ULCER
what is the pathophysiology of herpetic keratitis?
After initial infection virus spreads from epithelial cells to sensory nerve endings to cell body of CNV
ganglion
Formation of DENDRITIC ulcer
what is the pathophysiology of adenovirus keratitis?
Highly contagious – eye secretions, air droplets
what is the pathophysiology of fungal keratitis?
Trauma with vege/organic matter
Grows slowly then proliferates and breaks into anterior chamber
what are the clinical features of bacterial keratitis?
Anterior chamber reaction +/- hypopyon Painful red eye Visual loss Corneal inflam Ciliary injection Eyelid oedema Ulcer = opacity
what are the clinical features of herpetic keratitis?
Pain Photophobia Blurred vision Tearing Redness Recurrent Dendritic ulcer -branches/tree Vesicular lid lesions Follicular conjunctivitis, preauricular nodes
what are the clinical features of adenovirus keratitis?
Bilateral
Blurring/photophobia
Subepithelial infiltrates – central ulceration with irregular border + grey dots
Redness of bulbar and palpebral conjunctiva
Preauricular lymphadenopathy
Conjunctivitis if severe
what are the clinical features of fungal keratitis?
Conjunctival injection Epithelial defect Suppuration Stromal infiltrate Redness Hypopyon Gray/brown pigmentation
what is the management of bacterial keratitis?
Eye threatening
Hourly drops of topical steroids
Abx e.g luxacin
what is the management of herpetic keratitis?
AVOID steroids
Gangcyclovir for ulcer
what is the management of adenovirus keratitis?
Give topical AB to prevent secondary
Steroids to speed recovery if chronic
what are the causes of orbital cellulitis?
- Staphylococci
- Streptococci
- Coliforms
- Haemophilus Influenzae
- Anaerobic
what is the route of infection in orbital cellulitis?
o Direct extension from sinus
o Extension from focal orbital infection
o Post-operative
what is orbital cellulitis?
Infection of the soft tissues of the orbit posterior to the orbital septum
what is preorbital cellulitis?
Infection of soft tissue of the eyelids + periocular region anterior to the orbital septum
what are the clinical features of orbital cellulitis?
- 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
what is the management of orbital cellultitis?
- 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
what is endophtalmitis?
Extreme form of posterior uveitis
what is the cause of endophtalmitis?
- Often conjunctival “commensal”
* Most common staph epidermis – post surgery or penetrating injury
what are the clinical features of Endophthalmitis?
- 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
how is endophthalmitis diagnosed?
aqueous/vitreous for culture
what is the management of endophthalmitis?
- Intravitreal amikacin/ceftazidime/vancomycin
- Topical antibiotics
- EVS
what is the pathophysiology of endophthalmitis?
- 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
what is pan ophthalmitis?
inflammation of all coats of eye
what is the chorioretinitis?
inflammation of the choroid
what are the causes of chorioretinitis?
- CMV in AIDs
- Toxoplasma gondii – protoxin infection – cats + raw meat
- Toxocara canis – parasitic nematode
what are the clinical features of toxoplasmosis chorioretinitis?
Mild flu like illness Enters latent phase with cysts forming Scarring of sclera White fluffy thig Can reactivate
what are the clinical features of Toxocara chorioretinitis?
Worm cannot replicate – self limiting
Form granulomas
what are the general clinical features of Chorioretinitis?
Floating black spots Blurred vision Redness Excessive tearing Sensitivity to light
how is Chorioretinitis diagnosed?
serology
how is Chorioretinitis managed?
combo of steroids + antibiotics
