Ophth microbiology Flashcards
organisms that are seen in neonatal bacterial conjunctivitis
S aureus
Neisseria gonorrhea
Chlamydia trachomatis
refer all cases of neonatal conjunctivitis to phthalmology as likely cause = an __
STI
bacterial causes of conjunctivitis
S. aureus
H. influenzae (esp in kids)
strep pneumoniae
treatment for bacterial conjunctivitis
swab for culture
chloramphenicol unless allergy/ Hx of aplastic anaemia
signs of adenoviral conjunctivitis
very watery red eye, usually bilateral
after URTI
signs of a bacterial conjunctivitis
red eye, mucousy discharge
perhaps blurred vision
Herpes simplex conjunctivitis signs =
unilateral usually
maybe blistering rash on eyelid
maybe a dendritic ulcer
HZX sign that indicates nasociliary branch of ophthalmic nerve is affected
Hutchinson’s sign - vesicles on tip of nose
three signs that conjunctivitis may be due to chlamydia
chronic Hx
bilateral and unresponsive to Rx
in young adults
pathognomonic sign of chlamydial conjunctivitis
lymphatic collections in follicles on underside of eyelids = “rice grains”
bacterial keratitis s+S
large white lesion which stains with fluorescein (corneal ulcer)
hypopyon
bacterial keratitis is usually associated with another ____/___
corneal pathology (eg. reduced sensation) contact lenses
hypopyon =
white accumulation at bottom of iris
leukocytic exudate in anterior chamber
treatment for bacterial keratitis =
hrly drops (tobramycin-fortified or gentamicin-fortified) high risk moderate risk = topical quinolone low risk = topical polymyxin B/trimethoprim or sulfacetamide ophthalmic
herpetic keratitis is ___ on first occurrence and then on recurrences = ___
signs =
very painful
reduced corneal sensation
vision reduced acutely
dendritic ulcers
signs of adenoviral keratitis
subepithelial infiltrates (small and white) = blurred vision
bilateral
post URTI
___ usually only causes keratitis is contact lens users who swim
acanthamoeba
__+__ are organisms that cause keratitis in contact lens wearers
acanthamoeba
pseudomonas aeruginosa
s+S of orbital cellulitis
painful (esp on eye movements) proptosis ass w paranasal sinusitis often pyrexial sight threatening
if suspect orbital abscess then imaging =
CT
in optic nerve compression __ vision is first to go
colour vision
chalazion =
stye
dacrocystitis
blocked tear duct
__+__ - the two types of orbital cellulitis
chich do you watch closely
pre-septal
orbital - watch closely
organisms that cause orbital cellulitis
staph strep coliforms
h influ
anaerobes
Rx for orbital cellulitis
broad spectrum Abx
image orbital cellulitis if __/___
muscular or nerve dysfunction
endophthalmitis =
devastating infection of the whole eye globe
usual cause of endophthalmitis =
post-op
s+s of endophthalmitis
v v painful
reduced vision
v red eye
sight threatening
most common org of endophthalmitis =
org.s are usually ___ of the conjunctiva
S. epidermidis
commensals
treatment of endophthalmitis
prophylactic Abx during eye Sx
intravitreal amikacin and vancomicin + topical Abx
3 causes of chorioretinitis
CMV in IS/AIDs
toxoplasma gondii - reactivates in IC
toxocara canis =>granuloma and irreversible vision loss
corneal scrapes are used to diagnose
bacterial keratitis
swabs for culture from eye are used to diagnose
bacterial, chlamydial and viral conjunctivitis
aqueous/vitreous for culture is used to diagnose ___
endophthalmitis
microscopy/culture of eye is used to diagnose ___
acanthamoeba and contact lens cases
serology of eye to diagnose __+___
toxocara
toxoplasma
chloramphenicol inhibits _____
bactericidal for __+__
bacteriostatic for ____
side effects =
peptidyl transferase - bac protein formation
Strep + H influ
staph
allergy, irreversible aplastic anaemia, grey baby syndrome
__+___ attack bacterial cell wall = bacterio___ for __+__ treatment
penicillins and cephalosporins
cidal
cellulitis and dacrocystitis
keep eye drop bottles for up to __ as if longer then __
4 wks
contaminated esp by pseudomonas
antiviral used for dendritic ulcers of the cornea
aciclovir 3% drops
don’t give steroids for a dendritic ulcers as can cause __/___
corneal melt and perforation
Rx for bacterial conjunctivitis
chloramphenicol (for most except pseudo aeruginosa) fusidic acid (S. aureus) gentamicin (gram -ves - including P. aeruginosa)
Rx for chlamydial conjunctivitis =
topical oxytetracycline (+PO azithromycin for genital inf)
treatment for bacterial keratitis =
4- quinolone ofloxacin - most gram -ves but not strep pneum
gentamicin and cefuroxime - combo for most +ve and -ves
