Micro Flashcards
(28 cards)
Main causes of bacterial conjunctivitis in neonates
Staph aureus
Neisseria gonorrhoeae
Chlamydia trochamitis
Pt will have sticky eye for first 28 days (from birth canal -> sexually transmitted)
Main causes of bacterial conjunctivitis in non-neonates (all other ages)
Staph aureus
Strep pneumoniae
Haemophilus influenzae (esp. kids)
Treatment of bacterial conjunctivits
Self limiting in 14 days
If wanted to clear up faster:
Topical antibiotic (usually chloramphenicol)
Beware of allergy or aplastic anaemia
Main causes of viral conjunctivits
Adenovirus
Herpes simplex
Herpes zoster (inc. ophthalmicus)
History of chlamydial conjunctivitis
Unresponsive to treatment
Often bilateral conjunctivitis in young adult
May have vaginitis/urethritis symptoms
Bacterial keratitis associations
Contact lens wear
Corneal pathology
Will common have a hypopyon (build up of white cells in anterior chamber)
Treatment of bacterial keratitis
Hourly eye drops for 48 hours (day + night)
(antibiotic depending on pathogen)
4th generation quinolone (eg ofloxacin) will treat most gram negatives including coliforms and pseudomonas aeruginosa. (will not treat step pneumonia)
Gentamicin and cefuroxime combo will treat most gram negative and positive organisms
Treatment of herpetic keratitis
If recurrent give topical acyclovir
DO NOT GIVE STEROIDS - may cause corneal melt and perforation
Adenoviral keratitis history
Bilateral
Follows URTI usually
Contact with infected person (contagious)
Affects vision
Treatment of adenoviral keratitis
Give antibiotics to prevent a secondary infection
If the disease becomes chronic give steroids to speed up recovery
Common causes of fungal keratitis
Acanthamoeba
Pseudomonas aeruginosa
Common history of fungal keratitis
Contact lens use
Trauma preceding incident
Non-healing (slow to heal)
History of orbital cellulitis
Paranasal sinusitis
Pain (especially on moving eye)
Proptosis
Pyrexial
Orbital cellulitis management
Broad spectrum antibiotics (vancomycin + cefotaxime (add metronidazole if intracranial extension suspected))
Abscess drainage if necessary
Scan if there is suggestion of muscle restriction or optic nerve dysfunction
History of endophthalmitis
Recent surgery
Very painful and very red eye
Decreased vision
Most common endophthalmitis organism and treatment
Staph epidermidis (conjunctival commensal) Treatment is intra-vitreal amikacin and vancomycin + topical antibiotic
Common causes of chorioretinits
Cytomegalovirus (CMV) in AIDS Toxoplasma gondii (toxoplasmosis) toxocara canis (worm)
How does someone get toxocara canis and what are the issues associated
Through contact with an infected cat or dog
May form granulomas which can cause irreversible vision loss
Mode of action of chloramphenicol
Inhibits peptidyl transferase enzyme
Bacterocidal effect in strep. and haemophilus
Bacterostatic effect in staph
Side effects of chloramphenicol
Potential allergy
1:40,000 cases causes irreversible aplastic anaemia
Grey baby syndrome
How do penicillins and cephalosporins work
Contain a B-lactam ring which inhibits enzyme in bacteria which produces the cell wall
How do quinolones work and give examples
Levofloxacin, ofloxacin, ciprofloxacin etc.
Work by inhibiting DNA gyrase which is repsonsible for compressing bacterial DNA into supercoils. Therefore the coils decompress and bacteria die
How does aciclovir work?
Mimics guanine inhibiting viral DNA synthesis
Treatment of chlamydial conjunctivitis
Topical oxytetracycline
If genital infection in adults also: oral azithromycin too
