Ophthalmology Flashcards
What are the main bacterial causes of conjunctivitis in neonates?
Staph aureus
Neisseria gonnorrhoea
Chlamydia trachomatis
What are the main bacterial causes of conjunctivitis in adults and children?
Staph aureus
Strep pneumoniae
H. influenzae (especially in children)
What investigation should be done for bacterial conjunctivitis?
Swab
What is the treatment of bacterial conjunctivitis?
Topical chloramphenicol
When should chloramphenicol be avoided?
History of aplastic anaemia
Allergy
What are the main viral causes of conjunctivitis?
Herpes simplex
Herpes zoster
Adenovirus
Clinically, what is the main difference observed between viral and bacterial conjunctivitis?
Bacterial - pus discharge
Viral - watery discharge
What is observed in herpes simplex conjunctivitis?
White vesicles under the eye
What type of conjunctivitis should be suspected in young adults presenting with both eyes affected?
Chlamydial conjunctivitis
What is seen in chlamydial conjunctivitis?
White follicles
Subtarsal scarring
What is a hypopyon?
A level of white/yellow fliud at the bottom of the cornea due to WBC/infection
What is keratitis?
Inflammation of the cornea
What are the viral causes of keratitis?
Herpes
Adenovirus
What type of ulcer may be causes by herpetic keratitis?
Dendritic ulcer (looks like a branch)
Should you give steroids in herpetic keratitis?
NOOOO
Can cause corneal melt and perforation of cornea
What would you see in a slit lamp examination of adenoviral keratitis?
Subepithelial infiltrates
What are causes of keratitis due to wearing contact lens?
Acanthamoeba
Pseudomonas aeruginosa
What is orbital cellulitis?
Infection of soft tissues of orbit
What are the main organisms that cause orbital cellulitis?
Staph Strep Coliforms H. influenzae Anaerobes
What is the treatment of orbital cellulitis?
Broad spectrum AB and monitor for optic nerve/ muscle dysfunction
What is endophthalmitis?
Infection of whole eye
What are the common causes of endopthtalmitis?
Commensals e.g. staph epidermidis
Caused by surgery or trauma
What is the treatment of endophthalmitis?
Intravitreal amikacin and vancomycin and topical antibiotics
What is chorioretinitis?
Inflammation of choroid and retina
What are causes of chorioretinitis?
Cytomegalovirus (AIDs)
Toxoplasma gondii
Toxocara canis
What is toxoplasma gondii
A protoza (tic) that can cause toxoplasmosis
What is toxocara canis?
Worm parasite that can for granulomas that affects the growth of retinal epithelium, causing eye problems
What investigation is done for conjunctivitis?
Swab for culture - before LA or stain
What investigation is done for bacterial keratitis?
Corneal scrapes
What investigation is done for endophthalmitis?
Aqueous/ vitreous culture
What investigation is done for toxoplasma and toxocara?
Serology
How does chloramphenicol work?
Inhibit peptidyl transferase enzyme
What antibiotics inhibit cell wall synthesis?
Penicillins
Cephalosporins
(common B lactam ring)
What antibiotics inhibit nucleic acid synthesis?
Quinolones e.g. ofloxacin
What is the mechanism of action of aciclovir?
Antiviral - inhibits viral DNA synthesis
What organisms does chloramphenicol treat?
Most causes of bacterial conjunctivitis except pseudomonas aeruginosa
What does frusidic acid treat?
Staph aureus bacterial conjunctivitis
What does gentamicin treat?
Gram negative bacteria
What is the treatment for chlamydial conjunctivitis?
Topical oxytetracycline
If adult, give oral azithromycin for genital infection
What is the treatment for bacterial keratitis?
Gentamicin and cefuroxine (treats more gram negative and gram positive)
