Opthalmic infections Flashcards
What is conjunctivitis? What are the broad categories?
Inflammation of the conjuntiva.
- Infectious (viral or bacterial)
- Non-infectious (allergic or non-allergic)
What are the viral agents that can cause conjunctivitis?
mainly adenoviruses, sometimes enteroviruses
What are the clinical manifestations of viral conjunctivitis?
Pharyngeal conjunctival fever:
- Pharyngitis
- Fever
- Conjunctivitis
- +/- preauricular LAD
Isolated conjunctivitis
Epidemic keratoconjunctivitis
- conjunctivitis with keratitis
- stronger foreign body sensation
- may have subconjunctival hemorrhages
What are the manifestations of conjunctivitis? How to tell allergic vs. viral vs. bacterial?
- conjunctival hyperemia (engorgement of blood vessels)
- discharge, morning crusting of eye
- diffuse redness
- burning or itching
- conjunctival edema
Bacterial: unilateral, purulent discharge predominate complaint
Viral: watery discharge, burning or gritty feeling primary complaint, usually 2nd eye involved in 1-2 days
Allergic: bilateral, watery discharge, history.
***normal visual acuity***
What is the treatment for viral conjunctivitis?
Supportive care, usually resolves in days to weeks.
Cold compresses, eye lubricant drops, eye decongestant drops.
Possibly exclude from work/school because it is highly contagious
What are the bacterial agents that can cause conjunctivitis?
Acute:
- S. aureus
- S. pneumoniae
- S. pyogenes
- H. influenzae
- M. cattarhalis
Hyperacute:
- N. gonorrhoeae
Chronic
- Chlamydia trachomatis
What is the pathogenesis of allergic conjunctivitis? What are possible etiologies of non-allergic conjunctivits?
Allergic:
- allergen in air causes IgE mediated immune response
Non-Allergic
- post foreign body irritation
- chemical
- dryness
What is the clinical presentation of hyperacute conjunctivitis? How is it contracted?
Conjunctivitis with profuse purulent discharge (e.g. streaming down the face)
N. gonorrhea is passed genitals–>hands–> eyes
How does chlamydial conjunctivits differ from acute bacterial conjunctivitis? Types of conjunctivits
There is a follicular response (the inside of the eyelid is bumpy), and the is not usually a lot of purulent discharge.
Trachoma: self-limited follicular conjunctivitis, usually seen in children.
Adult inclusion conjunctivitis: caused by sertain strains of C. trachomatis, that is chronic and unilateral. Doesn’t respond to antibiotics.
What is the treatment for acute and hyperacute bacterial conjunctivitis?
Acute:
- antibiotic eyedrops (e.g. azithromycin)
Hyperacute:
- systemic therapy to cover gonorrhea (ceftriaxone) and chlamydia (doxycycline)
Define keratitis
Inflammation of the cornea
What is the pathophysiology of keratitis?
What are the risk factors fo keratitis?
Contact lenses****
Trauma to eye
eye surgery
topical corticosteroids
What are the clinical manifestations of keratitis?
- eye pain
- decreased vision
- photophobia
- foreign body sensation
- conjunctival injection
- tearing and discharge
- corneal infiltrate
What are the infectious causes of keratitis? Can they be distinguished by presentation?
Bacterial:
- S. aureus **
- S. pneumoniae
- S. pyogenes
- Pseudomonas
Viral
- HSV-1**
- Adenovirus
- VZV
Fungi
- Fusarium
Parasitic
- Acnthamoeba
**Can sometimes distinguish based on the pattern of corneal infiltrate**
What is the diagnostic approach to keratitis?
- Referral to an opthamologist
- Slit-lamp examination
- Corneal scrapings (bacterial culture, viral culture +PCR, fungal cultura, wet mounts, culture for Acanthamoaeba, Giemsa stain)
- Fluorescein dye
What is the treatment for bacterial keratitis?
Non-contact lens wearers
- fluoroquinolone drops
Contact lens wearer
- have to cover for pseudomonas –> aminoglycoside + pipercillin
What is the treatment for HSV viral keratitis?
What is the treatment for fungal keratitis?
What is the treatment for parasitic keratitis?
Viral:
- acyclovir drops
Fungal
- natamycin or amphotericin
Parasitic
- propamidine + chlorohexidine
What is endophthalmitis? What are the 2 main types?
Infection of the aqueous +/- vitreous humour
- exogenous (organism introduced from outside the body–> trauma, surgery, extension of keratitis)
- endogenous (organism seeded from within the body
What are the clinical manifestions of endophthalmitis?
Decreasing vision
eye ache
hypopyon
conjunctiva may be injected or edematous
What is the diagnostic approach to endopthalmitis?
- S/S, physical exam
- aspiration of vitreous humour –> bacterial and fungal cultures
What are the causative agents of endopthalmitis?
Bacteria
- CNS
- S. aureus
- Steptococci
- G(-) organisms
Fungal
- candida
What is the treatment for endopthalmitis?
- Medical emergency
- Intravitreal antibiotics (vancomycin + ceftazidime) for all
- Vitrectomy in severe cases or if trauma related (removal of vitreous humor)
- Systemic antibiotics if trauma realted, or endogenous
Define orbital and periorbital (preseptal) cellulitis
Periorbital (preseptal) cellulitis: inflammation of the anterior portion of teh eyelid
Orbital cellulitis: inflammation of the orbit (fat, ocular muscles)
