4: Microbiology Flashcards
What is conjunctivitis?
Infectious inflammation of the conjunctiva
What is keratitis?
Infectious inflammation of the cornea
What is endophthalmitis?
Infectious inflammation of the entire eye
What is chorioretinitis?
Inflammation of the choroid and retina (back of the eye)
What is dacrocystitis?
Infectious inflammation of the lacrimal SAC
Which microbes cause conjunctivits?
Bacteria
Viruses
How can you tell the difference between bacterial and viral conjunctivitis?
Bacterial - loads of pus
Viral - watery
What are the symptoms of conjunctivitis?
Red eye
Itchy, gritty, watery eye
All neonates with conjunctivitis should be referred to who?
Ophthalmology
Which bacteria can cause conjunctivitis?
Staph aureus
Strep pneumoniae
H. influenzae (especially in children)
Chlamydia trachomatis
Neisseria gonorrhoeae
Which bacteria causes bacterial conjunctivitis especially in children?
H. influenzae
Which STI can cause bacterial conjunctivits which is chronic, unresponsive to previous treatment and accompanied by urethritis or vaginitis?
Chlamydia trachomatis
What must you do if you diagnose chlamydial conjunctivitis?
Alert people the patient has been in contact with
What are some additional features of chlamydial conjunctivitis compared to normal bacterial conjunctivitis?
Follicles under eyelid - “rice grain pattern”
Subtarsal scarring if left untreated
How is bacterial conjunctivitis investigated?
Swab
How is bacterial conjunctivitis treated?
Topical antibiotics
Chloramphenicol drops (4x a day)
Oxytetracycline (for chlamydia)
Which viruses can cause conjunctivitis?
Adenovirus
Herpes simplex virus
Herpes zoster virus
What is the difference between bacterial and viral conjunctivitis?
Bacterial - pus
Viral - watery
What may you see along conjunctivitis in someone with herpes simplex infection?
Cold sores
Which virus reactivates in elderly people and can cause a painful rash in the dermatomes for CN V?
Herpes zoster virus
What is the technical name for shingles affecting the forehead and eye area?
Ophthalmic zoster
How is viral conjunctivitis investigated?
Swab
How is ophthalmic zoster treated?
Oral antivirals
Aciclovir
(add on antibiotics if at risk of secondary infection)
What can ophthalmic zoster cause if untreated?
Vision loss
Post-herpetic neuralgia
Which microbes can cause a keratitis?
Bacteria
Viruses
Fungi
What does a bacterial keratitis look like?
Red eye
Hypopyon
What is a hypopyon?
Exudate in anterior chamber at iridocorneal angle
Seen in bacterial keratitis
What name is given to a collection of pus in the anterior chamber as seen in bacterial keratitis?
Hypopyon
Which Gram negative bacillus is a common cause of keratitis in people who wear contact lenses?
Pseudomonas
How is bacterial keratitis treated?
Topical antibiotics
HOURLY chloramphenicol drops
ofloxacin
How would you treat Pseudomonas conjunctivitis?
Gentamicin
What is a pathognomic sign of viral keratitis due to herpes infection?
Dendritic ulcer
White ulcer with loads of projections
Viral keratitis is very ___ for the patient.
painful
What is seen in the cornea in viral keratitis caused by adenovirus?
Subepithelial infiltrates
Little white specks
Adenovirus keratitis is usually (unilateral / bilateral).
bilateral
What are the classic features of
a) herpes
b) adenovirus
keratitis?
a) Dendritic ulcer
b) Subepithelial infiltrates
How is viral keratitis treated?
Topical antivirals
e.g aciclovir
(add on topical antibiotics to prevent secondary infection)
What should you suspect in a patient with red eye with a hypopyon and a history of farming / trauma from vegetation?
Fungal keratitis
What should you suspect in a patient with a fever, painful eye movements and massive orbital swelling?
Orbital cellulitis
What is abnormal protrusion of the eye called?
Proptosis
How is orbital cellulitis investigated?
CT head
For abscesses
How is orbital cellulitis treated?
Broad spectrum antibiotics
ofloxacin, gentamin, cephalosporins…
What is a “devastating”, painful infection of the whole eye which is commonly caused by surgery?
Endophthlamitis
Endophthalmitis is commonly caused by commensal organisms.
What is an example?
How do they get into the eye?
Staph epidermidis
During surgery
How is endophthalmitis investigated?
Aqueous / vitreous fluid sample
seeing as it affects the whole eye
How is endophthalmitis treated?
Intravitreal antibiotics
Injected directly into the eye - amikacin, cephalosporins, vancomycin
What commonly causes chorioretinitis - infective inflammation of the retina?
Parasites
Cytomegalovirus in AIDS patients
What does the retina look like on fundoscopy of someone with chorioretinitis?
Pizza
What can be seen in the retina of someone with chorioretinitis?
Pizza
Parasites
Scar tissue
How is parasite infection of the eye investigated?
Serology (antibodies)
What investigations would you do for
a) orbital cellulitis
b) conjunctivitis
c) keratitis
d) endophthalmitis
e) parasitic chorioretinitis?
a) CT head
b) Swab
c) Corneal scrapes
d) Aqueous or vitreous fluid sample
e) Serology
How would you treat
a) uncomplicated bacterial conjunctivitis
b) chlamydial conjunctivitis
c) Pseudomonas conjunctivitis?
a) Chloramphenicol drops
b) Oxytetracycline drops
c) Gentamicin drops
How would you treat
a) viral conjunctivitis
b) viral keratitis
c) orbital cellulitis
d) fungal keratitis
e) endophthalmitis?
a) Topical antivirals (plus prophylactic antibiotics)
b) ““
c) Broad spectrum antibiotics (ofloxacin, gentamicin, cephs)
d) Topical antifungals
e) Intravitreal antibiotics (amikacin, cephs, vancomycin…)
