Infection Flashcards
Why do gram positive organisms stain purple?
They have a thick cell wall.
Examples include staph. aureus and strep. pneumoniae.
Why do gram negative organisms stain pink?
They have a thin cell wall.
An example is haemophilus influenzae.
What are the 3 main pathogens in bacterial conjunctivitis in neonates (those under 4 weeks of age)?
Staphylococcus aureus
Neisseria gonorrhoea
Chlamydia trachomatis
How should neonatal bacterial conjunctivitis be managed?
Refer to ophthalmology as STI causative organisms may cause scarring.
What are the 3 most common organisms responsible for conjunctivitis in adults?
Staphylococcus aureus
Streptococcus pneumoniae
Haemophilus influenzae
Patient presents with mucopurulent discharge from one eye, and complains that it feels stuck together in the morning - what is the most likely diagnosis?
Bacterial conjunctivitis
How is bacterial conjunctivitis treated?
Topic chloramphenicol
In which patients should chloramphenicol be avoided?
Those with a history of aplastic anaemia
Newborns
What typically precedes a viral conjunctivitis?
An URTI
May be caused by adenovirus, herpes simplex virus, and herpes zoster.
Does viral conjunctivitis cause sticky eyes?
No, they will be red only.
Can bacterial keratitis be managed in the community?
No, if suspected admit the patient.
What is keratitis?
Inflammation of the cornea
What is a dendritic ulcer?
A very painful presentation of herpes infection.
How is herpes keratitis treated?
Ganciclovir
DO NOT GIVE STEROIDS!
Can steroids be used to manage a dendritic ulcer?
No, as it may cause a corneal melt - can lead to perforation.
What usually precedes fungal keratitis?
Corneal abrasion
Treat this with topical anti-fungals.
What may result from washing contact lenses in tap water?
Acanthamoeba infection
Will cause severe pain.
How does orbital cellulitis present?
Pain on eye movement
May have proptosis
How is orbital cellulitis investigated?
CT scan
This looks for presence of an orbital abscess.
What is toxocara?
A parasitic nematode found n cats and dogs.
It can result in irreversible sight loss.
What are the 3 modes of antibiotic formation?
Inhibit protein synthesis
Inhibit cell wall synthesis
Inhibit nucleic acid synthesis
What may result if chloramphenicol is given to a newborn?
Grey baby syndrome
How are dendritic ulcers treated?
Ganciclovir
DO NOT GIVE STEROIDS as this may result in a corneal melt.
How should chlamydial conjunctivitis be treated?
Topical oxytetracycline
If in adults, may also need oral azithromycin to treat genital infection.
