Eye infections

Question 1

What is conjunctivitis?

Answer 1

inflammation of conjunctiva caused by dilation of blood vessels

Question 2

What are the 3 types of discharge?

Answer 2

1. Hyper-purulent: a lot and very sticky, indicative of gonococcal
2. Mucopurulent: bacterial conjunctivitis, yellowy greenish, sticky and crusty when dry
3. serous: clear, no pigment, watery, indicative of viral conjunctivitis but if itchy then allergy

Question 3

Describe the structure of adenovirus

Answer 3

ds DNA in core, capsid which gives protection against disinfection and has no envelope

Question 4

Describe viral conjunctivitis

Answer 4

most common cause, adenovirus (most contagious), herpes simplex or zoster, self-limiting, virus can remain infectious whilst in a dry area

Question 5

What treatment is given for an adenovirus infection

Answer 5

Nothing approved but Cidofivir inhibits DNA viral replication, Ribavarin is a broad spec antiviral + provide advice on good hygiene and bathing eye with warm water

Question 6

What are some common bacterial causes of conjunctivitis?

Answer 6

Haemophilus influenza (gram negative), Streptococcus pneumonia (gram positive), S. aureus (gram positive)

Question 7

How is bacterial conjunctivitis treated?

Answer 7

antibiotic eye-drops ( broad spectrum), e.g Chloramphenicol 0.5% drops for 7 days and 1% ointment for use at bedtime

Question 8

How can gonococcal conjunctivitis be identified and what treatment is given?

Answer 8

by obtaining swabs & ceftriaxone therapy

Question 9

Chlamydia conjunctivitis usually occurs with what type of infection?

Answer 9

genital infection

Question 10

What are the symptoms of chlamydial conjunctivitis and what treatment is given?

Answer 10

Conjunctival hyperaemia, discharge and lymphoid follicle formation. Treat with azithromycin or doxycycline

Question 11

What are the risk factors for infectious keratitis?

Answer 11

contact lenses, corneal abrasions/injury, chemical/physical trauma, diabetes, immunosuppressive disease, topical steroid use

Question 12

What are the signs and symptoms of infectious keratitis

Answer 12

cloudy cornea, eye is very red and inflamed

Question 13

What are the bacterial causes of keratitis?

Answer 13

S. aureus and pseudomonas aeruginosa

Question 14

Describe Pseudomonas aeruginosa and some virulence factors

Answer 14

lives in water, resistant to disinfectants, adheres to plastic (forms biofilms on contact lenses). Virulence factors include pili, flagella and protease production which allows it to acquire nutrients

Question 15

What are the signs and symptoms of bacterial keratitis?

Answer 15

pain, photophobia, decreased/blurred vision, redness, discharge, corneal infiltrates

Question 16

How is bacterial keratitis treated?

Answer 16

topical antibiotics, fluoroquinolone, Ciprofloxacin (broad spec), corneal grafting

Question 17

If BK suspected what drug should you not give?

Answer 17

chloramphenicol

Question 18

Herpes simplex keratitis is an important cause of what?

Answer 18

infectious blindness

Question 19

With herpes simplex keratitis what history should you check?

Answer 19

history regarding cold sores

Question 20

What are the adverse effects of topical antibiotics?

Answer 20

systemic adverse effects, liquid draining from eye can lead to skin irritations and rashes, Fluoroquinolones can cause local irritation, stinging, chemosis, conjunctival hyperaemia, corneal precipitations, and alteration of taste. sulfonamide, sulfacetamide and neomycin can cause skin irritation, itching or a rash

Question 21

What are the characteristics of an eye drop formulation?

Answer 21

approximate to tears, pH neutral, isotonic, contain preservatives if multi-dose is required, needs to be quite viscous as then it’s more likely to be absorbed which will improve drug delivery