Eye infections

Question 1

Why do pharmacists need to know about eye infections

Answer 1

They are a common presenting problem in primary care

Prompt diagnosis is essential with appropriate treatment

Question 2

What happens in infectious conjunctivitis

Answer 2

Conjunctival (the barrier between the cornea and the environment) blood vessels dilate and lead to inflammation

Question 3

Describe the structures of the eye

Answer 3

AT the front there is the conjunctiva which protects the cornea. Behind this is the iris, lens and cilliary muscle.

At the back of the eye there is a vitrious body (the globby bit) behind which is the retina and the sclera

Question 4

Can a patient presenting with blurred vision, pain, photophobia or hyperpurulent discharge be treated in the pharmacy

Answer 4

No, they must be refered to an opthamologist urgently as these symptoms require specialist treatment

Question 5

What sort of eye complaints can be treated in the pharmacy and what is the likely cause of each

Answer 5

• Mucopurulent discharge - bacterial conjunctivitis (non-gonococcal)
• Serous discharge without itching - viral conjunctivitis
• Serous discharge with itching/ just itching - allergic conjunctivitis

Question 6

What is the most common cause of conjunctivitis

Answer 6

The most common cause is a virus (60-90%)

Adenovirus is the most common, herpes simplex or zoster can also cause it

Self limiting - the adaptive immune response will resolve it within 7-14 days

Adenovirus conjunctivitis is very contagious. Can be transmitted via fomites and can evade disinfection mechanisms

The virus can remain infectious whilst dessicated (dried)

Question 7

How do we classify viruses

Answer 7

Using their nucleic acid

Adenovirus has a double stranded DNA nuclec acid structure

Question 8

How can we treat adenovirus conjunctivitis

Answer 8

Nothing approved for adenovirus infection

Cidofivir inhibits DNA virus replication

Ribavirin is a broad spectrum anti-viral - these drugs may be used in immunocompromised patients

Supportive care and advice - this is usually a self limiting illness. Talk about hygiene

Question 9

Which three types of bacteria cause bacterial conjunctivitis

Answer 9

Haemophilus influenzae (has nothing to do with flu!) gram neg

Streptococcus pneumoniae gram pos

Staphylococcus aureus gram pos

Question 10

How do we treat bacterial conjunctivitis

Answer 10

Antibiotic eye-drops associated with improved remission

Broad-spectrum agent is recommended because gram pos and gram neg can be the causative agent

Chloramphenicol 0.5% drops for 7 days (for over 12s)
1% ointment for use at bedtime

Question 11

Who is affected by gonococcal conjunctivitis

Answer 11

Neonates and sexually active young adults
It is, however, uncommon

This is a very serious infection. It can spread easily and if it makes its way to the brain it can cause bacterial meningitis

Question 12

How do we treat gonococcal conjunctivitis

Answer 12

We would ideally obtain swabs and refer to ophthalmologist

We treat it with ceftriaxone therapy.

Question 13

Who is at risk of developing chlamydial conjunctivitis

Answer 13

People who also have a genital chlamydial infection

Question 14

What are the symptoms of chlamydial conjunctivitis

Answer 14

Conjunctival hyperaemia, discharge and lymphoid follicle formation

Question 15

How do we treat chlamydial conjunctivitis

Answer 15

Immediate referral required as it can cause blindness

Azithromycin or Doxycycline treatment

Question 16

What is infectious keratitis

Answer 16

An infection of the cornea (has surpassed the conjunctiva)

Its an emergency as it is a significant cause of blindness

Question 17

What are the risk factors for infectious keratisis

Answer 17

Contact lenses (poor hygiene associated)
Corneal abrasions/injury
Chemical/physical trauma
Diabetes
Immunosuppressive disease
Topical steroid use (can compromise the conjunctiva)

Question 18

What are the causative agents of bacterial keratitis

Answer 18

• Staphylococcus aureus
• Coag. Negative Staphs
• Pseudomonas aeruginosa (contact lenses) Green colour and characteristic smell

Question 19

What are the viruolence factors associated with the pseudomonas aeruginosa

Answer 19

• Resistant to disinfectants and antimicrobial agents (contact lense solution)
• Very good at adhering to plastic and itself (forms biofilms)

Virulence factors:
Pili (allows for adhesion)
Flagella (motile)
Protease production (break down proteins allowing them to aquire nutrients)

Question 20

What are the signs and symptoms of bacterial keratitis

Answer 20

Pain
Photophobia
Decreased/Blurred vision
Redness
Discharge
Corneal Infiltrates
History of trauma/contact lense use/immunocompromised

Question 21

How do we treat bacterial keratitis

Answer 21

Topical Antibiotics

Monotherapy with a fluoroquinolone eg. Ciprofloxacin. Stops bacterial dna from coiling - inhibits topoisomerase

Corneal grafting?

If suspect BK do not provide chloramphenicol (only works against minor infections)

Question 22

What are some key points around herpes simplex keratitis

Answer 22

Important cause of infectious blindness
Can be recurrent
Check history regarding cold sores

Question 23

What are some adverse effects of topical antibiotics

Answer 23

Systemic adverse effect - must be used accurately

Large volume of liquid drains out of the eye

Some adverse effects include skin irritation, itching or rash with sulfonamide, sulfacetamide and neomycin

Fluoroquinolones can cause local irritation, stinging, chemosis, conjunctival hyperaemia, corneal precipitations and alteration of taste

Question 24

What are the formulation considerations for eyedrops

Answer 24

Must be approximate to tears to avoid irritation

Preservative if multi-dose is required (benzyl type)

Isotonicity

pH

Viscosity - needs to be failry viscous to ensure its absorbed and not run down the face