Micro/Immuno Eye Flashcards
What are three defenses of the eye?
Tears
Blinking
Lysozyme
What is conjunctivitis?
Infection and inflammation of the conjunctiva - Pink eye
What is a sty?
Infection of the eyelid
What is the etiology of conjunctivitis?
Viruses - rhinovirus, adenovirus, Herpes Simplex I
Bacteria - Haemophlius influenza, Strep pneumoniae, Staph aureus, Neisseria gonorrhea, Chlamidia trachomatis
What are the characteristics of Chlamidia trachomatis?
Small
Gram negative
Bacillus
Obligate intracellular
What is an obligate intracellular pathogen?
Can only replicate within certain host cells
Are obligate intracellular pathogens usually viral or bacterial?
Usually viral, chlamidia trachomatis is an example of bacterial
What is the reservoir for conjunctivitis?
Human
What is the transmission method for conjunctivitis?
Respiratory droplets
Secretions from eye to hand to fomites in eye
Contaminated contact lens
During birthing
What is the viral pathogenesis of conjunctivitis?
- Viruses attach to cells of conjunctiva
- Virus induce endocytosis and enter cells
- Replicates in cell
- Cell damage/lysis
- Release of cytokines and inflammatory mediators
- Inflammation of conjunctiva
What is the bacterial pathogenesis of conjunctivitis with the Chlamydia bacteria?
- Binds to host cells
- Induces endocytosis
- Differentiates and replicates inside host cell
- Leaves cell by exocytosis or lysis
- Release of cytokines and inflammatory mediators
- Inflammation of conjunctiva
How does the infection in conjunctivitis end?
Usually self limiting - no severe or permanent damage to conjunctiva or eye
Are the most severe symptoms of conjunctivitis bacterial or viral?
Bacterial
What are the signs and symptoms of conjunctivitis?
- Dilated blood vessels
- Redness of conjunctiva, one or both eyes
- Excessive tears
- Yellow exudate
- Itchiness, irritation
- Swelling of eyelids
- Stickiness of eyelids
- Photophobia
Is there pain associated with conjunctivitis?
NO PAIN - if pain, disease is more serious than conjunctivitis
What does exudate with a virus in conjunctivitis look like?
Little
What does exudate with a Chlamydia in conjunctivitis look like?
Medium
What does exudate with a bacteria in conjunctivitis look like?
Very sticky
What is the amount of stickiness of eyelids in the morning with viral conjunctivitis?
Not much or none
What is the amount of stickiness of eyelids in the morning with Chlamydia conjunctivitis?
Medium sticky
What is the amount of stickiness of eyelids in the morning with bacterial conjunctivitis?
Very sticky
What does inflammation with a viral in conjunctivitis look like?
Mild
What does inflammation with Chlamydia in conjunctivitis look like?
Medium
What does inflammation with a bacteria in conjunctivitis look like?
Severe
How do we diagnose conjunctivitis?
Signs and symptoms, lab culture of bacteria
Fluorescent antibodies against pathogens from eye scrapings
What is the treatment of conjunctivitis?
Antibiotic eye drops, only for bacterial
No treatment for viral
What is the epidemiology of conjunctivitis?
Most common eye infection in world
Most prevalent in tropics and subtropics