Conjunctivitis Flashcards
Define conjunctivitis.
Inflammation of the conjunctiva, the membranes lining the inside of the eyelid and sclera.
How common is conjunivitis? Who is most affected?
Males and females of all ages
~13/1000 cases per year in England
Bacterial conjunctivitis is more common in children, and viral conjunctivitis is more common in adults.
What is a common name for conjunctivitis?
Conjunctivitis is the common cause of “pink eye” (conjunctival hyperaemia)
What are the causes of conjunctivitis?
Bacterial - usually caused by Pneumococcus, Staph Aureus, Moraxella catarrhalis, Haemophilus influenzae . Rarely N. gonorrhoea, chlamydia.
Viral - adenovirus, herpes simples, Epstein-Barr, varicella zoster, molluscum contagiosum, coxsackie and enterovirus.
Allergic - atopic, seasonal, vernal
Contact lens wear –> keratoconjunctivitis/giant cell papillary conjunctivitis secondary to infrequent replacement.
Mechanical conjunctivitis - floppy eyelid syndrome in obesity, sleep apnoea, upper eyelid laxity and lid imbrication
Toxic/chemical conjunctivitis - exposure to chemicals
Ocular cicatrical pemphigoid - genetic predisposition or in response to certain topical medicines such as idoxuridine, pilocarpine, epinephrine
Neoplastic conjunctivitis is caused by a sebaceous gland carcinoma; secondary radiotherapy may also induce a chronic conjunctivitis.
What are the symptoms of conjunctivitis?
- Conjunctival hyperaemia - “pink eye”
- Chemosis - oedema of the eyelid.
- Crust and discharge
- “Foreign body sensation”
- Photophobia
How is conjunctivitis diagnosed?
Usually clinical diagnosis
How do you distinguish between bacterial and viral conjunctivitis?
The most 2 common types are bacterial and viral, you can see bacterial on the left – the giveaway is the yellow discharge/pus. Pus is typical of a bacterial infection because it is composed of dead neutrophils
Viral on the right has clear discharge
What are 4 differences between bacterial and viral conjunctivitis?
For bacterial, one cause is an STD and so you may also have urethritis or bacterial discharge from the vagina
Viral may be associated with fever and lymphadenopathy
What type of hypersensitivity reaction is allergic conjunctivitis? What other symptoms would you have?
Type 1 Hypersensitivity (IgE)
- pollen
- dust
- chemical scents
Other symptoms: itching, sneezing, red/water and oedematous eyes.
USUALLY BILATERAL
What investigation can you do for diagonsing adenovirus conjunctivitis?
Rapid adenovirus immunoassay - from tear sample; one visible control line is negative; 2 visible lines indicate a positive result
What should you suspect in newborns with a red eye?
Neonatal chlamydial conjunctivitis is a notifiable disease in the UK and should be suspected in newborns with a red eye. Mothers should be asked about sexually transmitted infections.
Why is chhlamydial conjunctivitis dangerous?
Spreads by direct/indirect contact of eye with genital secretions.
Caused by chlamydia trichomatis which can lead to progressive scarring, trichiasis, entropion and subsequent corneal scarring –> visual impairment or blindness.
Common cause of blindness worldwide; found mainly in tropic and the Middle East.
