Conjunctivitis

Question 1

What is conjunctivitis?

Answer 1

Inflammation of conjunctiva (Lining of eyeballs and lids)

Question 2

What is the aetiology of conjunctivitis?

Answer 2

Infection – Infective agents covered under Infection and Immunology section

Toxic/Chemical - Benzalkonium Chloride preservative in some eye preparations

Allergic – Part of triad with reactive arthritis (HLA-B27)

Neoplastic – Sebaceous gland carcinoma

Mechanical
Floppy Eyelid syndrome (causes irritation)
Associated with obesity, sleep apnoea and upper lid laxity

Question 3

What are the risk factors of conjunctivitis?

Answer 3

Exposure to infected individuals

Infection in one eye

Environmental Irritants

Allergen exposure + Atopy

Contact lens use – Keratoconjunctivitis

Ocular Prosthesis

Camps/Military Bases

Asthma and Hay Fever

Question 4

What is the epidemiology of conjunctivitis?

Answer 4

COMMON – 50% of all eye disease (1% of all GP consultations)

Bacterial more common in children, viral and allergic in adults

Question 5

What are the symptoms of conjunctivitis?

Answer 5

Discharge
Watery = Viral
Purulent = Bacterial
Ropy/Mucoid = Allergic

Itching

Eyelids stuck together

Burning pain in eye

Photophobia

Question 6

What are the signs of conjunctivitis?

Answer 6

Red and inflamed conjunctiva

Discharge
Watery = Viral
Purulent = Bacterial
Ropy/Mucoid = Allergic

Tender, Pre-auricular Lymphadenopathy

Unilateral disease (infective) - usually spreads to other eye in 2-5 days

Conjunctival follicles – lymphoid aggregates caused by adenovirus

Question 7

What are the investigations for conjunctivitis?

Answer 7

Rapid adenovirus immunoassay – Two visible lines indicates +

Culture (rarely done) - Suspected bacterial with no AB response

Patch test – Identify causative agent if allergen

Ocular pH – Suspected chemical damage (should be 7)