Conjunctivitis

Question 1

Define Conjunctivitis

Answer 1

Inflammation of the lining of the eyelids and eyeball

Question 2

Aetiology of Conjunctivitis

Answer 2

Bacteria: pneumococcus, s. aureus, H. influenzae
Viral: adenovirus, HSV, EBV, VZV
Contact lens wear: prolonged wearing time, infrequent replacement, poor hygiene
Mechanical: chronic irritation due to floppy eyelid syndrome
Toxic/chemical: irritation by exposure to chemicals
Neoplastic: sebaceous gland carcinoma

Question 3

Symptoms of Conjunctivitis

Answer 3

Discharge (Watery (viral) | Ropy, mucoid (allergic) | Purulent (bacterial) - copious purulent discharge over 12-24 hours indicates hyerpracute gonorrhoeal infection)
Itching (more predominant allergic)
Eyelids stuck together in the morning (bacterial or viral)
Vesicular skin rash (may indicate herpes zoster)
Superficial punctate keratopathy - red, watery, and sensitive to light

Question 4

Signs of conjunctivitis on examination

Answer 4

Discharge (Watery (viral) | Ropy, mucoid (allergic) | Purulent (bacterial) - copious purulent discharge over 12-24 hours indicates hyerpracute gonorrhoeal infection)
Tender, pre-auricular lymphadenopathy (more common in viral than bacterial)
Vesicular skin rash
Conjunctival follicles
Corneal subepithelial infiltrates
Corneal pannus (growth of fine blood vessels onto corneal surface)

Question 5

Investigations for Conjunctivitis

Answer 5

Rapid adenovirus immunoassay: +ve in adenovirus infection
Cell culture: bacterial or viral isolation
Gram stain: ?bacterial cause
PCR: viral or bacterial
ocular pH: suspected chemical cause