Conjunctivitis

SIMPLE BACTERIAL CONJUNCTIVITIS

Common and usually self-limiting, most commonly effects children. Spread of the infection is usually down to direct contact with infected secretions.

Presentation is w/acute redness, grittiness, burning and discharge. On waking the eyelids are frequently stuck together and difficult to open as a result of the accumulation of exudate during the night. Usually both eyes involved but one may become infected after the other

Signs - eyelids crusted and may be oedematous. Discharge initally watery mimicking viral conjunctivitis but becoming mucopurulent within a few days. Mucous strands may develop in the lower fornix. Injection is maximal in the fornices and least at the limbus. The tarsal conj has a beefy red appearance and shows mild papillary changes. Superficial punctate epithelial erosions are frequent but innocuous.

Treatment - often resolves itself within 10-14 days. First, clean eyelids and lashes of discharge. Broad spec antibiotic like chloramphenicol (every 1-2hrs) or fusidic acid (qid for 48 hours then bd) should be administered in drop form and as ointment at bed time until discharge has ceased.

VIRAL CONJUNCTIVITIS

Adenoviral keratoconjunctivitis can vary from almost inapparent disease to full blown infection. Transmission of this highly contagious virus is via respiratory or ocular secretions and dissemination by contaminated towels or tonometer heads. Incubation period is 4-10 days. Following the onset of conjunctivitis the virus is shed for about 12 days.

Causative viruses are

1. pharyngoconjunctival fever (PCF) is most frequently caused by adenovirus types 3, 4 & 7. It is transmitted by droplets and typically infects children who also develop an upper respiratory tract infection. Keratitis develops in about 30% of cases but is seldom severe.
2. Epidemic keratoconjunctivitis (EKC) is most frequently caused by adenovirus types 8 & 19. The infection is transmitted by hand to eye contact, instruments and solutions. It does not cause systemic symptoms. Keratitis, which may be severe, develops in about 80% of cases.

The conjunctivitis presents w/acute watering, redness, discomfort and photophobia frequently involving both eyes.

Signs

• Eyelid oedema
• Watery discharge and conjunctival follicles
• Subconjunctival haemorrhages, chemosis and pseudomembranes in severe cases

Treatment

• Largely symptomatic and supportive. Spontaneous resolution occurs within two weeks. Antiviral agents are avoided unless the inflammation is very severe.

Keratitis

• Signs: Stage 1 occurs within 7-10 days of the onset of symptoms and is characterised by a punctate epithelial keratitis which resolves within two weeks. Stage 2 is characterised by focal white subepithelial opacities which develop beneath the fading epithelial lesions. They are thought to be an immune response to the virus. Stage 3 is characterised by stromal infiltrates which gradually fade over months or years.
• Treatment w/topical steroids is indicated only if the eye is uncomfortable or VA diminished by stage 3 lesions. The steroids don't shorten the natural course of the disease but merely suppress the corneal inflammation so that the lesions tend to recur if steroid therapy is discontinued prematurely
  
• Treatment is w/topical steroids and indicated only if the eye is uncomfortable or VA dimini