Conjunctiva Flashcards
Name two viruses commonly causing conjunctivitis.
- Adenoviruses (multiple serotypes)
2. Herpes viruses
What is conjunctivitis?
Describes any form of conjunctival inflammation, but usually refers to bacterial or viral infection.
Name 6 bacteria commonly causing conjunctivitis.
- Staph aureus
- Staph epidermidis
- Strep pneumoniae
- H. Influenzae
- Neisseria gonorrhoeae (esp. in neonates)
- Chlamydia trachomatis
Name 7 causes of red eye.
- Infective conjunctivitis
- Allergic conjunctivitis
- Trauma
- Iritis
- Episcleritis
- Corneal problems (corneal ulceration should be excluded).
- Trauma
How does bacterial conjunctivitis manifest? 9 features listed.
- Sticky, red eye of acute onset
- Generally associated with mild to moderate itching
- May have burning or grittiness
- Little or no effect on vision (discharge may cause mild blurring)
- May be unilateral initially, but fellow eye follows suit shortly after
- Lid swelling
- Conjunctival hyperaemia
- Purulent discharge
- Papillae (flat bumps, usually on palpebral conjunctivae)
Management of bacterial conjunctivitis?
Most self-limiting within a few days with no Rx or Ix necessary.
However, prescription of a broad-spectrum topical Abx, such as chloramphenicol, is usual.
If infection fails to respond to topical Abx, a conjunctival swab is sent for microscopy and culture is helpful, but a viral cause is more likely.
Conjunctivitis often accompanies blepharitis, which requires treatment.
What features of bacterial conjunctivitis warrant referral to an ophthalmologist?
- Atypical features
- Particularly severe or persistent infection (eg. neisseria gonorrhoeae - can penetrate corneal epithelium and cause corneal infection. Mx is intensive specific antibiotic Rx).
How does chlamydial conjunctivitis characteristically present?
In young adults as an acute or subacute follicular conjunctivitis, clinically similar to a viral infection. Urethral or vaginal symptoms may occur.
How would you investigate and treat chlamydial conjunctivitis?
Microscopy, immunofluorescence and culture of conjunctival scrapes aid diagnosis.
Rx: oral Abx, tetracycline or erythromycin.
(Note: tetracycline unsuitable in neonate because of discolouration of growing teeth; use systemic erythromycin).
Differentiate the two types of chlamydia trachomatis eye infection.
- Inclusion conjunctivitis (serotypes D-K), sexually transmitted.
- Trachoma (serotypes A-C), endemic to areas with inadequate sanitary facilities. Chronic course leading to severe conjunctival cicatricial change with entropion, trichiasis, dry eye and secondary corneal ulceration and scarring. Trachoma is the third most common cause of blindness worldwide. Dx and Rx similar to chlamydial inclusion conjunctivitis.
True or false: conjunctival involvement cannot occur in the course of systemic childhood viral infections like measles and chicken pox.
False.
What is the main distinguishing symptomatic feature between bacterial and viral conjunctivitis? Plus another.
- Viral conjunctivitis has a watery discharge rather than purulent (although, night-time discharge causes the eyelids to be sticky in the morning).
- Viral has conjunctival follicles resembling grains of rice (vs papillae in bacterial).
Name some features of viral conjunctivitis. 9 listed.
- Watery discharge
- Conjunctival hyperaemia
- Unilateral progressing to bilateral involvement
- Moderate grittiness typical
- Frequently, petechial conjunctival haemorrhages
- Conjunctival follicles (resembling grains of rice).
- Punctate corneal epithelial erosions are frequent (corneal ulcerstion, such as the dendritic lesions of herpes simplex keratitis, should be excluded). Microscopic subepithelial corneal infiltrates may develop under the epithelial erosions and result in glare, which can persist following resolution of the acute conjunctivitis.
- Pre-auricular lymph node enlargement frequently present.
- Eyelid swelling, possibly severe enough to close the lids together and may extend down the face to the ear.
Can ophthalmic shingles cause conjunctivitis?
Yes. Characteristic skin changes may be mild and easily overlooked.
What is a follicular conjunctivitis caused by and how is it treated?
May be caused by viral particles shed from the lesion of molluscum contagiosum, a tiny whitish papillomatous lump on the eyelid margin that is easily treated by curettage.
In general, how is (non-severe) viral conjunctivitis treated?
Usually settles within about 2 weeks without treatment (also, specific Rx for majority of viral cases not available).
Symptoms of irritation, redness and stickiness after sleep may persist for months.
In refractory cases, Ix by means of conjunctival swabs and scrape is indicated. May identify an alternative organism such as chlamydia, or may suggest a distinct inflammatory process.
Two treatments for herpes simplex conjunctivitis?
Topical aciclovir and trifluorothymidine are effective.
Which conjunctivitis can cause epidemic infection?
Adenoviral.
Personal hygiene and avoidance of contact should be practised.
What are some treatments used in treating symptoms of viral conjunctivitis?
Vasoconstrictor/antihistamine combinations may reduce sx.
Topical Abx may be prophylactic against secondary bacterial infections.
Artifical tears can be soothing.
Topical steroids effectively reduce sx, but should only be used in cases where dx is certain and under ophthal supervision.
Neonatal conjunctivitis within the first few hours of birth is usually caused by what?
Usually chemically induced.
Thereafter, chlamydia and other bacteria likely.
Rapidly progressive disease suggests more serious infection like N gonorrhoea. Corneal examination is mandatory.
What are two conditions which may mimic neonatal conjunctivitis?
- Congenital glaucoma
2. Congenital nasolacrimal duct obstruction