2.02 Conjunctivitis (Pink Eye)

Presentation

Different symptoms suggest different etiologies. Tearing, preauricular lymphadenopathy and upper respiratory symptoms suggest a viral conjunctivitis. Pain upon awakening with lid crusting and a copious purulent exudate suggests a bacterial conjunctivitis. Few symptoms upon awakening but discomfort worsening during the day suggests a dry eye. Little conjunctival injection with a seasonal recurrence of chemosis and itching, and cobblestone hypertrophy of the tarsal conjunctiva suggests allergic (vernal) conjunctivitis. Physical and chemical conjunctivitis, caused by particles, solutions, vapors, natural or occupational irritants that inflame the conjunctiva, should be evident from the history.

What to do:

• Instill proparcaine anesthetic drops (Alcaine, Ophthaine) to allow for a more comfortable exam and to help determine if the patient's discomfort is limited to the conjunctiva and cornea or, if there is no pain relief, that the pain comes from deeper eye structures.
• Examine the eye, including visual acuity, inspection for foreign bodies, pupillary reaction fundoscopy, estimation of intraocular pressure by palpation of the globe above the tarsal plate, slit lamp examination (when available), and fluorescein and ultraviolet or cobalt blue light to assess the corneal epithelium.
• Ask about and look for any rash, arthritis, or mucous membrane involvement which could point to Stevens-Johnson syndrome, Kawasaki's, Reiter's, or some other syndrome that can present with conjunctivitis.
• For bacterial conjunctivitis, start the patient on warm compresses and seven days of topical antibiotics such as erythromycin, sulfacetamide, tobramycin or gentamycin ointment (which transiently blurs vision) every 4 hours, or solutions such as sulfacetamide 10%, tobramycin 0.3% or ciprofloxacin every 2 hours, with oral analgesics as needed. If it is unclear whether the problem is viral or bacterial, it is safest to treat it as bacterial.
• For viral and chemical conjunctivitis, use cold compresses and weak topical vasoconstrictors such as naphazoline 0.1% (Naphcon) every 3-4 hours, unless the patient has a shallow anterior chamber that would be prone to acute angle- closure glaucoma with mydriatics.
• For allergic conjunctivitis, use cold compresses and topical decongestant- antihistamine combinations such as drops of naphazoline with pheniramine (Naphcon A) or naphazoline with antazoline (Vasocon A) every 3-4 hours. Topical corticosteroid drops provide dramatic relief, but prolonged use increases the risk of opportunistic viral, fungal and bacterial corneal ulceration, cataract formation and glaucoma. If a severe contact dermatitis is suspected, then a short course of oral prednisone would be indicated.
• If the problem is dry eyes (keratoconjunctivitis sicca) use methylcellulose (Dacriose) artificial tear drops.
• Have the patient follow up with the ophthalmologist if the infection does not clearly resolve in 2 days. Obtain early consultation there is any involvement of cornea or iris.

What not to do:

• Do not forget to wash your hands and equipment after examining the patient, or you may spread herpes simplex or epidemic keratoconjunctivitis to yourself and other patients. Also, do not forget to instruct the patient on the importance of hand washing and separation of towels and pillows for ten days after the onset of symptoms.
• Do not patch an affected eye, as this interferes with the cleansing function of tear flow.
• Do not give steroids without arranging for ophthalmologic consultation, and never give steroids if a herpes simplex infection is suspected.

Discussion

Most bacterial conjunctivitis is caused by Streptococcus pneumoniae, Haemophilus aegyptus and Staphylococcus aureus. Routine conjunctival cultures are seldom of value, but you should Gram stain and culture a copious purulent exudate. Neisseria gonorrhoeae infection confirmed by Gram-negative intracellular diplococci on Gram stain requires immediate ophthalmologic consultation. Corneal ulceration, scarring and blindness can occur in a matter of hours. Chlamydial conjunctivitis will usually present with lid droop, mucopurulent discharge, photophobia and preauricular lymphadenopathy. Small white elevated conglomerations of lymphoid tissue can be seen on the upper and lower tarsal conjunctiva, and 90% of patients have concurrent genital infections. Doxycycline 100mg bid or erythromycin 400mg tid by mouth plus topical tetracycline (Achromycin Ophthalmic) for three weeks should control the infection (also treat any sexual partner).

Epidemic keratoconjunctivitis is a bilateral, painful, highly contagious conjunctivitis usually caused by an adenovirus. The eyes are extremely erythematous, sometimes with subconjunctival hemorrhages. There is copious watery discharge and preauricular lymphadenopathy. Treat the symptoms with analgesics, cold compresses, and, if necessary, corticosteroids. Because the infection can last as long as three weeks and may result in permanent corneal scarring, provide ophthalmologic consultation and referral. Herpes simplex conjunctivitis is usually unilateral. Symptoms include a red eye, photophobia, eye pain and mucoid discharge. There may be periorbital vesicles, and a branching (dendritic) pattern of fluorescein staining makes the diagnosis. Treat with trifluridine 1% (Viroptic), analgesics and cold compresses. Cycloplegics such as homatropine may help control pain from iridocyclitis. Topical corticosteroids are contraindicated, because they can extend the infection, and ophthalmological consultation is required.

Herpes zoster ophthalmicus is shingles of the opthalmic branch of the trigeminal nerve, which innervates the cornea and the tip of the nose. It begins with unilateral neuralgia, followed by a vesicular rash in the distribution of nerve. Ophthalmic consultation is again required, because of frequent ocular consultations, but topical corticosteroids may be used. Prescribe systemic acyclovir (Zovirax) 800mg q4h (five times a day) for ten days or famcyclovir (Famvir) 500mg tid for seven days.