Conjunctival disorders: Clinical sciences

Conjunctival disorders occur when the lubricating mucous membrane covering the eye becomes infected, damaged, or inflamed; and they’re the most common causes of a red eye encountered in the primary care setting. Emergent, vision-threatening conjunctival disorders include chemical injury and hyperacute bacterial conjunctivitis, while non-vision threatening conjunctival disorders include acute bacterial conjunctivitis, viral conjunctivitis, allergic conjunctivitis, and keratoconjunctivitis sicca.

Now, if a patient presents with a chief concern suggesting a conjunctival disorder, first obtain a focused history and physical examination.

Your patient will typically report redness of one or both eyes, while a physical exam will reveal conjunctival injection, commonly referred to as blood shot eyes, which is caused by dilation of the conjunctival blood vessels. With these findings, diagnose a conjunctival disorder!

Next, assess for red flags which indicate vision-threatening emergencies.

Red flags include severe pain, decreased visual acuity, photophobia, anterior chamber inflammation, and corneal epithelial defects. If any of these red flags are present, assess for the emergent underlying cause.

First up is chemical injury! Your patient will report a chemical or toxic exposure to something like household cleaners, for example bleach or ammonia. Other symptoms include pain and blurry vision. Your physical exam will reveal conjunctival injection, decreased visual acuity, and possibly eyelid edema. With these findings, diagnose chemical injury.

Treat with supportive care by removing any offending agents and providing adequate ocular irrigation for at least 30 minutes to reach a neutral pH. Also be sure to use artificial tears throughout all stages of healing and combine with medical therapy such as topical antibiotics for infection prophylaxis and topical steroids to reduce inflammation.

Here's a clinical pearl! The main pitfall in the initial management of chemical injury of the conjunctiva is inadequate irrigation, which results in ongoing exposure to the chemical. You can manage irrigation by applying a lens-like device to the eye which connects to intravenous tubing for continuous hands-free irrigation.

Okay, let’s move on to hyperacute bacterial conjunctivitis! These patients will report an abrupt onset of copious purulent discharge associated with pain and blurry vision. Adult patients are generally either sexually active or are immunocompromised, but don't forget this can also affect neonates who can be exposed to infectious agents during a vaginal delivery! Your physical exam may reveal conjunctival chemosis, which is a swelling of the conjunctiva; eyelid edema; or preauricular lymphadenopathy. With these findings, suspect hyperacute bacterial conjunctivitis, which is most commonly caused by Neisseria gonorrhoeae, so obtain a culture, PCR, and nucleic acid amplification testing, or NAAT for short. If testing comes back positive for gonorrhea, diagnose hyperacute bacterial conjunctivitis.

Treatment includes supportive care with saline irrigation and medical therapy with IV ceftriaxone!

Here’s a clinical pearl! Hyperacute bacterial conjunctivitis is a rare cause of blindness in neonates. Prophylactic treatment with erythromycin eye ointment can be used to prevent this condition if there is a risk that the neonate was exposed to infectious agents like Neisseria gonorrhoeae during vaginal delivery.

On the other hand, if red flags are not present, assess for a non-emergent underlying cause of conjunctival disorder.

First up is bacterial conjunctivitis! These patients typically report drainage of mucous or pus, morning matting of their eyes, and a foreign body sensation. These symptoms are unilateral, but may spread to the other eye through contact from unwashed hands. Physical exam reveals mucopurulent discharge. With these findings, diagnose bacterial conjunctivitis and treat with topical antibiotics.

The most common pathogens causing bacterial conjunctivitis include Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Staphylococcus aureus. Good choices to provide adequate antimicrobial coverage include aminoglycosides, macrolides, fluoroquinolones, or polymyxin B combination medications.