A 24-year-old woman comes to the office due to 3 days of left eye redness and discharge, with crusting of the eyelid and difficulty opening it in the morning. Today, the patient's right eye also became red. She has had no pain, itching, photophobia, or visual difficulty. Her boyfriend has had similar symptoms. The patient has no chronic medical conditions and takes no medications. Physical examination shows bilateral conjunctival erythema. There is thick, yellowish discharge at the corner of the eyes that quickly reaccumulates after wiping. The cornea is normal, and no ocular tenderness is present. Which of the following pathogens is most likely responsible for this patient's condition?
Acute conjunctivitis* | |||
Viral | Bacterial | Allergic | |
Distribution | Unilateral or bilateral | Unilateral or bilateral | Bilateral |
Discharge | Watery/mucoid | Purulent | Watery |
Conjunctival appearance | Diffuse injection; follicular ("bumpy") | Diffuse injection; nonfollicular | Diffuse injection; follicular ("bumpy") |
Associated findings | Viral prodrome | Unremitting discharge (reaccumulates within minutes) | Ocular pruritus, history of atopy (eg, allergic rhinitis, asthma) |
Duration | 1-2 weeks | 1-2 weeks | <30 minutes (often sudden onset) to perennial |
*Red flags suggestive of alternate etiology: decreased visual acuity, photophobia, pain with extraocular movement & fixed/distorted pupil. | |||
This patient with conjunctival erythema and thick eye discharge likely has bacterial conjunctivitis. Most cases occur after direct contact with secretions of an infected individual. Although bacterial conjunctivitis in children is caused by a wide range of pathogens (eg, Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae), most cases in adults are caused by Staphylococcus aureus.
Bacterial and viral conjunctivitis frequently affect both eyes and cause conjunctival erythema, discharge, and a "stuck shut" eye when waking. However, differentiation can often be made based on the quality of the eye discharge, as follows:
(Choice B) Chlamydia trachomatis can cause bacterial conjunctivitis but is a much less common cause than S aureus. In addition, most cases are marked by long-standing symptoms (eg, weeks or months) and concurrent urogenital infection.
(Choice C) Herpes simplex virus can cause a vision-threatening infection of the cornea. Although patients frequently have corneal injection, most cases are marked by eye pain, blurred vision, watery discharge, and characteristic dendritic lesions seen on the cornea by slit lamp.
(Choice D) Neisseria gonorrhoeae causes a rapidly progressive conjunctivitis with copious purulent discharge. Eye tenderness and a concomitant urogenital infection are typically present. It can also be seen in neonates when the mother is infected.
(Choice E) Pseudomonas aeruginosa eye infection is classically seen in patients who wear extended wear contact lenses. It typically causes an ulcerative keratitis associated with eye pain.
(Choice G) Staphylococcus epidermidis is not a common cause of bacterial conjunctivitis but can occasionally cause endophthalmitis in those with other nidi of infection (eg, infective endocarditis). This is generally marked by blurred vision and eye pain, not conjunctival erythema and discharge.
Educational objective:
Bacterial conjunctivitis should be suspected in patients with conjunctival erythema and thick, purulent eye discharge that reaccumulates within a few minutes after wiping. Most cases occur after direct contact with an infected individual, and one or both eyes may be affected. S aureus is the most common etiology in adults.