Infectious Conjunctivitis

Infectious Conjunctivitis Infectious conjunctivitis is one of the most common causes of red eye. Infectious conjunctivitis is commonly caused by bacterial or viral infection. I. Pathophysiology A. The clinical term "red eye" is applied to a variety of distinct infectious or inflammatory diseases of the eye. Conjunctivitis is the most common cause of red eye. Conjunctivitis consists of inflammation of the conjunctiva, which is caused by a broad group of conditions. The inflammation can be infectious or noninfectious in origin. B. Most frequently, conjunctivitis is caused by a bacterial or viral infection. Sexually transmitted diseases such as chlamydial infection and gonorrhea are less common causes of conjunctivitis. Ocular allergy is a major cause of chronic conjunctivitis.

Differential Diagnosis of a Red Eye Conjunctivitis

Keratitis

Infectious

Infectious. Bacterial, viral, fungal

Viral

Noninfectious. Recurrent epithelial erosion, foreign body

Bacterial (eg, staphylococcus, Chlamydia) Noninfectious

Uveitis Episcleritis/scleritis

Allergic conjunctivitis Dry eye

Acute glaucoma Eyelid abnormalities

Toxic or chemical reaction Contact lens use Foreign body

Orbital disorders Preseptal and orbital cellulitis Idiopathic orbital inflammation (pseudotumor)

Factitious conjunctivitis

II. Clinical Evaluation of Conjunctivitis A. An ocular, medical and medication history should establish whether the condition is acute, subacute, chronic or recurrent, whether it is unilateral or bilateral. B. Discharge 1.

A serous discharge (watery) is most commonly associated with viral or allergic ocular conditions.

2. A mucoid (stringy or ropy) discharge is highly characteristic of allergy or dry eyes. 3. A mucopurulent or purulent discharge, often associated with morning crusting and difficulty opening the eyelids, strongly suggests a bacterial infection. The possibility of Neisseria gonorrhoeae infection should be considered when the discharge is copiously purulent. C. Itching is highly suggestive of allergic conjunctivitis. In general, a red eye in the absence of itching is not caused by ocular allergy. A history of recurrent itching or a personal or family history of hay fever, allergic rhinitis, asthma or atopic dermatitis is also consistent with an ocular allergy. D. Unilateral or Bilateral Conjunctivitis 1. Allergic conjunctivitis is almost always secondary to environmental allergens and, therefore, usually presents with bilateral symptoms. Infections caused by viruses and bacteria are transmissible by eye-hand contact. Often, these infections initially present in one eye, with the second eye becoming involved a few days later. Pain, Photophobia and Blurred Vision

2. a.

Pain and photophobia do not usually occur with conjunctivitis, and these findings suggest an ocular or orbital disease processes, including uveitis, keratitis, acute glaucoma and orbital cellulitis.

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2 Infectious Conjunctivitis b.

Blurred vision that fails to clear with a blink is not characteristic of conjunctivitis. This finding is indicative of corneal or intraocular pathology.

E. Recent contact with an individual with an upper respiratory tract infection suggests adenoviral conjunctivitis. Chlamydial or gonococcal infection may be suggested by the patient's sexual history, including a history of urethral discharge. Use of topical medications (eg, vasoconstrictors or artificial tears), unusual cosmetics and contact lenses should be sought because they may cause conjunctivitis. III. Examination of the Eye A. Visual acuity should be tested before the examination. Regional lymphadenopathy should be sought and the face and eyelids should be examined. Viral or chlamydial inclusion conjunctivitis typically presents with a small, tender, preauricular or submandibular lymph node. Palpable adenopathy is rare in acute bacterial conjunctivitis. B. Herpes labialis or a dermatomal vesicular eruption is suggestive of shingles, indicative of a herpetic conjunctivitis. C. Purulent discharge suggests a bacterial infection, especially if the conjunctival injection is severe. Stringy mucoid discharge suggests allergy. Clear watery discharge can be associated with a viral infection, particularly if preauricular adenopathy is present.

Discharge Associated with Conjunctivitis Serous

Mucoid

Mucopurulent

Purulent

Viral

+

-

-

-

Chlamydial

-

+

+

-

Etiology

Bacterial

-

-

+

+

Allergic

+

+

-

-

IV.

Laboratory Studies A. Cultures and Gram stain usually are not required in patients with mild conjunctivitis of suspected viral, bacterial or allergic origin. However, bacterial cultures should be obtained in patients who have severe inflammation or chronic or recurrent conjunctivitis. Cultures also should be obtained in patients who do not respond to treatment.

V. Treatment of Bacterial Conjunctivitis A. Acute bacterial conjunctivitis typically presents with burning, irritation, tearing and, usually, a mucopurulent or purulent discharge. Patients often report that their eyelids are matted together on awakening. B. The three most common pathogens in bacterial conjunctivitis are Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus. Infections with S. pneumoniae and H. influenzae are more common in children, while S. aureus most frequently affects adults. C. Topical broad-spectrum antibiotics such as erythromycin ointment and bacitracin-polymyxin B ointment (eg, Polysporin ophthalmic ointment), as well as combination solutions such as trimethoprim-polymyxin B (eg, Polytrim), are well tolerated, and they provide excellent coverage for most conjunctival pathogens. Ointments are better tolerated by young children. Solutions are preferred by most adolescents and adults. 1.

Erythromycin ointment, apply to affected eye(s) q3-4h

2.

Bacitracin-polymyxin B ointment (Polysporin), ointment or solution, apply to affected eye(s) q3-4h

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Infectious Conjunctivitis 3 3.

Trimethoprim-polymyxin B (Polytrim), ointment or solution, apply to affected eye(s) q3-4h

D. Conjunctivitis due to H. influenzae, N. gonorrhoeae, and N. meningitidis requires systemic antibiotic therapy in addition to topical treatment. In patients with gonococcal conjunctivitis. If the cornea is not affected, gonococcal conjunctivitis may be treated with ceftriaxone (Rocephin) 1 g IM and topical erythromycin or bacitracin. E. Chlamydial conjunctivitis can occur as a result of contact with infected genital secretions. It can be present in newborns, in sexually active teenagers and in adults. Diagnosis is by antibody staining of ocular samples. Symptoms often include a mucopurulent discharge, moderate eyelid edema and injection. Treatment includes oral tetracycline, doxycycline (Vibramycin) or erythromycin for two weeks. F. Contact lenses should be discontinued until symptoms and signs have completely resolved. All ocular solutions should be discarded and lenses disinfected. The lenses or lens solution may be cultured. VI.

Viral Conjunctivitis A. Adenovirus is the most common cause of viral conjunctivitis. Viral conjunctivitis often occurs in epidemics, with the virus transmitted in schools, workplaces and physicians' offices by contaminated fingers, medical instruments and swimming pool water. B. Viral conjunctivitis typically presents with an acutely red eye, watery discharge, conjunctival swelling, a tender preauricular node, and, in some cases, photophobia and a foreign-body sensation. Some patients have an associated upper respiratory tract infection. C. Treatment consists of cold compresses and topical vasoconstrictors. Patients should avoid direct contact with other persons for at least one week after the onset of symptoms. D. Ocular herpes simplex and herpes zoster is managed with topical agents, including trifluridine (Viroptic) and systemic antiviral agents, including acyclovir (Zovirax), famciclovir (Famvir) and valacyclovir (Valtrex). §

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