Introduction
Background
Bacterial conjunctivitis is a microbial infection involving the mucous membrane of the surface of the eye. This condition, which is usually a benign self-limited illness, sometimes can be serious or signify a severe underlying systemic disease. Occasionally, significant ocular and systemic morbidity may result.
The purpose of this article is to help the practitioner recognize the character and significance of the condition, to avoid pitfalls in diagnosis, and to convey appropriate treatment modalities.
Pathophysiology
The surface tissues of the eye and the ocular adnexa are colonized by normal flora such as streptococci, staphylococci, and Corynebacterium strains. Alterations in the host defense or in the species of bacteria can lead to clinical infection. An alteration in the flora can occur by external contamination, by spread from adjacent sites, or via a blood-borne pathway.
The primary defense against infection is the epithelial layer covering the conjunctiva. Disruption of this barrier can lead to infection. Secondary defenses include hematologic immune mechanisms carried by the conjunctival vasculature; tear film immunoglobulins and lysozyme; and the rinsing action of lacrimation and blinking.
Frequency
United States
Bacterial conjunctivitis is a common condition in all areas of the United States. It is likely that most people will experience an episode. Most of the benign cases probably are treated by primary physicians or resolve spontaneously.
International
Bacterial conjunctivitis is common worldwide. Community sequelae can be devastating in areas affected by blinding infections of newborns as well as in areas heavily affected by Chlamydia trachomatis.
Mortality/Morbidity
Mortality in the setting of bacterial conjunctivitis is related to the failure to recognize and treat the underlying disease. Sepsis and meningitis caused by Neisseria gonorrhoeae can be life threatening. Chlamydial infection in the newborn can lead to pneumonia and/or otitis media. Morbidity in terms of discomfort, ocular discharge, and redness are common in benign cases and often lead to absence from work and school. Morbidity can be associated with misdiagnosis. Since many eye diseases cause the eye to be red, it is beneficial to have a solid approach to diagnosis.
Race
- Bacterial conjunctivitis occurs in all races.
- Differences in frequencies among races are likely to reflect geographical variations in the prevalence of pathogens.
Sex
- Probably, both sexes have an equal natural resistance to bacterial conjunctivitis.
- Differences in rates of infection probably reflect behavioral patterns, such as the exposure of female elementary school teachers to children affected by the condition.
Age
- Age is a relevant factor in the significance of bacterial conjunctivitis.
- The practitioner must be vigilant in considering sexually transmitted diseases caused by N gonorrhoeae and Chlamydia in sexually active age groups and in newborns who may have been exposed during birth. Tactful and confidential history taking are a necessary skill. It is important not to violate HIPPA Regulations during history taking and treatment. If a practitioner is mired in an ethical or medicolegal situation, it is a good idea to seek advice from administration and/or colleagues.
Clinical
History
Eliciting a clinical history from the patient is influenced by such factors as age and social habits and may occasionally focus on sensitive issues that can be embarrassing to discuss.
- Most cases of bacterial conjunctivitis occur in otherwise healthy individuals. In these cases, the history should take the following factors into consideration:
- Age is a consideration in determining whether the case may be related to defective host resistance of the elderly patient. If this is a consideration, it is appropriate to inquire about concomitant or recent increased susceptibility to other types of infections, for example, urinary tract or respiratory tract infections, which may hold clues as to the bacterial source.
- Patients at a sexually active age should be considered for venereal diseases.
- If the conjunctivitis is associated with copious purulence, severe injection, and chemosis, then a discussion of possible exposure to N gonorrhoeae must take place. Bacterial cultures, including Thayer-Martin and chocolate agar, and a Gram stain must be taken.
- A history of sexual partners must be obtained if the cultures/stain verify this condition so that they also can be treated.
- The practitioner must be aware that laws require reporting incidences of this disease to the appropriate Board of Health.
- A similar history must be obtained when chlamydial conjunctivitis is suspected.
- Clinical suspicion may be present at first presentation or upon treatment failure of an unsuspected case.
- It is probably desirable to have the nurse or other office-related personnel take the sexual history to avoid a sense of inappropriateness.
- It is better to ask the patient if friends or family members should leave the room for this aspect of the evaluation.
- Duration of the disease and previous attempts at therapy should be documented.
- It is usual for symptoms to be present for several days or weeks at the time of presentation. An uncommonly long duration or a frequent recurrence suggests that other factors or conditions may be present.
- For instance, a molluscum lesion at the lid margin may be shedding virus into the eye. Chlamydial infection or viral keratoconjunctivitis may be present. A history of resistance to therapy may prompt the practitioner to obtain a culture.
- History of recent exposure to other cases is helpful. An exposure to a case that healed uneventfully would be comforting, whereas exposure to someone with known epidemic keratoconjunctivitis or herpes simplex would raise concern.
- A brief history to assess possible occupational exposure may be appropriate.
- A brief history of systemic illness should be obtained to determine if a recent viral upper respiratory tract infection has occurred or if there are any major known systemic illnesses, such as AIDS or diabetes.
- A medication history is important to document what already has been tried and to rule out medicamentosa or other drug causes for the condition.
- Ocular redness and irritation may occur due to an antibacterial eye drop solution or the preservatives in the solution.
- Systemic chemotherapeutic agents can cause an irritative conjunctivitis.
- A history of allergies to medications should be established for avoidance purposes and recorded in the medical record prominently since this is often the only medical encounter with an otherwise healthy individual.
- Patients with typical bacterial conjunctivitis do not complain of photophobia. Sensitivity to light is a symptom of intraocular inflammation as in iritis or corneal lesions, such as those found in viral keratitis.
- A history of contact lens wear opens up an array of possibilities in the setting of a red eye. Corneal ulcers, which are infections within the stroma of the cornea, may occur with contact lens wear. Improper contact lens care and/or contaminated solutions can lead to corneal infections with bacteria, Acanthamoeba, or fungi. In early 2006, an outbreak of fungal infections with Fusarium species occurred due to a contact lens solution. In these cases, the infection involves the cornea and may be associated with a red eye.
Physical
The physical examination should evaluate the following signs:
- Conjunctival injection may be present segmentally or diffusely. The palpebral conjunctival pattern may hold clues as to the etiology.
- Using slit lamp biomicroscopy, the inflammation of the conjunctiva can be characterized as being follicular or papillary.
- A follicular pattern has blood vessels circumferentially around the base of the tiny elevated lesions. This pattern is characteristic of a viral or chlamydial conjunctivitis.
- A papillary pattern has vessels coming up the center of the tiny elevated lesion and is characteristic of bacterial or allergic conjunctivitis.
- The discharge in bacterial conjunctivitis is typically more purulent than the watery discharge of viral conjunctivitis. Thus, there is more "mattering" of the lid margins and associated difficulty in prying the lids open following sleep.
- In uncomplicated bacterial conjunctivitis, slit lamp examination reveals a quiet anterior chamber that is devoid of visible cells. The vitreous is also unaffected.
- A preauricular lymph node is unusual in bacterial conjunctivitis but is found in severe conjunctivitis caused by N gonorrhoeae. It is associated with viral ocular syndromes, typically herpes simplex keratitis and epidemic keratoconjunctivitis.
- Eyelid edema is often present, but it is mild in most cases of bacterial conjunctivitis. Severe lid edema in the presence of copious purulent discharge raises the suspicion N gonorrhoeae infection.
- Visual acuity is preserved in bacterial conjunctivitis, except for the expected mild blur secondary to the discharge and debris in the tear film.
- The pupil reacts normally in bacterial conjunctivitis. A fixed pupil in the setting of a red eye should raise the suspicion for angle-closure glaucoma or iritis with posterior synechiae.
- Dilation and tortuosity of the major vessel injection suggests a cavernous sinus-carotid artery fistula rather than conjunctivitis.
Causes
- Bacterial conjunctivitis occurs in otherwise healthy individuals.
- Risk factors include frequent exposure to infected individuals, sinusitis, immunodeficiency states, and exposure to agents of sexually transmitted disease at birth.
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| References |
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References
Hammerschlag MR, Cummings C, Roblin PM, Williams TH, Delke I. Efficacy of neonatal ocular prophylaxis for the prevention of chlamydial and gonococcal conjunctivitis. N Engl J Med. Mar 23 1989;320(12):769-72. [Medline].
Rapoza PA, Quinn TC, Kiessling LA, Taylor HR. Epidemiology of neonatal conjunctivitis. Ophthalmology. Apr 1986;93(4):456-61. [Medline].
Schachter J, Lum L, Gooding CA, Ostler B. Pneumonitis following inclusion blennorrhea. J Pediatr. Nov 1975;87(5):779-80. [Medline].
Tabbara KF, Hyndiuk RA. Infections of the Eye. Little, Brown and Company; 1996.
Ullman S, Roussel TJ, Culbertson WW, Forster RK, Alfonso E, Mendelsohn AD, et al. Neisseria gonorrhoeae keratoconjunctivitis. Ophthalmology. May 1987;94(5):525-31. [Medline].
Further Reading
Keywords
bacterial conjunctivitis, eye infection, pink eye, red eye
